drivers/power/reset/tdx-ec-poweroff.c

Source file repositories/reference/linux-study-clean/drivers/power/reset/tdx-ec-poweroff.c

File Facts

System
Linux kernel
Corpus path
drivers/power/reset/tdx-ec-poweroff.c
Extension
.c
Size
4236 bytes
Lines
170
Domain
Driver Families
Bucket
drivers/power
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Toradex Embedded Controller driver
 *
 * Copyright (C) 2025 Toradex
 *
 * Author: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
 */

#include <linux/array_size.h>
#include <linux/bug.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/types.h>

#define EC_CHIP_ID_REG                  0x00
#define EC_CHIP_ID_SMARC_IMX95          0x11
#define EC_CHIP_ID_SMARC_IMX8MP         0x12

#define EC_VERSION_REG_MAJOR            0x01
#define EC_VERSION_REG_MINOR            0x02
#define EC_ID_VERSION_LEN               3

#define EC_CMD_REG                      0xD0
#define EC_CMD_POWEROFF                 0x01
#define EC_CMD_RESET                    0x02

#define EC_REG_MAX                      0xD0

#define EC_CMD_TIMEOUT_MS             	1000

static const struct regmap_range volatile_ranges[] = {
	regmap_reg_range(EC_CMD_REG, EC_CMD_REG),
};

static const struct regmap_access_table volatile_table = {
	.yes_ranges	= volatile_ranges,
	.n_yes_ranges	= ARRAY_SIZE(volatile_ranges),
};

static const struct regmap_range read_ranges[] = {
	regmap_reg_range(EC_CHIP_ID_REG, EC_VERSION_REG_MINOR),
};

static const struct regmap_access_table read_table = {
	.yes_ranges	= read_ranges,
	.n_yes_ranges	= ARRAY_SIZE(read_ranges),
};

static const struct regmap_config regmap_config = {
	.reg_bits	= 8,
	.val_bits	= 8,
	.max_register	= EC_REG_MAX,
	.cache_type	= REGCACHE_RBTREE,
	.rd_table	= &read_table,
	.volatile_table = &volatile_table,
};

static int tdx_ec_cmd(struct regmap *regmap, u8 cmd)
{
	int err = regmap_write(regmap, EC_CMD_REG, cmd);

	if (err)
		dev_err(regmap_get_device(regmap), "Failed to send command 0x%02X: %d\n", cmd, err);

	return err;
}

static int tdx_ec_power_off(struct sys_off_data *data)
{
	struct regmap *regmap = data->cb_data;
	int err;

	err = tdx_ec_cmd(regmap, EC_CMD_POWEROFF);

	if (err) {
		dev_err(data->dev, "Failed to send power off command\n");
	} else {
		mdelay(EC_CMD_TIMEOUT_MS);
		WARN_ONCE(1, "Unable to power off system\n");
	}

	return err ? NOTIFY_BAD : NOTIFY_DONE;

Annotation

Implementation Notes