Subject: Re: [i2c] [PATCH 2/2] i2c: MPC8349E-mITX Power Management and GPIO expander driver

From: Ben Dooks <[email-masked]>
Date: Mon, 22 Sep 2008 23:45:40 +0100

On Fri, Sep 19, 2008 at 10:03:54PM +0400, Anton Vorontsov wrote:
> On MPC8349E-mITX, MPC8315E-RDB and MPC837x-RDB boards there is a
> Freescale MC9S08QG8 (MCU) chip with the custom firmware
> pre-programmed. The chip is used to power-off the board by the
> software, and to control some GPIO pins.

I suppose there's no other place for this sort of thing to go at
the moment other than drivers/i2c/chips.

I've also a driver for a similar PMU fitted to a number
of our boards that provides basic gpio (wakeup sources) and some
minimalist power management (so isn't really fit for regulator
framwork) and isn't really a gpio chip (so drivers/gpio isn't
really the place for it either.)
 
> Signed-off-by: Anton Vorontsov <[email-masked]>
> ---
>  drivers/i2c/chips/Kconfig            |   11 ++
>  drivers/i2c/chips/Makefile           |    1 +
>  drivers/i2c/chips/mcu_mpc8349emitx.c |  213 ++++++++++++++++++++++++++++++++++
>  3 files changed, 225 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/i2c/chips/mcu_mpc8349emitx.c
> 
> diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
> index a95cb94..1735682 100644
> --- a/drivers/i2c/chips/Kconfig
> +++ b/drivers/i2c/chips/Kconfig
> @@ -172,4 +172,15 @@ config MENELAUS
>  	  and other features that are often used in portable devices like
>  	  cell phones and PDAs.
>  
> +config MCU_MPC8349EMITX
> +	tristate "MPC8349E-mITX MCU driver"
> +	depends on I2C && PPC_83xx
> +	select GENERIC_GPIO
> +	select ARCH_REQUIRE_GPIOLIB
> +	help
> +	  Say Y here to enable soft power-off functionality on the Freescale
> +	  boards with the MPC8349E-mITX-compatible MCU chips. This driver will
> +	  also register MCU GPIOs with the generic GPIO API, so you'll able
> +	  to use MCU pins as GPIOs.
> +
>  endmenu
> diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
> index 39e3e69..ca520fa 100644
> --- a/drivers/i2c/chips/Makefile
> +++ b/drivers/i2c/chips/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_ISP1301_OMAP)	+= isp1301_omap.o
>  obj-$(CONFIG_TPS65010)		+= tps65010.o
>  obj-$(CONFIG_MENELAUS)		+= menelaus.o
>  obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
> +obj-$(CONFIG_MCU_MPC8349EMITX)	+= mcu_mpc8349emitx.o
>  
>  ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
>  EXTRA_CFLAGS += -DDEBUG
> diff --git a/drivers/i2c/chips/mcu_mpc8349emitx.c b/drivers/i2c/chips/mcu_mpc8349emitx.c
> new file mode 100644
> index 0000000..47b07b8
> --- /dev/null
> +++ b/drivers/i2c/chips/mcu_mpc8349emitx.c
> @@ -0,0 +1,213 @@
> +/*
> + * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
> + *
> + * Copyright (c) 2008  MontaVista Software, Inc.
> + *
> + * Author: Anton Vorontsov <[email-masked]>
> + *
> + * 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[] = {
> +	{ "mc9s08qg8-mpc8349emitx", },
> +	{ "mc9s08qg8-mpc8377rdb", },
> +	{ "mc9s08qg8-mpc8378rdb", },
> +	{ "mc9s08qg8-mpc8379rdb", },
> +	{ "mc9s08qg8-mpc8315rdb", },
> +	{},
> +};
> +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 <[email-masked]>");
> +MODULE_LICENSE("GPL");
> -- 
> 1.5.6.3
> 
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-- 
Ben ([email-masked], http://www.fluff.org/)

  'a smiley only costs 4 bytes'