drivers/spi/spi-sc18is602.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * NXP SC18IS602/603 SPI driver
  *
  * Copyright (C) Guenter Roeck <linux@roeck-us.net>
  */

 #include <linux/kernel.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/spi/spi.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/pm_runtime.h>
 #include <linux/of_device.h>
 #include <linux/of.h>
 #include <linux/platform_data/sc18is602.h>
 #include <linux/gpio/consumer.h>

 enum chips { sc18is602, sc18is602b, sc18is603 };

 #define SC18IS602_BUFSIZ		200
 #define SC18IS602_CLOCK			7372000

 #define SC18IS602_MODE_CPHA		BIT(2)
 #define SC18IS602_MODE_CPOL		BIT(3)
 #define SC18IS602_MODE_LSB_FIRST	BIT(5)
 #define SC18IS602_MODE_CLOCK_DIV_4	0x0
 #define SC18IS602_MODE_CLOCK_DIV_16	0x1
 #define SC18IS602_MODE_CLOCK_DIV_64	0x2
 #define SC18IS602_MODE_CLOCK_DIV_128	0x3

 struct sc18is602 {
 	struct spi_master	*master;
 	struct device		*dev;
 	u8			ctrl;
 	u32			freq;
 	u32			speed;

 	/* I2C data */
 	struct i2c_client	*client;
 	enum chips		id;
 	u8			buffer[SC18IS602_BUFSIZ + 1];
 	int			tlen;	/* Data queued for tx in buffer */
 	int			rindex;	/* Receive data index in buffer */

 	struct gpio_desc	*reset;
 };

 static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
 {
 	int i, err;
 	int usecs = 1000000 * len / hw->speed + 1;
 	u8 dummy[1];

 	for (i = 0; i < 10; i++) {
 		err = i2c_master_recv(hw->client, dummy, 1);
 		if (err >= 0)
 			return 0;
 		usleep_range(usecs, usecs * 2);
 	}
 	return -ETIMEDOUT;
 }

 static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg,
 			  struct spi_transfer *t, bool do_transfer)
 {
 	unsigned int len = t->len;
 	int ret;

 	if (hw->tlen == 0) {
 		/* First byte (I2C command) is chip select */
 		hw->buffer[0] = 1 << msg->spi->chip_select;
 		hw->tlen = 1;
 		hw->rindex = 0;
 	}
 	/*
 	 * We can not immediately send data to the chip, since each I2C message
 	 * resembles a full SPI message (from CS active to CS inactive).
 	 * Enqueue messages up to the first read or until do_transfer is true.
 	 */
 	if (t->tx_buf) {
 		memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
 		hw->tlen += len;
 		if (t->rx_buf)
 			do_transfer = true;
 		else
 			hw->rindex = hw->tlen - 1;
 	} else if (t->rx_buf) {
 		/*
 		 * For receive-only transfers we still need to perform a dummy
 		 * write to receive data from the SPI chip.
 		 * Read data starts at the end of transmit data (minus 1 to
 		 * account for CS).
 		 */
 		hw->rindex = hw->tlen - 1;
 		memset(&hw->buffer[hw->tlen], 0, len);
 		hw->tlen += len;
 		do_transfer = true;
 	}

 	if (do_transfer && hw->tlen > 1) {
 		ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
 		if (ret < 0)
 			return ret;
 		ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
 		if (ret < 0)
 			return ret;
 		if (ret != hw->tlen)
 			return -EIO;

 		if (t->rx_buf) {
 			int rlen = hw->rindex + len;

 			ret = sc18is602_wait_ready(hw, hw->tlen);
 			if (ret < 0)
 				return ret;
 			ret = i2c_master_recv(hw->client, hw->buffer, rlen);
 			if (ret < 0)
 				return ret;
 			if (ret != rlen)
 				return -EIO;
 			memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
 		}
 		hw->tlen = 0;
 	}
 	return len;
 }

 static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
 {
 	u8 ctrl = 0;
 	int ret;

 	if (mode & SPI_CPHA)
 		ctrl |= SC18IS602_MODE_CPHA;
 	if (mode & SPI_CPOL)
 		ctrl |= SC18IS602_MODE_CPOL;
 	if (mode & SPI_LSB_FIRST)
 		ctrl |= SC18IS602_MODE_LSB_FIRST;

 	/* Find the closest clock speed */
 	if (hz >= hw->freq / 4) {
 		ctrl |= SC18IS602_MODE_CLOCK_DIV_4;
 		hw->speed = hw->freq / 4;
 	} else if (hz >= hw->freq / 16) {
 		ctrl |= SC18IS602_MODE_CLOCK_DIV_16;
 		hw->speed = hw->freq / 16;
 	} else if (hz >= hw->freq / 64) {
 		ctrl |= SC18IS602_MODE_CLOCK_DIV_64;
 		hw->speed = hw->freq / 64;
 	} else {
 		ctrl |= SC18IS602_MODE_CLOCK_DIV_128;
 		hw->speed = hw->freq / 128;
 	}

 	/*
 	 * Don't do anything if the control value did not change. The initial
 	 * value of 0xff for hw->ctrl ensures that the correct mode will be set
 	 * with the first call to this function.
 	 */
 	if (ctrl == hw->ctrl)
 		return 0;

 	ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
 	if (ret < 0)
 		return ret;

 	hw->ctrl = ctrl;

 	return 0;
 }

 static int sc18is602_check_transfer(struct spi_device *spi,
 				    struct spi_transfer *t, int tlen)
 {
 	if (t && t->len + tlen > SC18IS602_BUFSIZ)
 		return -EINVAL;

 	return 0;
 }

 static int sc18is602_transfer_one(struct spi_master *master,
 				  struct spi_message *m)
 {
 	struct sc18is602 *hw = spi_master_get_devdata(master);
 	struct spi_device *spi = m->spi;
 	struct spi_transfer *t;
 	int status = 0;

 	hw->tlen = 0;
 	list_for_each_entry(t, &m->transfers, transfer_list) {
 		bool do_transfer;

 		status = sc18is602_check_transfer(spi, t, hw->tlen);
 		if (status < 0)
 			break;

 		status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
 		if (status < 0)
 			break;

 		do_transfer = t->cs_change || list_is_last(&t->transfer_list,
 							   &m->transfers);

 		if (t->len) {
 			status = sc18is602_txrx(hw, m, t, do_transfer);
 			if (status < 0)
 				break;
 			m->actual_length += status;
 		}
 		status = 0;

 		spi_transfer_delay_exec(t);
 	}
 	m->status = status;
 	spi_finalize_current_message(master);

 	return status;
 }

 static int sc18is602_setup(struct spi_device *spi)
 {
 	struct sc18is602 *hw = spi_master_get_devdata(spi->master);

 	/* SC18IS602 does not support CS2 */
 	if (hw->id == sc18is602 && spi->chip_select == 2)
 		return -ENXIO;

 	return 0;
 }

 static int sc18is602_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct device_node *np = dev->of_node;
 	struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
 	struct sc18is602 *hw;
 	struct spi_master *master;
 	int error;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
 		return -EINVAL;

 	master = spi_alloc_master(dev, sizeof(struct sc18is602));
 	if (!master)
 		return -ENOMEM;

 	hw = spi_master_get_devdata(master);
 	i2c_set_clientdata(client, hw);

 	/* assert reset and then release */
 	hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(hw->reset))
 		return PTR_ERR(hw->reset);
 	gpiod_set_value_cansleep(hw->reset, 0);

 	hw->master = master;
 	hw->client = client;
 	hw->dev = dev;
 	hw->ctrl = 0xff;

 	if (client->dev.of_node)
 		hw->id = (enum chips)of_device_get_match_data(&client->dev);
 	else
 		hw->id = id->driver_data;

 	switch (hw->id) {
 	case sc18is602:
 	case sc18is602b:
 		master->num_chipselect = 4;
 		hw->freq = SC18IS602_CLOCK;
 		break;
 	case sc18is603:
 		master->num_chipselect = 2;
 		if (pdata) {
 			hw->freq = pdata->clock_frequency;
 		} else {
 			const __be32 *val;
 			int len;

 			val = of_get_property(np, "clock-frequency", &len);
 			if (val && len >= sizeof(__be32))
 				hw->freq = be32_to_cpup(val);
 		}
 		if (!hw->freq)
 			hw->freq = SC18IS602_CLOCK;
 		break;
 	}
 	master->bus_num = np ? -1 : client->adapter->nr;
 	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
 	master->setup = sc18is602_setup;
 	master->transfer_one_message = sc18is602_transfer_one;
 	master->dev.of_node = np;
 	master->min_speed_hz = hw->freq / 128;
 	master->max_speed_hz = hw->freq / 4;

 	error = devm_spi_register_master(dev, master);
 	if (error)
 		goto error_reg;

 	return 0;

 error_reg:
 	spi_master_put(master);
 	return error;
 }

 static const struct i2c_device_id sc18is602_id[] = {
 	{ "sc18is602", sc18is602 },
 	{ "sc18is602b", sc18is602b },
 	{ "sc18is603", sc18is603 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, sc18is602_id);

 static const struct of_device_id sc18is602_of_match[] = {
 	{
 		.compatible = "nxp,sc18is602",
 		.data = (void *)sc18is602
 	},
 	{
 		.compatible = "nxp,sc18is602b",
 		.data = (void *)sc18is602b
 	},
 	{
 		.compatible = "nxp,sc18is603",
 		.data = (void *)sc18is603
 	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, sc18is602_of_match);

 static struct i2c_driver sc18is602_driver = {
 	.driver = {
 		.name = "sc18is602",
 		.of_match_table = of_match_ptr(sc18is602_of_match),
 	},
 	.probe = sc18is602_probe,
 	.id_table = sc18is602_id,
 };

 module_i2c_driver(sc18is602_driver);

 MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
 MODULE_AUTHOR("Guenter Roeck");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* NXP SC18IS602/603 SPI driver
	*
	* Copyright (C) Guenter Roeck <linux@roeck-us.net>
	*/

	#include <linux/kernel.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/spi/spi.h>
	#include <linux/i2c.h>
	#include <linux/delay.h>
	#include <linux/pm_runtime.h>
	#include <linux/of_device.h>
	#include <linux/of.h>
	#include <linux/platform_data/sc18is602.h>
	#include <linux/gpio/consumer.h>

	enum chips { sc18is602, sc18is602b, sc18is603 };

	#define SC18IS602_BUFSIZ 200
	#define SC18IS602_CLOCK 7372000

	#define SC18IS602_MODE_CPHA BIT(2)
	#define SC18IS602_MODE_CPOL BIT(3)
	#define SC18IS602_MODE_LSB_FIRST BIT(5)
	#define SC18IS602_MODE_CLOCK_DIV_4 0x0
	#define SC18IS602_MODE_CLOCK_DIV_16 0x1
	#define SC18IS602_MODE_CLOCK_DIV_64 0x2
	#define SC18IS602_MODE_CLOCK_DIV_128 0x3

	struct sc18is602 {
	struct spi_master *master;
	struct device *dev;
	u8 ctrl;
	u32 freq;
	u32 speed;

	/* I2C data */
	struct i2c_client *client;
	enum chips id;
	u8 buffer[SC18IS602_BUFSIZ + 1];
	int tlen; /* Data queued for tx in buffer */
	int rindex; /* Receive data index in buffer */

	struct gpio_desc *reset;
	};

	static int sc18is602_wait_ready(struct sc18is602 *hw, int len)
	{
	int i, err;
	int usecs = 1000000 * len / hw->speed + 1;
	u8 dummy[1];

	for (i = 0; i < 10; i++) {
	err = i2c_master_recv(hw->client, dummy, 1);
	if (err >= 0)
	return 0;
	usleep_range(usecs, usecs * 2);
	}
	return -ETIMEDOUT;
	}

	static int sc18is602_txrx(struct sc18is602 hw, struct spi_message msg,
	struct spi_transfer *t, bool do_transfer)
	{
	unsigned int len = t->len;
	int ret;

	if (hw->tlen == 0) {
	/* First byte (I2C command) is chip select */
	hw->buffer[0] = 1 << msg->spi->chip_select;
	hw->tlen = 1;
	hw->rindex = 0;
	}
	/*
	* We can not immediately send data to the chip, since each I2C message
	* resembles a full SPI message (from CS active to CS inactive).
	* Enqueue messages up to the first read or until do_transfer is true.
	*/
	if (t->tx_buf) {
	memcpy(&hw->buffer[hw->tlen], t->tx_buf, len);
	hw->tlen += len;
	if (t->rx_buf)
	do_transfer = true;
	else
	hw->rindex = hw->tlen - 1;
	} else if (t->rx_buf) {
	/*
	* For receive-only transfers we still need to perform a dummy
	* write to receive data from the SPI chip.
	* Read data starts at the end of transmit data (minus 1 to
	* account for CS).
	*/
	hw->rindex = hw->tlen - 1;
	memset(&hw->buffer[hw->tlen], 0, len);
	hw->tlen += len;
	do_transfer = true;
	}

	if (do_transfer && hw->tlen > 1) {
	ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ);
	if (ret < 0)
	return ret;
	ret = i2c_master_send(hw->client, hw->buffer, hw->tlen);
	if (ret < 0)
	return ret;
	if (ret != hw->tlen)
	return -EIO;

	if (t->rx_buf) {
	int rlen = hw->rindex + len;

	ret = sc18is602_wait_ready(hw, hw->tlen);
	if (ret < 0)
	return ret;
	ret = i2c_master_recv(hw->client, hw->buffer, rlen);
	if (ret < 0)
	return ret;
	if (ret != rlen)
	return -EIO;
	memcpy(t->rx_buf, &hw->buffer[hw->rindex], len);
	}
	hw->tlen = 0;
	}
	return len;
	}

	static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode)
	{
	u8 ctrl = 0;
	int ret;

	if (mode & SPI_CPHA)
	ctrl \|= SC18IS602_MODE_CPHA;
	if (mode & SPI_CPOL)
	ctrl \|= SC18IS602_MODE_CPOL;
	if (mode & SPI_LSB_FIRST)
	ctrl \|= SC18IS602_MODE_LSB_FIRST;

	/* Find the closest clock speed */
	if (hz >= hw->freq / 4) {
	ctrl \|= SC18IS602_MODE_CLOCK_DIV_4;
	hw->speed = hw->freq / 4;
	} else if (hz >= hw->freq / 16) {
	ctrl \|= SC18IS602_MODE_CLOCK_DIV_16;
	hw->speed = hw->freq / 16;
	} else if (hz >= hw->freq / 64) {
	ctrl \|= SC18IS602_MODE_CLOCK_DIV_64;
	hw->speed = hw->freq / 64;
	} else {
	ctrl \|= SC18IS602_MODE_CLOCK_DIV_128;
	hw->speed = hw->freq / 128;
	}

	/*
	* Don't do anything if the control value did not change. The initial
	* value of 0xff for hw->ctrl ensures that the correct mode will be set
	* with the first call to this function.
	*/
	if (ctrl == hw->ctrl)
	return 0;

	ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl);
	if (ret < 0)
	return ret;

	hw->ctrl = ctrl;

	return 0;
	}

	static int sc18is602_check_transfer(struct spi_device *spi,
	struct spi_transfer *t, int tlen)
	{
	if (t && t->len + tlen > SC18IS602_BUFSIZ)
	return -EINVAL;

	return 0;
	}

	static int sc18is602_transfer_one(struct spi_master *master,
	struct spi_message *m)
	{
	struct sc18is602 *hw = spi_master_get_devdata(master);
	struct spi_device *spi = m->spi;
	struct spi_transfer *t;
	int status = 0;

	hw->tlen = 0;
	list_for_each_entry(t, &m->transfers, transfer_list) {
	bool do_transfer;

	status = sc18is602_check_transfer(spi, t, hw->tlen);
	if (status < 0)
	break;

	status = sc18is602_setup_transfer(hw, t->speed_hz, spi->mode);
	if (status < 0)
	break;

	do_transfer = t->cs_change \|\| list_is_last(&t->transfer_list,
	&m->transfers);

	if (t->len) {
	status = sc18is602_txrx(hw, m, t, do_transfer);
	if (status < 0)
	break;
	m->actual_length += status;
	}
	status = 0;

	spi_transfer_delay_exec(t);
	}
	m->status = status;
	spi_finalize_current_message(master);

	return status;
	}

	static int sc18is602_setup(struct spi_device *spi)
	{
	struct sc18is602 *hw = spi_master_get_devdata(spi->master);

	/* SC18IS602 does not support CS2 */
	if (hw->id == sc18is602 && spi->chip_select == 2)
	return -ENXIO;

	return 0;
	}

	static int sc18is602_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	struct device_node *np = dev->of_node;
	struct sc18is602_platform_data *pdata = dev_get_platdata(dev);
	struct sc18is602 *hw;
	struct spi_master *master;
	int error;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C \|
	I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
	return -EINVAL;

	master = spi_alloc_master(dev, sizeof(struct sc18is602));
	if (!master)
	return -ENOMEM;

	hw = spi_master_get_devdata(master);
	i2c_set_clientdata(client, hw);

	/* assert reset and then release */
	hw->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(hw->reset))
	return PTR_ERR(hw->reset);
	gpiod_set_value_cansleep(hw->reset, 0);

	hw->master = master;
	hw->client = client;
	hw->dev = dev;
	hw->ctrl = 0xff;

	if (client->dev.of_node)
	hw->id = (enum chips)of_device_get_match_data(&client->dev);
	else
	hw->id = id->driver_data;

	switch (hw->id) {
	case sc18is602:
	case sc18is602b:
	master->num_chipselect = 4;
	hw->freq = SC18IS602_CLOCK;
	break;
	case sc18is603:
	master->num_chipselect = 2;
	if (pdata) {
	hw->freq = pdata->clock_frequency;
	} else {
	const __be32 *val;
	int len;

	val = of_get_property(np, "clock-frequency", &len);
	if (val && len >= sizeof(__be32))
	hw->freq = be32_to_cpup(val);
	}
	if (!hw->freq)
	hw->freq = SC18IS602_CLOCK;
	break;
	}
	master->bus_num = np ? -1 : client->adapter->nr;
	master->mode_bits = SPI_CPHA \| SPI_CPOL \| SPI_LSB_FIRST;
	master->bits_per_word_mask = SPI_BPW_MASK(8);
	master->setup = sc18is602_setup;
	master->transfer_one_message = sc18is602_transfer_one;
	master->dev.of_node = np;
	master->min_speed_hz = hw->freq / 128;
	master->max_speed_hz = hw->freq / 4;

	error = devm_spi_register_master(dev, master);
	if (error)
	goto error_reg;

	return 0;

	error_reg:
	spi_master_put(master);
	return error;
	}

	static const struct i2c_device_id sc18is602_id[] = {
	{ "sc18is602", sc18is602 },
	{ "sc18is602b", sc18is602b },
	{ "sc18is603", sc18is603 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, sc18is602_id);

	static const struct of_device_id sc18is602_of_match[] = {
	{
	.compatible = "nxp,sc18is602",
	.data = (void *)sc18is602
	},
	{
	.compatible = "nxp,sc18is602b",
	.data = (void *)sc18is602b
	},
	{
	.compatible = "nxp,sc18is603",
	.data = (void *)sc18is603
	},
	{ },
	};
	MODULE_DEVICE_TABLE(of, sc18is602_of_match);

	static struct i2c_driver sc18is602_driver = {
	.driver = {
	.name = "sc18is602",
	.of_match_table = of_match_ptr(sc18is602_of_match),
	},
	.probe = sc18is602_probe,
	.id_table = sc18is602_id,
	};

	module_i2c_driver(sc18is602_driver);

	MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver");
	MODULE_AUTHOR("Guenter Roeck");
	MODULE_LICENSE("GPL");