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Commit 6ca6ca5d authored by Fabio Baltieri's avatar Fabio Baltieri Committed by Kumar Gala
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powerpc/83xx: Add shutdown request support to MCU handling on MPC8349 MITX 



This patch add support for calling ctrl_alt_del() when the power button is
pressed for more than about 2 seconds on some freescale MPC83xx evaluation
boards and reference design.

The code uses a kthread to poll the CTRL_BTN bit each second.

Also change Kconfig entry of the driver to bool, as device's gpio
registration is broken when loading as module.

Tested on an MPC8315E RDB board.

Signed-off-by: default avatarFabio Baltieri <fabio.baltieri@gmail.com>
Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
parent 43a327b7

arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c

+57 −1
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#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>
@@ -30,6 +32,7 @@ 
 */

#define MCU_REG_CTRL	0x20

#define MCU_CTRL_POFF	0x40

#define MCU_CTRL_BTN	0x80



#define MCU_NUM_GPIO	2
@@ -42,13 +45,55 @@ struct mcu { 


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, S_IRUGO, 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(glob_mcu->client, MCU_REG_CTRL,

	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL,

				  mcu->reg_ctrl | MCU_CTRL_POFF);

	mutex_unlock(&mcu->lock);

}
@@ -130,6 +175,13 @@ static int __devinit mcu_probe(struct i2c_client *client, 
		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);
@@ -141,6 +193,10 @@ static int __devexit 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) {

		ppc_md.power_off = NULL;

		glob_mcu = NULL;

arch/powerpc/platforms/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ config SIMPLE_GPIO 
	  on-board peripherals.



config MCU_MPC8349EMITX

	tristate "MPC8349E-mITX MCU driver"

	bool "MPC8349E-mITX MCU driver"

	depends on I2C && PPC_83xx

	select GENERIC_GPIO

	select ARCH_REQUIRE_GPIOLIB