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Commit 9344a81e authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Wolfram Sang
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eeprom: at24: hide the read/write loop behind a macro 



Before splitting the read/write routines into smaller, more
specialized functions, unduplicate some code in advance.

Use a 'for' loop instead of 'do while' when waiting for the previous
write to complete and hide it behind a macro.

Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 318aa9c6

drivers/misc/eeprom/at24.c

+20 −22
Original line number Original line Diff line number Diff line
@@ -113,6 +113,22 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)"); 
	((1 << AT24_SIZE_FLAGS | (_flags)) 		\

	((1 << AT24_SIZE_FLAGS | (_flags)) 		\

	    << AT24_SIZE_BYTELEN | ilog2(_len))

	    << AT24_SIZE_BYTELEN | ilog2(_len))





/*

 * Both reads and writes fail if the previous write didn't complete yet. This

 * macro loops a few times waiting at least long enough for one entire page

 * write to work.

 *

 * It takes two parameters: a variable in which the future timeout in jiffies

 * will be stored and a temporary variable holding the time of the last

 * iteration of processing the request. Both should be unsigned integers

 * holding at least 32 bits.

 */

#define loop_until_timeout(tout, op_time)				\

	for (tout = jiffies + msecs_to_jiffies(write_timeout),		\

		op_time = jiffies;					\

	     time_before(op_time, tout);				\

	     usleep_range(1000, 1500), op_time = jiffies)



static const struct i2c_device_id at24_ids[] = {

static const struct i2c_device_id at24_ids[] = {

	/* needs 8 addresses as A0-A2 are ignored */

	/* needs 8 addresses as A0-A2 are ignored */

	{ "24c00",	AT24_DEVICE_MAGIC(128 / 8,	AT24_FLAG_TAKE8ADDR) },

	{ "24c00",	AT24_DEVICE_MAGIC(128 / 8,	AT24_FLAG_TAKE8ADDR) },
@@ -225,14 +241,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf, 
		msg[1].len = count;

		msg[1].len = count;

	}

	}





	/*

	loop_until_timeout(timeout, read_time) {

	 * Reads fail if the previous write didn't complete yet. We may

	 * loop a few times until this one succeeds, waiting at least

	 * long enough for one entire page write to work.

	 */

	timeout = jiffies + msecs_to_jiffies(write_timeout);

	do {

		read_time = jiffies;

		if (at24->use_smbus) {

		if (at24->use_smbus) {

			status = i2c_smbus_read_i2c_block_data_or_emulated(client, offset,

			status = i2c_smbus_read_i2c_block_data_or_emulated(client, offset,

									   count, buf);

									   count, buf);
@@ -246,9 +255,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf, 




		if (status == count)

		if (status == count)

			return count;

			return count;



	}

		usleep_range(1000, 1500);

	} while (time_before(read_time, timeout));





	return -ETIMEDOUT;

	return -ETIMEDOUT;

}

}
@@ -299,14 +306,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, 
		msg.len = i + count;

		msg.len = i + count;

	}

	}





	/*

	loop_until_timeout(timeout, write_time) {

	 * Writes fail if the previous one didn't complete yet. We may

	 * loop a few times until this one succeeds, waiting at least

	 * long enough for one entire page write to work.

	 */

	timeout = jiffies + msecs_to_jiffies(write_timeout);

	do {

		write_time = jiffies;

		if (at24->use_smbus_write) {

		if (at24->use_smbus_write) {

			switch (at24->use_smbus_write) {

			switch (at24->use_smbus_write) {

			case I2C_SMBUS_I2C_BLOCK_DATA:

			case I2C_SMBUS_I2C_BLOCK_DATA:
@@ -331,9 +331,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, 




		if (status == count)

		if (status == count)

			return count;

			return count;



	}

		usleep_range(1000, 1500);

	} while (time_before(write_time, timeout));





	return -ETIMEDOUT;

	return -ETIMEDOUT;

}

}