regmap: Add support for 12/20 register formatting

Devices such as the AD5628 require 32 bits of data divided in 12 bits
for dummy, command and address, and 20 for data and dummy. Eg:

XXXXCCCCAAAADDDDDDDDDDDDDDDDXXXX

Where X is dont care, C is command, A is address and D is data bits.

Which would requierd the following regmap_config:

static const struct regmap_config config_dac = {
	.reg_bits = 12,
	.val_bits = 20,
	.max_register = 0xff,
};

Signed-off-by: Ricardo Ribalda <ribalda@kernel.org>
Link: https://lore.kernel.org/r/20200917114727.1120373-1-ribalda@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 2807e54..51db0f8 100644 (file)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -209,6 +209,18 @@ static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
        return true;
 }
 
+static void regmap_format_12_20_write(struct regmap *map,
+                                    unsigned int reg, unsigned int val)
+{
+       u8 *out = map->work_buf;
+
+       out[0] = reg >> 4;
+       out[1] = (reg << 4) | (val >> 16);
+       out[2] = val >> 8;
+       out[3] = val;
+}
+
+
 static void regmap_format_2_6_write(struct regmap *map,
                                     unsigned int reg, unsigned int val)
 {
@@ -870,6 +882,16 @@ struct regmap *__regmap_init(struct device *dev,
                }
                break;
 
+       case 12:
+               switch (config->val_bits) {
+               case 20:
+                       map->format.format_write = regmap_format_12_20_write;
+                       break;
+               default:
+                       goto err_hwlock;
+               }
+               break;
+
        case 8:
                map->format.format_reg = regmap_format_8;
                break;