media: i2c: adv748x: Convert SW reset routine to function

The ADV748x is currently reset by writting a small table of registers to
the device.

The table lacks documentation and contains magic values to perform the
actions, including using a fake register address to introduce a delay
loop.

Remove the table, and convert to code, documenting the purpose of the
specific writes along the way.
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/adv748x/adv748x-core.c

@@ -389,15 +389,6 @@ static const struct media_entity_operations adv748x_media_ops = {
  * HW setup
  */
 
-static const struct adv748x_reg_value adv748x_sw_reset[] = {
-
-	{ADV748X_PAGE_IO, 0xff, 0xff},	/* SW reset */
-	{ADV748X_PAGE_WAIT, 0x00, 0x05},/* delay 5 */
-	{ADV748X_PAGE_IO, 0x01, 0x76},	/* ADI Required Write */
-	{ADV748X_PAGE_IO, 0xf2, 0x01},	/* Enable I2C Read Auto-Increment */
-	{ADV748X_PAGE_EOR, 0xff, 0xff}	/* End of register table */
-};
-
 /* Initialize CP Core with RGB888 format. */
 static const struct adv748x_reg_value adv748x_init_hdmi[] = {
 	/* Disable chip powerdown & Enable HDMI Rx block */
@@ -474,12 +465,33 @@ static const struct adv748x_reg_value adv748x_init_afe[] = {
 	{ADV748X_PAGE_EOR, 0xff, 0xff}	/* End of register table */
 };
 
+static int adv748x_sw_reset(struct adv748x_state *state)
+{
+	int ret;
+
+	ret = io_write(state, ADV748X_IO_REG_FF, ADV748X_IO_REG_FF_MAIN_RESET);
+	if (ret)
+		return ret;
+
+	usleep_range(5000, 6000);
+
+	/* Disable CEC Wakeup from power-down mode */
+	ret = io_clrset(state, ADV748X_IO_REG_01, ADV748X_IO_REG_01_PWRDN_MASK,
+			ADV748X_IO_REG_01_PWRDNB);
+	if (ret)
+		return ret;
+
+	/* Enable I2C Read Auto-Increment for consecutive reads */
+	return io_write(state, ADV748X_IO_REG_F2,
+			ADV748X_IO_REG_F2_READ_AUTO_INC);
+}
+
 static int adv748x_reset(struct adv748x_state *state)
 {
 	int ret;
 	u8 regval = 0;
 
-	ret = adv748x_write_regs(state, adv748x_sw_reset);
+	ret = adv748x_sw_reset(state);
 	if (ret < 0)
 		return ret;
 

drivers/media/i2c/adv748x/adv748x.h

@@ -211,6 +211,11 @@ struct adv748x_state {
 #define ADV748X_IO_PD			0x00	/* power down controls */
 #define ADV748X_IO_PD_RX_EN		BIT(6)
 
+#define ADV748X_IO_REG_01		0x01	/* pwrdn{2}b, prog_xtal_freq */
+#define ADV748X_IO_REG_01_PWRDN_MASK	(BIT(7) | BIT(6))
+#define ADV748X_IO_REG_01_PWRDN2B	BIT(7)	/* CEC Wakeup Support */
+#define ADV748X_IO_REG_01_PWRDNB	BIT(6)	/* CEC Wakeup Support */
+
 #define ADV748X_IO_REG_04		0x04
 #define ADV748X_IO_REG_04_FORCE_FR	BIT(0)	/* Force CP free-run */
 
@@ -229,8 +234,19 @@ struct adv748x_state {
 #define ADV748X_IO_CHIP_REV_ID_1	0xdf
 #define ADV748X_IO_CHIP_REV_ID_2	0xe0
 
+#define ADV748X_IO_REG_F2		0xf2
+#define ADV748X_IO_REG_F2_READ_AUTO_INC	BIT(0)
+
+/* For PAGE slave address offsets */
 #define ADV748X_IO_SLAVE_ADDR_BASE	0xf2
 
+/*
+ * The ADV748x_Recommended_Settings_PrA_2014-08-20.pdf details both 0x80 and
+ * 0xff as examples for performing a software reset.
+ */
+#define ADV748X_IO_REG_FF		0xff
+#define ADV748X_IO_REG_FF_MAIN_RESET	0xff
+
 /* HDMI RX Map */
 #define ADV748X_HDMI_LW1		0x07	/* line width_1 */
 #define ADV748X_HDMI_LW1_VERT_FILTER	BIT(7)