drivers/mfd/ab3100-core.c



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/*
 * Copyright (C) 2007-2010 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@stericsson.com>
 */

#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/random.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/mfd/core.h>
#include <linux/mfd/abx500.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

/*
 * I2C communication
 *
 * The AB3100 is usually assigned address 0x48 (7-bit)
 * The chip is defined in the platform i2c_board_data section.
 */
static int ab3100_get_chip_id(struct device *dev)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

	return (int)ab3100->chip_id;
}

static int ab3100_set_register_interruptible(struct ab3100 *ab3100,
	u8 reg, u8 regval)
{
	u8 regandval[2] = {reg, regval};
	int err;

	err = mutex_lock_interruptible(&ab3100->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->i2c_client, regandval, 2);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (write register): %d\n",
			err);
	} else if (err != 2) {
		dev_err(ab3100->dev,
			"write error (write register) "
			"%d bytes transferred (expected 2)\n",
			err);
		err = -EIO;
	} else {
		/* All is well */
		err = 0;
	}
	mutex_unlock(&ab3100->access_mutex);
	return err;
}

static int set_register_interruptible(struct device *dev,
	u8 bank, u8 reg, u8 value)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

	return ab3100_set_register_interruptible(ab3100, reg, value);
}

/*
 * 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_interruptible(struct ab3100 *ab3100,
				    u8 reg, u8 regval)
{
	u8 regandval[2] = {reg, regval};
	int err;

	err = mutex_lock_interruptible(&ab3100->access_mutex);
	if (err)
		return err;

	err = i2c_master_send(ab3100->testreg_client, regandval, 2);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (write test register): %d\n",
			err);
	} else if (err != 2) {
		dev_err(ab3100->dev,
			"write error (write test register) "
			"%d bytes transferred (expected 2)\n",
			err);
		err = -EIO;
	} else {
		/* All is well */
		err = 0;
	}
	mutex_unlock(&ab3100->access_mutex);

	return err;
}

static int ab3100_get_register_interruptible(struct ab3100 *ab3100,
					     u8 reg, u8 *regval)
{
	int err;

	err = mutex_lock_interruptible(&ab3100->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->i2c_client, &reg, 1);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (send register address): %d\n",
			err);
		goto get_reg_out_unlock;
	} else if (err != 1) {
		dev_err(ab3100->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->i2c_client, regval, 1);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (read register): %d\n",
			err);
		goto get_reg_out_unlock;
	} else if (err != 1) {
		dev_err(ab3100->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->access_mutex);
	return err;
}

static int get_register_interruptible(struct device *dev, u8 bank, u8 reg,
				      u8 *value)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

	return ab3100_get_register_interruptible(ab3100, reg, value);
}

static int ab3100_get_register_page_interruptible(struct ab3100 *ab3100,
			     u8 first_reg, u8 *regvals, u8 numregs)
{
	int err;

	if (ab3100->chip_id == 0xa0 ||
	    ab3100->chip_id == 0xa1)
		/* These don't support paged reads */
		return -EIO;

	err = mutex_lock_interruptible(&ab3100->access_mutex);
	if (err)
		return err;

	/*
	 * Paged read also require an I2C "stop" command.
	 */
	err = i2c_master_send(ab3100->i2c_client, &first_reg, 1);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (send first register address): %d\n",
			err);
		goto get_reg_page_out_unlock;
	} else if (err != 1) {
		dev_err(ab3100->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->i2c_client, regvals, numregs);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (read register page): %d\n",
			err);
		goto get_reg_page_out_unlock;
	} else if (err != numregs) {
		dev_err(ab3100->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->access_mutex);
	return err;
}

static int get_register_page_interruptible(struct device *dev, u8 bank,
	u8 first_reg, u8 *regvals, u8 numregs)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

	return ab3100_get_register_page_interruptible(ab3100,
			first_reg, regvals, numregs);
}

static int ab3100_mask_and_set_register_interruptible(struct ab3100 *ab3100,
				 u8 reg, u8 andmask, u8 ormask)
{
	u8 regandval[2] = {reg, 0};
	int err;

	err = mutex_lock_interruptible(&ab3100->access_mutex);
	if (err)
		return err;

	/* First read out the target register */
	err = i2c_master_send(ab3100->i2c_client, &reg, 1);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (maskset send address): %d\n",
			err);
		goto get_maskset_unlock;
	} else if (err != 1) {
		dev_err(ab3100->dev,
			"write error (maskset send address) "
			"%d bytes transferred (expected 1)\n",
			err);
		err = -EIO;
		goto get_maskset_unlock;
	}

	err = i2c_master_recv(ab3100->i2c_client, &regandval[1], 1);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (maskset read register): %d\n",
			err);
		goto get_maskset_unlock;
	} else if (err != 1) {
		dev_err(ab3100->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->i2c_client, regandval, 2);
	if (err < 0) {
		dev_err(ab3100->dev,
			"write error (write register): %d\n",
			err);
		goto get_maskset_unlock;
	} else if (err != 2) {
		dev_err(ab3100->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->access_mutex);
	return err;
}

static int mask_and_set_register_interruptible(struct device *dev, u8 bank,
	u8 reg, u8 bitmask, u8 bitvalues)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);

	return ab3100_mask_and_set_register_interruptible(ab3100,
			reg, bitmask, (bitmask & bitvalues));
}

/*
 * Register a simple callback for handling any AB3100 events.
 */
int ab3100_event_register(struct ab3100 *ab3100,
			  struct notifier_block *nb)
{
	return blocking_notifier_chain_register(&ab3100->event_subscribers,
					       nb);
}
EXPORT_SYMBOL(ab3100_event_register);

/*
 * Remove a previously registered callback.
 */
int ab3100_event_unregister(struct ab3100 *ab3100,
			    struct notifier_block *nb)
{
  return blocking_notifier_chain_unregister(&ab3100->event_subscribers,
					    nb);
}
EXPORT_SYMBOL(ab3100_event_unregister);


static int ab3100_event_registers_startup_state_get(struct device *dev,
					     u8 *event)
{
	struct ab3100 *ab3100 = dev_get_drvdata(dev->parent);
	if (!ab3100->startup_events_read)
		return -EAGAIN; /* Try again later */
	memcpy(event, ab3100->startup_events, 3);
	return 0;
}

static struct abx500_ops ab3100_ops = {
	.get_chip_id = ab3100_get_chip_id,
	.set_register = set_register_interruptible,
	.get_register = get_register_interruptible,
	.get_register_page = get_register_page_interruptible,
	.set_register_page = NULL,
	.mask_and_set_register = mask_and_set_register_interruptible,
	.event_registers_startup_state_get =
		ab3100_event_registers_startup_state_get,
	.startup_irq_enabled = NULL,
};

/*
 * This is a threaded interrupt handler so we can make some
 * I2C calls etc.
 */
static irqreturn_t ab3100_irq_handler(int irq, void *data)
{
	struct ab3100 *ab3100 = data;
	u8 event_regs[3];
	u32 fatevent;
	int err;

	add_interrupt_randomness(irq);

	err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
				       event_regs, 3);
	if (err)
		goto err_event;

	fatevent = (event_regs[0] << 16) |
		(event_regs[1] << 8) |
		event_regs[2];

	if (!ab3100->startup_events_read) {
		ab3100->startup_events[0] = event_regs[0];
		ab3100->startup_events[1] = event_regs[1];
		ab3100->startup_events[2] = event_regs[2];
		ab3100->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->event_subscribers,
				     fatevent, NULL);

	dev_dbg(ab3100->dev,
		"IRQ Event: 0x%08x\n", fatevent);

	return IRQ_HANDLED;

 err_event:
	dev_dbg(ab3100->dev,
		"error reading event status\n");
	return IRQ_HANDLED;
}

#ifdef CONFIG_DEBUG_FS
/*
 * Some debugfs entries only exposed if we're using debug
 */
static int ab3100_registers_print(struct seq_file *s, void *p)
{
	struct ab3100 *ab3100 = s->private;
	u8 value;
	u8 reg;

	seq_printf(s, "AB3100 registers:\n");

	for (reg = 0; reg < 0xff; reg++) {
		ab3100_get_register_interruptible(ab3100, 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,
};

struct ab3100_get_set_reg_priv {
	struct ab3100 *ab3100;
	bool mode;
};

static ssize_t ab3100_get_set_reg(struct file *file,
				  const char __user *user_buf,
				  size_t count, loff_t *ppos)
{
	struct ab3100_get_set_reg_priv *priv = file->private_data;
	struct ab3100 *ab3100 = priv->ab3100;
	char buf[32];
	ssize_t 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 (!priv->mode) {
		/* Reading */
		u8 reg = (u8) user_reg;
		u8 regvalue;

		ab3100_get_register_interruptible(ab3100, reg, &regvalue);

		dev_info(ab3100->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_interruptible(ab3100, reg, value);
		ab3100_get_register_interruptible(ab3100, reg, &regvalue);

		dev_info(ab3100->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 = simple_open,
	.write = ab3100_get_set_reg,
	.llseek = noop_llseek,
};

static struct dentry *ab3100_dir;
static struct dentry *ab3100_reg_file;
static struct ab3100_get_set_reg_priv ab3100_get_priv;
static struct dentry *ab3100_get_reg_file;
static struct ab3100_get_set_reg_priv ab3100_set_priv;
static struct dentry *ab3100_set_reg_file;

static void ab3100_setup_debugfs(struct ab3100 *ab3100)
{
	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, ab3100,
				&ab3100_registers_fops);
	if (!ab3100_reg_file) {
		err = -ENOMEM;
		goto exit_destroy_dir;
	}

	ab3100_get_priv.ab3100 = ab3100;
	ab3100_get_priv.mode = false;
	ab3100_get_reg_file = debugfs_create_file("get_reg",
				S_IWUSR, ab3100_dir, &ab3100_get_priv,
				&ab3100_get_set_reg_fops);
	if (!ab3100_get_reg_file) {
		err = -ENOMEM;
		goto exit_destroy_reg;
	}

	ab3100_set_priv.ab3100 = ab3100;
	ab3100_set_priv.mode = true;
	ab3100_set_reg_file = debugfs_create_file("set_reg",
				S_IWUSR, ab3100_dir, &ab3100_set_priv,
				&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(struct ab3100 *ab3100)
{
}
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.
 */

struct ab3100_init_setting {
	u8 abreg;
	u8 setting;
};

static const struct ab3100_init_setting __devinitconst
ab3100_init_settings[] = {
	{
		.abreg = AB3100_MCA,
		.setting = 0x01
	}, {
		.abreg = AB3100_MCB,
		.setting = 0x30
	}, {
		.abreg = AB3100_IMRA1,
		.setting = 0x00
	}, {
		.abreg = AB3100_IMRA2,
		.setting = 0xFF
	}, {
		.abreg = AB3100_IMRA3,
		.setting = 0x01
	}, {
		.abreg = AB3100_IMRB1,
		.setting = 0xBF
	}, {
		.abreg = AB3100_IMRB2,
		.setting = 0xFF
	}, {
		.abreg = AB3100_IMRB3,
		.setting = 0xFF
	}, {
		.abreg = AB3100_SUP,
		.setting = 0x00
	}, {
		.abreg = AB3100_DIS,
		.setting = 0xF0
	}, {
		.abreg = AB3100_D0C,
		.setting = 0x00
	}, {
		.abreg = AB3100_D1C,
		.setting = 0x00
	}, {
		.abreg = AB3100_D2C,
		.setting = 0x00
	}, {
		.abreg = AB3100_D3C,
		.setting = 0x00
	},
};

static int __devinit ab3100_setup(struct ab3100 *ab3100)
{
	int err = 0;
	int i;

	for (i = 0; i < ARRAY_SIZE(ab3100_init_settings); i++) {
		err = ab3100_set_register_interruptible(ab3100,
					  ab3100_init_settings[i].abreg,
					  ab3100_init_settings[i].setting);
		if (err)
			goto exit_no_setup;
	}

	/*
	 * Special trick to make the AB3100 use the 32kHz clock (RTC)
	 * bit 3 in test register 0x02 is a special, undocumented test