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media: imx274: add helper to read multibyte registers

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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: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Luca Ceresoli 2018-08-24 12:35:24 -04:00 committed by Mauro Carvalho Chehab
parent 1657c28d82
commit ca017467c7
1 changed files with 47 additions and 46 deletions
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93
drivers/media/i2c/imx274.c
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@ -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 @@ fail:
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 @@ fail:
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]);
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];
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);