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: Fabio Baltieri <fabio.baltieri@gmail.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
index 70798ac..ef6537b 100644
--- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
+++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
@@ -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 @@
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 @@
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 @@
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;
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 9fdb9b6..e458872 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -346,7 +346,7 @@
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