Date:	Tue, 19 May 2009 17:35:33 +0300
From:	Mike Rapoport <mike@...pulab.co.il>
To:	Linus Walleij <linus.ml.walleij@...il.com>
CC:	linux-kernel@...r.kernel.org, sameo@...ux.intel.com,
	linux-i2c@...r.kernel.org,
	Linus Walleij <linus.walleij@...ricsson.com>
Subject: Re: [PATCH 1/1] MFD: Add U300 AB3100 core support v2



Linus Walleij wrote:
> This adds a core driver for the AB3100 mixed-signal circuit
> found in the ST-Ericsson U300 series platforms. This driver
> is a singleton proxy for all accesses to the AB3100
> sub-drivers which will be merged on top of this one, RTC,
> regulators, battery and system power control, vibrator,
> LEDs, and an ALSA codec.
> 
> Signed-off-by: Linus Walleij <linus.walleij@...ricsson.com>
> Reviewed-by: Mike Rapoport <mike@...pulab.co.il>
> Reviewed-by: Samuel Ortiz <sameo@...ux.intel.com>
> ---
>  drivers/mfd/Kconfig        |   14 +
>  drivers/mfd/Makefile       |    3 +-
>  drivers/mfd/ab3100-core.c  |  961 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/ab3100.h |   98 +++++
>  4 files changed, 1078 insertions(+), 1 deletions(-)
>  create mode 100755 drivers/mfd/ab3100-core.c
>  create mode 100644 include/linux/mfd/ab3100.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index ee3927a..61f0346 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -241,6 +241,20 @@ config PCF50633_GPIO
>  	 Say yes here if you want to include support GPIO for pins on
>  	 the PCF50633 chip.
> 
> +config AB3100_CORE
> +	tristate "ST-Ericsson AB3100 Mixed Signal Circuit core functions"
> +	depends on I2C
> +	default y if ARCH_U300
> +	help
> +	  Select this to enable the AB3100 Mixed Signal IC core
> +	  functionality. This connects to a AB3100 on the I2C bus
> +	  and expose a number of symbols needed for dependent devices
> +	  to read and write registers and subscribe to events from
> +	  this multi-functional IC. This is needed to use other features
> +	  of the AB3100 such as battery-backed RTC, charging control,
> +	  LEDs, vibrator, system power and temperature, power management
> +	  and ALSA sound.
> +
>  endmenu
> 
>  menu "Multimedia Capabilities Port drivers"
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 3afb519..f5f3371 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -40,4 +40,5 @@ obj-$(CONFIG_PMIC_DA903X)	+= da903x.o
> 
>  obj-$(CONFIG_MFD_PCF50633)	+= pcf50633-core.o
>  obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
> -obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
> \ No newline at end of file
> +obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
> +obj-$(CONFIG_AB3100_CORE)	+= ab3100-core.o
> diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
> new file mode 100755
> index 0000000..c566b0f
> --- /dev/null
> +++ b/drivers/mfd/ab3100-core.c
> @@ -0,0 +1,961 @@
> +/*
> + * Copyright (C) 2007-2009 ST-Ericsson
> + * License terms: GNU General Public License (GPL) version 2
> + * Low-level core for exclusive access to the AB3100 IC on the I2C bus
> + * and some basic chip-configuration.
> + * Author: Linus Walleij <linus.walleij@...ricsson.com>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +#include <linux/list.h>
> +#include <linux/notifier.h>
> +#include <linux/err.h>
> +#include <linux/platform_device.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/workqueue.h>
> +#include <linux/debugfs.h>
> +#include <linux/seq_file.h>
> +#include <linux/uaccess.h>
> +#include <linux/mfd/ab3100.h>
> +
> +/* These are the only registers inside AB3100 used in this main file */
> +
> +/* Interrupt event registers */
> +#define AB3100_EVENTA1		0x21
> +#define AB3100_EVENTA2		0x22
> +#define AB3100_EVENTA3		0x23
> +
> +/* AB3100 DAC converter registers */
> +#define AB3100_DIS		0x00
> +#define AB3100_D0C		0x01
> +#define AB3100_D1C		0x02
> +#define AB3100_D2C		0x03
> +#define AB3100_D3C		0x04
> +
> +/* Chip ID register */
> +#define AB3100_CID		0x20
> +
> +/* AB3100 interrupt registers */
> +#define AB3100_IMRA1		0x24
> +#define AB3100_IMRA2		0x25
> +#define AB3100_IMRA3		0x26
> +#define AB3100_IMRB1		0x2B
> +#define AB3100_IMRB2		0x2C
> +#define AB3100_IMRB3		0x2D
> +
> +/* System Power Monitoring and control registers */
> +#define AB3100_MCA		0x2E
> +#define AB3100_MCB		0x2F
> +
> +/* SIM power up */
> +#define AB3100_SUP		0x50
> +
> +/* Initial settings of ab3100 registers */
> +#define DIS_SETTING		0xF0
> +#define D0C_SETTING		0x00
> +#define D1C_SETTING		0x00
> +#define D2C_SETTING		0x00
> +#define D3C_SETTING		0x00
> +
> +#define IMRA1_SETTING		0x00
> +#define IMRA2_SETTING		0xFF
> +#define IMRA3_SETTING		0x01
> +#define IMRB1_SETTING		0xFF
> +#define IMRB2_SETTING		0xFF
> +#define IMRB3_SETTING		0xFF
> +#define MCB_SETTING		0x30
> +#define SUP_SETTING		0x00
> +
> +/*
> + * I2C communication
> + *
> + * The AB3100 is assigned address 0x48 (7-bit)
> + * Since the driver does not require SMBus support, we
> + * cannot be sure to probe for the device address here,
> + * so the boot loader or modprobe may need to pass in a parameter
> + * like ab3100-core.force=0,0x48.
> + *
> + */
> +static unsigned short normal_i2c[] = { 0x48, I2C_CLIENT_END };
> +I2C_CLIENT_INSMOD_1(ab3100);
> +
> +/* A local all-containing singleton */
> +static struct ab3100 *ab3100_local;
> +
> +u8 ab3100_get_chip_type(struct ab3100 *ab3100_data)
> +{
> +	u8 chip = ABUNKNOWN;
> +
> +	switch (ab3100_data->chip_id & 0xf0) {
> +	case  0xa0:
> +		chip = AB3000;
> +		break;
> +	case  0xc0:
> +		chip = AB3100;
> +		break;
> +	}
> +	return chip;
> +}
> +EXPORT_SYMBOL(ab3100_get_chip_type);
> +
> +int ab3100_set_register(struct ab3100 *ab3100_data, u8 reg, u8 regval)
> +{
> +	u8 regandval[2] = {reg, regval};
> +	int err;
> +
> +	err = mutex_lock_interruptible(&ab3100_data->access_mutex);
> +	if (err)
> +		return err;
> +
> +	/*
> +	 * A two-byte write message with the first byte containing the register
> +	 * number and the second byte containing the value to be written
> +	 * effectively sets a register in the AB3100.
> +	 */
> +	err = i2c_master_send(ab3100_data->i2c_client, regandval, 2);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (write register): %d\n",
> +			err);
> +	} else if (err != 2) {
> +		dev_err(ab3100_data->dev,
> +			"write error (write register) "
> +			"%d bytes transferred (expected 2)\n",
> +			err);
> +		err = -EIO;
> +	} else {
> +		/* All is well */
> +		err = 0;
> +	}
> +	mutex_unlock(&ab3100_data->access_mutex);
> +	return 0;
> +}
> +EXPORT_SYMBOL(ab3100_set_register);
> +
> +/*
> + * The test registers exist at an I2C bus address up one
> + * from the ordinary base. They are not supposed to be used
> + * in production code, but sometimes you have to do that
> + * anyway. It's currently only used from this file so declare
> + * it static and do not export.
> + */
> +static int ab3100_set_test_register(u8 reg, u8 regval)
> +{
> +	u8 regandval[2] = {reg, regval};
> +	int err;
> +
> +	err = mutex_lock_interruptible(&ab3100_local->access_mutex);
> +	if (err)
> +		return err;
> +
> +	err = i2c_master_send(ab3100_local->testreg_client, regandval, 2);
> +	if (err < 0) {
> +		dev_err(ab3100_local->dev,
> +			"write error (write test register): %d\n",
> +			err);
> +	} else if (err != 2) {
> +		dev_err(ab3100_local->dev,
> +			"write error (write test register) "
> +			"%d bytes transferred (expected 2)\n",
> +			err);
> +		err = -EIO;
> +	} else {
> +		/* All is well */
> +		err = 0;
> +	}
> +	mutex_unlock(&ab3100_local->access_mutex);
> +
> +	return err;
> +}
> +
> +int ab3100_get_register(struct ab3100 *ab3100_data, u8 reg, u8 *regval)
> +{
> +	int err;
> +
> +	err = mutex_lock_interruptible(&ab3100_data->access_mutex);
> +	if (err)
> +		return err;
> +
> +	/*
> +	 * AB3100 require an I2C "stop" command between each message, else
> +	 * it will not work. The only way of achieveing this with the
> +	 * message transport layer is to send the read and write messages
> +	 * separately.
> +	 */
> +	err = i2c_master_send(ab3100_data->i2c_client, &reg, 1);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (send register address): %d\n",
> +			err);
> +		goto get_reg_out_unlock;
> +	} else if (err != 1) {
> +		dev_err(ab3100_data->dev,
> +			"write error (send register address) "
> +			"%d bytes transferred (expected 1)\n",
> +			err);
> +		err = -EIO;
> +		goto get_reg_out_unlock;
> +	} else {
> +		/* All is well */
> +		err = 0;
> +	}
> +
> +	err = i2c_master_recv(ab3100_data->i2c_client, regval, 1);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (read register): %d\n",
> +			err);
> +		goto get_reg_out_unlock;
> +	} else if (err != 1) {
> +		dev_err(ab3100_data->dev,
> +			"write error (read register) "
> +			"%d bytes transferred (expected 1)\n",
> +			err);
> +		err = -EIO;
> +		goto get_reg_out_unlock;
> +	} else {
> +		/* All is well */
> +		err = 0;
> +	}
> +
> + get_reg_out_unlock:
> +	mutex_unlock(&ab3100_data->access_mutex);
> +	return err;
> +}
> +EXPORT_SYMBOL(ab3100_get_register);
> +
> +int ab3100_get_register_page(struct ab3100 *ab3100_data,
> +			     u8 first_reg, u8 *regvals, u8 numregs)
> +{
> +	int err;
> +
> +	if (ab3100_data->chip_id == 0xa0 ||
> +	    ab3100_data->chip_id == 0xa1)
> +		/* These don't support paged reads */
> +		return -EIO;
> +
> +	err = mutex_lock_interruptible(&ab3100_data->access_mutex);
> +	if (err)
> +		return err;
> +
> +	/*
> +	 * Paged read also require an I2C "stop" command.
> +	 */
> +	err = i2c_master_send(ab3100_data->i2c_client, &first_reg, 1);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (send first register address): %d\n",
> +			err);
> +		goto get_reg_page_out_unlock;
> +	} else if (err != 1) {
> +		dev_err(ab3100_data->dev,
> +			"write error (send first register address) "
> +			"%d bytes transferred (expected 1)\n",
> +			err);
> +		err = -EIO;
> +		goto get_reg_page_out_unlock;
> +	}
> +
> +	err = i2c_master_recv(ab3100_data->i2c_client, regvals, numregs);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (read register page): %d\n",
> +			err);
> +		goto get_reg_page_out_unlock;
> +	} else if (err != numregs) {
> +		dev_err(ab3100_data->dev,
> +			"write error (read register page) "
> +			"%d bytes transferred (expected %d)\n",
> +			err, numregs);
> +		err = -EIO;
> +		goto get_reg_page_out_unlock;
> +	}
> +
> +	/* All is well */
> +	err = 0;
> +
> + get_reg_page_out_unlock:
> +	mutex_unlock(&ab3100_data->access_mutex);
> +	return err;
> +}
> +EXPORT_SYMBOL(ab3100_get_register_page);
> +
> +int ab3100_mask_and_set_register(struct ab3100 *ab3100_data,
> +				 u8 reg, u8 andmask, u8 ormask)
> +{
> +	u8 regandval[2] = {reg, 0};
> +	int err;
> +
> +	err = mutex_lock_interruptible(&ab3100_data->access_mutex);
> +	if (err)
> +		return err;
> +
> +	/* First read out the target register */
> +	err = i2c_master_send(ab3100_data->i2c_client, &reg, 1);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (maskset send address): %d\n",
> +			err);
> +		goto get_maskset_unlock;
> +	} else if (err != 1) {
> +		dev_err(ab3100_data->dev,
> +			"write error (maskset send address) "
> +			"%d bytes transferred (expected 1)\n",
> +			err);
> +		err = -EIO;
> +		goto get_maskset_unlock;
> +	}
> +
> +	err = i2c_master_recv(ab3100_data->i2c_client, &regandval[1], 1);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (maskset read register): %d\n",
> +			err);
> +		goto get_maskset_unlock;
> +	} else if (err != 1) {
> +		dev_err(ab3100_data->dev,
> +			"write error (maskset read register) "
> +			"%d bytes transferred (expected 1)\n",
> +			err);
> +		err = -EIO;
> +		goto get_maskset_unlock;
> +	}
> +
> +	/* Modify the register */
> +	regandval[1] &= andmask;
> +	regandval[1] |= ormask;
> +
> +	/* Write the register */
> +	err = i2c_master_send(ab3100_data->i2c_client, regandval, 2);
> +	if (err < 0) {
> +		dev_err(ab3100_data->dev,
> +			"write error (write register): %d\n",
> +			err);
> +		goto get_maskset_unlock;
> +	} else if (err != 2) {
> +		dev_err(ab3100_data->dev,
> +			"write error (write register) "
> +			"%d bytes transferred (expected 2)\n",
> +			err);
> +		err = -EIO;
> +		goto get_maskset_unlock;
> +	}
> +
> +	/* All is well */
> +	err = 0;
> +
> + get_maskset_unlock:
> +	mutex_unlock(&ab3100_data->access_mutex);
> +	return err;
> +}
> +EXPORT_SYMBOL(ab3100_mask_and_set_register);
> +
> +/*
> + * Register a simple callback for handling any AB3100 events.
> + */
> +int ab3100_event_register(struct ab3100 *ab3100_data,
> +			  struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_register(&ab3100_data->event_subscribers,
> +					       nb);
> +}
> +EXPORT_SYMBOL(ab3100_event_register);
> +
> +/*
> + * Remove a previously registered callback.
> + */
> +int ab3100_event_unregister(struct ab3100 *ab3100_data,
> +			    struct notifier_block *nb)
> +{
> +  return blocking_notifier_chain_unregister(&ab3100_data->event_subscribers,
> +					    nb);
> +}
> +EXPORT_SYMBOL(ab3100_event_unregister);
> +
> +
> +int ab3100_event_registers_startup_state_get(struct ab3100 *ab3100_data,
> +					     u32 *fatevent)
> +{
> +	if (!ab3100_data->startup_events_read)
> +		return -EAGAIN; /* Try again later */
> +	*fatevent = ab3100_data->startup_events;
> +	return 0;
> +}
> +EXPORT_SYMBOL(ab3100_event_registers_startup_state_get);
> +
> +/* Interrupt handling worker */
> +static void ab3100_work(struct work_struct *work)
> +{
> +	u8 event_regs[3];
> +	u32 fatevent;
> +	int err;
> +
> +	err = ab3100_get_register_page(ab3100_local, AB3100_EVENTA1,
> +				       event_regs, 3);
> +	if (err)
> +		goto err_event_wq;
> +
> +	fatevent = (event_regs[0] << 16) |
> +		(event_regs[1] << 8) |
> +		event_regs[2];
> +
> +	if (!ab3100_local->startup_events_read) {
> +		ab3100_local->startup_events = fatevent;
> +		ab3100_local->startup_events_read = true;
> +	}
> +	/*
> +	 * The notified parties will have to mask out the events
> +	 * they're interested in and react to them. They will be
> +	 * notified on all events, then they use the fatevent value
> +	 * to determine if they're interested.
> +	 */
> +	blocking_notifier_call_chain(&ab3100_local->event_subscribers,
> +				     fatevent, NULL);
> +
> +	dev_dbg(ab3100_local->dev,
> +		"IRQ Event: 0x%08x\n", fatevent);
> +
> +	/* By now the IRQ should be acked and deasserted so enable it again */
> +	enable_irq(ab3100_local->i2c_client->irq);
> +	return;
> +
> + err_event_wq:
> +	dev_dbg(ab3100_local->dev,
> +		"error in event workqueue\n");
> +	/* Enable the IRQ anyway, what choice do we have? */
> +	enable_irq(ab3100_local->i2c_client->irq);
> +	return;
> +}
> +
> +static irqreturn_t ab3100_irq_handler(int irq, void *data)
> +{
> +	/*
> +	 * Disable the IRQ and dispatch a worker to handle the
> +	 * event. Since the chip resides on I2C this is slow
> +	 * stuff and we will re-enable the interrupts once th
> +	 * worker has finished.
> +	 */
> +	disable_irq(ab3100_local->i2c_client->irq);
> +	schedule_work(&ab3100_local->work);
> +	return IRQ_HANDLED;
> +}
> +
> +#if defined(CONFIG_U300_DEBUG) && defined(CONFIG_DEBUG_FS)
> +/*
> + * Some debugfs entries only exposed if we're using debug
> + */
> +static int ab3100_registers_print(struct seq_file *s, void *p)
> +{
> +	u8 value;
> +	u8 reg;
> +
> +	seq_printf(s, "AB3100 registers:\n");
> +
> +	for (reg = 0; reg < 0xff; reg++) {
> +		ab3100_get_register(ab3100_local, reg, &value);
> +		seq_printf(s, "[0x%x]:  0x%x\n", reg, value);
> +	}
> +	return 0;
> +}
> +
> +static int ab3100_registers_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, ab3100_registers_print, inode->i_private);
> +}
> +
> +static const struct file_operations ab3100_registers_fops = {
> +	.open = ab3100_registers_open,
> +	.read = seq_read,
> +	.llseek = seq_lseek,
> +	.release = single_release,
> +	.owner = THIS_MODULE,
> +};
> +
> +static int ab3100_get_set_reg_open_file(struct inode *inode, struct file *file)
> +{
> +	file->private_data = inode->i_private;
> +	return 0;
> +}
> +
> +static int ab3100_get_set_reg(struct file *file,
> +			      const char __user *user_buf,
> +			      size_t count, loff_t *ppos)
> +{
> +	int mode = (int) file->private_data;
> +	char buf[32];
> +	int buf_size;
> +	int regp;
> +	unsigned long user_reg;
> +	int err;
> +	int i = 0;
> +
> +	/* Get userspace string and assure termination */
> +	buf_size = min(count, (sizeof(buf)-1));
> +	if (copy_from_user(buf, user_buf, buf_size))
> +		return -EFAULT;
> +	buf[buf_size] = 0;
> +
> +	/*
> +	 * The idea is here to parse a string which is either
> +	 * "0xnn" for reading a register, or "0xaa 0xbb" for
> +	 * writing 0xbb to the register 0xaa. First move past
> +	 * whitespace and then begin to parse the register.
> +	 */
> +	while ((i < buf_size) && (buf[i] == ' '))
> +		i++;
> +	regp = i;
> +
> +	/*
> +	 * Advance pointer to end of string then terminate
> +	 * the register string. This is needed to satisfy
> +	 * the strict_strtoul() function.
> +	 */
> +	while ((i < buf_size) && (buf[i] != ' '))
> +		i++;
> +	buf[i] = '\0';
> +
> +	err = strict_strtoul(&buf[regp], 16, &user_reg);
> +	if (err)
> +		return err;
> +	if (user_reg > 0xff)
> +		return -EINVAL;
> +
> +	/* Either we read or we write a register here */
> +	if (!mode) {
> +		/* Reading */
> +		u8 reg = (u8) user_reg;
> +		u8 regvalue;
> +
> +		ab3100_get_register(ab3100_local, reg, &regvalue);
> +
> +		dev_info(ab3100_local->dev,
> +			 "debug read AB3100 reg[0x%02x]: 0x%02x\n",
> +			 reg, regvalue);
> +	} else {
> +		int valp;
> +		unsigned long user_value;
> +		u8 reg = (u8) user_reg;
> +		u8 value;
> +		u8 regvalue;
> +
> +		/*
> +		 * Writing, we need some value to write to
> +		 * the register so keep parsing the string
> +		 * from userspace.
> +		 */
> +		i++;
> +		while ((i < buf_size) && (buf[i] == ' '))
> +			i++;
> +		valp = i;
> +		while ((i < buf_size) && (buf[i] != ' '))
> +			i++;
> +		buf[i] = '\0';
> +
> +		err = strict_strtoul(&buf[valp], 16, &user_value);
> +		if (err)
> +			return err;
> +		if (user_reg > 0xff)
> +			return -EINVAL;
> +
> +		value = (u8) user_value;
> +		ab3100_set_register(ab3100_local, reg, value);
> +		ab3100_get_register(ab3100_local, reg, &regvalue);
> +
> +		dev_info(ab3100_local->dev,
> +			 "debug write reg[0x%02x] with 0x%02x, "
> +			 "after readback: 0x%02x\n",
> +			 reg, value, regvalue);
> +	}
> +	return buf_size;
> +}
> +
> +static const struct file_operations ab3100_get_set_reg_fops = {
> +	.open = ab3100_get_set_reg_open_file,
> +	.write = ab3100_get_set_reg,
> +};
> +
> +static struct dentry *ab3100_dir;
> +static struct dentry *ab3100_reg_file;
> +static struct dentry *ab3100_get_reg_file;
> +static struct dentry *ab3100_set_reg_file;
> +
> +static void ab3100_setup_debugfs(void)
> +{
> +	int err;
> +
> +	ab3100_dir = debugfs_create_dir("ab3100", NULL);
> +	if (!ab3100_dir)
> +		goto exit_no_debugfs;
> +
> +	ab3100_reg_file = debugfs_create_file("registers",
> +				S_IRUGO, ab3100_dir, NULL,
> +				&ab3100_registers_fops);
> +	if (!ab3100_reg_file) {
> +		err = -ENOMEM;
> +		goto exit_destroy_dir;
> +	}
> +
> +	ab3100_get_reg_file = debugfs_create_file("get_reg",
> +				S_IRUGO, ab3100_dir, (void *) 0,
> +				&ab3100_get_set_reg_fops);
> +	if (!ab3100_get_reg_file) {
> +		err = -ENOMEM;
> +		goto exit_destroy_reg;
> +	}
> +
> +	ab3100_set_reg_file = debugfs_create_file("set_reg",
> +				S_IRUGO, ab3100_dir, (void *) 1,
> +				&ab3100_get_set_reg_fops);
> +	if (!ab3100_set_reg_file) {
> +		err = -ENOMEM;
> +		goto exit_destroy_get_reg;
> +	}
> +	return;
> +
> + exit_destroy_get_reg:
> +	debugfs_remove(ab3100_get_reg_file);
> + exit_destroy_reg:
> +	debugfs_remove(ab3100_reg_file);
> + exit_destroy_dir:
> +	debugfs_remove(ab3100_dir);
> + exit_no_debugfs:
> +	return;
> +}
> +static inline void ab3100_remove_debugfs(void)
> +{
> +	debugfs_remove(ab3100_set_reg_file);
> +	debugfs_remove(ab3100_get_reg_file);
> +	debugfs_remove(ab3100_reg_file);
> +	debugfs_remove(ab3100_dir);
> +}
> +#else
> +static inline void ab3100_setup_debugfs(void)
> +{
> +}
> +static inline void ab3100_remove_debugfs(void)
> +{
> +}
> +#endif
> +
> +/*
> + * Basic set-up, datastructure creation/destruction and I2C interface.
> + * This sets up a default config in the AB3100 chip so that it
> + * will work as expected.
> + */
> +static int __init ab3100_setup(void)
> +{
> +	int err = 0;
> +
> +	/* Force internal oscillator */
> +	err = ab3100_set_register(ab3100_local, AB3100_MCA, 0x01);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_MCB, MCB_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRA1, IMRA1_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRA2, IMRA2_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRA3, IMRA3_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRB1, IMRB1_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRB2, IMRB2_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_IMRB3, IMRB3_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_SUP, SUP_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_DIS, DIS_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_D0C, D0C_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_D1C, D1C_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_D2C, D2C_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	err = ab3100_set_register(ab3100_local, AB3100_D3C, D3C_SETTING);
> +	if (err)
> +		goto exit_no_setup;
> +
> +	/*
> +	 * Special trick to make the AB3100 use the 32kHz clock (RTC)
> +	 * bit 3 in test registe 0x02 is a special, undocumented test
> +	 * register bit that only exist in AB3100 P1E
> +	 */
> +	if (ab3100_local->chip_id == 0xc4) {
> +		dev_warn(ab3100_local->dev,
> +			 "AB3100 P1E variant detected, "
> +			 "forcing chip to 32KHz\n");
> +		err = ab3100_set_test_register(0x02, 0x08);
> +	}
> +
> + exit_no_setup:
> +	return err;
> +}
> +
> +/*
> + * Here we define all the platform devices that appear
> + * as children of the AB3100. These are regular platform
> + * devices with the IORESOURCE_IO .start and .end set
> + * to correspond to the internal AB3100 register range
> + * mapping to the corresponding subdevice.
> + */
> +
> +#define AB3100_DEVICE(devname, devid, regstart, regend)		\
> +static struct resource ab3100_##devname##_resource[] = {	\
> +	{							\
> +		.start	= regstart,				\
> +		.end	= regend,				\
> +		.flags	= IORESOURCE_IO,			\
> +	}							\
> +};								\
> +static struct platform_device ab3100_##devname##_device = {	\
> +	.name		= devid,				\
> +	.id		= -1,					\
> +	.resource	= ab3100_##devname##_resource,		\
> +	.num_resources	= 1,					\
> +}
> +
> +/*
> + * This lists all the subdevices and corresponding register
> + * ranges.
> + */
> +AB3100_DEVICE(dac, "ab3100-dac", 0x00, 0x0c);
> +/* LEDs actually 0x11-0x1f and 0x31-0x3f */
> +AB3100_DEVICE(leds, "ab3100-leds", 0x11, 0x3f);
> +AB3100_DEVICE(power, "ab3100-power", 0x20, 0x2f);
> +AB3100_DEVICE(regulators, "ab3100-regulators", 0x40, 0x4b);
> +AB3100_DEVICE(sim, "ab3100-sim", 0x50, 0x50);
> +AB3100_DEVICE(uart, "ab3100-uart", 0x51, 0x52);
> +AB3100_DEVICE(rtc, "ab3100-rtc", 0x53, 0x5f);
> +AB3100_DEVICE(charger, "ab3100-charger", 0x60, 0x64);
> +AB3100_DEVICE(boost, "ab3100-boost", 0x6a, 0x6b);
> +AB3100_DEVICE(adc, "ab3100-adc", 0x73, 0x95);
> +AB3100_DEVICE(fuelgauge, "ab3100-fuelgauge", 0x9a, 0x9f);
> +AB3100_DEVICE(vibrator, "ab3100-vibrator", 0xa0, 0xa2);
> +AB3100_DEVICE(otp, "ab3100-otp", 0xb0, 0xbf);
> +AB3100_DEVICE(codec, "ab3100-codec", 0xc0, 0xee);
> +
> +static struct platform_device *
> +ab3100_platform_devs[] = {
> +	&ab3100_dac_device,
> +	&ab3100_leds_device,
> +	&ab3100_power_device,
> +	&ab3100_regulators_device,
> +	&ab3100_sim_device,
> +	&ab3100_uart_device,
> +	&ab3100_rtc_device,
> +	&ab3100_charger_device,
> +	&ab3100_boost_device,
> +	&ab3100_adc_device,
> +	&ab3100_fuelgauge_device,
> +	&ab3100_vibrator_device,
> +	&ab3100_otp_device,
> +	&ab3100_codec_device,
> +};
> +
> +struct ab_family_id {
> +	u8	id;
> +	char	*name;
> +};
> +
> +static const struct ab_family_id ids[] __initdata = {
> +	{0xc0, "P1A"}, /* AB3100 */
> +	{0xc1, "P1B"},
> +	{0xc2, "P1C"},
> +	{0xc3, "P1D"},
> +	{0xc4, "P1E"},
> +	{0xc5, "P1F/R1A"},
> +	{0xc6, "P1G/R1A"},
> +	{0xc7, "P2A/R2A"},
> +	{0xc8, "P2B/R2B"},
> +	{0xa0, NULL}, /* AB3000 */
> +	{0xa1, NULL},
> +	{0xa2, NULL},
> +	{0xa3, NULL},
> +	{0xa4, NULL},
> +	{0xa5, NULL},
> +	{0xa6, NULL},
> +	{0xa7, NULL},
> +	{0x00, NULL}
> +};
> +
> +static int __init ab3100_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	int err;
> +	int i;
> +
> +	ab3100_local = kzalloc(sizeof(struct ab3100), GFP_KERNEL);
> +	if (!ab3100_local)
> +		return -ENOMEM;
> +
> +	/* Initialize data structure */
> +	mutex_init(&ab3100_local->access_mutex);
> +	BLOCKING_INIT_NOTIFIER_HEAD(&ab3100_local->event_subscribers);
> +
> +	ab3100_local->i2c_client = client;
> +	ab3100_local->dev = &ab3100_local->i2c_client->dev;
> +
> +	/* Read chip ID register */
> +	err = ab3100_get_register(ab3100_local, AB3100_CID,
> +				  &ab3100_local->chip_id);
> +	if (err) {
> +		dev_err(&client->dev,
> +			"could not communicate with the AB3100 analog "
> +			"baseband chip\n");
> +		goto exit_no_detect;
> +	}
> +
> +	for (i = 0; ids[i].id != 0x0; i++) {
> +		if (ids[i].id == ab3100_local->chip_id) {
> +			if (ids[i].name != NULL) {
> +				snprintf(&ab3100_local->chip_name[0],
> +					 sizeof(ab3100_local->chip_name) - 1,
> +					 "AB3100 %s",
> +					 ids[i].name);
> +				break;
> +			} else {
> +				dev_err(&client->dev,
> +					"AB3000 is not supported\n");
> +				goto exit_no_detect;
> +			}
> +		}
> +	}
> +
> +	if (ids[i].id == 0x0) {
> +		dev_err(&client->dev, "unknown analog baseband chip id: 0x%x\n",
> +			ab3100_local->chip_id);
> +		dev_err(&client->dev, "accepting it anyway. Please update "
> +			"the driver.\n");
> +		goto exit_no_detect;
> +	}
> +
> +	dev_info(&client->dev, "Detected chip: %s\n",
> +		 &ab3100_local->chip_name[0]);
> +
> +	/* Attach a second dummy i2c_client to the test register address */
> +	ab3100_local->testreg_client = i2c_new_dummy(client->adapter,
> +						     client->addr + 1);
> +	if (!ab3100_local->testreg_client) {
> +		err = -ENOMEM;
> +		goto exit_no_testreg_client;
> +	}
> +
> +	strlcpy(ab3100_local->testreg_client->name, id->name,
> +		sizeof(ab3100_local->testreg_client->name));
> +
> +	err = ab3100_setup();
> +	if (err)
> +		goto exit_no_setup;
> +
> +	INIT_WORK(&ab3100_local->work, ab3100_work);
> +
> +	/* This real unpredictable IRQ is of course sampled for entropy */
> +	err = request_irq(client->irq, ab3100_irq_handler,
> +			  IRQF_DISABLED | IRQF_SAMPLE_RANDOM,
> +			  "AB3100 IRQ", ab3100_local);
> +	if (err)
> +		goto exit_no_irq;
> +
> +	/* Set a pointer back to the container in device data */
> +	for (i = 0; i < ARRAY_SIZE(ab3100_platform_devs); i++)
> +		platform_set_drvdata(ab3100_platform_devs[i], ab3100_local);
> +
> +	/* Register the platform devices */
> +	platform_add_devices(ab3100_platform_devs,
> +			     ARRAY_SIZE(ab3100_platform_devs));

If you register sub-devices this way, they won't appear as ab3100 children.
Besides, setting the sub-devices drvdata to point to the master device makes it
impossible for sub-device drivers to use this field for their needs.

> +	ab3100_setup_debugfs();
> +
> +	return 0;
> +
> + exit_no_irq:
> + exit_no_setup:
> +	i2c_unregister_device(ab3100_local->testreg_client);
> + exit_no_testreg_client:
> + exit_no_detect:
> +	kfree(ab3100_local);
> +	return err;
> +}
> +
> +static int __exit ab3100_remove(struct i2c_client *client)
> +{
> +	int i;
> +
> +	/* Unregister subdevices */
> +	for (i = 0; i < ARRAY_SIZE(ab3100_platform_devs); i++)
> +		platform_device_unregister(ab3100_platform_devs[i]);
> +
> +	ab3100_remove_debugfs();
> +	i2c_unregister_device(ab3100_local->testreg_client);
> +
> +	/*
> +	 * At this point, all subscribers should have unregistered
> +	 * their notifiers so deactivate IRQ
> +	 */
> +	free_irq(client->irq, ab3100_local);
> +	kfree(ab3100_local);
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ab3100_id[] = {
> +	{ "ab3100", ab3100 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, ab3100_id);
> +
> +static struct i2c_driver ab3100_driver = {
> +	.driver = {
> +		.name	= "ab3100",
> +		.owner	= THIS_MODULE,
> +	},
> +	.id_table	= ab3100_id,
> +	.probe		= ab3100_probe,
> +	.remove		= __exit_p(ab3100_remove),
> +};
> +
> +static int __init ab3100_i2c_init(void)
> +{
> +	return i2c_add_driver(&ab3100_driver);
> +}
> +
> +static void __exit ab3100_i2c_exit(void)
> +{
> +	i2c_del_driver(&ab3100_driver);
> +}
> +
> +subsys_initcall(ab3100_i2c_init);
> +module_exit(ab3100_i2c_exit);
> +
> +MODULE_AUTHOR("Linus Walleij <linus.walleij@...ricsson.com>");
> +MODULE_DESCRIPTION("AB3100 core driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/ab3100.h b/include/linux/mfd/ab3100.h
> new file mode 100644
> index 0000000..494bc9a
> --- /dev/null
> +++ b/include/linux/mfd/ab3100.h
> @@ -0,0 +1,98 @@
> +/*
> + * Copyright (C) 2007-2009 ST-Ericsson AB
> + * License terms: GNU General Public License (GPL) version 2
> + * AB3100 core access functions
> + * Author: Linus Walleij <linus.walleij@...ricsson.com>
> + */
> +
> +#include <linux/device.h>
> +
> +#ifndef MFD_AB3100_H
> +#define MFD_AB3100_H
> +
> +#define ABUNKNOWN	0
> +#define	AB3000		1
> +#define	AB3100		2
> +
> +/*
> + * AB3100, EVENTA1, A2 and A3 event register flags
> + * these are catenated into a single 32-bit flag in the code
> + * for event notification broadcasts.
> + */
> +#define AB3100_EVENTA1_ONSWA				(0x01<<16)
> +#define AB3100_EVENTA1_ONSWB				(0x02<<16)
> +#define AB3100_EVENTA1_ONSWC				(0x04<<16)
> +#define AB3100_EVENTA1_DCIO				(0x08<<16)
> +#define AB3100_EVENTA1_OVER_TEMP			(0x10<<16)
> +#define AB3100_EVENTA1_SIM_OFF				(0x20<<16)
> +#define AB3100_EVENTA1_VBUS				(0x40<<16)
> +#define AB3100_EVENTA1_VSET_USB				(0x80<<16)
> +
> +#define AB3100_EVENTA2_READY_TX				(0x01<<8)
> +#define AB3100_EVENTA2_READY_RX				(0x02<<8)
> +#define AB3100_EVENTA2_OVERRUN_ERROR			(0x04<<8)
> +#define AB3100_EVENTA2_FRAMING_ERROR			(0x08<<8)
> +#define AB3100_EVENTA2_CHARG_OVERCURRENT		(0x10<<8)
> +#define AB3100_EVENTA2_MIDR				(0x20<<8)
> +#define AB3100_EVENTA2_BATTERY_REM			(0x40<<8)
> +#define AB3100_EVENTA2_ALARM				(0x80<<8)
> +
> +#define AB3100_EVENTA3_ADC_TRIG5			(0x01)
> +#define AB3100_EVENTA3_ADC_TRIG4			(0x02)
> +#define AB3100_EVENTA3_ADC_TRIG3			(0x04)
> +#define AB3100_EVENTA3_ADC_TRIG2			(0x08)
> +#define AB3100_EVENTA3_ADC_TRIGVBAT			(0x10)
> +#define AB3100_EVENTA3_ADC_TRIGVTX			(0x20)
> +#define AB3100_EVENTA3_ADC_TRIG1			(0x40)
> +#define AB3100_EVENTA3_ADC_TRIG0			(0x80)
> +
> +/* AB3100, STR register flags */
> +#define AB3100_STR_ONSWA				(0x01)
> +#define AB3100_STR_ONSWB				(0x02)
> +#define AB3100_STR_ONSWC				(0x04)
> +#define AB3100_STR_DCIO					(0x08)
> +#define AB3100_STR_BOOT_MODE				(0x10)
> +#define AB3100_STR_SIM_OFF				(0x20)
> +#define AB3100_STR_BATT_REMOVAL				(0x40)
> +#define AB3100_STR_VBUS					(0x80)
> +
> +/*
> + * This struct is PRIVATE and devices using it should NOT
> + * access ANY fields. It is used as a token for calling the
> + * AB3100 functions.
> + */

If the struct is private, probably it should be placed rather in the ".c" file?

> +struct ab3100 {
> +	/* Lock out concurrent accesses to the AB3100 registers */
> +	struct mutex access_mutex;
> +	/* Pointer to the containing device */
> +	struct device *dev;
> +	/* I2C client */
> +	struct i2c_client *i2c_client;
> +	/* Secondary client for test registers */
> +	struct i2c_client *testreg_client;
> +	/* Self-describing fields */
> +	char chip_name[32];
> +	u8 chip_id;
> +	/* The event handling and event subscriber list */
> +	struct work_struct work;
> +	struct blocking_notifier_head event_subscribers;
> +	/* Save the first reading of the event registers */
> +	u32 startup_events;
> +	bool startup_events_read;
> +};
> +
> +int ab3100_set_register(struct ab3100 *ab3100_data, u8 reg, u8 regval);
> +int ab3100_get_register(struct ab3100 *ab3100_data, u8 reg, u8 *regval);
> +int ab3100_get_register_page(struct ab3100 *ab3100_data,
> +			     u8 first_reg, u8 *regvals, u8 numregs);
> +int ab3100_mask_and_set_register(struct ab3100 *ab3100_data,
> +				 u8 reg, u8 andmask, u8 ormask);
> +u8 ab3100_get_chip_type(struct ab3100 *ab3100_data);
> +int ab3100_event_register(struct ab3100 *ab3100_data,
> +			  struct notifier_block *nb);
> +int ab3100_event_unregister(struct ab3100 *ab3100_data,
> +			    struct notifier_block *nb);
> +int ab3100_event_registers_startup_state_get(struct ab3100 *ab3100_data,
> +					     u32 *fatevent);
> +
> +#endif

-- 
Sincerely yours,
Mike.

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