Commit cd0c8615 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Wolfram Sang
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eeprom: at24: split at24_eeprom_write() into specialized functions 



Split at24_eeprom_write() into three smaller functions - one for the
i2c operations and two for the smbus extensions (separate routines for
block and byte transfers). Assign them in at24_probe() depending on
the bus capabilities.

Also: in order to avoid duplications move code adjusting the count
argument into a separate function and use it for i2c and smbus block
writes (no need for a roll-over for byte writes as we're always
writing one byte).

Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 9afd6866

drivers/misc/eeprom/at24.c

+91 −43
Original line number Diff line number Diff line
@@ -281,21 +281,15 @@ static ssize_t at24_eeprom_read_i2c(struct at24_data *at24, char *buf, 
 * chip is normally write protected. But there are plenty of product

 * variants here, including OTP fuses and partial chip protect.

 *

 * We only use page mode writes; the alternative is sloooow. This routine

 * writes at most one page.

 * We only use page mode writes; the alternative is sloooow. These routines

 * write at most one page.

 */

static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,



static size_t at24_adjust_write_count(struct at24_data *at24,

				      unsigned int offset, size_t count)

{

	struct i2c_client *client;

	struct i2c_msg msg;

	ssize_t status = 0;

	unsigned long timeout, write_time;

	unsigned next_page;



	/* Get corresponding I2C address and adjust offset */

	client = at24_translate_offset(at24, &offset);



	/* write_max is at most a page */

	if (count > at24->write_max)

		count = at24->write_max;
@@ -305,10 +299,73 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, 
	if (offset + count > next_page)

		count = next_page - offset;



	/* If we'll use I2C calls for I/O, set up the message */

	if (!at24->use_smbus) {

	return count;

}



static ssize_t at24_eeprom_write_smbus_block(struct at24_data *at24,

					     const char *buf,

					     unsigned int offset, size_t count)

{

	unsigned long timeout, write_time;

	struct i2c_client *client;

	ssize_t status = 0;



	client = at24_translate_offset(at24, &offset);

	count = at24_adjust_write_count(at24, offset, count);



	loop_until_timeout(timeout, write_time) {

		status = i2c_smbus_write_i2c_block_data(client,

							offset, count, buf);

		if (status == 0)

			status = count;



		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",

				count, offset, status, jiffies);



		if (status == count)

			return count;

	}



	return -ETIMEDOUT;

}



static ssize_t at24_eeprom_write_smbus_byte(struct at24_data *at24,

					    const char *buf,

					    unsigned int offset, size_t count)

{

	unsigned long timeout, write_time;

	struct i2c_client *client;

	ssize_t status = 0;



	client = at24_translate_offset(at24, &offset);



	loop_until_timeout(timeout, write_time) {

		status = i2c_smbus_write_byte_data(client, offset, buf[0]);

		if (status == 0)

			status = count;



		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",

				count, offset, status, jiffies);



		if (status == count)

			return count;

	}



	return -ETIMEDOUT;

}



static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf,

				     unsigned int offset, size_t count)

{

	unsigned long timeout, write_time;

	struct i2c_client *client;

	struct i2c_msg msg;

	ssize_t status = 0;

	int i = 0;



	client = at24_translate_offset(at24, &offset);

	count = at24_adjust_write_count(at24, offset, count);



	msg.addr = client->addr;

	msg.flags = 0;
@@ -320,28 +377,12 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, 
	msg.buf[i++] = offset;

	memcpy(&msg.buf[i], buf, count);

	msg.len = i + count;

	}



	loop_until_timeout(timeout, write_time) {

		if (at24->use_smbus_write) {

			switch (at24->use_smbus_write) {

			case I2C_SMBUS_I2C_BLOCK_DATA:

				status = i2c_smbus_write_i2c_block_data(client,

						offset, count, buf);

				break;

			case I2C_SMBUS_BYTE_DATA:

				status = i2c_smbus_write_byte_data(client,

						offset, buf[0]);

				break;

			}



			if (status == 0)

				status = count;

		} else {

		status = i2c_transfer(client->adapter, &msg, 1);

		if (status == 1)

			status = count;

		}



		dev_dbg(&client->dev, "write %zu@%d --> %zd (%ld)\n",

				count, offset, status, jiffies);
@@ -538,7 +579,14 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) 


	at24->read_func = at24->use_smbus ? at24_eeprom_read_smbus

					  : at24_eeprom_read_i2c;

	at24->write_func = at24_eeprom_write;

	if (at24->use_smbus) {

		if (at24->use_smbus_write == I2C_SMBUS_I2C_BLOCK_DATA)

			at24->write_func = at24_eeprom_write_smbus_block;

		else

			at24->write_func = at24_eeprom_write_smbus_byte;

	} else {

		at24->write_func = at24_eeprom_write_i2c;

	}



	writable = !(chip.flags & AT24_FLAG_READONLY);

	if (writable) {

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