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>

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 0621937..2efb572 100644 (file)
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -113,6 +113,22 @@ MODULE_PARM_DESC(write_timeout, "Time (in ms) to try writes (default 25)");
        ((1 << AT24_SIZE_FLAGS | (_flags))              \
            << 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[] = {
        /* needs 8 addresses as A0-A2 are ignored */
        { "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;
        }
 
-       /*
-        * 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;
+       loop_until_timeout(timeout, read_time) {
                if (at24->use_smbus) {
                        status = i2c_smbus_read_i2c_block_data_or_emulated(client, offset,
                                                                           count, buf);
@@ -246,9 +255,7 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 
                if (status == count)
                        return count;
-
-               usleep_range(1000, 1500);
-       } while (time_before(read_time, timeout));
+       }
 
        return -ETIMEDOUT;
 }
@@ -299,14 +306,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
                msg.len = i + count;
        }
 
-       /*
-        * 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;
+       loop_until_timeout(timeout, write_time) {
                if (at24->use_smbus_write) {
                        switch (at24->use_smbus_write) {
                        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)
                        return count;
-
-               usleep_range(1000, 1500);
-       } while (time_before(write_time, timeout));
+       }
 
        return -ETIMEDOUT;
 }