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