Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
 *
 * Copyright (c) 2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 */
 
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/i2c.h>
#include <linux/gpio/driver.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/reboot.h>
#include <asm/prom.h>
#include <asm/machdep.h>
 
/*
 * I don't have specifications for the MCU firmware, I found this register
 * and bits positions by the trial&error method.
 */
#define MCU_REG_CTRL	0x20
#define MCU_CTRL_POFF	0x40
#define MCU_CTRL_BTN	0x80
 
#define MCU_NUM_GPIO	2
 
struct mcu {
<------>struct mutex lock;
<------>struct i2c_client *client;
<------>struct gpio_chip gc;
<------>u8 reg_ctrl;
};
 
static struct mcu *glob_mcu;
 
struct task_struct *shutdown_thread;
static int shutdown_thread_fn(void *data)
{
<------>int ret;
<------>struct mcu *mcu = glob_mcu;
 
<------>while (!kthread_should_stop()) {
<------><------>ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
<------><------>if (ret < 0)
<------><------><------>pr_err("MCU status reg read failed.\n");
<------><------>mcu->reg_ctrl = ret;
 
 
<------><------>if (mcu->reg_ctrl & MCU_CTRL_BTN) {
<------><------><------>i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
<------><------><------><------><------><------>  mcu->reg_ctrl & ~MCU_CTRL_BTN);
 
<------><------><------>ctrl_alt_del();
<------><------>}
 
<------><------>set_current_state(TASK_INTERRUPTIBLE);
<------><------>schedule_timeout(HZ);
<------>}
 
<------>return 0;
}
 
static ssize_t show_status(struct device *d,
<------><------><------>   struct device_attribute *attr, char *buf)
{
<------>int ret;
<------>struct mcu *mcu = glob_mcu;
 
<------>ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
<------>if (ret < 0)
<------><------>return -ENODEV;
<------>mcu->reg_ctrl = ret;
 
<------>return sprintf(buf, "%02x\n", ret);
}
static DEVICE_ATTR(status, 0444, show_status, NULL);
 
static void mcu_power_off(void)
{
<------>struct mcu *mcu = glob_mcu;
 
<------>pr_info("Sending power-off request to the MCU...\n");
<------>mutex_lock(&mcu->lock);
<------>i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,
<------><------><------><------>  mcu->reg_ctrl | MCU_CTRL_POFF);
<------>mutex_unlock(&mcu->lock);
}
 
static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
<------>struct mcu *mcu = gpiochip_get_data(gc);
<------>u8 bit = 1 << (4 + gpio);
 
<------>mutex_lock(&mcu->lock);
<------>if (val)
<------><------>mcu->reg_ctrl &= ~bit;
<------>else
<------><------>mcu->reg_ctrl |= bit;
 
<------>i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
<------>mutex_unlock(&mcu->lock);
}
 
static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
<------>mcu_gpio_set(gc, gpio, val);
<------>return 0;
}
 
static int mcu_gpiochip_add(struct mcu *mcu)
{
<------>struct device_node *np;
<------>struct gpio_chip *gc = &mcu->gc;
 
<------>np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
<------>if (!np)
<------><------>return -ENODEV;
 
<------>gc->owner = THIS_MODULE;
<------>gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
<------>gc->can_sleep = 1;
<------>gc->ngpio = MCU_NUM_GPIO;
<------>gc->base = -1;
<------>gc->set = mcu_gpio_set;
<------>gc->direction_output = mcu_gpio_dir_out;
<------>gc->of_node = np;
 
<------>return gpiochip_add_data(gc, mcu);
}
 
static int mcu_gpiochip_remove(struct mcu *mcu)
{
<------>kfree(mcu->gc.label);
<------>gpiochip_remove(&mcu->gc);
<------>return 0;
}
 
static int mcu_probe(struct i2c_client *client)
{
<------>struct mcu *mcu;
<------>int ret;
 
<------>mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
<------>if (!mcu)
<------><------>return -ENOMEM;
 
<------>mutex_init(&mcu->lock);
<------>mcu->client = client;
<------>i2c_set_clientdata(client, mcu);
 
<------>ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
<------>if (ret < 0)
<------><------>goto err;
<------>mcu->reg_ctrl = ret;
 
<------>ret = mcu_gpiochip_add(mcu);
<------>if (ret)
<------><------>goto err;
 
<------>/* XXX: this is potentially racy, but there is no lock for pm_power_off */
<------>if (!pm_power_off) {
<------><------>glob_mcu = mcu;
<------><------>pm_power_off = mcu_power_off;
<------><------>dev_info(&client->dev, "will provide power-off service\n");
<------>}
 
<------>if (device_create_file(&client->dev, &dev_attr_status))
<------><------>dev_err(&client->dev,
<------><------><------>"couldn't create device file for status\n");
 
<------>shutdown_thread = kthread_run(shutdown_thread_fn, NULL,
<------><------><------><------>      "mcu-i2c-shdn");
 
<------>return 0;
err:
<------>kfree(mcu);
<------>return ret;
}
 
static int mcu_remove(struct i2c_client *client)
{
<------>struct mcu *mcu = i2c_get_clientdata(client);
<------>int ret;
 
<------>kthread_stop(shutdown_thread);
 
<------>device_remove_file(&client->dev, &dev_attr_status);
 
<------>if (glob_mcu == mcu) {
<------><------>pm_power_off = NULL;
<------><------>glob_mcu = NULL;
<------>}
 
<------>ret = mcu_gpiochip_remove(mcu);
<------>if (ret)
<------><------>return ret;
<------>kfree(mcu);
<------>return 0;
}
 
static const struct i2c_device_id mcu_ids[] = {
<------>{ "mcu-mpc8349emitx", },
<------>{},
};
MODULE_DEVICE_TABLE(i2c, mcu_ids);
 
static const struct of_device_id mcu_of_match_table[] = {
<------>{ .compatible = "fsl,mcu-mpc8349emitx", },
<------>{ },
};
 
static struct i2c_driver mcu_driver = {
<------>.driver = {
<------><------>.name = "mcu-mpc8349emitx",
<------><------>.of_match_table = mcu_of_match_table,
<------>},
<------>.probe_new = mcu_probe,
<------>.remove	= mcu_remove,
<------>.id_table = mcu_ids,
};
 
module_i2c_driver(mcu_driver);
 
MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
<------><------>   "MPC8349E-mITX-compatible MCU");
MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
MODULE_LICENSE("GPL");