summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c')
-rw-r--r--arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c224
1 files changed, 224 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..77ed61306
--- /dev/null
+++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
@@ -0,0 +1,224 @@
+// 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/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+#include <linux/gpio/driver.h>
+#include <linux/slab.h>
+#include <linux/kthread.h>
+#include <linux/property.h>
+#include <linux/reboot.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 *dev = &mcu->client->dev;
+ struct gpio_chip *gc = &mcu->gc;
+
+ gc->owner = THIS_MODULE;
+ gc->label = kasprintf(GFP_KERNEL, "%pfw", dev_fwnode(dev));
+ 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->parent = dev;
+
+ return gpiochip_add_data(gc, mcu);
+}
+
+static void mcu_gpiochip_remove(struct mcu *mcu)
+{
+ kfree(mcu->gc.label);
+ gpiochip_remove(&mcu->gc);
+}
+
+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 void mcu_remove(struct i2c_client *client)
+{
+ struct mcu *mcu = i2c_get_clientdata(client);
+
+ kthread_stop(shutdown_thread);
+
+ device_remove_file(&client->dev, &dev_attr_status);
+
+ if (glob_mcu == mcu) {
+ pm_power_off = NULL;
+ glob_mcu = NULL;
+ }
+
+ mcu_gpiochip_remove(mcu);
+ kfree(mcu);
+}
+
+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");