diff options
Diffstat (limited to 'drivers/net/dsa/realtek/realtek-smi.c')
| -rw-r--r-- | drivers/net/dsa/realtek/realtek-smi.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/net/dsa/realtek/realtek-smi.c b/drivers/net/dsa/realtek/realtek-smi.c new file mode 100644 index 000000000000..972e22218418 --- /dev/null +++ b/drivers/net/dsa/realtek/realtek-smi.c @@ -0,0 +1,408 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* Realtek Simple Management Interface (SMI) driver + * It can be discussed how "simple" this interface is. + * + * The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels + * but the protocol is not MDIO at all. Instead it is a Realtek + * pecularity that need to bit-bang the lines in a special way to + * communicate with the switch. + * + * ASICs we intend to support with this driver: + * + * RTL8366 - The original version, apparently + * RTL8369 - Similar enough to have the same datsheet as RTL8366 + * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite + * different register layout from the other two + * RTL8366S - Is this "RTL8366 super"? + * RTL8367 - Has an OpenWRT driver as well + * RTL8368S - Seems to be an alternative name for RTL8366RB + * RTL8370 - Also uses SMI + * + * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> + * Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com> + * Copyright (C) 2010 Roman Yeryomin <roman@advem.lv> + * Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com> + * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org> + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/spinlock.h> +#include <linux/skbuff.h> +#include <linux/of.h> +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/bitops.h> +#include <linux/if_bridge.h> + +#include "realtek.h" +#include "realtek-smi.h" +#include "rtl83xx.h" + +#define REALTEK_SMI_ACK_RETRY_COUNT 5 + +static inline void realtek_smi_clk_delay(struct realtek_priv *priv) +{ + ndelay(priv->variant->clk_delay); +} + +static void realtek_smi_start(struct realtek_priv *priv) +{ + /* Set GPIO pins to output mode, with initial state: + * SCK = 0, SDA = 1 + */ + gpiod_direction_output(priv->mdc, 0); + gpiod_direction_output(priv->mdio, 1); + realtek_smi_clk_delay(priv); + + /* CLK 1: 0 -> 1, 1 -> 0 */ + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 0); + realtek_smi_clk_delay(priv); + + /* CLK 2: */ + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdio, 0); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 0); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdio, 1); +} + +static void realtek_smi_stop(struct realtek_priv *priv) +{ + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdio, 0); + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdio, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 0); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 1); + + /* Add a click */ + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 0); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 1); + + /* Set GPIO pins to input mode */ + gpiod_direction_input(priv->mdio); + gpiod_direction_input(priv->mdc); +} + +static void realtek_smi_write_bits(struct realtek_priv *priv, u32 data, u32 len) +{ + for (; len > 0; len--) { + realtek_smi_clk_delay(priv); + + /* Prepare data */ + gpiod_set_value(priv->mdio, !!(data & (1 << (len - 1)))); + realtek_smi_clk_delay(priv); + + /* Clocking */ + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + gpiod_set_value(priv->mdc, 0); + } +} + +static void realtek_smi_read_bits(struct realtek_priv *priv, u32 len, u32 *data) +{ + gpiod_direction_input(priv->mdio); + + for (*data = 0; len > 0; len--) { + u32 u; + + realtek_smi_clk_delay(priv); + + /* Clocking */ + gpiod_set_value(priv->mdc, 1); + realtek_smi_clk_delay(priv); + u = !!gpiod_get_value(priv->mdio); + gpiod_set_value(priv->mdc, 0); + + *data |= (u << (len - 1)); + } + + gpiod_direction_output(priv->mdio, 0); +} + +static int realtek_smi_wait_for_ack(struct realtek_priv *priv) +{ + int retry_cnt; + + retry_cnt = 0; + do { + u32 ack; + + realtek_smi_read_bits(priv, 1, &ack); + if (ack == 0) + break; + + if (++retry_cnt > REALTEK_SMI_ACK_RETRY_COUNT) { + dev_err(priv->dev, "ACK timeout\n"); + return -ETIMEDOUT; + } + } while (1); + + return 0; +} + +static int realtek_smi_write_byte(struct realtek_priv *priv, u8 data) +{ + realtek_smi_write_bits(priv, data, 8); + return realtek_smi_wait_for_ack(priv); +} + +static int realtek_smi_write_byte_noack(struct realtek_priv *priv, u8 data) +{ + realtek_smi_write_bits(priv, data, 8); + return 0; +} + +static int realtek_smi_read_byte0(struct realtek_priv *priv, u8 *data) +{ + u32 t; + + /* Read data */ + realtek_smi_read_bits(priv, 8, &t); + *data = (t & 0xff); + + /* Send an ACK */ + realtek_smi_write_bits(priv, 0x00, 1); + + return 0; +} + +static int realtek_smi_read_byte1(struct realtek_priv *priv, u8 *data) +{ + u32 t; + + /* Read data */ + realtek_smi_read_bits(priv, 8, &t); + *data = (t & 0xff); + + /* Send an ACK */ + realtek_smi_write_bits(priv, 0x01, 1); + + return 0; +} + +static int realtek_smi_read_reg(struct realtek_priv *priv, u32 addr, u32 *data) +{ + unsigned long flags; + u8 lo = 0; + u8 hi = 0; + int ret; + + spin_lock_irqsave(&priv->lock, flags); + + realtek_smi_start(priv); + + /* Send READ command */ + ret = realtek_smi_write_byte(priv, priv->variant->cmd_read); + if (ret) + goto out; + + /* Set ADDR[7:0] */ + ret = realtek_smi_write_byte(priv, addr & 0xff); + if (ret) + goto out; + + /* Set ADDR[15:8] */ + ret = realtek_smi_write_byte(priv, addr >> 8); + if (ret) + goto out; + + /* Read DATA[7:0] */ + realtek_smi_read_byte0(priv, &lo); + /* Read DATA[15:8] */ + realtek_smi_read_byte1(priv, &hi); + + *data = ((u32)lo) | (((u32)hi) << 8); + + ret = 0; + + out: + realtek_smi_stop(priv); + spin_unlock_irqrestore(&priv->lock, flags); + + return ret; +} + +static int realtek_smi_write_reg(struct realtek_priv *priv, + u32 addr, u32 data, bool ack) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&priv->lock, flags); + + realtek_smi_start(priv); + + /* Send WRITE command */ + ret = realtek_smi_write_byte(priv, priv->variant->cmd_write); + if (ret) + goto out; + + /* Set ADDR[7:0] */ + ret = realtek_smi_write_byte(priv, addr & 0xff); + if (ret) + goto out; + + /* Set ADDR[15:8] */ + ret = realtek_smi_write_byte(priv, addr >> 8); + if (ret) + goto out; + + /* Write DATA[7:0] */ + ret = realtek_smi_write_byte(priv, data & 0xff); + if (ret) + goto out; + + /* Write DATA[15:8] */ + if (ack) + ret = realtek_smi_write_byte(priv, data >> 8); + else + ret = realtek_smi_write_byte_noack(priv, data >> 8); + if (ret) + goto out; + + ret = 0; + + out: + realtek_smi_stop(priv); + spin_unlock_irqrestore(&priv->lock, flags); + + return ret; +} + +/* There is one single case when we need to use this accessor and that + * is when issueing soft reset. Since the device reset as soon as we write + * that bit, no ACK will come back for natural reasons. + */ +static int realtek_smi_write_reg_noack(void *ctx, u32 reg, u32 val) +{ + return realtek_smi_write_reg(ctx, reg, val, false); +} + +/* Regmap accessors */ + +static int realtek_smi_write(void *ctx, u32 reg, u32 val) +{ + struct realtek_priv *priv = ctx; + + return realtek_smi_write_reg(priv, reg, val, true); +} + +static int realtek_smi_read(void *ctx, u32 reg, u32 *val) +{ + struct realtek_priv *priv = ctx; + + return realtek_smi_read_reg(priv, reg, val); +} + +static const struct realtek_interface_info realtek_smi_info = { + .reg_read = realtek_smi_read, + .reg_write = realtek_smi_write, +}; + +/** + * realtek_smi_probe() - Probe a platform device for an SMI-connected switch + * @pdev: platform_device to probe on. + * + * This function should be used as the .probe in a platform_driver. After + * calling the common probe function for both interfaces, it initializes the + * values specific for SMI-connected devices. Finally, it calls a common + * function to register the DSA switch. + * + * Context: Can sleep. Takes and releases priv->map_lock. + * Return: Returns 0 on success, a negative error on failure. + */ +int realtek_smi_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct realtek_priv *priv; + int ret; + + priv = rtl83xx_probe(dev, &realtek_smi_info); + if (IS_ERR(priv)) + return PTR_ERR(priv); + + /* Fetch MDIO pins */ + priv->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW); + if (IS_ERR(priv->mdc)) { + rtl83xx_remove(priv); + return PTR_ERR(priv->mdc); + } + + priv->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW); + if (IS_ERR(priv->mdio)) { + rtl83xx_remove(priv); + return PTR_ERR(priv->mdio); + } + + priv->write_reg_noack = realtek_smi_write_reg_noack; + + ret = rtl83xx_register_switch(priv); + if (ret) { + rtl83xx_remove(priv); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(realtek_smi_probe, "REALTEK_DSA"); + +/** + * realtek_smi_remove() - Remove the driver of a SMI-connected switch + * @pdev: platform_device to be removed. + * + * This function should be used as the .remove in a platform_driver. First + * it unregisters the DSA switch and then it calls the common remove function. + * + * Context: Can sleep. + * Return: Nothing. + */ +void realtek_smi_remove(struct platform_device *pdev) +{ + struct realtek_priv *priv = platform_get_drvdata(pdev); + + if (!priv) + return; + + rtl83xx_unregister_switch(priv); + + rtl83xx_remove(priv); +} +EXPORT_SYMBOL_NS_GPL(realtek_smi_remove, "REALTEK_DSA"); + +/** + * realtek_smi_shutdown() - Shutdown the driver of a SMI-connected switch + * @pdev: platform_device shutting down. + * + * This function should be used as the .shutdown in a platform_driver. It calls + * the common shutdown function. + * + * Context: Can sleep. + * Return: Nothing. + */ +void realtek_smi_shutdown(struct platform_device *pdev) +{ + struct realtek_priv *priv = platform_get_drvdata(pdev); + + if (!priv) + return; + + rtl83xx_shutdown(priv); +} +EXPORT_SYMBOL_NS_GPL(realtek_smi_shutdown, "REALTEK_DSA"); |