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// SPDX-License-Identifier: GPL-2.0+
/*
* Acer Iconia Tab A500 Embedded Controller Driver
*
* Copyright 2020 GRATE-driver project
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#define A500_EC_I2C_ERR_TIMEOUT 500
#define A500_EC_POWER_CMD_TIMEOUT 1000
/*
* Controller's firmware expects specific command opcodes to be used for the
* corresponding registers. Unsupported commands are skipped by the firmware.
*/
#define CMD_SHUTDOWN 0x0
#define CMD_WARM_REBOOT 0x0
#define CMD_COLD_REBOOT 0x1
enum {
REG_CURRENT_NOW = 0x03,
REG_SHUTDOWN = 0x52,
REG_WARM_REBOOT = 0x54,
REG_COLD_REBOOT = 0x55,
};
static struct i2c_client *a500_ec_client_pm_off;
static int a500_ec_read(void *context, const void *reg_buf, size_t reg_size,
void *val_buf, size_t val_sizel)
{
struct i2c_client *client = context;
unsigned int reg, retries = 5;
u16 *ret_val = val_buf;
s32 ret = 0;
reg = *(u8 *)reg_buf;
while (retries-- > 0) {
ret = i2c_smbus_read_word_data(client, reg);
if (ret >= 0)
break;
msleep(A500_EC_I2C_ERR_TIMEOUT);
}
if (ret < 0) {
dev_err(&client->dev, "read 0x%x failed: %d\n", reg, ret);
return ret;
}
*ret_val = ret;
if (reg == REG_CURRENT_NOW)
fsleep(10000);
return 0;
}
static int a500_ec_write(void *context, const void *data, size_t count)
{
struct i2c_client *client = context;
unsigned int reg, val, retries = 5;
s32 ret = 0;
reg = *(u8 *)(data + 0);
val = *(u16 *)(data + 1);
while (retries-- > 0) {
ret = i2c_smbus_write_word_data(client, reg, val);
if (ret >= 0)
break;
msleep(A500_EC_I2C_ERR_TIMEOUT);
}
if (ret < 0) {
dev_err(&client->dev, "write 0x%x failed: %d\n", reg, ret);
return ret;
}
return 0;
}
static const struct regmap_config a500_ec_regmap_config = {
.name = "KB930",
.reg_bits = 8,
.val_bits = 16,
.max_register = 0xff,
};
static const struct regmap_bus a500_ec_regmap_bus = {
.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
.write = a500_ec_write,
.read = a500_ec_read,
.max_raw_read = 2,
};
static void a500_ec_poweroff(void)
{
i2c_smbus_write_word_data(a500_ec_client_pm_off,
REG_SHUTDOWN, CMD_SHUTDOWN);
mdelay(A500_EC_POWER_CMD_TIMEOUT);
}
static int a500_ec_restart_notify(struct notifier_block *this,
unsigned long reboot_mode, void *data)
{
if (reboot_mode == REBOOT_WARM)
i2c_smbus_write_word_data(a500_ec_client_pm_off,
REG_WARM_REBOOT, CMD_WARM_REBOOT);
else
i2c_smbus_write_word_data(a500_ec_client_pm_off,
REG_COLD_REBOOT, CMD_COLD_REBOOT);
mdelay(A500_EC_POWER_CMD_TIMEOUT);
return NOTIFY_DONE;
}
static struct notifier_block a500_ec_restart_handler = {
.notifier_call = a500_ec_restart_notify,
.priority = 200,
};
static const struct mfd_cell a500_ec_cells[] = {
{ .name = "acer-a500-iconia-battery", },
{ .name = "acer-a500-iconia-leds", },
};
static int a500_ec_probe(struct i2c_client *client)
{
struct regmap *regmap;
int err;
regmap = devm_regmap_init(&client->dev, &a500_ec_regmap_bus,
client, &a500_ec_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
err = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO,
a500_ec_cells, ARRAY_SIZE(a500_ec_cells),
NULL, 0, NULL);
if (err) {
dev_err(&client->dev, "failed to add sub-devices: %d\n", err);
return err;
}
if (of_device_is_system_power_controller(client->dev.of_node)) {
a500_ec_client_pm_off = client;
err = register_restart_handler(&a500_ec_restart_handler);
if (err)
return err;
if (!pm_power_off)
pm_power_off = a500_ec_poweroff;
}
return 0;
}
static int a500_ec_remove(struct i2c_client *client)
{
if (of_device_is_system_power_controller(client->dev.of_node)) {
if (pm_power_off == a500_ec_poweroff)
pm_power_off = NULL;
unregister_restart_handler(&a500_ec_restart_handler);
}
return 0;
}
static const struct of_device_id a500_ec_match[] = {
{ .compatible = "acer,a500-iconia-ec" },
{ }
};
MODULE_DEVICE_TABLE(of, a500_ec_match);
static struct i2c_driver a500_ec_driver = {
.driver = {
.name = "acer-a500-embedded-controller",
.of_match_table = a500_ec_match,
},
.probe_new = a500_ec_probe,
.remove = a500_ec_remove,
};
module_i2c_driver(a500_ec_driver);
MODULE_DESCRIPTION("Acer Iconia Tab A500 Embedded Controller driver");
MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
MODULE_LICENSE("GPL");
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