drivers/mfd/gateworks-gsc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * The Gateworks System Controller (GSC) is a multi-function
  * device designed for use in Gateworks Single Board Computers.
  * The control interface is I2C, with an interrupt. The device supports
  * system functions such as push-button monitoring, multiple ADC's for
  * voltage and temperature monitoring, fan controller and watchdog monitor.
  *
  * Copyright (C) 2020 Gateworks Corporation
  */

 #include <linux/device.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/gsc.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>

 #include <asm/unaligned.h>

 /*
  * The GSC suffers from an errata where occasionally during
  * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
  * register access we place retries around register access.
  */
 #define I2C_RETRIES	3

 int gsc_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct i2c_client *client = context;
 	int retry, ret;

 	for (retry = 0; retry < I2C_RETRIES; retry++) {
 		ret = i2c_smbus_write_byte_data(client, reg, val);
 		/*
 		 * -EAGAIN returned when the i2c host controller is busy
 		 * -EIO returned when i2c device is busy
 		 */
 		if (ret != -EAGAIN && ret != -EIO)
 			break;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(gsc_write);

 int gsc_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct i2c_client *client = context;
 	int retry, ret;

 	for (retry = 0; retry < I2C_RETRIES; retry++) {
 		ret = i2c_smbus_read_byte_data(client, reg);
 		/*
 		 * -EAGAIN returned when the i2c host controller is busy
 		 * -EIO returned when i2c device is busy
 		 */
 		if (ret != -EAGAIN && ret != -EIO)
 			break;
 	}
 	*val = ret & 0xff;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(gsc_read);

 /*
  * gsc_powerdown - API to use GSC to power down board for a specific time
  *
  * secs - number of seconds to remain powered off
  */
 static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
 {
 	int ret;
 	unsigned char regs[4];

 	dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
 		 secs);

 	put_unaligned_le32(secs, regs);
 	ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
 	if (ret)
 		return ret;

 	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
 				 BIT(GSC_CTRL_1_SLEEP_ADD),
 				 BIT(GSC_CTRL_1_SLEEP_ADD));
 	if (ret)
 		return ret;

 	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
 				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
 				 BIT(GSC_CTRL_1_SLEEP_ENABLE),
 				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
 				 BIT(GSC_CTRL_1_SLEEP_ENABLE));


 	return ret;
 }

 static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
 			char *buf)
 {
 	struct gsc_dev *gsc = dev_get_drvdata(dev);
 	const char *name = attr->attr.name;
 	int rz = 0;

 	if (strcasecmp(name, "fw_version") == 0)
 		rz = sprintf(buf, "%d\n", gsc->fwver);
 	else if (strcasecmp(name, "fw_crc") == 0)
 		rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
 	else
 		dev_err(dev, "invalid command: '%s'\n", name);

 	return rz;
 }

 static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count)
 {
 	struct gsc_dev *gsc = dev_get_drvdata(dev);
 	const char *name = attr->attr.name;
 	long value;

 	if (strcasecmp(name, "powerdown") == 0) {
 		if (kstrtol(buf, 0, &value) == 0)
 			gsc_powerdown(gsc, value);
 	} else {
 		dev_err(dev, "invalid command: '%s\n", name);
 	}

 	return count;
 }

 static struct device_attribute attr_fwver =
 	__ATTR(fw_version, 0440, gsc_show, NULL);
 static struct device_attribute attr_fwcrc =
 	__ATTR(fw_crc, 0440, gsc_show, NULL);
 static struct device_attribute attr_pwrdown =
 	__ATTR(powerdown, 0220, NULL, gsc_store);

 static struct attribute *gsc_attrs[] = {
 	&attr_fwver.attr,
 	&attr_fwcrc.attr,
 	&attr_pwrdown.attr,
 	NULL,
 };

 static struct attribute_group attr_group = {
 	.attrs = gsc_attrs,
 };

 static const struct of_device_id gsc_of_match[] = {
 	{ .compatible = "gw,gsc", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, gsc_of_match);

 static struct regmap_bus gsc_regmap_bus = {
 	.reg_read = gsc_read,
 	.reg_write = gsc_write,
 };

 static const struct regmap_config gsc_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.cache_type = REGCACHE_NONE,
 	.max_register = GSC_WP,
 };

 static const struct regmap_irq gsc_irqs[] = {
 	REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
 	REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
 	REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
 	REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
 	REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
 	REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
 	REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
 	REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
 };

 static const struct regmap_irq_chip gsc_irq_chip = {
 	.name = "gateworks-gsc",
 	.irqs = gsc_irqs,
 	.num_irqs = ARRAY_SIZE(gsc_irqs),
 	.num_regs = 1,
 	.status_base = GSC_IRQ_STATUS,
 	.mask_base = GSC_IRQ_ENABLE,
 	.mask_invert = true,
 	.ack_base = GSC_IRQ_STATUS,
 	.ack_invert = true,
 };

 static int gsc_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct gsc_dev *gsc;
 	struct regmap_irq_chip_data *irq_data;
 	int ret;
 	unsigned int reg;

 	gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
 	if (!gsc)
 		return -ENOMEM;

 	gsc->dev = &client->dev;
 	gsc->i2c = client;
 	i2c_set_clientdata(client, gsc);

 	gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
 				       &gsc_regmap_config);
 	if (IS_ERR(gsc->regmap))
 		return PTR_ERR(gsc->regmap);

 	if (regmap_read(gsc->regmap, GSC_FW_VER, &reg))
 		return -EIO;
 	gsc->fwver = reg;

 	regmap_read(gsc->regmap, GSC_FW_CRC, &reg);
 	gsc->fwcrc = reg;
 	regmap_read(gsc->regmap, GSC_FW_CRC + 1, &reg);
 	gsc->fwcrc |= reg << 8;

 	gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
 						   GSC_HWMON);
 	if (IS_ERR(gsc->i2c_hwmon)) {
 		dev_err(dev, "Failed to allocate I2C device for HWMON\n");
 		return PTR_ERR(gsc->i2c_hwmon);
 	}

 	ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
 				       IRQF_ONESHOT | IRQF_SHARED |
 				       IRQF_TRIGGER_LOW, 0,
 				       &gsc_irq_chip, &irq_data);
 	if (ret)
 		return ret;

 	dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
 		 gsc->fwver, gsc->fwcrc);

 	ret = sysfs_create_group(&dev->kobj, &attr_group);
 	if (ret)
 		dev_err(dev, "failed to create sysfs attrs\n");

 	ret = devm_of_platform_populate(dev);
 	if (ret) {
 		sysfs_remove_group(&dev->kobj, &attr_group);
 		return ret;
 	}

 	return 0;
 }

 static int gsc_remove(struct i2c_client *client)
 {
 	sysfs_remove_group(&client->dev.kobj, &attr_group);

 	return 0;
 }

 static struct i2c_driver gsc_driver = {
 	.driver = {
 		.name	= "gateworks-gsc",
 		.of_match_table = gsc_of_match,
 	},
 	.probe_new	= gsc_probe,
 	.remove		= gsc_remove,
 };
 module_i2c_driver(gsc_driver);

 MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
 MODULE_DESCRIPTION("I2C Core interface for GSC");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* The Gateworks System Controller (GSC) is a multi-function
	* device designed for use in Gateworks Single Board Computers.
	* The control interface is I2C, with an interrupt. The device supports
	* system functions such as push-button monitoring, multiple ADC's for
	* voltage and temperature monitoring, fan controller and watchdog monitor.
	*
	* Copyright (C) 2020 Gateworks Corporation
	*/

	#include <linux/device.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/mfd/gsc.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>

	#include <asm/unaligned.h>

	/*
	* The GSC suffers from an errata where occasionally during
	* ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
	* register access we place retries around register access.
	*/
	#define I2C_RETRIES 3

	int gsc_write(void *context, unsigned int reg, unsigned int val)
	{
	struct i2c_client *client = context;
	int retry, ret;

	for (retry = 0; retry < I2C_RETRIES; retry++) {
	ret = i2c_smbus_write_byte_data(client, reg, val);
	/*
	* -EAGAIN returned when the i2c host controller is busy
	* -EIO returned when i2c device is busy
	*/
	if (ret != -EAGAIN && ret != -EIO)
	break;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(gsc_write);

	int gsc_read(void context, unsigned int reg, unsigned int val)
	{
	struct i2c_client *client = context;
	int retry, ret;

	for (retry = 0; retry < I2C_RETRIES; retry++) {
	ret = i2c_smbus_read_byte_data(client, reg);
	/*
	* -EAGAIN returned when the i2c host controller is busy
	* -EIO returned when i2c device is busy
	*/
	if (ret != -EAGAIN && ret != -EIO)
	break;
	}
	*val = ret & 0xff;

	return 0;
	}
	EXPORT_SYMBOL_GPL(gsc_read);

	/*
	* gsc_powerdown - API to use GSC to power down board for a specific time
	*
	* secs - number of seconds to remain powered off
	*/
	static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
	{
	int ret;
	unsigned char regs[4];

	dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
	secs);

	put_unaligned_le32(secs, regs);
	ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
	if (ret)
	return ret;

	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
	BIT(GSC_CTRL_1_SLEEP_ADD),
	BIT(GSC_CTRL_1_SLEEP_ADD));
	if (ret)
	return ret;

	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
	BIT(GSC_CTRL_1_SLEEP_ACTIVATE) \|
	BIT(GSC_CTRL_1_SLEEP_ENABLE),
	BIT(GSC_CTRL_1_SLEEP_ACTIVATE) \|
	BIT(GSC_CTRL_1_SLEEP_ENABLE));


	return ret;
	}

	static ssize_t gsc_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	struct gsc_dev *gsc = dev_get_drvdata(dev);
	const char *name = attr->attr.name;
	int rz = 0;

	if (strcasecmp(name, "fw_version") == 0)
	rz = sprintf(buf, "%d\n", gsc->fwver);
	else if (strcasecmp(name, "fw_crc") == 0)
	rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
	else
	dev_err(dev, "invalid command: '%s'\n", name);

	return rz;
	}

	static ssize_t gsc_store(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct gsc_dev *gsc = dev_get_drvdata(dev);
	const char *name = attr->attr.name;
	long value;

	if (strcasecmp(name, "powerdown") == 0) {
	if (kstrtol(buf, 0, &value) == 0)
	gsc_powerdown(gsc, value);
	} else {
	dev_err(dev, "invalid command: '%s\n", name);
	}

	return count;
	}

	static struct device_attribute attr_fwver =
	__ATTR(fw_version, 0440, gsc_show, NULL);
	static struct device_attribute attr_fwcrc =
	__ATTR(fw_crc, 0440, gsc_show, NULL);
	static struct device_attribute attr_pwrdown =
	__ATTR(powerdown, 0220, NULL, gsc_store);

	static struct attribute *gsc_attrs[] = {
	&attr_fwver.attr,
	&attr_fwcrc.attr,
	&attr_pwrdown.attr,
	NULL,
	};

	static struct attribute_group attr_group = {
	.attrs = gsc_attrs,
	};

	static const struct of_device_id gsc_of_match[] = {
	{ .compatible = "gw,gsc", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, gsc_of_match);

	static struct regmap_bus gsc_regmap_bus = {
	.reg_read = gsc_read,
	.reg_write = gsc_write,
	};

	static const struct regmap_config gsc_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.cache_type = REGCACHE_NONE,
	.max_register = GSC_WP,
	};

	static const struct regmap_irq gsc_irqs[] = {
	REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
	REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
	REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
	REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
	REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
	REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
	REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
	REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
	};

	static const struct regmap_irq_chip gsc_irq_chip = {
	.name = "gateworks-gsc",
	.irqs = gsc_irqs,
	.num_irqs = ARRAY_SIZE(gsc_irqs),
	.num_regs = 1,
	.status_base = GSC_IRQ_STATUS,
	.mask_base = GSC_IRQ_ENABLE,
	.mask_invert = true,
	.ack_base = GSC_IRQ_STATUS,
	.ack_invert = true,
	};

	static int gsc_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct gsc_dev *gsc;
	struct regmap_irq_chip_data *irq_data;
	int ret;
	unsigned int reg;

	gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
	if (!gsc)
	return -ENOMEM;

	gsc->dev = &client->dev;
	gsc->i2c = client;
	i2c_set_clientdata(client, gsc);

	gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
	&gsc_regmap_config);
	if (IS_ERR(gsc->regmap))
	return PTR_ERR(gsc->regmap);

	if (regmap_read(gsc->regmap, GSC_FW_VER, &reg))
	return -EIO;
	gsc->fwver = reg;

	regmap_read(gsc->regmap, GSC_FW_CRC, &reg);
	gsc->fwcrc = reg;
	regmap_read(gsc->regmap, GSC_FW_CRC + 1, &reg);
	gsc->fwcrc \|= reg << 8;

	gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
	GSC_HWMON);
	if (IS_ERR(gsc->i2c_hwmon)) {
	dev_err(dev, "Failed to allocate I2C device for HWMON\n");
	return PTR_ERR(gsc->i2c_hwmon);
	}

	ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
	IRQF_ONESHOT \| IRQF_SHARED \|
	IRQF_TRIGGER_LOW, 0,
	&gsc_irq_chip, &irq_data);
	if (ret)
	return ret;

	dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
	gsc->fwver, gsc->fwcrc);

	ret = sysfs_create_group(&dev->kobj, &attr_group);
	if (ret)
	dev_err(dev, "failed to create sysfs attrs\n");

	ret = devm_of_platform_populate(dev);
	if (ret) {
	sysfs_remove_group(&dev->kobj, &attr_group);
	return ret;
	}

	return 0;
	}

	static int gsc_remove(struct i2c_client *client)
	{
	sysfs_remove_group(&client->dev.kobj, &attr_group);

	return 0;
	}

	static struct i2c_driver gsc_driver = {
	.driver = {
	.name = "gateworks-gsc",
	.of_match_table = gsc_of_match,
	},
	.probe_new = gsc_probe,
	.remove = gsc_remove,
	};
	module_i2c_driver(gsc_driver);

	MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
	MODULE_DESCRIPTION("I2C Core interface for GSC");
	MODULE_LICENSE("GPL v2");