+/*
+ * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
+ *
+ * Copyright (c) 2008 MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.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_NUM_GPIO 2
+
+struct mcu {
+ struct mutex lock;
+ struct device_node *np;
+ struct i2c_client *client;
+ struct of_gpio_chip of_gc;
+ u8 reg_ctrl;
+};
+
+static struct mcu *glob_mcu;
+
+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,
+ 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 of_gpio_chip *of_gc = to_of_gpio_chip(gc);
+ struct mcu *mcu = container_of(of_gc, struct mcu, of_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 of_gpio_chip *of_gc = &mcu->of_gc;
+ struct gpio_chip *gc = &of_gc->gc;
+ int ret;
+
+ np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
+ if (!np)
+ return -ENODEV;
+
+ gc->owner = THIS_MODULE;
+ gc->label = np->full_name;
+ gc->can_sleep = 1;
+ gc->ngpio = MCU_NUM_GPIO;
+ gc->base = -1;
+ gc->set = mcu_gpio_set;
+ gc->direction_output = mcu_gpio_dir_out;
+ of_gc->gpio_cells = 2;
+ of_gc->xlate = of_gpio_simple_xlate;
+
+ np->data = of_gc;
+ mcu->np = np;
+
+ /*
+ * We don't want to lose the node, its ->data and ->full_name...
+ * So, if succeeded, we don't put the node here.
+ */
+ ret = gpiochip_add(gc);
+ if (ret)
+ of_node_put(np);
+ return ret;
+}
+
+static int mcu_gpiochip_remove(struct mcu *mcu)
+{
+ int ret;
+
+ ret = gpiochip_remove(&mcu->of_gc.gc);
+ if (ret)
+ return ret;
+ of_node_put(mcu->np);
+
+ return 0;
+}
+
+static int __devinit mcu_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ 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 ppc_md */
+ if (!ppc_md.power_off) {
+ glob_mcu = mcu;
+ ppc_md.power_off = mcu_power_off;
+ dev_info(&client->dev, "will provide power-off service\n");
+ }
+
+ return 0;
+err:
+ kfree(mcu);
+ return ret;
+}
+
+static int __devexit mcu_remove(struct i2c_client *client)
+{
+ struct mcu *mcu = i2c_get_clientdata(client);
+ int ret;
+
+ if (glob_mcu == mcu) {
+ ppc_md.power_off = NULL;
+ glob_mcu = NULL;
+ }
+
+ ret = mcu_gpiochip_remove(mcu);
+ if (ret)
+ return ret;
+ i2c_set_clientdata(client, NULL);
+ kfree(mcu);
+ return 0;
+}
+
+static const struct i2c_device_id mcu_ids[] = {
+ { "mcu-mpc8349emitx", },
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, mcu_ids);
+
+static struct i2c_driver mcu_driver = {
+ .driver = {
+ .name = "mcu-mpc8349emitx",
+ .owner = THIS_MODULE,
+ },
+ .probe = mcu_probe,
+ .remove = __devexit_p(mcu_remove),
+ .id_table = mcu_ids,
+};
+
+static int __init mcu_init(void)
+{
+ return i2c_add_driver(&mcu_driver);
+}
+module_init(mcu_init);
+
+static void __exit mcu_exit(void)
+{
+ i2c_del_driver(&mcu_driver);
+}
+module_exit(mcu_exit);
+
+MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
+ "MPC8349E-mITX-compatible MCU");
+MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
+MODULE_LICENSE("GPL");
projects / deliverable / linux.git / commitdiff
