Commit 30e7b039 authored by Ed Swierk's avatar Ed Swierk Committed by Linus Torvalds
Browse files

rtc-ds1307: true SMBus compatibility 



Allow the rtc-ds1307 driver to work with SMBus controllers like nforce2
that do not support i2c block transfers.

Signed-off-by: default avatarEd Swierk <eswierk@aristanetworks.com>
Acked-by: default avatarJean Delvare <khali@linux-fr.org>
Acked-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: BARRE Sebastien <sbarre@sdelcc.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b250c96e

drivers/rtc/rtc-ds1307.c

+97 −12
Original line number Diff line number Diff line
@@ -94,6 +94,10 @@ struct ds1307 { 
	struct i2c_client	*client;

	struct rtc_device	*rtc;

	struct work_struct	work;

	s32 (*read_block_data)(struct i2c_client *client, u8 command,

			       u8 length, u8 *values);

	s32 (*write_block_data)(struct i2c_client *client, u8 command,

				u8 length, const u8 *values);

};



struct chip_desc {
@@ -132,6 +136,79 @@ MODULE_DEVICE_TABLE(i2c, ds1307_id); 


/*----------------------------------------------------------------------*/



#define BLOCK_DATA_MAX_TRIES 10



static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,

				  u8 length, u8 *values)

{

	s32 i, data;



	for (i = 0; i < length; i++) {

		data = i2c_smbus_read_byte_data(client, command + i);

		if (data < 0)

			return data;

		values[i] = data;

	}

	return i;

}



static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,

				  u8 length, u8 *values)

{

	u8 oldvalues[I2C_SMBUS_BLOCK_MAX];

	s32 ret;

	int tries = 0;



	dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);

	ret = ds1307_read_block_data_once(client, command, length, values);

	if (ret < 0)

		return ret;

	do {

		if (++tries > BLOCK_DATA_MAX_TRIES) {

			dev_err(&client->dev,

				"ds1307_read_block_data failed\n");

			return -EIO;

		}

		memcpy(oldvalues, values, length);

		ret = ds1307_read_block_data_once(client, command, length,

						  values);

		if (ret < 0)

			return ret;

	} while (memcmp(oldvalues, values, length));

	return length;

}



static s32 ds1307_write_block_data(struct i2c_client *client, u8 command,

				   u8 length, const u8 *values)

{

	u8 currvalues[I2C_SMBUS_BLOCK_MAX];

	int tries = 0;



	dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);

	do {

		s32 i, ret;



		if (++tries > BLOCK_DATA_MAX_TRIES) {

			dev_err(&client->dev,

				"ds1307_write_block_data failed\n");

			return -EIO;

		}

		for (i = 0; i < length; i++) {

			ret = i2c_smbus_write_byte_data(client, command + i,

							values[i]);

			if (ret < 0)

				return ret;

		}

		ret = ds1307_read_block_data_once(client, command, length,

						  currvalues);

		if (ret < 0)

			return ret;

	} while (memcmp(currvalues, values, length));

	return length;

}



/*----------------------------------------------------------------------*/



/*

 * The IRQ logic includes a "real" handler running in IRQ context just

 * long enough to schedule this workqueue entry.   We need a task context
@@ -202,7 +279,7 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t) 
	int		tmp;



	/* read the RTC date and time registers all at once */

	tmp = i2c_smbus_read_i2c_block_data(ds1307->client,

	tmp = ds1307->read_block_data(ds1307->client,

		DS1307_REG_SECS, 7, ds1307->regs);

	if (tmp != 7) {

		dev_err(dev, "%s error %d\n", "read", tmp);
@@ -279,7 +356,7 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t) 
		"write", buf[0], buf[1], buf[2], buf[3],

		buf[4], buf[5], buf[6]);



	result = i2c_smbus_write_i2c_block_data(ds1307->client, 0, 7, buf);

	result = ds1307->write_block_data(ds1307->client, 0, 7, buf);

	if (result < 0) {

		dev_err(dev, "%s error %d\n", "write", result);

		return result;
@@ -297,7 +374,7 @@ static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t) 
		return -EINVAL;



	/* read all ALARM1, ALARM2, and status registers at once */

	ret = i2c_smbus_read_i2c_block_data(client,

	ret = ds1307->read_block_data(client,

			DS1339_REG_ALARM1_SECS, 9, ds1307->regs);

	if (ret != 9) {

		dev_err(dev, "%s error %d\n", "alarm read", ret);
@@ -356,7 +433,7 @@ static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t) 
		t->enabled, t->pending);



	/* read current status of both alarms and the chip */

	ret = i2c_smbus_read_i2c_block_data(client,

	ret = ds1307->read_block_data(client,

			DS1339_REG_ALARM1_SECS, 9, buf);

	if (ret != 9) {

		dev_err(dev, "%s error %d\n", "alarm write", ret);
@@ -391,7 +468,7 @@ static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t) 
	}

	buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);



	ret = i2c_smbus_write_i2c_block_data(client,

	ret = ds1307->write_block_data(client,

			DS1339_REG_ALARM1_SECS, 9, buf);

	if (ret < 0) {

		dev_err(dev, "can't set alarm time\n");
@@ -479,7 +556,7 @@ ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr, 
	if (unlikely(!count))

		return count;



	result = i2c_smbus_read_i2c_block_data(client, 8 + off, count, buf);

	result = ds1307->read_block_data(client, 8 + off, count, buf);

	if (result < 0)

		dev_err(&client->dev, "%s error %d\n", "nvram read", result);

	return result;
@@ -490,9 +567,11 @@ ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr, 
		char *buf, loff_t off, size_t count)

{

	struct i2c_client	*client;

	struct ds1307		*ds1307;

	int			result;



	client = kobj_to_i2c_client(kobj);

	ds1307 = i2c_get_clientdata(client);



	if (unlikely(off >= NVRAM_SIZE))

		return -EFBIG;
@@ -501,7 +580,7 @@ ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr, 
	if (unlikely(!count))

		return count;



	result = i2c_smbus_write_i2c_block_data(client, 8 + off, count, buf);

	result = ds1307->write_block_data(client, 8 + off, count, buf);

	if (result < 0) {

		dev_err(&client->dev, "%s error %d\n", "nvram write", result);

		return result;
@@ -535,9 +614,8 @@ static int __devinit ds1307_probe(struct i2c_client *client, 
	int			want_irq = false;

	unsigned char		*buf;



	if (!i2c_check_functionality(adapter,

			I2C_FUNC_SMBUS_WRITE_BYTE_DATA |

			I2C_FUNC_SMBUS_I2C_BLOCK))

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)

	    && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))

		return -EIO;



	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
@@ -547,6 +625,13 @@ static int __devinit ds1307_probe(struct i2c_client *client, 
	i2c_set_clientdata(client, ds1307);

	ds1307->type = id->driver_data;

	buf = ds1307->regs;

	if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {

		ds1307->read_block_data = i2c_smbus_read_i2c_block_data;

		ds1307->write_block_data = i2c_smbus_write_i2c_block_data;

	} else {

		ds1307->read_block_data = ds1307_read_block_data;

		ds1307->write_block_data = ds1307_write_block_data;

	}



	switch (ds1307->type) {

	case ds_1337:
@@ -557,7 +642,7 @@ static int __devinit ds1307_probe(struct i2c_client *client, 
			want_irq = true;

		}

		/* get registers that the "rtc" read below won't read... */

		tmp = i2c_smbus_read_i2c_block_data(ds1307->client,

		tmp = ds1307->read_block_data(ds1307->client,

				DS1337_REG_CONTROL, 2, buf);

		if (tmp != 2) {

			pr_debug("read error %d\n", tmp);
@@ -595,7 +680,7 @@ static int __devinit ds1307_probe(struct i2c_client *client, 


read_rtc:

	/* read RTC registers */

	tmp = i2c_smbus_read_i2c_block_data(ds1307->client, 0, 8, buf);

	tmp = ds1307->read_block_data(ds1307->client, 0, 8, buf);

	if (tmp != 8) {

		pr_debug("read error %d\n", tmp);

		err = -EIO;

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