tdx-ec-poweroff.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Toradex Embedded Controller driver
  4 *
  5 * Copyright (C) 2025 Toradex
  6 *
  7 * Author: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
  8 */
  9
 10#include <linux/array_size.h>
 11#include <linux/bug.h>
 12#include <linux/delay.h>
 13#include <linux/device.h>
 14#include <linux/dev_printk.h>
 15#include <linux/err.h>
 16#include <linux/i2c.h>
 17#include <linux/mod_devicetable.h>
 18#include <linux/module.h>
 19#include <linux/reboot.h>
 20#include <linux/regmap.h>
 21#include <linux/types.h>
 22
 23#define EC_CHIP_ID_REG                  0x00
 24#define EC_CHIP_ID_SMARC_IMX95          0x11
 25#define EC_CHIP_ID_SMARC_IMX8MP         0x12
 26
 27#define EC_VERSION_REG_MAJOR            0x01
 28#define EC_VERSION_REG_MINOR            0x02
 29#define EC_ID_VERSION_LEN               3
 30
 31#define EC_CMD_REG                      0xD0
 32#define EC_CMD_POWEROFF                 0x01
 33#define EC_CMD_RESET                    0x02
 34
 35#define EC_REG_MAX                      0xD0
 36
 37#define EC_CMD_TIMEOUT_MS             	1000
 38
 39static const struct regmap_range volatile_ranges[] = {
 40	regmap_reg_range(EC_CMD_REG, EC_CMD_REG),
 41};
 42
 43static const struct regmap_access_table volatile_table = {
 44	.yes_ranges	= volatile_ranges,
 45	.n_yes_ranges	= ARRAY_SIZE(volatile_ranges),
 46};
 47
 48static const struct regmap_range read_ranges[] = {
 49	regmap_reg_range(EC_CHIP_ID_REG, EC_VERSION_REG_MINOR),
 50};
 51
 52static const struct regmap_access_table read_table = {
 53	.yes_ranges	= read_ranges,
 54	.n_yes_ranges	= ARRAY_SIZE(read_ranges),
 55};
 56
 57static const struct regmap_config regmap_config = {
 58	.reg_bits	= 8,
 59	.val_bits	= 8,
 60	.max_register	= EC_REG_MAX,
 61	.cache_type	= REGCACHE_RBTREE,
 62	.rd_table	= &read_table,
 63	.volatile_table = &volatile_table,
 64};
 65
 66static int tdx_ec_cmd(struct regmap *regmap, u8 cmd)
 67{
 68	int err = regmap_write(regmap, EC_CMD_REG, cmd);
 69
 70	if (err)
 71		dev_err(regmap_get_device(regmap), "Failed to send command 0x%02X: %d\n", cmd, err);
 72
 73	return err;
 74}
 75
 76static int tdx_ec_power_off(struct sys_off_data *data)
 77{
 78	struct regmap *regmap = data->cb_data;
 79	int err;
 80
 81	err = tdx_ec_cmd(regmap, EC_CMD_POWEROFF);
 82
 83	if (err) {
 84		dev_err(data->dev, "Failed to send power off command\n");
 85	} else {
 86		mdelay(EC_CMD_TIMEOUT_MS);
 87		WARN_ONCE(1, "Unable to power off system\n");
 88	}
 89
 90	return err ? NOTIFY_BAD : NOTIFY_DONE;
 91}
 92
 93static int tdx_ec_restart(struct sys_off_data *data)
 94{
 95	struct regmap *regmap = data->cb_data;
 96	int err;
 97
 98	err = tdx_ec_cmd(regmap, EC_CMD_RESET);
 99
100	if (err) {
101		dev_err(data->dev, "Failed to send restart command\n");
102	} else {
103		mdelay(EC_CMD_TIMEOUT_MS);
104		WARN_ONCE(1, "Unable to restart system\n");
105	}
106
107	return err ? NOTIFY_BAD : NOTIFY_DONE;
108}
109
110static int tdx_ec_register_power_off_restart(struct device *dev, struct regmap *regmap)
111{
112	int err;
113
114	err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART,
115					    SYS_OFF_PRIO_FIRMWARE,
116					    tdx_ec_restart, regmap);
117	if (err)
118		return err;
119
120	return devm_register_sys_off_handler(dev, SYS_OFF_MODE_POWER_OFF,
121					     SYS_OFF_PRIO_FIRMWARE,
122					     tdx_ec_power_off, regmap);
123}
124
125static int tdx_ec_probe(struct i2c_client *client)
126{
127	struct device *dev = &client->dev;
128	u8 reg_val[EC_ID_VERSION_LEN];
129	struct regmap *regmap;
130	int err;
131
132	regmap = devm_regmap_init_i2c(client, &regmap_config);
133	if (IS_ERR(regmap))
134		return PTR_ERR(regmap);
135
136	err = regmap_bulk_read(regmap, EC_CHIP_ID_REG, &reg_val, EC_ID_VERSION_LEN);
137	if (err)
138		return dev_err_probe(dev, err,
139				     "Cannot read id and version registers\n");
140
141	dev_info(dev, "Toradex Embedded Controller id %x - Firmware %u.%u\n",
142		 reg_val[0], reg_val[1], reg_val[2]);
143
144	err = tdx_ec_register_power_off_restart(dev, regmap);
145	if (err)
146		return dev_err_probe(dev, err,
147				     "Cannot register system restart handler\n");
148
149	return 0;
150}
151
152static const struct of_device_id __maybe_unused of_tdx_ec_match[] = {
153	{ .compatible = "toradex,smarc-ec" },
154	{}
155};
156MODULE_DEVICE_TABLE(of, of_tdx_ec_match);
157
158static struct i2c_driver tdx_ec_driver = {
159	.probe			= tdx_ec_probe,
160	.driver			= {
161		.name		= "toradex-smarc-ec",
162		.of_match_table = of_tdx_ec_match,
163	},
164};
165module_i2c_driver(tdx_ec_driver);
166
167MODULE_AUTHOR("Emanuele Ghidoli <emanuele.ghidoli@toradex.com>");
168MODULE_DESCRIPTION("Toradex SMARC Embedded Controller driver");
169MODULE_LICENSE("GPL");