regmap: Add support for padding between register and address
Some devices, especially those with high speed control interfaces, require
padding between the register and the data. Support this in the regmap API
by providing a pad_bits configuration parameter.
Only devices with integer byte counts are supported.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 1a02b75..e33f1be 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -22,6 +22,7 @@
struct regmap_format {
size_t buf_size;
size_t reg_bytes;
+ size_t pad_bytes;
size_t val_bytes;
void (*format_write)(struct regmap *map,
unsigned int reg, unsigned int val);
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index be10a4f..e9c2ac0 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -160,7 +160,9 @@
mutex_init(&map->lock);
map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
map->format.reg_bytes = config->reg_bits / 8;
+ map->format.pad_bytes = config->pad_bits / 8;
map->format.val_bytes = config->val_bits / 8;
+ map->format.buf_size += map->format.pad_bytes;
map->dev = dev;
map->bus = bus;
map->max_register = config->max_register;
@@ -235,7 +237,7 @@
!(map->format.format_reg && map->format.format_val))
goto err_map;
- map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
+ map->work_buf = kzalloc(map->format.buf_size, GFP_KERNEL);
if (map->work_buf == NULL) {
ret = -ENOMEM;
goto err_map;
@@ -329,23 +331,28 @@
* send the work_buf directly, otherwise try to do a gather
* write.
*/
- if (val == map->work_buf + map->format.reg_bytes)
+ if (val == (map->work_buf + map->format.pad_bytes +
+ map->format.reg_bytes))
ret = map->bus->write(map->dev, map->work_buf,
- map->format.reg_bytes + val_len);
+ map->format.reg_bytes +
+ map->format.pad_bytes +
+ val_len);
else if (map->bus->gather_write)
ret = map->bus->gather_write(map->dev, map->work_buf,
- map->format.reg_bytes,
+ map->format.reg_bytes +
+ map->format.pad_bytes,
val, val_len);
/* If that didn't work fall back on linearising by hand. */
if (ret == -ENOTSUPP) {
- len = map->format.reg_bytes + val_len;
- buf = kmalloc(len, GFP_KERNEL);
+ len = map->format.reg_bytes + map->format.pad_bytes + val_len;
+ buf = kzalloc(len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
memcpy(buf, map->work_buf, map->format.reg_bytes);
- memcpy(buf + map->format.reg_bytes, val, val_len);
+ memcpy(buf + map->format.reg_bytes + map->format.pad_bytes,
+ val, val_len);
ret = map->bus->write(map->dev, buf, len);
kfree(buf);
@@ -387,10 +394,12 @@
return ret;
} else {
- map->format.format_val(map->work_buf + map->format.reg_bytes,
- val);
+ map->format.format_val(map->work_buf + map->format.reg_bytes
+ + map->format.pad_bytes, val);
return _regmap_raw_write(map, reg,
- map->work_buf + map->format.reg_bytes,
+ map->work_buf +
+ map->format.reg_bytes +
+ map->format.pad_bytes,
map->format.val_bytes);
}
}
@@ -473,7 +482,8 @@
trace_regmap_hw_read_start(map->dev, reg,
val_len / map->format.val_bytes);
- ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
+ ret = map->bus->read(map->dev, map->work_buf,
+ map->format.reg_bytes + map->format.pad_bytes,
val, val_len);
trace_regmap_hw_read_done(map->dev, reg,
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index eb93921..a6ed6e6 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -44,6 +44,7 @@
* Configuration for the register map of a device.
*
* @reg_bits: Number of bits in a register address, mandatory.
+ * @pad_bits: Number of bits of padding between register and value.
* @val_bits: Number of bits in a register value, mandatory.
*
* @writeable_reg: Optional callback returning true if the register
@@ -74,6 +75,7 @@
*/
struct regmap_config {
int reg_bits;
+ int pad_bits;
int val_bits;
bool (*writeable_reg)(struct device *dev, unsigned int reg);