blob: c954ed265de81c925a1e58ec790dc851256cfe84 [file] [log] [blame]
// 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,
.unmask_base = GSC_IRQ_ENABLE,
.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 void gsc_remove(struct i2c_client *client)
{
sysfs_remove_group(&client->dev.kobj, &attr_group);
}
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");