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Commit ca017467 authored by Luca Ceresoli's avatar Luca Ceresoli Committed by Mauro Carvalho Chehab
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media: imx274: add helper to read multibyte registers 



Currently 2-bytes and 3-bytes registers are read one byte at a time,
doing the needed shift & mask each time.

Replace all of this code by a unique helper function that calls
regmap_bulk_read(), which has two advantages:
 - reads all the bytes in a unique I2C transaction
 - simplifies code to read multibyte registers

Signed-off-by: default avatarLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 1657c28d

drivers/media/i2c/imx274.c

+47 −46
Original line number Diff line number Diff line
@@ -659,6 +659,41 @@ static inline int imx274_write_reg(struct stimx274 *priv, u16 addr, u8 val) 
	return err;

}



/**

 * Read a multibyte register.

 *

 * Uses a bulk read where possible.

 *

 * @priv: Pointer to device structure

 * @addr: Address of the LSB register.  Other registers must be

 *        consecutive, least-to-most significant.

 * @val: Pointer to store the register value (cpu endianness)

 * @nbytes: Number of bytes to read (range: [1..3]).

 *          Other bytes are zet to 0.

 *

 * Return: 0 on success, errors otherwise

 */

static int imx274_read_mbreg(struct stimx274 *priv, u16 addr, u32 *val,

			     size_t nbytes)

{

	__le32 val_le = 0;

	int err;



	err = regmap_bulk_read(priv->regmap, addr, &val_le, nbytes);

	if (err) {

		dev_err(&priv->client->dev,

			"%s : i2c bulk read failed, %x (%zu bytes)\n",

			__func__, addr, nbytes);

	} else {

		*val = le32_to_cpu(val_le);

		dev_dbg(&priv->client->dev,

			"%s : addr 0x%x, val=0x%x (%zu bytes)\n",

			__func__, addr, *val, nbytes);

	}



	return err;

}



/**

 * Write a multibyte register.

 *
@@ -1377,37 +1412,17 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on) 
static int imx274_get_frame_length(struct stimx274 *priv, u32 *val)

{

	int err;

	u16 svr;

	u32 svr;

	u32 vmax;

	u8 reg_val[3];



	/* svr */

	err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);

	err = imx274_read_mbreg(priv, IMX274_SVR_REG_LSB, &svr, 2);

	if (err)

		goto fail;



	err = imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);

	err = imx274_read_mbreg(priv, IMX274_VMAX_REG_3, &vmax, 3);

	if (err)

		goto fail;



	svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];



	/* vmax */

	err = imx274_read_reg(priv, IMX274_VMAX_REG_3, &reg_val[0]);

	if (err)

		goto fail;



	err = imx274_read_reg(priv, IMX274_VMAX_REG_2, &reg_val[1]);

	if (err)

		goto fail;



	err = imx274_read_reg(priv, IMX274_VMAX_REG_1, &reg_val[2]);

	if (err)

		goto fail;



	vmax = ((reg_val[2] & IMX274_MASK_LSB_3_BITS) << IMX274_SHIFT_16_BITS)

		+ (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];



	*val = vmax * (svr + 1);



	return 0;
@@ -1588,8 +1603,7 @@ static int imx274_set_coarse_time(struct stimx274 *priv, u32 *val) 
static int imx274_set_exposure(struct stimx274 *priv, int val)

{

	int err;

	u16 hmax;

	u8 reg_val[2];

	u32 hmax;

	u32 coarse_time; /* exposure time in unit of line (HMAX)*/



	dev_dbg(&priv->client->dev,
@@ -1597,14 +1611,10 @@ static int imx274_set_exposure(struct stimx274 *priv, int val) 


	/* step 1: convert input exposure_time (val) into number of 1[HMAX] */



	/* obtain HMAX value */

	err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);

	if (err)

		goto fail;

	err = imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);

	err = imx274_read_mbreg(priv, IMX274_HMAX_REG_LSB, &hmax, 2);

	if (err)

		goto fail;

	hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];



	if (hmax == 0) {

		err = -EINVAL;

		goto fail;
@@ -1739,9 +1749,8 @@ static int imx274_set_frame_interval(struct stimx274 *priv, 
{

	int err;

	u32 frame_length, req_frame_rate;

	u16 svr;

	u16 hmax;

	u8 reg_val[2];

	u32 svr;

	u32 hmax;



	dev_dbg(&priv->client->dev, "%s: input frame interval = %d / %d",

		__func__, frame_interval.numerator,
@@ -1769,25 +1778,17 @@ static int imx274_set_frame_interval(struct stimx274 *priv, 
	 * frame_length (i.e. VMAX) = (frame_interval) x 72M /(SVR+1) / HMAX

	 */



	/* SVR */

	err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);

	err = imx274_read_mbreg(priv, IMX274_SVR_REG_LSB, &svr, 2);

	if (err)

		goto fail;

	err = imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);

	if (err)

		goto fail;

	svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];



	dev_dbg(&priv->client->dev,

		"%s : register SVR = %d\n", __func__, svr);



	/* HMAX */

	err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);

	err = imx274_read_mbreg(priv, IMX274_HMAX_REG_LSB, &hmax, 2);

	if (err)

		goto fail;

	err = imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);

	if (err)

		goto fail;

	hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];



	dev_dbg(&priv->client->dev,

		"%s : register HMAX = %d\n", __func__, hmax);