drivers/i2c/ast_i2c.c - u-boot-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2012-2020  ASPEED Technology Inc.
  * Copyright 2016 IBM Corporation
  * Copyright 2017 Google, Inc.
  */

 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <fdtdec.h>
 #include <i2c.h>
 #include <asm/io.h>
 #include <asm/arch/scu_ast2500.h>

 #include "ast_i2c.h"

 #define I2C_TIMEOUT_US 100000
 #define I2C_SLEEP_STEP_US 20

 #define HIGHSPEED_TTIMEOUT		3

 /*
  * Device private data
  */
 struct ast_i2c_priv {
 	/* This device's clock */
 	struct clk clk;
 	/* Device registers */
 	struct ast_i2c_regs *regs;
 	/* I2C speed in Hz */
 	int speed;
 };

 /*
  * Given desired divider ratio, return the value that needs to be set
  * in Clock and AC Timing Control register
  */
 static u32 get_clk_reg_val(ulong divider_ratio)
 {
 	ulong inc = 0, div;
 	ulong scl_low, scl_high, data;

 	for (div = 0; divider_ratio >= 16; div++) {
 		inc |= (divider_ratio & 1);
 		divider_ratio >>= 1;
 	}
 	divider_ratio += inc;
 	scl_low = (divider_ratio >> 1) - 1;
 	scl_high = divider_ratio - scl_low - 2;
 	data = I2CD_CACTC_BASE
 			| (scl_high << I2CD_TCKHIGH_SHIFT)
 			| (scl_low << I2CD_TCKLOW_SHIFT)
 			| (div << I2CD_BASE_DIV_SHIFT);

 	return data;
 }

 static void ast_i2c_clear_interrupts(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);

 	writel(~0, &priv->regs->isr);
 }

 static void ast_i2c_init_bus(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);

 	/* Reset device */
 	writel(0, &priv->regs->fcr);
 	/* Enable Master Mode. Assuming single-master */
 	writel(I2CD_MASTER_EN
 	       | I2CD_M_SDA_LOCK_EN
 	       | I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN,
 	       &priv->regs->fcr);
 	/* Enable Interrupts */
 	writel(I2CD_INTR_TX_ACK
 	       | I2CD_INTR_TX_NAK
 	       | I2CD_INTR_RX_DONE
 	       | I2CD_INTR_BUS_RECOVER_DONE
 	       | I2CD_INTR_NORMAL_STOP
 	       | I2CD_INTR_ABNORMAL, &priv->regs->icr);
 }

 static int ast_i2c_ofdata_to_platdata(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	int ret;

 	priv->regs = devfdt_get_addr_ptr(dev);
 	if (IS_ERR(priv->regs))
 		return PTR_ERR(priv->regs);

 	ret = clk_get_by_index(dev, 0, &priv->clk);
 	if (ret < 0) {
 		debug("%s: Can't get clock for %s: %d\n", __func__, dev->name,
 		      ret);
 		return ret;
 	}

 	return 0;
 }

 static int ast_i2c_probe(struct udevice *dev)
 {
 	struct ast2500_scu *scu;

 	debug("Enabling I2C%u\n", dev->seq);

 	/*
 	 * Get all I2C devices out of Reset.
 	 * Only needs to be done once, but doing it for every
 	 * device does not hurt.
 	 */
 	scu = ast_get_scu();
 	ast_scu_unlock(scu);
 	clrbits_le32(&scu->sysreset_ctrl1, SCU_SYSRESET_I2C);
 	ast_scu_lock(scu);

 	ast_i2c_init_bus(dev);

 	return 0;
 }

 static int ast_i2c_wait_isr(struct udevice *dev, u32 flag)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	int timeout = I2C_TIMEOUT_US;

 	while (!(readl(&priv->regs->isr) & flag) && timeout > 0) {
 		udelay(I2C_SLEEP_STEP_US);
 		timeout -= I2C_SLEEP_STEP_US;
 	}

 	ast_i2c_clear_interrupts(dev);
 	if (timeout <= 0)
 		return -ETIMEDOUT;

 	return 0;
 }

 static int ast_i2c_send_stop(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);

 	writel(I2CD_M_STOP_CMD, &priv->regs->csr);

 	return ast_i2c_wait_isr(dev, I2CD_INTR_NORMAL_STOP);
 }

 static int ast_i2c_wait_tx(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	int timeout = I2C_TIMEOUT_US;
 	u32 flag = I2CD_INTR_TX_ACK | I2CD_INTR_TX_NAK;
 	u32 status = readl(&priv->regs->isr) & flag;
 	int ret = 0;

 	while (!status && timeout > 0) {
 		status = readl(&priv->regs->isr) & flag;
 		udelay(I2C_SLEEP_STEP_US);
 		timeout -= I2C_SLEEP_STEP_US;
 	}

 	if (status == I2CD_INTR_TX_NAK)
 		ret = -EREMOTEIO;

 	if (timeout <= 0)
 		ret = -ETIMEDOUT;

 	ast_i2c_clear_interrupts(dev);

 	return ret;
 }

 static int ast_i2c_start_txn(struct udevice *dev, uint devaddr)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);

 	/* Start and Send Device Address */
 	writel(devaddr, &priv->regs->trbbr);
 	writel(I2CD_M_START_CMD | I2CD_M_TX_CMD, &priv->regs->csr);

 	return ast_i2c_wait_tx(dev);
 }

 static int ast_i2c_read_data(struct udevice *dev, u8 chip_addr, u8 *buffer,
 			     size_t len, bool send_stop)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	u32 i2c_cmd = I2CD_M_RX_CMD;
 	int ret;

 	ret = ast_i2c_start_txn(dev, (chip_addr << 1) | I2C_M_RD);
 	if (ret < 0)
 		return ret;

 	for (; len > 0; len--, buffer++) {
 		if (len == 1)
 			i2c_cmd |= I2CD_M_S_RX_CMD_LAST;
 		writel(i2c_cmd, &priv->regs->csr);
 		ret = ast_i2c_wait_isr(dev, I2CD_INTR_RX_DONE);
 		if (ret < 0)
 			return ret;
 		*buffer = (readl(&priv->regs->trbbr) & I2CD_RX_DATA_MASK)
 				>> I2CD_RX_DATA_SHIFT;
 	}
 	ast_i2c_clear_interrupts(dev);

 	if (send_stop)
 		return ast_i2c_send_stop(dev);

 	return 0;
 }

 static int ast_i2c_write_data(struct udevice *dev, u8 chip_addr, u8
 			      *buffer, size_t len, bool send_stop)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	int ret;

 	ret = ast_i2c_start_txn(dev, (chip_addr << 1));
 	if (ret < 0)
 		return ret;

 	for (; len > 0; len--, buffer++) {
 		writel(*buffer, &priv->regs->trbbr);
 		writel(I2CD_M_TX_CMD, &priv->regs->csr);
 		ret = ast_i2c_wait_tx(dev);
 		if (ret < 0)
 			return ret;
 	}

 	if (send_stop)
 		return ast_i2c_send_stop(dev);

 	return 0;
 }

 static int ast_i2c_deblock(struct udevice *dev)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	struct ast_i2c_regs *regs = priv->regs;
 	u32 csr = readl(&regs->csr);
 	bool sda_high = csr & I2CD_SDA_LINE_STS;
 	bool scl_high = csr & I2CD_SCL_LINE_STS;
 	int ret = 0;

 	if (sda_high && scl_high) {
 		/* Bus is idle, no deblocking needed. */
 		return 0;
 	} else if (sda_high) {
 		/* Send stop command */
 		debug("Unterminated TXN in (%x), sending stop\n", csr);
 		ret = ast_i2c_send_stop(dev);
 	} else if (scl_high) {
 		/* Possibly stuck slave */
 		debug("Bus stuck (%x), attempting recovery\n", csr);
 		writel(I2CD_BUS_RECOVER_CMD, &regs->csr);
 		ret = ast_i2c_wait_isr(dev, I2CD_INTR_BUS_RECOVER_DONE);
 	} else {
 		/* Just try to reinit the device. */
 		ast_i2c_init_bus(dev);
 	}

 	return ret;
 }

 static int ast_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
 {
 	int ret;

 	ret = ast_i2c_deblock(dev);
 	if (ret < 0)
 		return ret;

 	debug("i2c_xfer: %d messages\n", nmsgs);
 	for (; nmsgs > 0; nmsgs--, msg++) {
 		if (msg->flags & I2C_M_RD) {
 			debug("i2c_read: chip=0x%x, len=0x%x, flags=0x%x\n",
 			      msg->addr, msg->len, msg->flags);
 			ret = ast_i2c_read_data(dev, msg->addr, msg->buf,
 						msg->len, (nmsgs == 1));
 		} else {
 			debug("i2c_write: chip=0x%x, len=0x%x, flags=0x%x\n",
 			      msg->addr, msg->len, msg->flags);
 			ret = ast_i2c_write_data(dev, msg->addr, msg->buf,
 						 msg->len, (nmsgs == 1));
 		}
 		if (ret) {
 			debug("%s: error (%d)\n", __func__, ret);
 			return -EREMOTEIO;
 		}
 	}

 	return 0;
 }

 static int ast_i2c_set_speed(struct udevice *dev, unsigned int speed)
 {
 	struct ast_i2c_priv *priv = dev_get_priv(dev);
 	struct ast_i2c_regs *regs = priv->regs;
 	ulong i2c_rate, divider;

 	debug("Setting speed for I2C%d to <%u>\n", dev->seq, speed);
 	if (!speed) {
 		debug("No valid speed specified\n");
 		return -EINVAL;
 	}

 	i2c_rate = clk_get_rate(&priv->clk);
 	divider = i2c_rate / speed;

 	priv->speed = speed;
 	if (speed > I2C_HIGHSPEED_RATE) {
 		debug("Enable High Speed\n");
 		setbits_le32(&regs->fcr, I2CD_M_HIGH_SPEED_EN
 			     | I2CD_M_SDA_DRIVE_1T_EN
 			     | I2CD_SDA_DRIVE_1T_EN);
 		writel(HIGHSPEED_TTIMEOUT, &regs->cactcr2);
 	} else {
 		debug("Enabling Normal Speed\n");
 		writel(I2CD_NO_TIMEOUT_CTRL, &regs->cactcr2);
 	}

 	writel(get_clk_reg_val(divider), &regs->cactcr1);
 	ast_i2c_clear_interrupts(dev);

 	return 0;
 }

 static const struct dm_i2c_ops ast_i2c_ops = {
 	.xfer = ast_i2c_xfer,
 	.set_bus_speed = ast_i2c_set_speed,
 	.deblock = ast_i2c_deblock,
 };

 static const struct udevice_id ast_i2c_ids[] = {
 	{ .compatible = "aspeed,ast2400-i2c-bus" },
 	{ .compatible = "aspeed,ast2500-i2c-bus" },
 	{ },
 };

 U_BOOT_DRIVER(ast_i2c) = {
 	.name = "ast_i2c",
 	.id = UCLASS_I2C,
 	.of_match = ast_i2c_ids,
 	.probe = ast_i2c_probe,
 	.ofdata_to_platdata = ast_i2c_ofdata_to_platdata,
 	.priv_auto_alloc_size = sizeof(struct ast_i2c_priv),
 	.ops = &ast_i2c_ops,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2012-2020 ASPEED Technology Inc.
	* Copyright 2016 IBM Corporation
	* Copyright 2017 Google, Inc.
	*/

	#include <common.h>
	#include <clk.h>
	#include <dm.h>
	#include <errno.h>
	#include <fdtdec.h>
	#include <i2c.h>
	#include <asm/io.h>
	#include <asm/arch/scu_ast2500.h>

	#include "ast_i2c.h"

	#define I2C_TIMEOUT_US 100000
	#define I2C_SLEEP_STEP_US 20

	#define HIGHSPEED_TTIMEOUT 3

	/*
	* Device private data
	*/
	struct ast_i2c_priv {
	/* This device's clock */
	struct clk clk;
	/* Device registers */
	struct ast_i2c_regs *regs;
	/* I2C speed in Hz */
	int speed;
	};

	/*
	* Given desired divider ratio, return the value that needs to be set
	* in Clock and AC Timing Control register
	*/
	static u32 get_clk_reg_val(ulong divider_ratio)
	{
	ulong inc = 0, div;
	ulong scl_low, scl_high, data;

	for (div = 0; divider_ratio >= 16; div++) {
	inc \|= (divider_ratio & 1);
	divider_ratio >>= 1;
	}
	divider_ratio += inc;
	scl_low = (divider_ratio >> 1) - 1;
	scl_high = divider_ratio - scl_low - 2;
	data = I2CD_CACTC_BASE
	\| (scl_high << I2CD_TCKHIGH_SHIFT)
	\| (scl_low << I2CD_TCKLOW_SHIFT)
	\| (div << I2CD_BASE_DIV_SHIFT);

	return data;
	}

	static void ast_i2c_clear_interrupts(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);

	writel(~0, &priv->regs->isr);
	}

	static void ast_i2c_init_bus(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);

	/* Reset device */
	writel(0, &priv->regs->fcr);
	/* Enable Master Mode. Assuming single-master */
	writel(I2CD_MASTER_EN
	\| I2CD_M_SDA_LOCK_EN
	\| I2CD_MULTI_MASTER_DIS \| I2CD_M_SCL_DRIVE_EN,
	&priv->regs->fcr);
	/* Enable Interrupts */
	writel(I2CD_INTR_TX_ACK
	\| I2CD_INTR_TX_NAK
	\| I2CD_INTR_RX_DONE
	\| I2CD_INTR_BUS_RECOVER_DONE
	\| I2CD_INTR_NORMAL_STOP
	\| I2CD_INTR_ABNORMAL, &priv->regs->icr);
	}

	static int ast_i2c_ofdata_to_platdata(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	int ret;

	priv->regs = devfdt_get_addr_ptr(dev);
	if (IS_ERR(priv->regs))
	return PTR_ERR(priv->regs);

	ret = clk_get_by_index(dev, 0, &priv->clk);
	if (ret < 0) {
	debug("%s: Can't get clock for %s: %d\n", __func__, dev->name,
	ret);
	return ret;
	}

	return 0;
	}

	static int ast_i2c_probe(struct udevice *dev)
	{
	struct ast2500_scu *scu;

	debug("Enabling I2C%u\n", dev->seq);

	/*
	* Get all I2C devices out of Reset.
	* Only needs to be done once, but doing it for every
	* device does not hurt.
	*/
	scu = ast_get_scu();
	ast_scu_unlock(scu);
	clrbits_le32(&scu->sysreset_ctrl1, SCU_SYSRESET_I2C);
	ast_scu_lock(scu);

	ast_i2c_init_bus(dev);

	return 0;
	}

	static int ast_i2c_wait_isr(struct udevice *dev, u32 flag)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	int timeout = I2C_TIMEOUT_US;

	while (!(readl(&priv->regs->isr) & flag) && timeout > 0) {
	udelay(I2C_SLEEP_STEP_US);
	timeout -= I2C_SLEEP_STEP_US;
	}

	ast_i2c_clear_interrupts(dev);
	if (timeout <= 0)
	return -ETIMEDOUT;

	return 0;
	}

	static int ast_i2c_send_stop(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);

	writel(I2CD_M_STOP_CMD, &priv->regs->csr);

	return ast_i2c_wait_isr(dev, I2CD_INTR_NORMAL_STOP);
	}

	static int ast_i2c_wait_tx(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	int timeout = I2C_TIMEOUT_US;
	u32 flag = I2CD_INTR_TX_ACK \| I2CD_INTR_TX_NAK;
	u32 status = readl(&priv->regs->isr) & flag;
	int ret = 0;

	while (!status && timeout > 0) {
	status = readl(&priv->regs->isr) & flag;
	udelay(I2C_SLEEP_STEP_US);
	timeout -= I2C_SLEEP_STEP_US;
	}

	if (status == I2CD_INTR_TX_NAK)
	ret = -EREMOTEIO;

	if (timeout <= 0)
	ret = -ETIMEDOUT;

	ast_i2c_clear_interrupts(dev);

	return ret;
	}

	static int ast_i2c_start_txn(struct udevice *dev, uint devaddr)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);

	/* Start and Send Device Address */
	writel(devaddr, &priv->regs->trbbr);
	writel(I2CD_M_START_CMD \| I2CD_M_TX_CMD, &priv->regs->csr);

	return ast_i2c_wait_tx(dev);
	}

	static int ast_i2c_read_data(struct udevice dev, u8 chip_addr, u8 buffer,
	size_t len, bool send_stop)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	u32 i2c_cmd = I2CD_M_RX_CMD;
	int ret;

	ret = ast_i2c_start_txn(dev, (chip_addr << 1) \| I2C_M_RD);
	if (ret < 0)
	return ret;

	for (; len > 0; len--, buffer++) {
	if (len == 1)
	i2c_cmd \|= I2CD_M_S_RX_CMD_LAST;
	writel(i2c_cmd, &priv->regs->csr);
	ret = ast_i2c_wait_isr(dev, I2CD_INTR_RX_DONE);
	if (ret < 0)
	return ret;
	*buffer = (readl(&priv->regs->trbbr) & I2CD_RX_DATA_MASK)
	>> I2CD_RX_DATA_SHIFT;
	}
	ast_i2c_clear_interrupts(dev);

	if (send_stop)
	return ast_i2c_send_stop(dev);

	return 0;
	}

	static int ast_i2c_write_data(struct udevice *dev, u8 chip_addr, u8
	*buffer, size_t len, bool send_stop)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	int ret;

	ret = ast_i2c_start_txn(dev, (chip_addr << 1));
	if (ret < 0)
	return ret;

	for (; len > 0; len--, buffer++) {
	writel(*buffer, &priv->regs->trbbr);
	writel(I2CD_M_TX_CMD, &priv->regs->csr);
	ret = ast_i2c_wait_tx(dev);
	if (ret < 0)
	return ret;
	}

	if (send_stop)
	return ast_i2c_send_stop(dev);

	return 0;
	}

	static int ast_i2c_deblock(struct udevice *dev)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	struct ast_i2c_regs *regs = priv->regs;
	u32 csr = readl(&regs->csr);
	bool sda_high = csr & I2CD_SDA_LINE_STS;
	bool scl_high = csr & I2CD_SCL_LINE_STS;
	int ret = 0;

	if (sda_high && scl_high) {
	/* Bus is idle, no deblocking needed. */
	return 0;
	} else if (sda_high) {
	/* Send stop command */
	debug("Unterminated TXN in (%x), sending stop\n", csr);
	ret = ast_i2c_send_stop(dev);
	} else if (scl_high) {
	/* Possibly stuck slave */
	debug("Bus stuck (%x), attempting recovery\n", csr);
	writel(I2CD_BUS_RECOVER_CMD, &regs->csr);
	ret = ast_i2c_wait_isr(dev, I2CD_INTR_BUS_RECOVER_DONE);
	} else {
	/* Just try to reinit the device. */
	ast_i2c_init_bus(dev);
	}

	return ret;
	}

	static int ast_i2c_xfer(struct udevice dev, struct i2c_msg msg, int nmsgs)
	{
	int ret;

	ret = ast_i2c_deblock(dev);
	if (ret < 0)
	return ret;

	debug("i2c_xfer: %d messages\n", nmsgs);
	for (; nmsgs > 0; nmsgs--, msg++) {
	if (msg->flags & I2C_M_RD) {
	debug("i2c_read: chip=0x%x, len=0x%x, flags=0x%x\n",
	msg->addr, msg->len, msg->flags);
	ret = ast_i2c_read_data(dev, msg->addr, msg->buf,
	msg->len, (nmsgs == 1));
	} else {
	debug("i2c_write: chip=0x%x, len=0x%x, flags=0x%x\n",
	msg->addr, msg->len, msg->flags);
	ret = ast_i2c_write_data(dev, msg->addr, msg->buf,
	msg->len, (nmsgs == 1));
	}
	if (ret) {
	debug("%s: error (%d)\n", __func__, ret);
	return -EREMOTEIO;
	}
	}

	return 0;
	}

	static int ast_i2c_set_speed(struct udevice *dev, unsigned int speed)
	{
	struct ast_i2c_priv *priv = dev_get_priv(dev);
	struct ast_i2c_regs *regs = priv->regs;
	ulong i2c_rate, divider;

	debug("Setting speed for I2C%d to <%u>\n", dev->seq, speed);
	if (!speed) {
	debug("No valid speed specified\n");
	return -EINVAL;
	}

	i2c_rate = clk_get_rate(&priv->clk);
	divider = i2c_rate / speed;

	priv->speed = speed;
	if (speed > I2C_HIGHSPEED_RATE) {
	debug("Enable High Speed\n");
	setbits_le32(&regs->fcr, I2CD_M_HIGH_SPEED_EN
	\| I2CD_M_SDA_DRIVE_1T_EN
	\| I2CD_SDA_DRIVE_1T_EN);
	writel(HIGHSPEED_TTIMEOUT, &regs->cactcr2);
	} else {
	debug("Enabling Normal Speed\n");
	writel(I2CD_NO_TIMEOUT_CTRL, &regs->cactcr2);
	}

	writel(get_clk_reg_val(divider), &regs->cactcr1);
	ast_i2c_clear_interrupts(dev);

	return 0;
	}

	static const struct dm_i2c_ops ast_i2c_ops = {
	.xfer = ast_i2c_xfer,
	.set_bus_speed = ast_i2c_set_speed,
	.deblock = ast_i2c_deblock,
	};

	static const struct udevice_id ast_i2c_ids[] = {
	{ .compatible = "aspeed,ast2400-i2c-bus" },
	{ .compatible = "aspeed,ast2500-i2c-bus" },
	{ },
	};

	U_BOOT_DRIVER(ast_i2c) = {
	.name = "ast_i2c",
	.id = UCLASS_I2C,
	.of_match = ast_i2c_ids,
	.probe = ast_i2c_probe,
	.ofdata_to_platdata = ast_i2c_ofdata_to_platdata,
	.priv_auto_alloc_size = sizeof(struct ast_i2c_priv),
	.ops = &ast_i2c_ops,
	};