Note half writes currently assume address numbers are even only.
That's a pain for caching so other suggestions welcome. I could set
it as a 7 bit address and increase the padding to 9 bits. That makes
the write bit a little strange though as it will be going into the
padding.
Not signed off by Jonathan Cameron <jic23@xxxxxxxxx>
---
drivers/base/regmap/internal.h | 1 +
drivers/base/regmap/regmap.c | 42 ++++++++++++++++++++++++++++++++++-----
include/linux/regmap.h | 6 +++++
3 files changed, 43 insertions(+), 6 deletions(-)
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 7e14d5a..a6fb2f4 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 val_bytes;
+ bool half_write;
void (*format_write)(struct regmap *map,
unsigned int reg, unsigned int val);
void (*format_reg)(void *buf, unsigned int reg);
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index e7adfe7..41f1e7f 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -71,6 +71,16 @@ static void regmap_format_4_12_write(struct regmap *map,
*out = cpu_to_be16((reg << 12) | val);
}
+static void regmap_format_8_16_half_write(struct regmap *map,
+ unsigned int reg, unsigned int val)
+{
+ u8 *out8 = map->work_buf;
+ out8[0] = reg | map->write_flag_mask;;
+ out8[1] = val;
+ out8[2] = (reg + 1) | map->write_flag_mask;
+ out8[3] = val >> 8;
+}
+
static void regmap_format_7_9_write(struct regmap *map,
unsigned int reg, unsigned int val)
{
@@ -136,9 +146,12 @@ struct regmap *regmap_init(struct device *dev,
}
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.buf_size = (config->reg_bits +
+ config->reg_pad_bits +
+ config->val_bits) / 8;
+ map->format.reg_bytes = (config->reg_bits + config->reg_pad_bits)/ 8;
map->format.val_bytes = config->val_bits / 8;
+ map->format.half_write = config->half_write;
map->dev = dev;
map->bus = bus;
map->max_register = config->max_register;
@@ -176,6 +189,9 @@ struct regmap *regmap_init(struct device *dev,
break;
case 8:
+ if (map->format.half_write)
+ map->format.format_write =
+ regmap_format_8_16_half_write;
map->format.format_reg = regmap_format_8;
break;
@@ -256,13 +272,27 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
* send the work_buf directly, otherwise try to do a gather
* write.
*/
- if (val == map->work_buf + map->format.reg_bytes)
- ret = map->bus->write(map->dev, map->work_buf,
- map->format.reg_bytes + val_len);
- else if (map->bus->gather_write)
+ if (val == map->work_buf + map->format.reg_bytes) {
+ if (map->format.half_write) {
+ ret = map->bus->write(map->dev, map->work_buf,
+ (map->format.reg_bytes +
+ val_len) >> 1);
+ if (ret >= 0)
+ ret = map->bus->write(map->dev,
+ map->work_buf +
+ ((map->format.reg_bytes +
+ val_len) >> 1),
+ (map->format.reg_bytes +
+ val_len) >> 1);
+ } else {
+ ret = map->bus->write(map->dev, map->work_buf,
+ map->format.reg_bytes + val_len);
+ }
+ } else if (map->bus->gather_write) {
ret = map->bus->gather_write(map->dev, map->work_buf,
map->format.reg_bytes,
val, val_len);
+ }
/* If that didn't work fall back on linearising by hand. */
if (ret == -ENOTSUPP) {
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 18d4afa..564d703 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -37,6 +37,8 @@ struct reg_default {
* Configuration for the register map of a device.
*
* @reg_bits: Number of bits in a register address, mandatory.
+ * @reg_pad_bits: Number of bits of padding between register
+ * address and start of value.
* @val_bits: Number of bits in a register value, mandatory.
*
* @writeable_reg: Optional callback returning true if the register
@@ -59,9 +61,12 @@ struct reg_default {
* @write_flag_mask: Mask to be set in the top byte of the register when doing
* a write. If both read_flag_mask and write_flag_mask are
* empty the regmap_bus default masks are used.
+ * @half_write: Flag to indicate that writes are done in two parts, half of
+ * the register in each.
*/
struct regmap_config {
int reg_bits;
+ int reg_pad_bits;
int val_bits;
bool (*writeable_reg)(struct device *dev, unsigned int reg);
@@ -75,6 +80,7 @@ struct regmap_config {
u8 read_flag_mask;
u8 write_flag_mask;
+ bool half_write;
};
typedef int (*regmap_hw_write)(struct device *dev, const void *data,
--
1.7.3.4
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