From ca017467c78bd0e451facea2e512cfa8881eb003 Mon Sep 17 00:00:00 2001 From: Luca Ceresoli Date: Fri, 24 Aug 2018 12:35:24 -0400 Subject: [PATCH] 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: Luca Ceresoli Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- drivers/media/i2c/imx274.c | 93 +++++++++++++++++++------------------- 1 file changed, 47 insertions(+), 46 deletions(-) diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c index 07bc41f537c5..783277068b45 100644 --- a/drivers/media/i2c/imx274.c +++ b/drivers/media/i2c/imx274.c @@ -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, ®_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, ®_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, ®_val[0]); - if (err) - goto fail; - - err = imx274_read_reg(priv, IMX274_VMAX_REG_2, ®_val[1]); - if (err) - goto fail; - - err = imx274_read_reg(priv, IMX274_VMAX_REG_1, ®_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, ®_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, ®_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, ®_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, ®_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, ®_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, ®_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);