diff options
Diffstat (limited to 'drivers/mfd/ene-kb3930.c')
| -rw-r--r-- | drivers/mfd/ene-kb3930.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/mfd/ene-kb3930.c b/drivers/mfd/ene-kb3930.c new file mode 100644 index 0000000000..fa0ad2f14a --- /dev/null +++ b/drivers/mfd/ene-kb3930.c @@ -0,0 +1,210 @@ +// SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0-or-later +/* + * ENE KB3930 Embedded Controller Driver + * + * Copyright (C) 2020 Lubomir Rintel + */ + +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/mfd/core.h> +#include <linux/module.h> +#include <linux/reboot.h> +#include <linux/regmap.h> + +/* I2C registers that are multiplexing access to the EC RAM. */ +enum { + EC_DATA_IN = 0x00, + EC_RAM_OUT = 0x80, + EC_RAM_IN = 0x81, +}; + +/* EC RAM registers. */ +enum { + EC_MODEL = 0x30, + EC_VERSION_MAJ = 0x31, + EC_VERSION_MIN = 0x32, +}; + +struct kb3930 { + struct i2c_client *client; + struct regmap *ram_regmap; + struct gpio_descs *off_gpios; +}; + +static struct kb3930 *kb3930_power_off; + +#define EC_GPIO_WAVE 0 +#define EC_GPIO_OFF_MODE 1 + +#define EC_OFF_MODE_REBOOT 0 +#define EC_OFF_MODE_POWER 1 + +static void kb3930_off(struct kb3930 *ddata, int off_mode) +{ + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_OFF_MODE], + off_mode); + + /* + * This creates a 10 Hz wave on EC_GPIO_WAVE that signals a + * shutdown request to the EC. Once the EC detects it, it will + * proceed to turn the power off or reset the board depending on + * the value of EC_GPIO_OFF_MODE. + */ + while (1) { + mdelay(50); + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 0); + mdelay(50); + gpiod_direction_output(ddata->off_gpios->desc[EC_GPIO_WAVE], 1); + } +} + +static int kb3930_restart(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + kb3930_off(kb3930_power_off, EC_OFF_MODE_REBOOT); + return NOTIFY_DONE; +} + +static void kb3930_pm_power_off(void) +{ + kb3930_off(kb3930_power_off, EC_OFF_MODE_POWER); +} + +static struct notifier_block kb3930_restart_nb = { + .notifier_call = kb3930_restart, +}; + +static const struct mfd_cell ariel_ec_cells[] = { + { .name = "dell-wyse-ariel-led", }, + { .name = "dell-wyse-ariel-power", }, +}; + +static int kb3930_ec_ram_reg_write(void *context, unsigned int reg, + unsigned int val) +{ + struct kb3930 *ddata = context; + + return i2c_smbus_write_word_data(ddata->client, EC_RAM_OUT, + (val << 8) | reg); +} + +static int kb3930_ec_ram_reg_read(void *context, unsigned int reg, + unsigned int *val) +{ + struct kb3930 *ddata = context; + int ret; + + ret = i2c_smbus_write_word_data(ddata->client, EC_RAM_IN, reg); + if (ret < 0) + return ret; + + ret = i2c_smbus_read_word_data(ddata->client, EC_DATA_IN); + if (ret < 0) + return ret; + + *val = ret >> 8; + return 0; +} + +static const struct regmap_config kb3930_ram_regmap_config = { + .name = "ec_ram", + .reg_bits = 8, + .val_bits = 8, + .reg_stride = 1, + .max_register = 0xff, + .reg_write = kb3930_ec_ram_reg_write, + .reg_read = kb3930_ec_ram_reg_read, + .fast_io = false, +}; + +static int kb3930_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct device_node *np = dev->of_node; + struct kb3930 *ddata; + unsigned int model; + int ret; + + ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); + if (!ddata) + return -ENOMEM; + + kb3930_power_off = ddata; + ddata->client = client; + i2c_set_clientdata(client, ddata); + + ddata->ram_regmap = devm_regmap_init(dev, NULL, ddata, + &kb3930_ram_regmap_config); + if (IS_ERR(ddata->ram_regmap)) + return PTR_ERR(ddata->ram_regmap); + + ret = regmap_read(ddata->ram_regmap, EC_MODEL, &model); + if (ret < 0) + return ret; + + /* Currently we only support the cells present on Dell Ariel model. */ + if (model != 'J') { + dev_err(dev, "unknown board model: %02x\n", model); + return -ENODEV; + } + + ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, + ariel_ec_cells, + ARRAY_SIZE(ariel_ec_cells), + NULL, 0, NULL); + if (ret) + return ret; + + if (of_property_read_bool(np, "system-power-controller")) { + ddata->off_gpios = + devm_gpiod_get_array_optional(dev, "off", GPIOD_IN); + if (IS_ERR(ddata->off_gpios)) + return PTR_ERR(ddata->off_gpios); + if (ddata->off_gpios->ndescs < 2) { + dev_err(dev, "invalid off-gpios property\n"); + return -EINVAL; + } + } + + if (ddata->off_gpios) { + register_restart_handler(&kb3930_restart_nb); + if (!pm_power_off) + pm_power_off = kb3930_pm_power_off; + } + + return 0; +} + +static void kb3930_remove(struct i2c_client *client) +{ + struct kb3930 *ddata = i2c_get_clientdata(client); + + if (ddata->off_gpios) { + if (pm_power_off == kb3930_pm_power_off) + pm_power_off = NULL; + unregister_restart_handler(&kb3930_restart_nb); + } + kb3930_power_off = NULL; +} + +static const struct of_device_id kb3930_dt_ids[] = { + { .compatible = "ene,kb3930" }, + { } +}; +MODULE_DEVICE_TABLE(of, kb3930_dt_ids); + +static struct i2c_driver kb3930_driver = { + .probe = kb3930_probe, + .remove = kb3930_remove, + .driver = { + .name = "ene-kb3930", + .of_match_table = kb3930_dt_ids, + }, +}; +module_i2c_driver(kb3930_driver); + +MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); +MODULE_DESCRIPTION("ENE KB3930 Embedded Controller Driver"); +MODULE_LICENSE("Dual BSD/GPL"); |