diff options
Diffstat (limited to 'drivers/mfd/acer-ec-a500.c')
| -rw-r--r-- | drivers/mfd/acer-ec-a500.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/mfd/acer-ec-a500.c b/drivers/mfd/acer-ec-a500.c new file mode 100644 index 000000000..7fd8b9988 --- /dev/null +++ b/drivers/mfd/acer-ec-a500.c @@ -0,0 +1,200 @@ +// 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 void 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); + } +} + +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"); |