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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: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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commit
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1 changed files with 20 additions and 22 deletions
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@ -113,6 +113,22 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
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((1 << AT24_SIZE_FLAGS | (_flags)) \
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<< AT24_SIZE_BYTELEN | ilog2(_len))
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/*
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* Both reads and writes fail if the previous write didn't complete yet. This
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* macro loops a few times waiting at least long enough for one entire page
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* write to work.
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*
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* It takes two parameters: a variable in which the future timeout in jiffies
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* will be stored and a temporary variable holding the time of the last
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* iteration of processing the request. Both should be unsigned integers
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* holding at least 32 bits.
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*/
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#define loop_until_timeout(tout, op_time) \
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for (tout = jiffies + msecs_to_jiffies(write_timeout), \
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op_time = jiffies; \
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time_before(op_time, tout); \
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usleep_range(1000, 1500), op_time = jiffies)
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static const struct i2c_device_id at24_ids[] = {
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/* needs 8 addresses as A0-A2 are ignored */
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{ "24c00", AT24_DEVICE_MAGIC(128 / 8, AT24_FLAG_TAKE8ADDR) },
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@ -225,14 +241,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
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msg[1].len = count;
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}
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/*
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* Reads fail if the previous write didn't complete yet. We may
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* loop a few times until this one succeeds, waiting at least
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* long enough for one entire page write to work.
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*/
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timeout = jiffies + msecs_to_jiffies(write_timeout);
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do {
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read_time = jiffies;
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loop_until_timeout(timeout, read_time) {
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if (at24->use_smbus) {
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status = i2c_smbus_read_i2c_block_data_or_emulated(client, offset,
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count, buf);
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@ -246,9 +255,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
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if (status == count)
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return count;
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usleep_range(1000, 1500);
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} while (time_before(read_time, timeout));
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}
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return -ETIMEDOUT;
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}
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@ -299,14 +306,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
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msg.len = i + count;
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}
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/*
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* Writes fail if the previous one didn't complete yet. We may
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* loop a few times until this one succeeds, waiting at least
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* long enough for one entire page write to work.
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*/
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timeout = jiffies + msecs_to_jiffies(write_timeout);
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do {
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write_time = jiffies;
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loop_until_timeout(timeout, write_time) {
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if (at24->use_smbus_write) {
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switch (at24->use_smbus_write) {
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case I2C_SMBUS_I2C_BLOCK_DATA:
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@ -331,9 +331,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
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if (status == count)
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return count;
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usleep_range(1000, 1500);
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} while (time_before(write_time, timeout));
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}
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return -ETIMEDOUT;
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}
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