diff options
Diffstat (limited to 'arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c')
| -rw-r--r-- | arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c new file mode 100644 index 000000000..409481016 --- /dev/null +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c @@ -0,0 +1,234 @@ +// 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"); |