diff options
Diffstat (limited to 'drivers/tty/serial/sc16is7xx.c')
| -rw-r--r-- | drivers/tty/serial/sc16is7xx.c | 1768 |
1 files changed, 1768 insertions, 0 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c new file mode 100644 index 000000000000..1fd64a47341d --- /dev/null +++ b/drivers/tty/serial/sc16is7xx.c @@ -0,0 +1,1768 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * SC16IS7xx tty serial driver - common code + * + * Copyright (C) 2014 GridPoint + * Author: Jon Ringle <jringle@gridpoint.com> + * Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru> + */ + +#undef DEFAULT_SYMBOL_NAMESPACE +#define DEFAULT_SYMBOL_NAMESPACE "SERIAL_NXP_SC16IS7XX" + +#include <linux/bits.h> +#include <linux/cleanup.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/export.h> +#include <linux/gpio/consumer.h> +#include <linux/gpio/driver.h> +#include <linux/idr.h> +#include <linux/kthread.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/regmap.h> +#include <linux/sched.h> +#include <linux/serial_core.h> +#include <linux/serial.h> +#include <linux/string.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/uaccess.h> +#include <linux/units.h> + +#include "sc16is7xx.h" + +#define SC16IS7XX_MAX_DEVS 8 + +/* SC16IS7XX register definitions */ +#define SC16IS7XX_RHR_REG (0x00) /* RX FIFO */ +#define SC16IS7XX_THR_REG (0x00) /* TX FIFO */ +#define SC16IS7XX_IER_REG (0x01) /* Interrupt enable */ +#define SC16IS7XX_IIR_REG (0x02) /* Interrupt Identification */ +#define SC16IS7XX_FCR_REG (0x02) /* FIFO control */ +#define SC16IS7XX_LCR_REG (0x03) /* Line Control */ +#define SC16IS7XX_MCR_REG (0x04) /* Modem Control */ +#define SC16IS7XX_LSR_REG (0x05) /* Line Status */ +#define SC16IS7XX_MSR_REG (0x06) /* Modem Status */ +#define SC16IS7XX_SPR_REG (0x07) /* Scratch Pad */ +#define SC16IS7XX_TXLVL_REG (0x08) /* TX FIFO level */ +#define SC16IS7XX_RXLVL_REG (0x09) /* RX FIFO level */ +#define SC16IS7XX_IODIR_REG (0x0a) /* I/O Direction - only on 75x/76x */ +#define SC16IS7XX_IOSTATE_REG (0x0b) /* I/O State - only on 75x/76x */ +#define SC16IS7XX_IOINTENA_REG (0x0c) /* I/O Interrupt Enable - only on 75x/76x */ +#define SC16IS7XX_IOCONTROL_REG (0x0e) /* I/O Control - only on 75x/76x */ +#define SC16IS7XX_EFCR_REG (0x0f) /* Extra Features Control */ + +/* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */ +#define SC16IS7XX_TCR_REG (0x06) /* Transmit control */ +#define SC16IS7XX_TLR_REG (0x07) /* Trigger level */ + +/* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */ +#define SC16IS7XX_DLL_REG (0x00) /* Divisor Latch Low */ +#define SC16IS7XX_DLH_REG (0x01) /* Divisor Latch High */ + +/* Enhanced Register set: Only if (LCR == 0xBF) */ +#define SC16IS7XX_EFR_REG (0x02) /* Enhanced Features */ +#define SC16IS7XX_XON1_REG (0x04) /* Xon1 word */ +#define SC16IS7XX_XON2_REG (0x05) /* Xon2 word */ +#define SC16IS7XX_XOFF1_REG (0x06) /* Xoff1 word */ +#define SC16IS7XX_XOFF2_REG (0x07) /* Xoff2 word */ + +/* IER register bits */ +#define SC16IS7XX_IER_RDI_BIT BIT(0) /* Enable RX data interrupt */ +#define SC16IS7XX_IER_THRI_BIT BIT(1) /* Enable TX holding register interrupt */ +#define SC16IS7XX_IER_RLSI_BIT BIT(2) /* Enable RX line status interrupt */ +#define SC16IS7XX_IER_MSI_BIT BIT(3) /* Enable Modem status interrupt */ + +/* IER register bits - write only if (EFR[4] == 1) */ +#define SC16IS7XX_IER_SLEEP_BIT BIT(4) /* Enable Sleep mode */ +#define SC16IS7XX_IER_XOFFI_BIT BIT(5) /* Enable Xoff interrupt */ +#define SC16IS7XX_IER_RTSI_BIT BIT(6) /* Enable nRTS interrupt */ +#define SC16IS7XX_IER_CTSI_BIT BIT(7) /* Enable nCTS interrupt */ + +/* FCR register bits */ +#define SC16IS7XX_FCR_FIFO_BIT BIT(0) /* Enable FIFO */ +#define SC16IS7XX_FCR_RXRESET_BIT BIT(1) /* Reset RX FIFO */ +#define SC16IS7XX_FCR_TXRESET_BIT BIT(2) /* Reset TX FIFO */ +#define SC16IS7XX_FCR_RXLVLL_BIT BIT(6) /* RX Trigger level LSB */ +#define SC16IS7XX_FCR_RXLVLH_BIT BIT(7) /* RX Trigger level MSB */ + +/* FCR register bits - write only if (EFR[4] == 1) */ +#define SC16IS7XX_FCR_TXLVLL_BIT BIT(4) /* TX Trigger level LSB */ +#define SC16IS7XX_FCR_TXLVLH_BIT BIT(5) /* TX Trigger level MSB */ + +/* IIR register bits */ +#define SC16IS7XX_IIR_NO_INT_BIT 0x01 /* No interrupts pending */ +#define SC16IS7XX_IIR_ID_MASK GENMASK(5, 1) /* Mask for the interrupt ID */ +#define SC16IS7XX_IIR_THRI_SRC 0x02 /* TX holding register empty */ +#define SC16IS7XX_IIR_RDI_SRC 0x04 /* RX data interrupt */ +#define SC16IS7XX_IIR_RLSE_SRC 0x06 /* RX line status error */ +#define SC16IS7XX_IIR_RTOI_SRC 0x0c /* RX time-out interrupt */ +#define SC16IS7XX_IIR_MSI_SRC 0x00 /* Modem status interrupt + * - only on 75x/76x + */ +#define SC16IS7XX_IIR_INPIN_SRC 0x30 /* Input pin change of state + * - only on 75x/76x + */ +#define SC16IS7XX_IIR_XOFFI_SRC 0x10 /* Received Xoff */ +#define SC16IS7XX_IIR_CTSRTS_SRC 0x20 /* nCTS,nRTS change of state from active + * (LOW) to inactive (HIGH) + */ +/* LCR register bits */ +#define SC16IS7XX_LCR_LENGTH0_BIT BIT(0) /* Word length bit 0 */ +#define SC16IS7XX_LCR_LENGTH1_BIT BIT(1) /* Word length bit 1 + * + * Word length bits table: + * 00 -> 5 bit words + * 01 -> 6 bit words + * 10 -> 7 bit words + * 11 -> 8 bit words + */ +#define SC16IS7XX_LCR_STOPLEN_BIT BIT(2) /* STOP length bit + * + * STOP length bit table: + * 0 -> 1 stop bit + * 1 -> 1-1.5 stop bits if word length is 5, + * 2 stop bits otherwise + */ +#define SC16IS7XX_LCR_PARITY_BIT BIT(3) /* Parity bit enable */ +#define SC16IS7XX_LCR_EVENPARITY_BIT BIT(4) /* Even parity bit enable */ +#define SC16IS7XX_LCR_FORCEPARITY_BIT BIT(5) /* 9-bit multidrop parity */ +#define SC16IS7XX_LCR_TXBREAK_BIT BIT(6) /* TX break enable */ +#define SC16IS7XX_LCR_DLAB_BIT BIT(7) /* Divisor Latch enable */ +#define SC16IS7XX_LCR_WORD_LEN_5 (0x00) +#define SC16IS7XX_LCR_WORD_LEN_6 (0x01) +#define SC16IS7XX_LCR_WORD_LEN_7 (0x02) +#define SC16IS7XX_LCR_WORD_LEN_8 (0x03) +#define SC16IS7XX_LCR_REG_SET_SPECIAL SC16IS7XX_LCR_DLAB_BIT /* Special reg set */ +#define SC16IS7XX_LCR_REG_SET_ENHANCED 0xBF /* Enhanced reg set */ + +/* MCR register bits */ +#define SC16IS7XX_MCR_DTR_BIT BIT(0) /* DTR complement - only on 75x/76x */ +#define SC16IS7XX_MCR_RTS_BIT BIT(1) /* RTS complement */ +#define SC16IS7XX_MCR_TCRTLR_BIT BIT(2) /* TCR/TLR registers enable */ +#define SC16IS7XX_MCR_LOOP_BIT BIT(4) /* Enable loopback test mode */ +#define SC16IS7XX_MCR_XONANY_BIT BIT(5) /* Enable Xon Any + * - write enabled if (EFR[4] == 1) + */ +#define SC16IS7XX_MCR_IRDA_BIT BIT(6) /* Enable IrDA mode + * - write enabled if (EFR[4] == 1) + */ +#define SC16IS7XX_MCR_CLKSEL_BIT BIT(7) /* Divide clock by 4 + * - write enabled if (EFR[4] == 1) + */ + +/* LSR register bits */ +#define SC16IS7XX_LSR_DR_BIT BIT(0) /* Receiver data ready */ +#define SC16IS7XX_LSR_OE_BIT BIT(1) /* Overrun Error */ +#define SC16IS7XX_LSR_PE_BIT BIT(2) /* Parity Error */ +#define SC16IS7XX_LSR_FE_BIT BIT(3) /* Frame Error */ +#define SC16IS7XX_LSR_BI_BIT BIT(4) /* Break Interrupt */ +#define SC16IS7XX_LSR_BRK_ERROR_MASK \ + (SC16IS7XX_LSR_OE_BIT | \ + SC16IS7XX_LSR_PE_BIT | \ + SC16IS7XX_LSR_FE_BIT | \ + SC16IS7XX_LSR_BI_BIT) + +#define SC16IS7XX_LSR_THRE_BIT BIT(5) /* TX holding register empty */ +#define SC16IS7XX_LSR_TEMT_BIT BIT(6) /* Transmitter empty */ +#define SC16IS7XX_LSR_FIFOE_BIT BIT(7) /* Fifo Error */ + +/* MSR register bits */ +#define SC16IS7XX_MSR_DCTS_BIT BIT(0) /* Delta CTS Clear To Send */ +#define SC16IS7XX_MSR_DDSR_BIT BIT(1) /* Delta DSR Data Set Ready or (IO4) + * - only on 75x/76x + */ +#define SC16IS7XX_MSR_DRI_BIT BIT(2) /* Delta RI Ring Indicator or (IO7) + * - only on 75x/76x + */ +#define SC16IS7XX_MSR_DCD_BIT BIT(3) /* Delta CD Carrier Detect or (IO6) + * - only on 75x/76x + */ +#define SC16IS7XX_MSR_CTS_BIT BIT(4) /* CTS */ +#define SC16IS7XX_MSR_DSR_BIT BIT(5) /* DSR (IO4) - only on 75x/76x */ +#define SC16IS7XX_MSR_RI_BIT BIT(6) /* RI (IO7) - only on 75x/76x */ +#define SC16IS7XX_MSR_CD_BIT BIT(7) /* CD (IO6) - only on 75x/76x */ + +/* + * TCR register bits + * TCR trigger levels are available from 0 to 60 characters with a granularity + * of four. + * The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is + * no built-in hardware check to make sure this condition is met. Also, the TCR + * must be programmed with this condition before auto RTS or software flow + * control is enabled to avoid spurious operation of the device. + */ +#define SC16IS7XX_TCR_RX_HALT(words) ((((words) / 4) & 0x0f) << 0) +#define SC16IS7XX_TCR_RX_RESUME(words) ((((words) / 4) & 0x0f) << 4) + +/* + * TLR register bits + * If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the + * FIFO Control Register (FCR) are used for the transmit and receive FIFO + * trigger levels. Trigger levels from 4 characters to 60 characters are + * available with a granularity of four. + * + * When the trigger level setting in TLR is zero, the SC16IS74x/75x/76x uses the + * trigger level setting defined in FCR. If TLR has non-zero trigger level value + * the trigger level defined in FCR is discarded. This applies to both transmit + * FIFO and receive FIFO trigger level setting. + * + * When TLR is used for RX trigger level control, FCR[7:6] should be left at the + * default state, that is, '00'. + */ +#define SC16IS7XX_TLR_TX_TRIGGER(words) ((((words) / 4) & 0x0f) << 0) +#define SC16IS7XX_TLR_RX_TRIGGER(words) ((((words) / 4) & 0x0f) << 4) + +/* IOControl register bits (Only 75x/76x) */ +#define SC16IS7XX_IOCONTROL_LATCH_BIT BIT(0) /* Enable input latching */ +#define SC16IS7XX_IOCONTROL_MODEM_A_BIT BIT(1) /* Enable GPIO[7:4] as modem A pins */ +#define SC16IS7XX_IOCONTROL_MODEM_B_BIT BIT(2) /* Enable GPIO[3:0] as modem B pins */ +#define SC16IS7XX_IOCONTROL_SRESET_BIT BIT(3) /* Software Reset */ + +/* EFCR register bits */ +#define SC16IS7XX_EFCR_9BIT_MODE_BIT BIT(0) /* Enable 9-bit or Multidrop mode (RS485) */ +#define SC16IS7XX_EFCR_RXDISABLE_BIT BIT(1) /* Disable receiver */ +#define SC16IS7XX_EFCR_TXDISABLE_BIT BIT(2) /* Disable transmitter */ +#define SC16IS7XX_EFCR_AUTO_RS485_BIT BIT(4) /* Auto RS485 RTS direction */ +#define SC16IS7XX_EFCR_RTS_INVERT_BIT BIT(5) /* RTS output inversion */ +#define SC16IS7XX_EFCR_IRDA_MODE_BIT BIT(7) /* IrDA mode + * 0 = rate up to 115.2 kbit/s - Only 75x/76x + * 1 = rate up to 1.152 Mbit/s - Only 76x + */ + +/* EFR register bits */ +#define SC16IS7XX_EFR_AUTORTS_BIT BIT(6) /* Auto RTS flow ctrl enable */ +#define SC16IS7XX_EFR_AUTOCTS_BIT BIT(7) /* Auto CTS flow ctrl enable */ +#define SC16IS7XX_EFR_XOFF2_DETECT_BIT BIT(5) /* Enable Xoff2 detection */ +#define SC16IS7XX_EFR_ENABLE_BIT BIT(4) /* Enable enhanced functions and writing to + * IER[7:4], FCR[5:4], MCR[7:5] + */ +#define SC16IS7XX_EFR_SWFLOW3_BIT BIT(3) +#define SC16IS7XX_EFR_SWFLOW2_BIT BIT(2) + /* + * SWFLOW bits 3 & 2 table: + * 00 -> no transmitter flow control + * 01 -> transmitter generates XON2 and XOFF2 + * 10 -> transmitter generates XON1 and XOFF1 + * 11 -> transmitter generates XON1, XON2, + * XOFF1 and XOFF2 + */ +#define SC16IS7XX_EFR_SWFLOW1_BIT BIT(1) +#define SC16IS7XX_EFR_SWFLOW0_BIT BIT(0) + /* + * SWFLOW bits 1 & 0 table: + * 00 -> no received flow control + * 01 -> receiver compares XON2 and XOFF2 + * 10 -> receiver compares XON1 and XOFF1 + * 11 -> receiver compares XON1, XON2, + * XOFF1 and XOFF2 + */ +#define SC16IS7XX_EFR_FLOWCTRL_BITS (SC16IS7XX_EFR_AUTORTS_BIT | \ + SC16IS7XX_EFR_AUTOCTS_BIT | \ + SC16IS7XX_EFR_XOFF2_DETECT_BIT | \ + SC16IS7XX_EFR_SWFLOW3_BIT | \ + SC16IS7XX_EFR_SWFLOW2_BIT | \ + SC16IS7XX_EFR_SWFLOW1_BIT | \ + SC16IS7XX_EFR_SWFLOW0_BIT) + + +/* Misc definitions */ +#define SC16IS7XX_FIFO_SIZE (64) +#define SC16IS7XX_GPIOS_PER_BANK 4 + +#define SC16IS7XX_POLL_PERIOD_MS 10 +#define SC16IS7XX_RECONF_MD BIT(0) +#define SC16IS7XX_RECONF_IER BIT(1) +#define SC16IS7XX_RECONF_RS485 BIT(2) + +struct sc16is7xx_one_config { + unsigned int flags; + u8 ier_mask; + u8 ier_val; +}; + +struct sc16is7xx_one { + struct uart_port port; + struct regmap *regmap; + struct mutex lock; /* For registers sharing same address space. */ + struct kthread_work tx_work; + struct kthread_work reg_work; + struct kthread_delayed_work ms_work; + struct sc16is7xx_one_config config; + unsigned char buf[SC16IS7XX_FIFO_SIZE]; /* Rx buffer. */ + unsigned int old_mctrl; + u8 old_lcr; /* Value before EFR access. */ + bool irda_mode; +}; + +struct sc16is7xx_port { + const struct sc16is7xx_devtype *devtype; + struct clk *clk; +#ifdef CONFIG_GPIOLIB + struct gpio_chip gpio; + unsigned long gpio_valid_mask; +#endif + u8 mctrl_mask; + struct kthread_worker kworker; + struct task_struct *kworker_task; + struct kthread_delayed_work poll_work; + bool polling; + struct sc16is7xx_one p[]; +}; + +static DEFINE_IDA(sc16is7xx_lines); + +static struct uart_driver sc16is7xx_uart = { + .owner = THIS_MODULE, + .driver_name = KBUILD_MODNAME, + .dev_name = "ttySC", + .nr = SC16IS7XX_MAX_DEVS, +}; + +#define to_sc16is7xx_one(p) container_of((p), struct sc16is7xx_one, port) + +static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + unsigned int val = 0; + + regmap_read(one->regmap, reg, &val); + + return val; +} + +static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + regmap_write(one->regmap, reg, val); +} + +static void sc16is7xx_fifo_read(struct uart_port *port, u8 *rxbuf, unsigned int rxlen) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, rxbuf, rxlen); +} + +static void sc16is7xx_fifo_write(struct uart_port *port, u8 *txbuf, u8 to_send) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + /* + * Don't send zero-length data, at least on SPI it confuses the chip + * delivering wrong TXLVL data. + */ + if (unlikely(!to_send)) + return; + + regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, txbuf, to_send); +} + +static void sc16is7xx_port_update(struct uart_port *port, u8 reg, + u8 mask, u8 val) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + regmap_update_bits(one->regmap, reg, mask, val); +} + +static void sc16is7xx_power(struct uart_port *port, int on) +{ + sc16is7xx_port_update(port, SC16IS7XX_IER_REG, + SC16IS7XX_IER_SLEEP_BIT, + on ? 0 : SC16IS7XX_IER_SLEEP_BIT); +} + +/* + * In an amazing feat of design, the enhanced register set shares the + * addresses 0x02 and 0x04-0x07 with the general register set. + * The special register set also shares the addresses 0x00-0x01 with the + * general register set. + * + * Access to the enhanced or special register set is enabled by writing a magic + * value to the Line Control Register (LCR). When enhanced register set access + * is enabled, for example, any interrupt firing during this time will see the + * EFR where it expects the IIR to be, leading to + * "Unexpected interrupt" messages. + * + * Prevent this possibility by claiming a mutex when access to the enhanced + * or special register set is enabled, and claiming the same mutex from within + * the interrupt handler. This is similar to disabling the interrupt, but that + * doesn't work because the bulk of the interrupt processing is run as a + * workqueue job in thread context. + */ +static void sc16is7xx_regs_lock(struct uart_port *port, u8 register_set) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + mutex_lock(&one->lock); + + /* Backup content of LCR. */ + one->old_lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG); + + /* Enable access to the desired register set */ + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, register_set); + + /* Disable cache updates when writing to non-general registers */ + regcache_cache_bypass(one->regmap, true); +} + +static void sc16is7xx_regs_unlock(struct uart_port *port) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + /* Re-enable cache updates when writing to general registers */ + regcache_cache_bypass(one->regmap, false); + + /* Restore original content of LCR */ + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, one->old_lcr); + + mutex_unlock(&one->lock); +} + +static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + lockdep_assert_held_once(&port->lock); + + one->config.flags |= SC16IS7XX_RECONF_IER; + one->config.ier_mask |= bit; + one->config.ier_val &= ~bit; + kthread_queue_work(&s->kworker, &one->reg_work); +} + +static void sc16is7xx_ier_set(struct uart_port *port, u8 bit) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + lockdep_assert_held_once(&port->lock); + + one->config.flags |= SC16IS7XX_RECONF_IER; + one->config.ier_mask |= bit; + one->config.ier_val |= bit; + kthread_queue_work(&s->kworker, &one->reg_work); +} + +static void sc16is7xx_stop_tx(struct uart_port *port) +{ + sc16is7xx_ier_clear(port, SC16IS7XX_IER_THRI_BIT); +} + +static void sc16is7xx_stop_rx(struct uart_port *port) +{ + sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT); +} + +const struct sc16is7xx_devtype sc16is74x_devtype = { + .name = "SC16IS74X", + .nr_gpio = 0, + .nr_uart = 1, +}; +EXPORT_SYMBOL_GPL(sc16is74x_devtype); + +const struct sc16is7xx_devtype sc16is750_devtype = { + .name = "SC16IS750", + .nr_gpio = 8, + .nr_uart = 1, +}; +EXPORT_SYMBOL_GPL(sc16is750_devtype); + +const struct sc16is7xx_devtype sc16is752_devtype = { + .name = "SC16IS752", + .nr_gpio = 8, + .nr_uart = 2, +}; +EXPORT_SYMBOL_GPL(sc16is752_devtype); + +const struct sc16is7xx_devtype sc16is760_devtype = { + .name = "SC16IS760", + .nr_gpio = 8, + .nr_uart = 1, +}; +EXPORT_SYMBOL_GPL(sc16is760_devtype); + +const struct sc16is7xx_devtype sc16is762_devtype = { + .name = "SC16IS762", + .nr_gpio = 8, + .nr_uart = 2, +}; +EXPORT_SYMBOL_GPL(sc16is762_devtype); + +static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SC16IS7XX_RHR_REG: /* Shared address space with THR & DLL */ + case SC16IS7XX_IIR_REG: /* Shared address space with FCR & EFR */ + case SC16IS7XX_LSR_REG: /* Shared address space with XON2 */ + case SC16IS7XX_MSR_REG: /* Shared address space with TCR & XOFF1 */ + case SC16IS7XX_SPR_REG: /* Shared address space with TLR & XOFF2 */ + case SC16IS7XX_TXLVL_REG: + case SC16IS7XX_RXLVL_REG: + case SC16IS7XX_IOSTATE_REG: + case SC16IS7XX_IOCONTROL_REG: + return true; + default: + return false; + } +} + +static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SC16IS7XX_RHR_REG: + return true; + default: + return false; + } +} + +static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg) +{ + return reg == SC16IS7XX_RHR_REG; +} + +/* + * Configure programmable baud rate generator (divisor) according to the + * desired baud rate. + * + * From the datasheet, the divisor is computed according to: + * + * XTAL1 input frequency + * ----------------------- + * prescaler + * divisor = --------------------------- + * baud-rate x sampling-rate + */ +static int sc16is7xx_set_baud(struct uart_port *port, int baud) +{ + unsigned int prescaler = 1; + unsigned long clk = port->uartclk, div = clk / 16 / baud; + + if (div >= BIT(16)) { + prescaler = 4; + div /= prescaler; + } + + /* If bit MCR_CLKSEL is set, the divide by 4 prescaler is activated. */ + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, + SC16IS7XX_MCR_CLKSEL_BIT, + prescaler == 1 ? 0 : SC16IS7XX_MCR_CLKSEL_BIT); + + /* Access special register set (DLL/DLH) */ + sc16is7xx_regs_lock(port, SC16IS7XX_LCR_REG_SET_SPECIAL); + + /* Write the new divisor */ + sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256); + sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256); + + /* Restore access to general register set */ + sc16is7xx_regs_unlock(port); + + return DIV_ROUND_CLOSEST((clk / prescaler) / 16, div); +} + +static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen, + unsigned int iir) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + unsigned int lsr = 0, bytes_read, i; + bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC); + u8 ch, flag; + + if (unlikely(rxlen >= sizeof(one->buf))) { + dev_warn_ratelimited(port->dev, + "ttySC%i: Possible RX FIFO overrun: %d\n", + port->line, rxlen); + port->icount.buf_overrun++; + /* Ensure sanity of RX level */ + rxlen = sizeof(one->buf); + } + + while (rxlen) { + /* Only read lsr if there are possible errors in FIFO */ + if (read_lsr) { + lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG); + if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT)) + read_lsr = false; /* No errors left in FIFO */ + } else + lsr = 0; + + if (read_lsr) { + one->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG); + bytes_read = 1; + } else { + sc16is7xx_fifo_read(port, one->buf, rxlen); + bytes_read = rxlen; + } + + lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK; + + port->icount.rx++; + flag = TTY_NORMAL; + + if (unlikely(lsr)) { + if (lsr & SC16IS7XX_LSR_BI_BIT) { + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } else if (lsr & SC16IS7XX_LSR_PE_BIT) + port->icount.parity++; + else if (lsr & SC16IS7XX_LSR_FE_BIT) + port->icount.frame++; + else if (lsr & SC16IS7XX_LSR_OE_BIT) + port->icount.overrun++; + + lsr &= port->read_status_mask; + if (lsr & SC16IS7XX_LSR_BI_BIT) + flag = TTY_BREAK; + else if (lsr & SC16IS7XX_LSR_PE_BIT) + flag = TTY_PARITY; + else if (lsr & SC16IS7XX_LSR_FE_BIT) + flag = TTY_FRAME; + else if (lsr & SC16IS7XX_LSR_OE_BIT) + flag = TTY_OVERRUN; + } + + for (i = 0; i < bytes_read; ++i) { + ch = one->buf[i]; + if (uart_handle_sysrq_char(port, ch)) + continue; + + if (lsr & port->ignore_status_mask) + continue; + + uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch, + flag); + } + rxlen -= bytes_read; + } + + tty_flip_buffer_push(&port->state->port); +} + +static void sc16is7xx_handle_tx(struct uart_port *port) +{ + struct tty_port *tport = &port->state->port; + unsigned long flags; + unsigned int txlen; + unsigned char *tail; + + if (unlikely(port->x_char)) { + sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char); + port->icount.tx++; + port->x_char = 0; + return; + } + + if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) { + uart_port_lock_irqsave(port, &flags); + sc16is7xx_stop_tx(port); + uart_port_unlock_irqrestore(port, flags); + return; + } + + /* Limit to space available in TX FIFO */ + txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG); + if (txlen > SC16IS7XX_FIFO_SIZE) { + dev_err_ratelimited(port->dev, + "chip reports %d free bytes in TX fifo, but it only has %d", + txlen, SC16IS7XX_FIFO_SIZE); + txlen = 0; + } + + txlen = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, txlen); + sc16is7xx_fifo_write(port, tail, txlen); + uart_xmit_advance(port, txlen); + + uart_port_lock_irqsave(port, &flags); + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) + uart_write_wakeup(port); + + if (kfifo_is_empty(&tport->xmit_fifo)) + sc16is7xx_stop_tx(port); + else + sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT); + uart_port_unlock_irqrestore(port, flags); +} + +static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port) +{ + u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG); + unsigned int mctrl = 0; + + mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0; + mctrl |= (msr & SC16IS7XX_MSR_DSR_BIT) ? TIOCM_DSR : 0; + mctrl |= (msr & SC16IS7XX_MSR_CD_BIT) ? TIOCM_CAR : 0; + mctrl |= (msr & SC16IS7XX_MSR_RI_BIT) ? TIOCM_RNG : 0; + return mctrl; +} + +static void sc16is7xx_update_mlines(struct sc16is7xx_one *one) +{ + struct uart_port *port = &one->port; + unsigned long flags; + unsigned int status, changed; + + /* Lock required as MSR address is shared with TCR and XOFF1. */ + lockdep_assert_held_once(&one->lock); + + status = sc16is7xx_get_hwmctrl(port); + changed = status ^ one->old_mctrl; + + if (changed == 0) + return; + + one->old_mctrl = status; + + uart_port_lock_irqsave(port, &flags); + if ((changed & TIOCM_RNG) && (status & TIOCM_RNG)) + port->icount.rng++; + if (changed & TIOCM_DSR) + port->icount.dsr++; + if (changed & TIOCM_CAR) + uart_handle_dcd_change(port, status & TIOCM_CAR); + if (changed & TIOCM_CTS) + uart_handle_cts_change(port, status & TIOCM_CTS); + + wake_up_interruptible(&port->state->port.delta_msr_wait); + uart_port_unlock_irqrestore(port, flags); +} + +static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno) +{ + unsigned int iir, rxlen; + struct uart_port *port = &s->p[portno].port; + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + guard(mutex)(&one->lock); + + iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG); + if (iir & SC16IS7XX_IIR_NO_INT_BIT) + return false; + + iir &= SC16IS7XX_IIR_ID_MASK; + + switch (iir) { + case SC16IS7XX_IIR_RDI_SRC: + case SC16IS7XX_IIR_RLSE_SRC: + case SC16IS7XX_IIR_RTOI_SRC: + case SC16IS7XX_IIR_XOFFI_SRC: + rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG); + + /* + * There is a silicon bug that makes the chip report a + * time-out interrupt but no data in the FIFO. This is + * described in errata section 18.1.4. + * + * When this happens, read one byte from the FIFO to + * clear the interrupt. + */ + if (iir == SC16IS7XX_IIR_RTOI_SRC && !rxlen) + rxlen = 1; + + if (rxlen) + sc16is7xx_handle_rx(port, rxlen, iir); + break; + /* CTSRTS interrupt comes only when CTS goes inactive */ + case SC16IS7XX_IIR_CTSRTS_SRC: + case SC16IS7XX_IIR_MSI_SRC: + sc16is7xx_update_mlines(one); + break; + case SC16IS7XX_IIR_THRI_SRC: + sc16is7xx_handle_tx(port); + break; + default: + dev_err_ratelimited(port->dev, + "ttySC%i: Unexpected interrupt: %x", + port->line, iir); + break; + } + + return true; +} + +static irqreturn_t sc16is7xx_irq(int irq, void *dev_id) +{ + struct sc16is7xx_port *s = dev_id; + bool keep_polling; + + do { + int i; + + keep_polling = false; + + for (i = 0; i < s->devtype->nr_uart; ++i) + keep_polling |= sc16is7xx_port_irq(s, i); + } while (keep_polling); + + return IRQ_HANDLED; +} + +static void sc16is7xx_poll_proc(struct kthread_work *ws) +{ + struct sc16is7xx_port *s = container_of(ws, struct sc16is7xx_port, poll_work.work); + + /* Reuse standard IRQ handler. Interrupt ID is unused in this context. */ + sc16is7xx_irq(0, s); + + /* Setup delay based on SC16IS7XX_POLL_PERIOD_MS */ + kthread_queue_delayed_work(&s->kworker, &s->poll_work, + msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS)); +} + +static void sc16is7xx_tx_proc(struct kthread_work *ws) +{ + struct sc16is7xx_one *one = container_of(ws, struct sc16is7xx_one, tx_work); + struct uart_port *port = &one->port; + + if ((port->rs485.flags & SER_RS485_ENABLED) && + (port->rs485.delay_rts_before_send > 0)) + msleep(port->rs485.delay_rts_before_send); + + guard(mutex)(&one->lock); + sc16is7xx_handle_tx(port); +} + +static void sc16is7xx_reconf_rs485(struct uart_port *port) +{ + const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT | + SC16IS7XX_EFCR_RTS_INVERT_BIT; + u32 efcr = 0; + struct serial_rs485 *rs485 = &port->rs485; + unsigned long irqflags; + + uart_port_lock_irqsave(port, &irqflags); + if (rs485->flags & SER_RS485_ENABLED) { + efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT; + + if (rs485->flags & SER_RS485_RTS_AFTER_SEND) + efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT; + } + uart_port_unlock_irqrestore(port, irqflags); + + sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr); +} + +static void sc16is7xx_reg_proc(struct kthread_work *ws) +{ + struct sc16is7xx_one *one = container_of(ws, struct sc16is7xx_one, reg_work); + struct sc16is7xx_one_config config; + unsigned long irqflags; + + uart_port_lock_irqsave(&one->port, &irqflags); + config = one->config; + memset(&one->config, 0, sizeof(one->config)); + uart_port_unlock_irqrestore(&one->port, irqflags); + + if (config.flags & SC16IS7XX_RECONF_MD) { + u8 mcr = 0; + + /* Device ignores RTS setting when hardware flow is enabled */ + if (one->port.mctrl & TIOCM_RTS) + mcr |= SC16IS7XX_MCR_RTS_BIT; + + if (one->port.mctrl & TIOCM_DTR) + mcr |= SC16IS7XX_MCR_DTR_BIT; + + if (one->port.mctrl & TIOCM_LOOP) + mcr |= SC16IS7XX_MCR_LOOP_BIT; + sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG, + SC16IS7XX_MCR_RTS_BIT | + SC16IS7XX_MCR_DTR_BIT | + SC16IS7XX_MCR_LOOP_BIT, + mcr); + } + + if (config.flags & SC16IS7XX_RECONF_IER) + sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG, + config.ier_mask, config.ier_val); + + if (config.flags & SC16IS7XX_RECONF_RS485) + sc16is7xx_reconf_rs485(&one->port); +} + +static void sc16is7xx_ms_proc(struct kthread_work *ws) +{ + struct sc16is7xx_one *one = container_of(ws, struct sc16is7xx_one, ms_work.work); + struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev); + + if (one->port.state) { + scoped_guard(mutex, &one->lock) + sc16is7xx_update_mlines(one); + + kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ); + } +} + +static void sc16is7xx_enable_ms(struct uart_port *port) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + + lockdep_assert_held_once(&port->lock); + + kthread_queue_delayed_work(&s->kworker, &one->ms_work, 0); +} + +static void sc16is7xx_start_tx(struct uart_port *port) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + kthread_queue_work(&s->kworker, &one->tx_work); +} + +static void sc16is7xx_throttle(struct uart_port *port) +{ + unsigned long flags; + + /* + * Hardware flow control is enabled and thus the device ignores RTS + * value set in MCR register. Stop reading data from RX FIFO so the + * AutoRTS feature will de-activate RTS output. + */ + uart_port_lock_irqsave(port, &flags); + sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT); + uart_port_unlock_irqrestore(port, flags); +} + +static void sc16is7xx_unthrottle(struct uart_port *port) +{ + unsigned long flags; + + uart_port_lock_irqsave(port, &flags); + sc16is7xx_ier_set(port, SC16IS7XX_IER_RDI_BIT); + uart_port_unlock_irqrestore(port, flags); +} + +static unsigned int sc16is7xx_tx_empty(struct uart_port *port) +{ + unsigned int lsr; + + lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG); + + return (lsr & SC16IS7XX_LSR_TEMT_BIT) ? TIOCSER_TEMT : 0; +} + +static unsigned int sc16is7xx_get_mctrl(struct uart_port *port) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + /* Called with port lock taken so we can only return cached value */ + return one->old_mctrl; +} + +static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + one->config.flags |= SC16IS7XX_RECONF_MD; + kthread_queue_work(&s->kworker, &one->reg_work); +} + +static void sc16is7xx_break_ctl(struct uart_port *port, int break_state) +{ + sc16is7xx_port_update(port, SC16IS7XX_LCR_REG, + SC16IS7XX_LCR_TXBREAK_BIT, + break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0); +} + +static void sc16is7xx_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + unsigned int lcr, flow = 0; + int baud; + unsigned long flags; + + kthread_cancel_delayed_work_sync(&one->ms_work); + + /* Mask termios capabilities we don't support */ + termios->c_cflag &= ~CMSPAR; + + /* Word size */ + switch (termios->c_cflag & CSIZE) { + case CS5: + lcr = SC16IS7XX_LCR_WORD_LEN_5; + break; + case CS6: + lcr = SC16IS7XX_LCR_WORD_LEN_6; + break; + case CS7: + lcr = SC16IS7XX_LCR_WORD_LEN_7; + break; + case CS8: + lcr = SC16IS7XX_LCR_WORD_LEN_8; + break; + default: + lcr = SC16IS7XX_LCR_WORD_LEN_8; + termios->c_cflag &= ~CSIZE; + termios->c_cflag |= CS8; + break; + } + + /* Parity */ + if (termios->c_cflag & PARENB) { + lcr |= SC16IS7XX_LCR_PARITY_BIT; + if (!(termios->c_cflag & PARODD)) + lcr |= SC16IS7XX_LCR_EVENPARITY_BIT; + } + + /* Stop bits */ + if (termios->c_cflag & CSTOPB) + lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */ + + /* Set read status mask */ + port->read_status_mask = SC16IS7XX_LSR_OE_BIT; + if (termios->c_iflag & INPCK) + port->read_status_mask |= SC16IS7XX_LSR_PE_BIT | + SC16IS7XX_LSR_FE_BIT; + if (termios->c_iflag & (BRKINT | PARMRK)) + port->read_status_mask |= SC16IS7XX_LSR_BI_BIT; + + /* Set status ignore mask */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNBRK) + port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT; + if (!(termios->c_cflag & CREAD)) + port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK; + + /* Configure flow control */ + port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); + if (termios->c_cflag & CRTSCTS) { + flow |= SC16IS7XX_EFR_AUTOCTS_BIT | + SC16IS7XX_EFR_AUTORTS_BIT; + port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; + } + if (termios->c_iflag & IXON) + flow |= SC16IS7XX_EFR_SWFLOW3_BIT; + if (termios->c_iflag & IXOFF) + flow |= SC16IS7XX_EFR_SWFLOW1_BIT; + + /* Update LCR register */ + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr); + + /* Update EFR registers */ + sc16is7xx_regs_lock(port, SC16IS7XX_LCR_REG_SET_ENHANCED); + sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]); + sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]); + sc16is7xx_port_update(port, SC16IS7XX_EFR_REG, + SC16IS7XX_EFR_FLOWCTRL_BITS, flow); + sc16is7xx_regs_unlock(port); + + /* Get baud rate generator configuration */ + baud = uart_get_baud_rate(port, termios, old, + port->uartclk / 16 / 4 / 0xffff, + port->uartclk / 16); + + /* Setup baudrate generator */ + baud = sc16is7xx_set_baud(port, baud); + + uart_port_lock_irqsave(port, &flags); + + /* Update timeout according to new baud rate */ + uart_update_timeout(port, termios->c_cflag, baud); + + if (UART_ENABLE_MS(port, termios->c_cflag)) + sc16is7xx_enable_ms(port); + + uart_port_unlock_irqrestore(port, flags); +} + +static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + if (rs485->flags & SER_RS485_ENABLED) { + /* + * RTS signal is handled by HW, it's timing can't be influenced. + * However, it's sometimes useful to delay TX even without RTS + * control therefore we try to handle .delay_rts_before_send. + */ + if (rs485->delay_rts_after_send) + return -EINVAL; + } + + one->config.flags |= SC16IS7XX_RECONF_RS485; + kthread_queue_work(&s->kworker, &one->reg_work); + + return 0; +} + +static int sc16is7xx_startup(struct uart_port *port) +{ + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + unsigned int val; + unsigned long flags; + + sc16is7xx_power(port, 1); + + /* Reset FIFOs */ + val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT; + sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val); + udelay(5); + sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, + SC16IS7XX_FCR_FIFO_BIT); + + /* Enable TCR/TLR */ + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, + SC16IS7XX_MCR_TCRTLR_BIT, + SC16IS7XX_MCR_TCRTLR_BIT); + + /* Configure flow control levels */ + /* Flow control halt level 48, resume level 24 */ + sc16is7xx_port_write(port, SC16IS7XX_TCR_REG, + SC16IS7XX_TCR_RX_RESUME(24) | + SC16IS7XX_TCR_RX_HALT(48)); + + /* Disable TCR/TLR access */ + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, 0); + + /* Now, initialize the UART */ + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8); + + /* Enable IrDA mode if requested in DT */ + /* This bit must be written with LCR[7] = 0 */ + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, + SC16IS7XX_MCR_IRDA_BIT, + one->irda_mode ? SC16IS7XX_MCR_IRDA_BIT : 0); + + /* Enable the Rx and Tx FIFO */ + sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, + SC16IS7XX_EFCR_RXDISABLE_BIT | + SC16IS7XX_EFCR_TXDISABLE_BIT, + 0); + + /* Enable RX, CTS change and modem lines interrupts */ + val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_CTSI_BIT | + SC16IS7XX_IER_MSI_BIT; + sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val); + + /* Enable modem status polling */ + uart_port_lock_irqsave(port, &flags); + sc16is7xx_enable_ms(port); + uart_port_unlock_irqrestore(port, flags); + + if (s->polling) + kthread_queue_delayed_work(&s->kworker, &s->poll_work, + msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS)); + + return 0; +} + +static void sc16is7xx_shutdown(struct uart_port *port) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + struct sc16is7xx_one *one = to_sc16is7xx_one(port); + + kthread_cancel_delayed_work_sync(&one->ms_work); + + /* Disable all interrupts */ + sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0); + /* Disable TX/RX */ + sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, + SC16IS7XX_EFCR_RXDISABLE_BIT | + SC16IS7XX_EFCR_TXDISABLE_BIT, + SC16IS7XX_EFCR_RXDISABLE_BIT | + SC16IS7XX_EFCR_TXDISABLE_BIT); + + sc16is7xx_power(port, 0); + + if (s->polling) + kthread_cancel_delayed_work_sync(&s->poll_work); + + kthread_flush_worker(&s->kworker); +} + +static const char *sc16is7xx_type(struct uart_port *port) +{ + struct sc16is7xx_port *s = dev_get_drvdata(port->dev); + + return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL; +} + +static int sc16is7xx_request_port(struct uart_port *port) +{ + /* Do nothing */ + return 0; +} + +static void sc16is7xx_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) + port->type = PORT_SC16IS7XX; +} + +static int sc16is7xx_verify_port(struct uart_port *port, + struct serial_struct *s) +{ + if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX)) + return -EINVAL; + if (s->irq != port->irq) + return -EINVAL; + + return 0; +} + +static void sc16is7xx_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) +{ + sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0); +} + +static void sc16is7xx_null_void(struct uart_port *port) +{ + /* Do nothing */ +} + +static const struct uart_ops sc16is7xx_ops = { + .tx_empty = sc16is7xx_tx_empty, + .set_mctrl = sc16is7xx_set_mctrl, + .get_mctrl = sc16is7xx_get_mctrl, + .stop_tx = sc16is7xx_stop_tx, + .start_tx = sc16is7xx_start_tx, + .throttle = sc16is7xx_throttle, + .unthrottle = sc16is7xx_unthrottle, + .stop_rx = sc16is7xx_stop_rx, + .enable_ms = sc16is7xx_enable_ms, + .break_ctl = sc16is7xx_break_ctl, + .startup = sc16is7xx_startup, + .shutdown = sc16is7xx_shutdown, + .set_termios = sc16is7xx_set_termios, + .type = sc16is7xx_type, + .request_port = sc16is7xx_request_port, + .release_port = sc16is7xx_null_void, + .config_port = sc16is7xx_config_port, + .verify_port = sc16is7xx_verify_port, + .pm = sc16is7xx_pm, +}; + +#ifdef CONFIG_GPIOLIB +static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + unsigned int val; + struct sc16is7xx_port *s = gpiochip_get_data(chip); + struct uart_port *port = &s->p[0].port; + + val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG); + + return !!(val & BIT(offset)); +} + +static int sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned int offset, + int val) +{ + struct sc16is7xx_port *s = gpiochip_get_data(chip); + struct uart_port *port = &s->p[0].port; + + sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset), + val ? BIT(offset) : 0); + + return 0; +} + +static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip, + unsigned offset) +{ + struct sc16is7xx_port *s = gpiochip_get_data(chip); + struct uart_port *port = &s->p[0].port; + + sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0); + + return 0; +} + +static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip, + unsigned offset, int val) +{ + struct sc16is7xx_port *s = gpiochip_get_data(chip); + struct uart_port *port = &s->p[0].port; + u8 state = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG); + + if (val) + state |= BIT(offset); + else + state &= ~BIT(offset); + + /* + * If we write IOSTATE first, and then IODIR, the output value is not + * transferred to the corresponding I/O pin. + * The datasheet states that each register bit will be transferred to + * the corresponding I/O pin programmed as output when writing to + * IOSTATE. Therefore, configure direction first with IODIR, and then + * set value after with IOSTATE. + */ + sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), + BIT(offset)); + sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state); + + return 0; +} + +static int sc16is7xx_gpio_init_valid_mask(struct gpio_chip *chip, + unsigned long *valid_mask, + unsigned int ngpios) +{ + struct sc16is7xx_port *s = gpiochip_get_data(chip); + + *valid_mask = s->gpio_valid_mask; + + return 0; +} + +static int sc16is7xx_setup_gpio_chip(struct sc16is7xx_port *s) +{ + struct device *dev = s->p[0].port.dev; + + if (!s->devtype->nr_gpio) + return 0; + + switch (s->mctrl_mask) { + case 0: + s->gpio_valid_mask = GENMASK(7, 0); + break; + case SC16IS7XX_IOCONTROL_MODEM_A_BIT: + s->gpio_valid_mask = GENMASK(3, 0); + break; + case SC16IS7XX_IOCONTROL_MODEM_B_BIT: + s->gpio_valid_mask = GENMASK(7, 4); + break; + default: + break; + } + + if (s->gpio_valid_mask == 0) + return 0; + + s->gpio.owner = THIS_MODULE; + s->gpio.parent = dev; + s->gpio.label = dev_name(dev); + s->gpio.init_valid_mask = sc16is7xx_gpio_init_valid_mask; + s->gpio.direction_input = sc16is7xx_gpio_direction_input; + s->gpio.get = sc16is7xx_gpio_get; + s->gpio.direction_output = sc16is7xx_gpio_direction_output; + s->gpio.set = sc16is7xx_gpio_set; + s->gpio.base = -1; + s->gpio.ngpio = s->devtype->nr_gpio; + s->gpio.can_sleep = 1; + + return gpiochip_add_data(&s->gpio, s); +} +#endif + +static void sc16is7xx_setup_irda_ports(struct sc16is7xx_port *s) +{ + int i; + int ret; + int count; + u32 irda_port[SC16IS7XX_MAX_PORTS]; + struct device *dev = s->p[0].port.dev; + + count = device_property_count_u32(dev, "irda-mode-ports"); + if (count < 0 || count > ARRAY_SIZE(irda_port)) + return; + + ret = device_property_read_u32_array(dev, "irda-mode-ports", + irda_port, count); + if (ret) + return; + + for (i = 0; i < count; i++) { + if (irda_port[i] < s->devtype->nr_uart) + s->p[irda_port[i]].irda_mode = true; + } +} + +/* + * Configure ports designated to operate as modem control lines. + */ +static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s, + struct regmap *regmap) +{ + int i; + int ret; + int count; + u32 mctrl_port[SC16IS7XX_MAX_PORTS]; + struct device *dev = s->p[0].port.dev; + + count = device_property_count_u32(dev, "nxp,modem-control-line-ports"); + if (count < 0 || count > ARRAY_SIZE(mctrl_port)) + return 0; + + ret = device_property_read_u32_array(dev, "nxp,modem-control-line-ports", + mctrl_port, count); + if (ret) + return ret; + + s->mctrl_mask = 0; + + for (i = 0; i < count; i++) { + /* Use GPIO lines as modem control lines */ + if (mctrl_port[i] == 0) + s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_A_BIT; + else if (mctrl_port[i] == 1) + s->mctrl_mask |= SC16IS7XX_IOCONTROL_MODEM_B_BIT; + } + + if (s->mctrl_mask) + regmap_update_bits( + regmap, + SC16IS7XX_IOCONTROL_REG, + SC16IS7XX_IOCONTROL_MODEM_A_BIT | + SC16IS7XX_IOCONTROL_MODEM_B_BIT, s->mctrl_mask); + + return 0; +} + +static const struct serial_rs485 sc16is7xx_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, /* Not supported but keep returning -EINVAL */ +}; + +/* Reset device, purging any pending irq / data */ +static int sc16is7xx_reset(struct device *dev, struct regmap *regmap) +{ + struct gpio_desc *reset_gpio; + + /* Assert reset GPIO if defined and valid. */ + reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(reset_gpio)) + return dev_err_probe(dev, PTR_ERR(reset_gpio), "Failed to get reset GPIO\n"); + + if (reset_gpio) { + /* The minimum reset pulse width is 3 us. */ + fsleep(5); + gpiod_set_value_cansleep(reset_gpio, 0); /* Deassert GPIO */ + } else { + /* Software reset */ + regmap_write(regmap, SC16IS7XX_IOCONTROL_REG, + SC16IS7XX_IOCONTROL_SRESET_BIT); + } + + return 0; +} + +static int sc16is7xx_setup_channel(struct sc16is7xx_one *one, int i, + bool *port_registered) +{ + struct uart_port *port = &one->port; + int ret; + + ret = ida_alloc_max(&sc16is7xx_lines, SC16IS7XX_MAX_DEVS - 1, GFP_KERNEL); + if (ret < 0) + return ret; + + port->line = ret; + + /* Initialize port data */ + port->type = PORT_SC16IS7XX; + port->fifosize = SC16IS7XX_FIFO_SIZE; + port->flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY; + port->iobase = i; + /* + * Use all ones as membase to make sure uart_configure_port() in + * serial_core.c does not abort for SPI/I2C devices where the + * membase address is not applicable. + */ + port->membase = (void __iomem *)~0; + port->iotype = UPIO_PORT; + port->rs485_config = sc16is7xx_config_rs485; + port->rs485_supported = sc16is7xx_rs485_supported; + port->ops = &sc16is7xx_ops; + one->old_mctrl = 0; + + mutex_init(&one->lock); + + ret = uart_get_rs485_mode(port); + if (ret) + return ret; + + /* Enable access to general register set */ + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, 0x00); + + /* Disable all interrupts */ + sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0); + /* Disable TX/RX */ + sc16is7xx_port_write(port, SC16IS7XX_EFCR_REG, + SC16IS7XX_EFCR_RXDISABLE_BIT | + SC16IS7XX_EFCR_TXDISABLE_BIT); + + /* Initialize kthread work structs */ + kthread_init_work(&one->tx_work, sc16is7xx_tx_proc); + kthread_init_work(&one->reg_work, sc16is7xx_reg_proc); + kthread_init_delayed_work(&one->ms_work, sc16is7xx_ms_proc); + + /* Register port */ + ret = uart_add_one_port(&sc16is7xx_uart, port); + if (ret) + return ret; + + *port_registered = true; + + sc16is7xx_regs_lock(port, SC16IS7XX_LCR_REG_SET_ENHANCED); + /* Enable write access to enhanced features */ + sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, + SC16IS7XX_EFR_ENABLE_BIT); + sc16is7xx_regs_unlock(port); + + /* Go to suspend mode */ + sc16is7xx_power(port, 0); + + return 0; +} + +int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype, + struct regmap *regmaps[], int irq) +{ + unsigned long freq = 0, *pfreq = dev_get_platdata(dev); + unsigned int val; + u32 uartclk = 0; + int i, ret; + struct sc16is7xx_port *s; + bool port_registered[SC16IS7XX_MAX_PORTS]; + + for (i = 0; i < devtype->nr_uart; i++) + if (IS_ERR(regmaps[i])) + return PTR_ERR(regmaps[i]); + + /* + * This device does not have an identification register that would + * tell us if we are really connected to the correct device. + * The best we can do is to check if communication is at all possible. + * + * Note: regmap[0] is used in the probe function to access registers + * common to all channels/ports, as it is guaranteed to be present on + * all variants. + */ + ret = regmap_read(regmaps[0], SC16IS7XX_LSR_REG, &val); + if (ret < 0) + return -EPROBE_DEFER; + + /* Alloc port structure */ + s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL); + if (!s) + return -ENOMEM; + + /* Always ask for fixed clock rate from a property. */ + device_property_read_u32(dev, "clock-frequency", &uartclk); + + s->polling = (irq <= 0); + if (s->polling) + dev_dbg(dev, + "No interrupt pin definition, falling back to polling mode\n"); + + s->clk = devm_clk_get_optional(dev, NULL); + if (IS_ERR(s->clk)) + return PTR_ERR(s->clk); + + ret = clk_prepare_enable(s->clk); + if (ret) + return ret; + + freq = clk_get_rate(s->clk); + if (freq == 0) { + if (uartclk) + freq = uartclk; + if (pfreq) + freq = *pfreq; + if (freq) + dev_dbg(dev, "Clock frequency: %luHz\n", freq); + else + return -EINVAL; + } + + s->devtype = devtype; + dev_set_drvdata(dev, s); + + kthread_init_worker(&s->kworker); + s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker, + "sc16is7xx"); + if (IS_ERR(s->kworker_task)) { + ret = PTR_ERR(s->kworker_task); + goto out_clk; + } + sched_set_fifo(s->kworker_task); + + ret = sc16is7xx_reset(dev, regmaps[0]); + if (ret) + goto out_kthread; + + /* Mark each port line and status as uninitialised. */ + for (i = 0; i < devtype->nr_uart; ++i) { + s->p[i].port.line = SC16IS7XX_MAX_DEVS; + port_registered[i] = false; + } + + for (i = 0; i < devtype->nr_uart; ++i) { + s->p[i].port.dev = dev; + s->p[i].port.irq = irq; + s->p[i].port.uartclk = freq; + s->p[i].regmap = regmaps[i]; + + ret = sc16is7xx_setup_channel(&s->p[i], i, &port_registered[i]); + if (ret) + goto out_ports; + } + + sc16is7xx_setup_irda_ports(s); + + ret = sc16is7xx_setup_mctrl_ports(s, regmaps[0]); + if (ret) + goto out_ports; + +#ifdef CONFIG_GPIOLIB + ret = sc16is7xx_setup_gpio_chip(s); + if (ret) + goto out_ports; +#endif + + if (s->polling) { + /* Initialize kernel thread for polling */ + kthread_init_delayed_work(&s->poll_work, sc16is7xx_poll_proc); + return 0; + } + + /* + * Setup interrupt. We first try to acquire the IRQ line as level IRQ. + * If that succeeds, we can allow sharing the interrupt as well. + * In case the interrupt controller doesn't support that, we fall + * back to a non-shared falling-edge trigger. + */ + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, + IRQF_TRIGGER_LOW | IRQF_SHARED | + IRQF_ONESHOT, + dev_name(dev), s); + if (!ret) + return 0; + + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, + IRQF_TRIGGER_FALLING | IRQF_ONESHOT, + dev_name(dev), s); + if (!ret) + return 0; + +#ifdef CONFIG_GPIOLIB + if (s->gpio_valid_mask) + gpiochip_remove(&s->gpio); +#endif + +out_ports: + for (i = 0; i < devtype->nr_uart; i++) { + if (s->p[i].port.line < SC16IS7XX_MAX_DEVS) + ida_free(&sc16is7xx_lines, s->p[i].port.line); + if (port_registered[i]) + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); + } + +out_kthread: + kthread_stop(s->kworker_task); + +out_clk: + clk_disable_unprepare(s->clk); + + return ret; +} +EXPORT_SYMBOL_GPL(sc16is7xx_probe); + +void sc16is7xx_remove(struct device *dev) +{ + struct sc16is7xx_port *s = dev_get_drvdata(dev); + int i; + +#ifdef CONFIG_GPIOLIB + if (s->gpio_valid_mask) + gpiochip_remove(&s->gpio); +#endif + + for (i = 0; i < s->devtype->nr_uart; i++) { + kthread_cancel_delayed_work_sync(&s->p[i].ms_work); + ida_free(&sc16is7xx_lines, s->p[i].port.line); + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); + sc16is7xx_power(&s->p[i].port, 0); + } + + if (s->polling) + kthread_cancel_delayed_work_sync(&s->poll_work); + + kthread_flush_worker(&s->kworker); + kthread_stop(s->kworker_task); + + clk_disable_unprepare(s->clk); +} +EXPORT_SYMBOL_GPL(sc16is7xx_remove); + +const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = { + { .compatible = "nxp,sc16is740", .data = &sc16is74x_devtype, }, + { .compatible = "nxp,sc16is741", .data = &sc16is74x_devtype, }, + { .compatible = "nxp,sc16is750", .data = &sc16is750_devtype, }, + { .compatible = "nxp,sc16is752", .data = &sc16is752_devtype, }, + { .compatible = "nxp,sc16is760", .data = &sc16is760_devtype, }, + { .compatible = "nxp,sc16is762", .data = &sc16is762_devtype, }, + { } +}; +EXPORT_SYMBOL_GPL(sc16is7xx_dt_ids); +MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids); + +const struct regmap_config sc16is7xx_regcfg = { + .reg_bits = 5, + .pad_bits = 3, + .val_bits = 8, + .cache_type = REGCACHE_MAPLE, + .volatile_reg = sc16is7xx_regmap_volatile, + .precious_reg = sc16is7xx_regmap_precious, + .writeable_noinc_reg = sc16is7xx_regmap_noinc, + .readable_noinc_reg = sc16is7xx_regmap_noinc, + .max_raw_read = SC16IS7XX_FIFO_SIZE, + .max_raw_write = SC16IS7XX_FIFO_SIZE, + .max_register = SC16IS7XX_EFCR_REG, +}; +EXPORT_SYMBOL_GPL(sc16is7xx_regcfg); + +const char *sc16is7xx_regmap_name(u8 port_id) +{ + switch (port_id) { + case 0: return "port0"; + case 1: return "port1"; + default: + WARN_ON(true); + return NULL; + } +} +EXPORT_SYMBOL_GPL(sc16is7xx_regmap_name); + +unsigned int sc16is7xx_regmap_port_mask(unsigned int port_id) +{ + /* CH1,CH0 are at bits 2:1. */ + return port_id << 1; +} +EXPORT_SYMBOL_GPL(sc16is7xx_regmap_port_mask); + +static int __init sc16is7xx_init(void) +{ + return uart_register_driver(&sc16is7xx_uart); +} +module_init(sc16is7xx_init); + +static void __exit sc16is7xx_exit(void) +{ + uart_unregister_driver(&sc16is7xx_uart); +} +module_exit(sc16is7xx_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>"); +MODULE_DESCRIPTION(KBUILD_MODNAME " tty serial core driver"); |