[PATCH 1/8] media: adv748x: add a device-specific wrapper for register block read

[Alex Riesen]

Some of the devices I2C-accessible registers (for instance, cs_data for
stereo channel information or tmds_params for TMDS channel information)
located in adjacent cells. According to manufacturers information, these
registers can be read using block transactions.

Signed-off-by: Alexander Riesen <alexander.riesen@xxxxxxxxxxx>
---
 drivers/media/i2c/adv748x/adv748x-core.c | 15 +++++++++++++++
 drivers/media/i2c/adv748x/adv748x.h      |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/media/i2c/adv748x/adv748x-core.c b/drivers/media/i2c/adv748x/adv748x-core.c
index 23e02ff27b17..bc49aa93793c 100644
--- a/drivers/media/i2c/adv748x/adv748x-core.c
+++ b/drivers/media/i2c/adv748x/adv748x-core.c
@@ -97,6 +97,21 @@ static const struct adv748x_register_map adv748x_default_addresses[] = {
 	[ADV748X_PAGE_TXA] = { "txa", 0x4a },
 };
 
+int adv748x_read_block(struct adv748x_state *state, u8 client_page, u8 reg,
+		       void *val, size_t reg_count)
+{
+	struct i2c_client *client = state->i2c_clients[client_page];
+	int err;
+
+	err = regmap_bulk_read(state->regmap[client_page], reg, val, reg_count);
+	if (err) {
+		adv_err(state, "error reading %02x, %02x-%02lx: %d\n",
+				client->addr, reg, reg + reg_count - 1, err);
+		return err;
+	}
+	return 0;
+}
+
 static int adv748x_read_check(struct adv748x_state *state,
 			      int client_page, u8 reg)
 {
diff --git a/drivers/media/i2c/adv748x/adv748x.h b/drivers/media/i2c/adv748x/adv748x.h
index 5042f9e94aee..db6346a06351 100644
--- a/drivers/media/i2c/adv748x/adv748x.h
+++ b/drivers/media/i2c/adv748x/adv748x.h
@@ -387,6 +387,8 @@ struct adv748x_state {
 /* Register handling */
 
 int adv748x_read(struct adv748x_state *state, u8 addr, u8 reg);
+int adv748x_read_block(struct adv748x_state *state, u8 page, u8 reg,
+		       void *val, size_t reg_count);
 int adv748x_write(struct adv748x_state *state, u8 page, u8 reg, u8 value);
 int adv748x_write_block(struct adv748x_state *state, int client_page,
 			unsigned int init_reg, const void *val,
-- 
2.24.1.508.g91d2dafee0