diff options
Diffstat (limited to 'drivers/i2c/chips/mcu_mpc8349emitx.c')
| -rw-r--r-- | drivers/i2c/chips/mcu_mpc8349emitx.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/drivers/i2c/chips/mcu_mpc8349emitx.c b/drivers/i2c/chips/mcu_mpc8349emitx.c new file mode 100644 index 0000000..82a9bcb --- /dev/null +++ b/drivers/i2c/chips/mcu_mpc8349emitx.c @@ -0,0 +1,209 @@ +/* + * 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"); |
