210 lines
4.4 KiB
C
210 lines
4.4 KiB
C
/*
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* Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
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*
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* Copyright (c) 2008 MontaVista Software, Inc.
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*
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* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/i2c.h>
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#include <linux/gpio.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <asm/prom.h>
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#include <asm/machdep.h>
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/*
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* I don't have specifications for the MCU firmware, I found this register
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* and bits positions by the trial&error method.
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*/
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#define MCU_REG_CTRL 0x20
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#define MCU_CTRL_POFF 0x40
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#define MCU_NUM_GPIO 2
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struct mcu {
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struct mutex lock;
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struct device_node *np;
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struct i2c_client *client;
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struct of_gpio_chip of_gc;
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u8 reg_ctrl;
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};
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static struct mcu *glob_mcu;
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static void mcu_power_off(void)
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{
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struct mcu *mcu = glob_mcu;
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pr_info("Sending power-off request to the MCU...\n");
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mutex_lock(&mcu->lock);
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i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
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mcu->reg_ctrl | MCU_CTRL_POFF);
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mutex_unlock(&mcu->lock);
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}
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static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
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struct mcu *mcu = container_of(of_gc, struct mcu, of_gc);
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u8 bit = 1 << (4 + gpio);
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mutex_lock(&mcu->lock);
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if (val)
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mcu->reg_ctrl &= ~bit;
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else
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mcu->reg_ctrl |= bit;
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i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
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mutex_unlock(&mcu->lock);
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}
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static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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mcu_gpio_set(gc, gpio, val);
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return 0;
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}
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static int mcu_gpiochip_add(struct mcu *mcu)
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{
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struct device_node *np;
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struct of_gpio_chip *of_gc = &mcu->of_gc;
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struct gpio_chip *gc = &of_gc->gc;
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int ret;
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np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
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if (!np)
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return -ENODEV;
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gc->owner = THIS_MODULE;
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gc->label = np->full_name;
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gc->can_sleep = 1;
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gc->ngpio = MCU_NUM_GPIO;
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gc->base = -1;
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gc->set = mcu_gpio_set;
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gc->direction_output = mcu_gpio_dir_out;
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of_gc->gpio_cells = 2;
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of_gc->xlate = of_gpio_simple_xlate;
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np->data = of_gc;
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mcu->np = np;
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/*
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* We don't want to lose the node, its ->data and ->full_name...
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* So, if succeeded, we don't put the node here.
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*/
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ret = gpiochip_add(gc);
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if (ret)
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of_node_put(np);
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return ret;
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}
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static int mcu_gpiochip_remove(struct mcu *mcu)
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{
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int ret;
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ret = gpiochip_remove(&mcu->of_gc.gc);
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if (ret)
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return ret;
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of_node_put(mcu->np);
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return 0;
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}
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static int __devinit mcu_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct mcu *mcu;
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int ret;
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mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
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if (!mcu)
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return -ENOMEM;
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mutex_init(&mcu->lock);
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mcu->client = client;
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i2c_set_clientdata(client, mcu);
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ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
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if (ret < 0)
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goto err;
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mcu->reg_ctrl = ret;
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ret = mcu_gpiochip_add(mcu);
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if (ret)
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goto err;
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/* XXX: this is potentially racy, but there is no lock for ppc_md */
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if (!ppc_md.power_off) {
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glob_mcu = mcu;
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ppc_md.power_off = mcu_power_off;
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dev_info(&client->dev, "will provide power-off service\n");
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}
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return 0;
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err:
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kfree(mcu);
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return ret;
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}
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static int __devexit mcu_remove(struct i2c_client *client)
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{
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struct mcu *mcu = i2c_get_clientdata(client);
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int ret;
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if (glob_mcu == mcu) {
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ppc_md.power_off = NULL;
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glob_mcu = NULL;
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}
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ret = mcu_gpiochip_remove(mcu);
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if (ret)
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return ret;
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i2c_set_clientdata(client, NULL);
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kfree(mcu);
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return 0;
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}
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static const struct i2c_device_id mcu_ids[] = {
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{ "mcu-mpc8349emitx", },
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{},
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};
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MODULE_DEVICE_TABLE(i2c, mcu_ids);
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static struct i2c_driver mcu_driver = {
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.driver = {
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.name = "mcu-mpc8349emitx",
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.owner = THIS_MODULE,
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},
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.probe = mcu_probe,
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.remove = __devexit_p(mcu_remove),
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.id_table = mcu_ids,
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};
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static int __init mcu_init(void)
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{
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return i2c_add_driver(&mcu_driver);
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}
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module_init(mcu_init);
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static void __exit mcu_exit(void)
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{
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i2c_del_driver(&mcu_driver);
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}
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module_exit(mcu_exit);
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MODULE_DESCRIPTION("Power Management and GPIO expander driver for "
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"MPC8349E-mITX-compatible MCU");
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MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
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MODULE_LICENSE("GPL");
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