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