Initial commit

target/linux/realtek/files-6.6/drivers/i2c/busses/i2c-rtl9300.c

@@ -0,0 +1,483 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include "i2c-rtl9300.h"
+
+#define REG(i, x)	(i->base + x + (i->scl_num ? i->mst2_offset : 0))
+#define REG_MASK(i, clear, set, reg)	\
+			writel((readl(REG(i, reg)) & ~(clear)) | (set), REG(i, reg))
+
+struct i2c_drv_data {
+	int scl0_pin;
+	int scl1_pin;
+	int sda0_pin;
+	struct i2c_algorithm *algo;
+	int (*read)(struct rtl9300_i2c *i2c, u8 *buf, int len);
+	int (*write)(struct rtl9300_i2c *i2c, u8 *buf, int len);
+	void (*reg_addr_set)(struct rtl9300_i2c *i2c, u32 reg, u16 len);
+	int (*config_xfer)(struct rtl9300_i2c *i2c, u16 addr, u16 len);
+	int (*execute_xfer)(struct rtl9300_i2c *i2c, char read_write, int size,
+			    union i2c_smbus_data * data, int len);
+	void (*writel)(struct rtl9300_i2c *i2c, u32 data);
+	void (*config_io)(struct rtl9300_i2c *i2c, int scl_num, int sda_num);
+	u32 mst2_offset;
+};
+
+DEFINE_MUTEX(i2c_lock);
+
+static void rtl9300_i2c_reg_addr_set(struct rtl9300_i2c *i2c, u32 reg, u16 len)
+{
+	/* Set register address width */
+	REG_MASK(i2c, 0x3 << RTL9300_I2C_CTRL2_MADDR_WIDTH, len << RTL9300_I2C_CTRL2_MADDR_WIDTH,
+		 RTL9300_I2C_CTRL2);
+
+	/* Set register address */
+	REG_MASK(i2c, 0xffffff << RTL9300_I2C_CTRL1_MEM_ADDR, reg << RTL9300_I2C_CTRL1_MEM_ADDR,
+		 RTL9300_I2C_CTRL1);
+}
+
+static void rtl9310_i2c_reg_addr_set(struct rtl9300_i2c *i2c, u32 reg, u16 len)
+{
+	/* Set register address width */
+	REG_MASK(i2c, 0x3 << RTL9310_I2C_CTRL_MADDR_WIDTH, len << RTL9310_I2C_CTRL_MADDR_WIDTH,
+		 RTL9310_I2C_CTRL);
+
+	/* Set register address */
+	writel(reg, REG(i2c, RTL9310_I2C_MEMADDR));
+}
+
+static void rtl9300_i2c_config_io(struct rtl9300_i2c *i2c, int scl_num, int sda_num)
+{
+	u32 v;
+
+	/* Set SCL pin */
+	REG_MASK(i2c, 0, BIT(RTL9300_I2C_CTRL1_GPIO8_SCL_SEL), RTL9300_I2C_CTRL1);
+
+	/* Set SDA pin */
+	REG_MASK(i2c, 0x7 << RTL9300_I2C_CTRL1_SDA_OUT_SEL,
+		 i2c->sda_num << RTL9300_I2C_CTRL1_SDA_OUT_SEL, RTL9300_I2C_CTRL1);
+
+	/* Set SDA pin to I2C functionality */
+	v = readl(i2c->base + RTL9300_I2C_MST_GLB_CTRL);
+	v |= BIT(i2c->sda_num);
+	writel(v, i2c->base + RTL9300_I2C_MST_GLB_CTRL);
+}
+
+static void rtl9310_i2c_config_io(struct rtl9300_i2c *i2c, int scl_num, int sda_num)
+{
+	u32 v;
+
+	/* Set SCL pin */
+	REG_MASK(i2c, 0, BIT(RTL9310_I2C_MST_IF_SEL_GPIO_SCL_SEL + scl_num), RTL9310_I2C_MST_IF_SEL);
+
+	/* Set SDA pin */
+	REG_MASK(i2c, 0x7 << RTL9310_I2C_CTRL_SDA_OUT_SEL,
+		 i2c->sda_num << RTL9310_I2C_CTRL_SDA_OUT_SEL, RTL9310_I2C_CTRL);
+
+	/* Set SDA pin to I2C functionality */
+	v = readl(i2c->base + RTL9310_I2C_MST_IF_SEL);
+	v |= BIT(i2c->sda_num);
+	writel(v, i2c->base + RTL9310_I2C_MST_IF_SEL);
+}
+
+static int rtl9300_i2c_config_xfer(struct rtl9300_i2c *i2c, u16 addr, u16 len)
+{
+	/* Set bus frequency */
+	REG_MASK(i2c, 0x3 << RTL9300_I2C_CTRL2_SCL_FREQ,
+		 i2c->bus_freq << RTL9300_I2C_CTRL2_SCL_FREQ, RTL9300_I2C_CTRL2);
+
+	/* Set slave device address */
+	REG_MASK(i2c, 0x7f << RTL9300_I2C_CTRL2_DEV_ADDR,
+		 addr << RTL9300_I2C_CTRL2_DEV_ADDR, RTL9300_I2C_CTRL2);
+
+	/* Set data length */
+	REG_MASK(i2c, 0xf << RTL9300_I2C_CTRL2_DATA_WIDTH,
+		 ((len - 1) & 0xf) << RTL9300_I2C_CTRL2_DATA_WIDTH, RTL9300_I2C_CTRL2);
+
+	/* Set read mode to random */
+	REG_MASK(i2c, 0x1 << RTL9300_I2C_CTRL2_READ_MODE, 0, RTL9300_I2C_CTRL2);
+
+	return 0;
+}
+
+static int rtl9310_i2c_config_xfer(struct rtl9300_i2c *i2c, u16 addr, u16 len)
+{
+	/* Set bus frequency */
+	REG_MASK(i2c, 0x3 << RTL9310_I2C_CTRL_SCL_FREQ,
+		 i2c->bus_freq << RTL9310_I2C_CTRL_SCL_FREQ, RTL9310_I2C_CTRL);
+
+	/* Set slave device address */
+	REG_MASK(i2c, 0x7f << RTL9310_I2C_CTRL_DEV_ADDR,
+		 addr << RTL9310_I2C_CTRL_DEV_ADDR, RTL9310_I2C_CTRL);
+
+	/* Set data length */
+	REG_MASK(i2c, 0xf << RTL9310_I2C_CTRL_DATA_WIDTH,
+		 ((len - 1) & 0xf) << RTL9310_I2C_CTRL_DATA_WIDTH, RTL9310_I2C_CTRL);
+
+	/* Set read mode to random */
+	REG_MASK(i2c, 0x1 << RTL9310_I2C_CTRL_READ_MODE, 0, RTL9310_I2C_CTRL);
+
+	return 0;
+}
+
+static int i2c_read(void __iomem *r0, u8 *buf, int len)
+{
+	if (len > 16)
+		return -EIO;
+
+	for (int i = 0; i < len; i++) {
+		u32 v;
+
+		if (i % 4 == 0)
+			v = readl(r0 + i);
+		buf[i] = v;
+		v >>= 8;
+	}
+
+	return len;
+}
+
+static int i2c_write(void __iomem *r0, u8 *buf, int len)
+{
+	if (len > 16)
+		return -EIO;
+
+	for (int i = 0; i < len; i++) {
+		u32 v;
+
+		if (! (i % 4))
+			v = 0;
+		v <<= 8;
+		v |= buf[i];
+		if (i % 4 == 3 || i == len - 1)
+			writel(v, r0 + (i / 4) * 4);
+	}
+
+	return len;
+}
+
+static int rtl9300_i2c_read(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	return i2c_read(REG(i2c, RTL9300_I2C_DATA_WORD0), buf, len);
+}
+
+static int rtl9300_i2c_write(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	return i2c_write(REG(i2c, RTL9300_I2C_DATA_WORD0), buf, len);
+}
+
+static int rtl9310_i2c_read(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	return i2c_read(REG(i2c, RTL9310_I2C_DATA), buf, len);
+}
+
+static int rtl9310_i2c_write(struct rtl9300_i2c *i2c, u8 *buf, int len)
+{
+	return i2c_write(REG(i2c, RTL9310_I2C_DATA), buf, len);
+}
+
+static void rtl9300_writel(struct rtl9300_i2c *i2c, u32 data)
+{
+	writel(data, REG(i2c, RTL9300_I2C_DATA_WORD0));
+}
+
+static void rtl9310_writel(struct rtl9300_i2c *i2c, u32 data)
+{
+	writel(data, REG(i2c, RTL9310_I2C_DATA));
+}
+
+
+static int rtl9300_execute_xfer(struct rtl9300_i2c *i2c, char read_write,
+				int size, union i2c_smbus_data * data, int len)
+{
+	u32 v;
+
+	if (read_write == I2C_SMBUS_READ)
+		REG_MASK(i2c, BIT(RTL9300_I2C_CTRL1_RWOP), 0, RTL9300_I2C_CTRL1);
+	else
+		REG_MASK(i2c, 0, BIT(RTL9300_I2C_CTRL1_RWOP), RTL9300_I2C_CTRL1);
+
+	REG_MASK(i2c, 0, BIT(RTL9300_I2C_CTRL1_I2C_TRIG), RTL9300_I2C_CTRL1);
+	do {
+		v = readl(REG(i2c, RTL9300_I2C_CTRL1));
+	} while (v & BIT(RTL9300_I2C_CTRL1_I2C_TRIG));
+
+	if (v & BIT(RTL9300_I2C_CTRL1_I2C_FAIL))
+		return -EIO;
+
+	if (read_write == I2C_SMBUS_READ) {
+		if (size == I2C_SMBUS_BYTE || size == I2C_SMBUS_BYTE_DATA){
+			data->byte = readl(REG(i2c, RTL9300_I2C_DATA_WORD0));
+		} else if (size == I2C_SMBUS_WORD_DATA) {
+			data->word = readl(REG(i2c, RTL9300_I2C_DATA_WORD0));
+		} else if (len > 0) {
+			rtl9300_i2c_read(i2c, &data->block[0], len);
+		}
+	}
+
+	return 0;
+}
+
+static int rtl9310_execute_xfer(struct rtl9300_i2c *i2c, char read_write,
+				int size, union i2c_smbus_data * data, int len)
+{
+	u32 v;
+
+	if (read_write == I2C_SMBUS_READ)
+		REG_MASK(i2c, BIT(RTL9310_I2C_CTRL_RWOP), 0, RTL9310_I2C_CTRL);
+	else
+		REG_MASK(i2c, 0, BIT(RTL9310_I2C_CTRL_RWOP), RTL9310_I2C_CTRL);
+
+	REG_MASK(i2c, 0, BIT(RTL9310_I2C_CTRL_I2C_TRIG), RTL9310_I2C_CTRL);
+	do {
+		v = readl(REG(i2c, RTL9310_I2C_CTRL));
+	} while (v & BIT(RTL9310_I2C_CTRL_I2C_TRIG));
+
+	if (v & BIT(RTL9310_I2C_CTRL_I2C_FAIL))
+		return -EIO;
+
+	if (read_write == I2C_SMBUS_READ) {
+		if (size == I2C_SMBUS_BYTE || size == I2C_SMBUS_BYTE_DATA){
+			data->byte = readl(REG(i2c, RTL9310_I2C_DATA));
+		} else if (size == I2C_SMBUS_WORD_DATA) {
+			data->word = readl(REG(i2c, RTL9310_I2C_DATA));
+		} else if (len > 0) {
+			rtl9310_i2c_read(i2c, &data->block[0], len);
+		}
+	}
+
+	return 0;
+}
+
+static int rtl9300_i2c_smbus_xfer(struct i2c_adapter * adap, u16 addr,
+		  unsigned short flags, char read_write,
+		  u8 command, int size, union i2c_smbus_data * data)
+{
+	struct rtl9300_i2c *i2c = i2c_get_adapdata(adap);
+	struct i2c_drv_data *drv_data = (struct i2c_drv_data *)device_get_match_data(i2c->dev);
+	int len = 0, ret;
+
+	mutex_lock(&i2c_lock);
+	switch (size) {
+	case I2C_SMBUS_QUICK:
+		drv_data->config_xfer(i2c, addr, 0);
+		drv_data->reg_addr_set(i2c, 0, 0);
+		break;
+
+	case I2C_SMBUS_BYTE:
+		if (read_write == I2C_SMBUS_WRITE) {
+			drv_data->config_xfer(i2c, addr, 0);
+			drv_data->reg_addr_set(i2c, command, 1);
+		} else {
+			drv_data->config_xfer(i2c, addr, 1);
+			drv_data->reg_addr_set(i2c, 0, 0);
+		}
+		break;
+
+	case I2C_SMBUS_BYTE_DATA:
+		pr_debug("I2C_SMBUS_BYTE_DATA %02x, read %d cmd %02x\n", addr, read_write, command);
+		drv_data->reg_addr_set(i2c, command, 1);
+		drv_data->config_xfer(i2c, addr, 1);
+
+		if (read_write == I2C_SMBUS_WRITE) {
+			pr_debug("--> data %02x\n", data->byte);
+			drv_data->writel(i2c, data->byte);
+		}
+		break;
+
+	case I2C_SMBUS_WORD_DATA:
+		pr_debug("I2C_SMBUS_WORD %02x, read %d\n", addr, read_write);
+		drv_data->reg_addr_set(i2c, command, 1);
+		drv_data->config_xfer(i2c, addr, 2);
+		if (read_write == I2C_SMBUS_WRITE)
+			drv_data->writel(i2c, data->word);
+		break;
+
+	case I2C_SMBUS_BLOCK_DATA:
+		pr_debug("I2C_SMBUS_BLOCK_DATA %02x, read %d, len %d\n",
+			addr, read_write, data->block[0]);
+		drv_data->reg_addr_set(i2c, command, 1);
+		drv_data->config_xfer(i2c, addr, data->block[0]);
+		if (read_write == I2C_SMBUS_WRITE)
+			drv_data->write(i2c, &data->block[1], data->block[0]);
+		len = data->block[0];
+		break;
+
+	default:
+		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
+		return -EOPNOTSUPP;
+	}
+
+	ret = drv_data->execute_xfer(i2c, read_write, size, data, len);
+
+	mutex_unlock(&i2c_lock);
+
+	return ret;
+}
+
+static u32 rtl9300_i2c_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+	       I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm rtl9300_i2c_algo = {
+	.smbus_xfer	= rtl9300_i2c_smbus_xfer,
+	.functionality	= rtl9300_i2c_func,
+};
+
+struct i2c_adapter_quirks rtl9300_i2c_quirks = {
+	.flags		= I2C_AQ_NO_CLK_STRETCH,
+	.max_read_len	= 16,
+	.max_write_len	= 16,
+};
+
+static int rtl9300_i2c_probe(struct platform_device *pdev)
+{
+	struct rtl9300_i2c *i2c;
+	struct i2c_adapter *adap;
+	struct i2c_drv_data *drv_data;
+	struct device_node *node = pdev->dev.of_node;
+	u32 clock_freq, pin;
+	int ret = 0;
+
+	pr_info("%s probing I2C adapter\n", __func__);
+
+	if (!node) {
+		dev_err(i2c->dev, "No DT found\n");
+		return -EINVAL;
+	}
+
+	drv_data = (struct i2c_drv_data *) device_get_match_data(&pdev->dev);
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(struct rtl9300_i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	i2c->base = devm_platform_ioremap_resource(pdev, 0);
+	i2c->mst2_offset = drv_data->mst2_offset;
+	if (IS_ERR(i2c->base))
+		return PTR_ERR(i2c->base);
+
+	pr_debug("%s base memory %08x\n", __func__, (u32)i2c->base);
+	i2c->dev = &pdev->dev;
+
+	if (of_property_read_u32(node, "clock-frequency", &clock_freq)) {
+		clock_freq = I2C_MAX_STANDARD_MODE_FREQ;
+	}
+	switch(clock_freq) {
+	case I2C_MAX_STANDARD_MODE_FREQ:
+		i2c->bus_freq = RTL9300_I2C_STD_FREQ;
+		break;
+
+	case I2C_MAX_FAST_MODE_FREQ:
+		i2c->bus_freq = RTL9300_I2C_FAST_FREQ;
+		break;
+	default:
+		dev_warn(i2c->dev, "clock-frequency %d not supported\n", clock_freq);
+		return -EINVAL;
+	}
+
+	dev_info(&pdev->dev, "SCL speed %d, mode is %d\n", clock_freq, i2c->bus_freq);
+
+	if (of_property_read_u32(node, "scl-pin", &pin)) {
+		dev_warn(i2c->dev, "SCL pin not found in DT, using default\n");
+		pin = drv_data->scl0_pin;
+	}
+	if (!(pin == drv_data->scl0_pin || pin == drv_data->scl1_pin)) {
+		dev_warn(i2c->dev, "SCL pin %d not supported\n", pin);
+		return -EINVAL;
+	}
+	i2c->scl_num = pin == drv_data->scl0_pin ? 0 : 1;
+	pr_info("%s scl_num %d\n", __func__, i2c->scl_num);
+
+	if (of_property_read_u32(node, "sda-pin", &pin)) {
+		dev_warn(i2c->dev, "SDA pin not found in DT, using default \n");
+		pin = drv_data->sda0_pin;
+	}
+	i2c->sda_num = pin - drv_data->sda0_pin;
+	if (i2c->sda_num < 0 || i2c->sda_num > 7) {
+		dev_warn(i2c->dev, "SDA pin %d not supported\n", pin);
+		return -EINVAL;
+	}
+	pr_info("%s sda_num %d\n", __func__, i2c->sda_num);
+
+	adap = &i2c->adap;
+	adap->owner = THIS_MODULE;
+	adap->algo = &rtl9300_i2c_algo;
+	adap->retries = 3;
+	adap->dev.parent = &pdev->dev;
+	i2c_set_adapdata(adap, i2c);
+	adap->dev.of_node = node;
+	strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+
+	platform_set_drvdata(pdev, i2c);
+
+	drv_data->config_io(i2c, i2c->scl_num, i2c->sda_num);
+
+	ret = i2c_add_adapter(adap);
+
+	return ret;
+}
+
+static int rtl9300_i2c_remove(struct platform_device *pdev)
+{
+	struct rtl9300_i2c *i2c = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c->adap);
+
+	return 0;
+}
+
+struct i2c_drv_data rtl9300_i2c_drv_data = {
+	.scl0_pin = 8,
+	.scl1_pin = 17,
+	.sda0_pin = 9,
+	.read = rtl9300_i2c_read,
+	.read = rtl9300_i2c_write,
+	.reg_addr_set = rtl9300_i2c_reg_addr_set,
+	.config_xfer = rtl9300_i2c_config_xfer,
+	.execute_xfer = rtl9300_execute_xfer,
+	.writel = rtl9300_writel,
+	.config_io = rtl9300_i2c_config_io,
+	.mst2_offset = 0x1c,
+};
+
+struct i2c_drv_data rtl9310_i2c_drv_data = {
+	.scl0_pin = 13,
+	.scl1_pin = 14,
+	.sda0_pin = 0,
+	.read = rtl9310_i2c_read,
+	.read = rtl9310_i2c_write,
+	.reg_addr_set = rtl9310_i2c_reg_addr_set,
+	.config_xfer = rtl9310_i2c_config_xfer,
+	.execute_xfer = rtl9310_execute_xfer,
+	.writel = rtl9310_writel,
+	.config_io = rtl9310_i2c_config_io,
+	.mst2_offset = 0x18,
+};
+
+static const struct of_device_id i2c_rtl9300_dt_ids[] = {
+	{ .compatible = "realtek,rtl9300-i2c", .data = (void *) &rtl9300_i2c_drv_data },
+	{ .compatible = "realtek,rtl9310-i2c", .data = (void *) &rtl9310_i2c_drv_data },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rtl838x_eth_of_ids);
+
+static struct platform_driver rtl9300_i2c_driver = {
+	.probe		= rtl9300_i2c_probe,
+	.remove		= rtl9300_i2c_remove,
+	.driver		= {
+		.name	= "i2c-rtl9300",
+		.pm 	= NULL,
+		.of_match_table = i2c_rtl9300_dt_ids,
+	},
+};
+
+module_platform_driver(rtl9300_i2c_driver);
+
+MODULE_AUTHOR("Birger Koblitz");
+MODULE_DESCRIPTION("RTL9300 I2C host driver");
+MODULE_LICENSE("GPL v2");

target/linux/realtek/files-6.6/drivers/i2c/busses/i2c-rtl9300.h

@@ -0,0 +1,62 @@
+#ifndef I2C_RTL9300_H
+#define I2C_RTL9300_H
+
+#include <linux/i2c.h>
+
+#define RTL9300_I2C_CTRL1			0x00
+#define RTL9300_I2C_CTRL1_MEM_ADDR		8
+#define RTL9300_I2C_CTRL1_SDA_OUT_SEL		4
+#define RTL9300_I2C_CTRL1_GPIO8_SCL_SEL		3
+#define RTL9300_I2C_CTRL1_RWOP			2
+#define RTL9300_I2C_CTRL1_I2C_FAIL		1
+#define RTL9300_I2C_CTRL1_I2C_TRIG		0
+
+#define RTL9300_I2C_CTRL2			0x04
+#define RTL9300_I2C_CTRL2_DRIVE_ACK_DELAY	20
+#define RTL9300_I2C_CTRL2_CHECK_ACK_DELAY	16
+#define RTL9300_I2C_CTRL2_READ_MODE		15
+#define RTL9300_I2C_CTRL2_DEV_ADDR		8
+#define RTL9300_I2C_CTRL2_DATA_WIDTH		4
+#define RTL9300_I2C_CTRL2_MADDR_WIDTH		2
+#define RTL9300_I2C_CTRL2_SCL_FREQ		0
+
+#define RTL9300_I2C_DATA_WORD0			0x08
+
+#define RTL9300_I2C_MST_GLB_CTRL		0x18
+
+#define RTL9310_I2C_MST_IF_CTRL			0x00
+
+#define RTL9310_I2C_MST_IF_SEL			0x04
+#define RTL9310_I2C_MST_IF_SEL_GPIO_SCL_SEL	12
+
+#define RTL9310_I2C_CTRL			0x08
+#define RTL9310_I2C_CTRL_SCL_FREQ		30
+#define RTL9310_I2C_CTRL_CHECK_ACK_DELAY	26
+#define RTL9310_I2C_CTRL_DRIVE_ACK_DELAY	22
+#define RTL9310_I2C_CTRL_SDA_OUT_SEL		18
+#define RTL9310_I2C_CTRL_DEV_ADDR		11
+#define RTL9310_I2C_CTRL_MADDR_WIDTH		9
+#define RTL9310_I2C_CTRL_DATA_WIDTH		5
+#define RTL9310_I2C_CTRL_READ_MODE		4
+#define RTL9310_I2C_CTRL_RWOP			2
+#define RTL9310_I2C_CTRL_I2C_FAIL		1
+#define RTL9310_I2C_CTRL_I2C_TRIG		0
+
+#define RTL9310_I2C_MEMADDR			0x0c
+
+#define RTL9310_I2C_DATA			0x10
+
+#define RTL9300_I2C_STD_FREQ		0
+#define RTL9300_I2C_FAST_FREQ		1
+
+struct rtl9300_i2c {
+	void __iomem *base;
+	u32 mst2_offset;
+	struct device *dev;
+	struct i2c_adapter adap;
+	u8 bus_freq;
+	u8 sda_num;			/* SDA channel number */
+	u8 scl_num;			/* SCL channel, mapping to master 1 or 2 */
+};
+
+#endif

target/linux/realtek/files-6.6/drivers/i2c/muxes/i2c-mux-rtl9300.c

@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C multiplexer for the 2 I2C Masters of the RTL9300
+ * with up to 8 channels each, but which are not entirely
+ * independent of each other
+ */
+#include <linux/i2c-mux.h>
+#include <linux/module.h>
+#include <linux/mux/consumer.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+#include "../busses/i2c-rtl9300.h"
+
+#define NUM_MASTERS		2
+#define NUM_BUSSES		8
+
+#define REG(mst, x)	(mux->base + x + (mst ? mux->i2c->mst2_offset : 0))
+#define REG_MASK(mst, clear, set, reg)	\
+			writel((readl(REG((mst),(reg))) & ~(clear)) | (set), REG((mst),(reg)))
+
+struct channel {
+	u8 sda_num;
+	u8 scl_num;
+};
+
+static struct channel channels[NUM_MASTERS * NUM_BUSSES];
+
+struct rtl9300_mux {
+	void __iomem *base;
+	struct device *dev;
+	struct i2c_adapter *parent;
+	struct rtl9300_i2c * i2c;
+};
+
+struct i2c_mux_data  {
+	int scl0_pin;
+	int scl1_pin;
+	int sda0_pin;
+	int sda_pins;
+	int (*i2c_mux_select)(struct i2c_mux_core *muxc, u32 chan);
+	int (*i2c_mux_deselect)(struct i2c_mux_core *muxc, u32 chan);
+	void (*sda_sel)(struct i2c_mux_core *muxc, int pin);
+};
+
+static int rtl9300_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct rtl9300_mux *mux = i2c_mux_priv(muxc);
+
+	/* Set SCL pin */
+	REG_MASK(channels[chan].scl_num, 0,
+		 BIT(RTL9300_I2C_CTRL1_GPIO8_SCL_SEL), RTL9300_I2C_CTRL1);
+
+	/* Set SDA pin */
+	REG_MASK(channels[chan].scl_num, 0x7 << RTL9300_I2C_CTRL1_SDA_OUT_SEL,
+		 channels[chan].sda_num << RTL9300_I2C_CTRL1_SDA_OUT_SEL, RTL9300_I2C_CTRL1);
+
+	mux->i2c->sda_num = channels[chan].sda_num;
+	mux->i2c->scl_num = channels[chan].scl_num;
+
+	return 0;
+}
+
+static int rtl9310_i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct rtl9300_mux *mux = i2c_mux_priv(muxc);
+
+	/* Set SCL pin */
+	REG_MASK(0, 0, BIT(RTL9310_I2C_MST_IF_SEL_GPIO_SCL_SEL + channels[chan].scl_num),
+		 RTL9310_I2C_MST_IF_SEL);
+
+	/* Set SDA pin */
+	REG_MASK(channels[chan].scl_num, 0xf << RTL9310_I2C_CTRL_SDA_OUT_SEL,
+		 channels[chan].sda_num << RTL9310_I2C_CTRL_SDA_OUT_SEL, RTL9310_I2C_CTRL);
+
+	mux->i2c->sda_num = channels[chan].sda_num;
+	mux->i2c->scl_num = channels[chan].scl_num;
+
+	return 0;
+}
+
+static int rtl9300_i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
+{
+	return 0;
+}
+
+static void rtl9300_sda_sel(struct i2c_mux_core *muxc, int pin)
+{
+	struct rtl9300_mux *mux = i2c_mux_priv(muxc);
+	u32 v;
+
+	/* Set SDA pin to I2C functionality */
+	v = readl(REG(0, RTL9300_I2C_MST_GLB_CTRL));
+	v |= BIT(pin);
+	writel(v, REG(0, RTL9300_I2C_MST_GLB_CTRL));
+}
+
+static void rtl9310_sda_sel(struct i2c_mux_core *muxc, int pin)
+{
+	struct rtl9300_mux *mux = i2c_mux_priv(muxc);
+	u32 v;
+
+	/* Set SDA pin to I2C functionality */
+	v = readl(REG(0, RTL9310_I2C_MST_IF_SEL));
+	v |= BIT(pin);
+	writel(v, REG(0, RTL9310_I2C_MST_IF_SEL));
+}
+
+static struct device_node *mux_parent_adapter(struct device *dev, struct rtl9300_mux *mux)
+{
+	struct device_node *node = dev->of_node;
+	struct device_node *parent_np;
+	struct i2c_adapter *parent;
+
+	parent_np = of_parse_phandle(node, "i2c-parent", 0);
+	if (!parent_np) {
+		dev_err(dev, "Cannot parse i2c-parent\n");
+		return ERR_PTR(-ENODEV);
+	}
+	parent = of_find_i2c_adapter_by_node(parent_np);
+	of_node_put(parent_np);
+	if (!parent)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	if (!(of_device_is_compatible(parent_np, "realtek,rtl9300-i2c") ||
+	    of_device_is_compatible(parent_np, "realtek,rtl9310-i2c"))){
+		dev_err(dev, "I2C parent not an RTL9300 I2C controller\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	mux->parent = parent;
+	mux->i2c = (struct rtl9300_i2c *)i2c_get_adapdata(parent);
+	mux->base = mux->i2c->base;
+
+	return parent_np;
+}
+
+struct i2c_mux_data rtl9300_i2c_mux_data = {
+	.scl0_pin = 8,
+	.scl1_pin = 17,
+	.sda0_pin = 9,
+	.sda_pins = 8,
+	.i2c_mux_select = rtl9300_i2c_mux_select,
+	.i2c_mux_deselect = rtl9300_i2c_mux_deselect,
+	.sda_sel = rtl9300_sda_sel,
+};
+
+struct i2c_mux_data rtl9310_i2c_mux_data = {
+	.scl0_pin = 13,
+	.scl1_pin = 14,
+	.sda0_pin = 0,
+	.sda_pins = 16,
+	.i2c_mux_select = rtl9310_i2c_mux_select,
+	.i2c_mux_deselect = rtl9300_i2c_mux_deselect,
+	.sda_sel = rtl9310_sda_sel,
+};
+
+static const struct of_device_id rtl9300_i2c_mux_of_match[] = {
+	{ .compatible = "realtek,i2c-mux-rtl9300", .data = (void *) &rtl9300_i2c_mux_data},
+	{ .compatible = "realtek,i2c-mux-rtl9310", .data = (void *) &rtl9310_i2c_mux_data},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, rtl9300_i2c_mux_of_match);
+
+static int rtl9300_i2c_mux_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct device_node *parent_np;
+	struct device_node *child;
+	struct i2c_mux_core *muxc;
+	struct rtl9300_mux *mux;
+	struct i2c_mux_data *mux_data;
+	int children;
+	int ret;
+
+	pr_info("%s probing I2C adapter\n", __func__);
+
+	if (!node) {
+		dev_err(dev, "No DT found\n");
+		return -EINVAL;
+	}
+
+	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return -ENOMEM;
+
+	mux->dev = dev;
+
+	mux_data = (struct i2c_mux_data *) device_get_match_data(dev);
+
+	parent_np = mux_parent_adapter(dev, mux);
+	if (IS_ERR(parent_np))
+		return dev_err_probe(dev, PTR_ERR(parent_np), "i2c-parent adapter not found\n");
+
+	pr_info("%s base memory %08x\n", __func__, (u32)mux->base);
+
+	children = of_get_child_count(node);
+
+	muxc = i2c_mux_alloc(mux->parent, dev, children, 0, 0,
+			     mux_data->i2c_mux_select, mux_data->i2c_mux_deselect);
+	if (!muxc) {
+		ret = -ENOMEM;
+		goto err_parent;
+	}
+	muxc->priv = mux;
+
+	platform_set_drvdata(pdev, muxc);
+
+	for_each_child_of_node(node, child) {
+		u32 chan;
+		u32 pin;
+
+		ret = of_property_read_u32(child, "reg", &chan);
+		if (ret < 0) {
+			dev_err(dev, "no reg property for node '%pOFn'\n",
+				child);
+			goto err_children;
+		}
+
+		if (chan >= NUM_MASTERS * NUM_BUSSES) {
+			dev_err(dev, "invalid reg %u\n", chan);
+			ret = -EINVAL;
+			goto err_children;
+		}
+
+		if (of_property_read_u32(child, "scl-pin", &pin)) {
+			dev_warn(dev, "SCL pin not found in DT, using default\n");
+			pin = mux_data->scl0_pin;
+		}
+		if (!(pin == mux_data->scl0_pin || pin == mux_data->scl1_pin)) {
+			dev_warn(dev, "SCL pin %d not supported\n", pin);
+			ret = -EINVAL;
+			goto err_children;
+		}
+		channels[chan].scl_num = pin == mux_data->scl0_pin ? 0 : 1;
+		pr_info("%s channel %d scl_num %d\n", __func__, chan, channels[chan].scl_num);
+
+		if (of_property_read_u32(child, "sda-pin", &pin)) {
+			dev_warn(dev, "SDA pin not found in DT, using default \n");
+			pin = mux_data->sda0_pin;
+		}
+		channels[chan].sda_num = pin - mux_data->sda0_pin;
+		if (channels[chan].sda_num < 0 || channels[chan].sda_num >= mux_data->sda_pins) {
+			dev_warn(dev, "SDA pin %d not supported\n", pin);
+			return -EINVAL;
+		}
+		pr_info("%s channel %d sda_num %d\n", __func__, chan, channels[chan].sda_num);
+
+		mux_data->sda_sel(muxc, channels[chan].sda_num);
+
+		ret = i2c_mux_add_adapter(muxc, 0, chan, 0);
+		if (ret)
+			goto err_children;
+	}
+
+	dev_info(dev, "%d-port mux on %s adapter\n", children, mux->parent->name);
+
+	return 0;
+
+err_children:
+	i2c_mux_del_adapters(muxc);
+err_parent:
+	i2c_put_adapter(mux->parent);
+
+	return ret;
+}
+
+static int rtl9300_i2c_mux_remove(struct platform_device *pdev)
+{
+	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
+
+	i2c_mux_del_adapters(muxc);
+	i2c_put_adapter(muxc->parent);
+
+	return 0;
+}
+
+static struct platform_driver i2c_mux_driver = {
+	.probe	= rtl9300_i2c_mux_probe,
+	.remove	= rtl9300_i2c_mux_remove,
+	.driver	= {
+		.name	= "i2c-mux-rtl9300",
+		.of_match_table = rtl9300_i2c_mux_of_match,
+	},
+};
+module_platform_driver(i2c_mux_driver);
+
+MODULE_DESCRIPTION("RTL9300 I2C multiplexer driver");
+MODULE_AUTHOR("Birger Koblitz");
+MODULE_LICENSE("GPL v2");