diff options
Diffstat (limited to 'drivers/spi/spi-loongson-core.c')
| -rw-r--r-- | drivers/spi/spi-loongson-core.c | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/drivers/spi/spi-loongson-core.c b/drivers/spi/spi-loongson-core.c new file mode 100644 index 000000000000..f97800b6fd65 --- /dev/null +++ b/drivers/spi/spi-loongson-core.c @@ -0,0 +1,279 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Loongson SPI Support +// Copyright (C) 2023 Loongson Technology Corporation Limited + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/spi/spi.h> + +#include "spi-loongson.h" + +static inline void loongson_spi_write_reg(struct loongson_spi *spi, unsigned char reg, + unsigned char data) +{ + writeb(data, spi->base + reg); +} + +static inline char loongson_spi_read_reg(struct loongson_spi *spi, unsigned char reg) +{ + return readb(spi->base + reg); +} + +static void loongson_spi_set_cs(struct spi_device *spi, bool en) +{ + int cs; + unsigned char mask = (BIT(4) | BIT(0)) << spi_get_chipselect(spi, 0); + unsigned char val = en ? mask : (BIT(0) << spi_get_chipselect(spi, 0)); + struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller); + + cs = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SFCS_REG) & ~mask; + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SFCS_REG, val | cs); +} + +static void loongson_spi_set_clk(struct loongson_spi *loongson_spi, unsigned int hz) +{ + unsigned char val; + unsigned int div, div_tmp; + static const char rdiv[12] = {0, 1, 4, 2, 3, 5, 6, 7, 8, 9, 10, 11}; + + div = clamp_val(DIV_ROUND_UP_ULL(loongson_spi->clk_rate, hz), 2, 4096); + div_tmp = rdiv[fls(div - 1)]; + loongson_spi->spcr = (div_tmp & GENMASK(1, 0)) >> 0; + loongson_spi->sper = (div_tmp & GENMASK(3, 2)) >> 2; + val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG); + val &= ~GENMASK(1, 0); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, val | + loongson_spi->spcr); + val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPER_REG); + val &= ~GENMASK(1, 0); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPER_REG, val | + loongson_spi->sper); + loongson_spi->hz = hz; +} + +static void loongson_spi_set_mode(struct loongson_spi *loongson_spi, + struct spi_device *spi) +{ + unsigned char val; + + val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG); + val &= ~(LOONGSON_SPI_SPCR_CPOL | LOONGSON_SPI_SPCR_CPHA); + if (spi->mode & SPI_CPOL) + val |= LOONGSON_SPI_SPCR_CPOL; + if (spi->mode & SPI_CPHA) + val |= LOONGSON_SPI_SPCR_CPHA; + + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, val); + loongson_spi->mode |= spi->mode; +} + +static int loongson_spi_update_state(struct loongson_spi *loongson_spi, + struct spi_device *spi, struct spi_transfer *t) +{ + if (t && loongson_spi->hz != t->speed_hz) + loongson_spi_set_clk(loongson_spi, t->speed_hz); + + if ((spi->mode ^ loongson_spi->mode) & SPI_MODE_X_MASK) + loongson_spi_set_mode(loongson_spi, spi); + + return 0; +} + +static int loongson_spi_setup(struct spi_device *spi) +{ + struct loongson_spi *loongson_spi; + + loongson_spi = spi_controller_get_devdata(spi->controller); + if (spi->bits_per_word % 8) + return -EINVAL; + + if (spi_get_chipselect(spi, 0) >= spi->controller->num_chipselect) + return -EINVAL; + + loongson_spi->hz = 0; + loongson_spi_set_cs(spi, true); + + return 0; +} + +static int loongson_spi_write_read_8bit(struct spi_device *spi, const u8 **tx_buf, + u8 **rx_buf, unsigned int num) +{ + int ret; + struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller); + + if (tx_buf && *tx_buf) + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_FIFO_REG, *((*tx_buf)++)); + else + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_FIFO_REG, 0); + + ret = readb_poll_timeout(loongson_spi->base + LOONGSON_SPI_SPSR_REG, + loongson_spi->spsr, (loongson_spi->spsr & + LOONGSON_SPI_SPSR_RFEMPTY) != LOONGSON_SPI_SPSR_RFEMPTY, + 1, USEC_PER_MSEC); + + if (rx_buf && *rx_buf) + *(*rx_buf)++ = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_FIFO_REG); + else + loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_FIFO_REG); + + return ret; +} + +static int loongson_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer) +{ + int ret; + unsigned int count; + const u8 *tx = xfer->tx_buf; + u8 *rx = xfer->rx_buf; + + count = xfer->len; + do { + ret = loongson_spi_write_read_8bit(spi, &tx, &rx, count); + if (ret) + break; + } while (--count); + + return ret; +} + +static int loongson_spi_prepare_message(struct spi_controller *ctlr, struct spi_message *m) +{ + struct loongson_spi *loongson_spi = spi_controller_get_devdata(ctlr); + + loongson_spi->para = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_PARA_REG); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para & + ~LOONGSON_SPI_PARA_MEM_EN); + + return 0; +} + +static int loongson_spi_transfer_one(struct spi_controller *ctrl, struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct loongson_spi *loongson_spi = spi_controller_get_devdata(spi->controller); + + loongson_spi_update_state(loongson_spi, spi, xfer); + if (xfer->len) + return loongson_spi_write_read(spi, xfer); + + return 0; +} + +static int loongson_spi_unprepare_message(struct spi_controller *ctrl, struct spi_message *m) +{ + struct loongson_spi *loongson_spi = spi_controller_get_devdata(ctrl); + + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para); + + return 0; +} + +static void loongson_spi_reginit(struct loongson_spi *loongson_spi_dev) +{ + unsigned char val; + + val = loongson_spi_read_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG); + val &= ~LOONGSON_SPI_SPCR_SPE; + loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG, val); + + loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPSR_REG, + (LOONGSON_SPI_SPSR_SPIF | LOONGSON_SPI_SPSR_WCOL)); + + val = loongson_spi_read_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG); + val |= LOONGSON_SPI_SPCR_SPE; + loongson_spi_write_reg(loongson_spi_dev, LOONGSON_SPI_SPCR_REG, val); +} + +int loongson_spi_init_controller(struct device *dev, void __iomem *regs) +{ + struct spi_controller *controller; + struct loongson_spi *spi; + struct clk *clk; + + controller = devm_spi_alloc_host(dev, sizeof(struct loongson_spi)); + if (controller == NULL) + return -ENOMEM; + + controller->mode_bits = SPI_MODE_X_MASK | SPI_CS_HIGH; + controller->setup = loongson_spi_setup; + controller->prepare_message = loongson_spi_prepare_message; + controller->transfer_one = loongson_spi_transfer_one; + controller->unprepare_message = loongson_spi_unprepare_message; + controller->set_cs = loongson_spi_set_cs; + controller->num_chipselect = 4; + device_set_node(&controller->dev, dev_fwnode(dev)); + dev_set_drvdata(dev, controller); + + spi = spi_controller_get_devdata(controller); + spi->base = regs; + spi->controller = controller; + + clk = devm_clk_get_optional(dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(dev, PTR_ERR(clk), "unable to get clock\n"); + + spi->clk_rate = clk_get_rate(clk); + loongson_spi_reginit(spi); + + spi->mode = 0; + + return devm_spi_register_controller(dev, controller); +} +EXPORT_SYMBOL_NS_GPL(loongson_spi_init_controller, SPI_LOONGSON_CORE); + +static int __maybe_unused loongson_spi_suspend(struct device *dev) +{ + struct loongson_spi *loongson_spi; + struct spi_controller *controller; + + controller = dev_get_drvdata(dev); + spi_controller_suspend(controller); + + loongson_spi = spi_controller_get_devdata(controller); + + loongson_spi->spcr = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG); + loongson_spi->sper = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPER_REG); + loongson_spi->spsr = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPSR_REG); + loongson_spi->para = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_PARA_REG); + loongson_spi->sfcs = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SFCS_REG); + loongson_spi->timi = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_TIMI_REG); + + return 0; +} + +static int __maybe_unused loongson_spi_resume(struct device *dev) +{ + struct loongson_spi *loongson_spi; + struct spi_controller *controller; + + controller = dev_get_drvdata(dev); + loongson_spi = spi_controller_get_devdata(controller); + + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPCR_REG, loongson_spi->spcr); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPER_REG, loongson_spi->sper); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SPSR_REG, loongson_spi->spsr); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_PARA_REG, loongson_spi->para); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_SFCS_REG, loongson_spi->sfcs); + loongson_spi_write_reg(loongson_spi, LOONGSON_SPI_TIMI_REG, loongson_spi->timi); + + spi_controller_resume(controller); + + return 0; +} + +const struct dev_pm_ops loongson_spi_dev_pm_ops = { + .suspend = loongson_spi_suspend, + .resume = loongson_spi_resume, +}; +EXPORT_SYMBOL_NS_GPL(loongson_spi_dev_pm_ops, SPI_LOONGSON_CORE); + +MODULE_DESCRIPTION("Loongson SPI core driver"); +MODULE_LICENSE("GPL"); |