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