Re: [PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Todor Tomov]

On 26.04.2018 15:04, Sakari Ailus wrote:
> On Thu, Apr 26, 2018 at 10:16:56AM +0300, Sakari Ailus wrote:
>> On Thu, Apr 26, 2018 at 10:04:25AM +0300, Todor Tomov wrote:
>>> Hi Sakari,
>>>
>>> On 26.04.2018 09:50, Sakari Ailus wrote:
 Hi Todor,

 On Wed, Apr 25, 2018 at 07:20:46PM +0300, Todor Tomov wrote:
 ...
> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> +{
> + u8 regbuf[3];
> + int ret;
> +
> + regbuf[0] = reg >> 8;
> + regbuf[1] = reg & 0xff;
> + regbuf[2] = val;
> +
> + ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> + if (ret < 0) {
> + dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
> + __func__, ret, reg, val);
> + return ret;
> + }
> +
> + return 0;

 How about:

return ov7251_write_seq_regs(ov7251, reg, , 1);

 And put the function below ov2751_write_seq_regs().
>>>
>>> I'm not sure... It will calculate message length each time and then check
>>> that it is not greater than 5, which it is. Seems redundant.
>>>

> +}
> +
> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
> +  u8 num)
> +{
> + const u8 maxregbuf = 5;
> + u8 regbuf[maxregbuf];
> 
> Apparently this leads to bad positive sparse warning. I'd fix it by:
> 
> diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
> index 3e2c0c03dfa9..d3ebb7529fca 100644
> --- a/drivers/media/i2c/ov7251.c
> +++ b/drivers/media/i2c/ov7251.c
> @@ -643,12 +643,11 @@ static int ov7251_write_reg(struct ov7251 *ov7251, u16 
> reg, u8 val)
>  static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
>  u8 num)
>  {
> -   const u8 maxregbuf = 5;
> -   u8 regbuf[maxregbuf];
> +   u8 regbuf[5];
> u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> int ret = 0;
>  
> -   if (nregbuf > maxregbuf)
> +   if (nregbuf > sizeof(regbuf))
> return -EINVAL;
>  
> regbuf[0] = reg >> 8;
> 
> Let me know if you're happy with that; I can merge it to the original
> patch.

Yes, thanks.

> 
> + u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> + int ret = 0;
> +
> + if (nregbuf > maxregbuf)
> + return -EINVAL;
> +
> + regbuf[0] = reg >> 8;
> + regbuf[1] = reg & 0xff;
> +
> + memcpy(regbuf + 2, val, num);
> +
> + ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
> + if (ret < 0) {
> + dev_err(ov7251->dev, "%s: write seq regs error %d: first 
> reg=%x\n",

 This line is over 80... 
>>>
>>> Yes indeed. Somehow checkpatch does not report this line, I don't know why.
>>>

 If you're happy with these, I can make the changes, too; they're trivial.
>>>
>>> Only the second one? Thanks :)
>>
>> Works for me. I'd still think the overhead of managing the buffer is
>> irrelevant where to having an extra function to do essentially the same
>> thing is a source of maintenance and review work. Note that we're even now
>> spending time to discuss it. ;-)
>>
>> -- 
>> Kind regards,
>>
>> Sakari Ailus
>> e-mail: sakari.ai...@iki.fi
> 

-- 
Best regards,
Todor Tomov

Re: [PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Sakari Ailus]

On Thu, Apr 26, 2018 at 10:16:56AM +0300, Sakari Ailus wrote:
> On Thu, Apr 26, 2018 at 10:04:25AM +0300, Todor Tomov wrote:
> > Hi Sakari,
> > 
> > On 26.04.2018 09:50, Sakari Ailus wrote:
> > > Hi Todor,
> > > 
> > > On Wed, Apr 25, 2018 at 07:20:46PM +0300, Todor Tomov wrote:
> > > ...
> > >> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> > >> +{
> > >> +u8 regbuf[3];
> > >> +int ret;
> > >> +
> > >> +regbuf[0] = reg >> 8;
> > >> +regbuf[1] = reg & 0xff;
> > >> +regbuf[2] = val;
> > >> +
> > >> +ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> > >> +if (ret < 0) {
> > >> +dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, 
> > >> val=%x\n",
> > >> +__func__, ret, reg, val);
> > >> +return ret;
> > >> +}
> > >> +
> > >> +return 0;
> > > 
> > > How about:
> > > 
> > >   return ov7251_write_seq_regs(ov7251, reg, , 1);
> > > 
> > > And put the function below ov2751_write_seq_regs().
> > 
> > I'm not sure... It will calculate message length each time and then check
> > that it is not greater than 5, which it is. Seems redundant.
> > 
> > > 
> > >> +}
> > >> +
> > >> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 
> > >> *val,
> > >> + u8 num)
> > >> +{
> > >> +const u8 maxregbuf = 5;
> > >> +u8 regbuf[maxregbuf];

Apparently this leads to bad positive sparse warning. I'd fix it by:

diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
index 3e2c0c03dfa9..d3ebb7529fca 100644
--- a/drivers/media/i2c/ov7251.c
+++ b/drivers/media/i2c/ov7251.c
@@ -643,12 +643,11 @@ static int ov7251_write_reg(struct ov7251 *ov7251, u16 
reg, u8 val)
 static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
 u8 num)
 {
-   const u8 maxregbuf = 5;
-   u8 regbuf[maxregbuf];
+   u8 regbuf[5];
u8 nregbuf = sizeof(reg) + num * sizeof(*val);
int ret = 0;
 
-   if (nregbuf > maxregbuf)
+   if (nregbuf > sizeof(regbuf))
return -EINVAL;
 
regbuf[0] = reg >> 8;

Let me know if you're happy with that; I can merge it to the original
patch.

> > >> +u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> > >> +int ret = 0;
> > >> +
> > >> +if (nregbuf > maxregbuf)
> > >> +return -EINVAL;
> > >> +
> > >> +regbuf[0] = reg >> 8;
> > >> +regbuf[1] = reg & 0xff;
> > >> +
> > >> +memcpy(regbuf + 2, val, num);
> > >> +
> > >> +ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
> > >> +if (ret < 0) {
> > >> +dev_err(ov7251->dev, "%s: write seq regs error %d: 
> > >> first reg=%x\n",
> > > 
> > > This line is over 80... 
> > 
> > Yes indeed. Somehow checkpatch does not report this line, I don't know why.
> > 
> > > 
> > > If you're happy with these, I can make the changes, too; they're trivial.
> > 
> > Only the second one? Thanks :)
> 
> Works for me. I'd still think the overhead of managing the buffer is
> irrelevant where to having an extra function to do essentially the same
> thing is a source of maintenance and review work. Note that we're even now
> spending time to discuss it. ;-)
> 
> -- 
> Kind regards,
> 
> Sakari Ailus
> e-mail: sakari.ai...@iki.fi

-- 
Sakari Ailus
e-mail: sakari.ai...@iki.fi

Re: [PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Sakari Ailus]

On Thu, Apr 26, 2018 at 10:04:25AM +0300, Todor Tomov wrote:
> Hi Sakari,
> 
> On 26.04.2018 09:50, Sakari Ailus wrote:
> > Hi Todor,
> > 
> > On Wed, Apr 25, 2018 at 07:20:46PM +0300, Todor Tomov wrote:
> > ...
> >> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> >> +{
> >> +  u8 regbuf[3];
> >> +  int ret;
> >> +
> >> +  regbuf[0] = reg >> 8;
> >> +  regbuf[1] = reg & 0xff;
> >> +  regbuf[2] = val;
> >> +
> >> +  ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> >> +  if (ret < 0) {
> >> +  dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
> >> +  __func__, ret, reg, val);
> >> +  return ret;
> >> +  }
> >> +
> >> +  return 0;
> > 
> > How about:
> > 
> > return ov7251_write_seq_regs(ov7251, reg, , 1);
> > 
> > And put the function below ov2751_write_seq_regs().
> 
> I'm not sure... It will calculate message length each time and then check
> that it is not greater than 5, which it is. Seems redundant.
> 
> > 
> >> +}
> >> +
> >> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
> >> +   u8 num)
> >> +{
> >> +  const u8 maxregbuf = 5;
> >> +  u8 regbuf[maxregbuf];
> >> +  u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> >> +  int ret = 0;
> >> +
> >> +  if (nregbuf > maxregbuf)
> >> +  return -EINVAL;
> >> +
> >> +  regbuf[0] = reg >> 8;
> >> +  regbuf[1] = reg & 0xff;
> >> +
> >> +  memcpy(regbuf + 2, val, num);
> >> +
> >> +  ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
> >> +  if (ret < 0) {
> >> +  dev_err(ov7251->dev, "%s: write seq regs error %d: first 
> >> reg=%x\n",
> > 
> > This line is over 80... 
> 
> Yes indeed. Somehow checkpatch does not report this line, I don't know why.
> 
> > 
> > If you're happy with these, I can make the changes, too; they're trivial.
> 
> Only the second one? Thanks :)

Works for me. I'd still think the overhead of managing the buffer is
irrelevant where to having an extra function to do essentially the same
thing is a source of maintenance and review work. Note that we're even now
spending time to discuss it. ;-)

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ai...@iki.fi

Re: [PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Todor Tomov]

Hi Sakari,

On 26.04.2018 09:50, Sakari Ailus wrote:
> Hi Todor,
> 
> On Wed, Apr 25, 2018 at 07:20:46PM +0300, Todor Tomov wrote:
> ...
>> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
>> +{
>> +u8 regbuf[3];
>> +int ret;
>> +
>> +regbuf[0] = reg >> 8;
>> +regbuf[1] = reg & 0xff;
>> +regbuf[2] = val;
>> +
>> +ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
>> +if (ret < 0) {
>> +dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
>> +__func__, ret, reg, val);
>> +return ret;
>> +}
>> +
>> +return 0;
> 
> How about:
> 
>   return ov7251_write_seq_regs(ov7251, reg, , 1);
> 
> And put the function below ov2751_write_seq_regs().

I'm not sure... It will calculate message length each time and then check
that it is not greater than 5, which it is. Seems redundant.

> 
>> +}
>> +
>> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
>> + u8 num)
>> +{
>> +const u8 maxregbuf = 5;
>> +u8 regbuf[maxregbuf];
>> +u8 nregbuf = sizeof(reg) + num * sizeof(*val);
>> +int ret = 0;
>> +
>> +if (nregbuf > maxregbuf)
>> +return -EINVAL;
>> +
>> +regbuf[0] = reg >> 8;
>> +regbuf[1] = reg & 0xff;
>> +
>> +memcpy(regbuf + 2, val, num);
>> +
>> +ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
>> +if (ret < 0) {
>> +dev_err(ov7251->dev, "%s: write seq regs error %d: first 
>> reg=%x\n",
> 
> This line is over 80... 

Yes indeed. Somehow checkpatch does not report this line, I don't know why.

> 
> If you're happy with these, I can make the changes, too; they're trivial.

Only the second one? Thanks :)

> 
>> +__func__, ret, reg);
>> +return ret;
>> +}
>> +
>> +return 0;
>> +}
> 

-- 
Best regards,
Todor Tomov

Re: [PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Sakari Ailus]

Hi Todor,

On Wed, Apr 25, 2018 at 07:20:46PM +0300, Todor Tomov wrote:
...
> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> +{
> + u8 regbuf[3];
> + int ret;
> +
> + regbuf[0] = reg >> 8;
> + regbuf[1] = reg & 0xff;
> + regbuf[2] = val;
> +
> + ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> + if (ret < 0) {
> + dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
> + __func__, ret, reg, val);
> + return ret;
> + }
> +
> + return 0;

How about:

return ov7251_write_seq_regs(ov7251, reg, , 1);

And put the function below ov2751_write_seq_regs().

> +}
> +
> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
> +  u8 num)
> +{
> + const u8 maxregbuf = 5;
> + u8 regbuf[maxregbuf];
> + u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> + int ret = 0;
> +
> + if (nregbuf > maxregbuf)
> + return -EINVAL;
> +
> + regbuf[0] = reg >> 8;
> + regbuf[1] = reg & 0xff;
> +
> + memcpy(regbuf + 2, val, num);
> +
> + ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
> + if (ret < 0) {
> + dev_err(ov7251->dev, "%s: write seq regs error %d: first 
> reg=%x\n",

This line is over 80... 

If you're happy with these, I can make the changes, too; they're trivial.

> + __func__, ret, reg);
> + return ret;
> + }
> +
> + return 0;
> +}

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ai...@iki.fi

[PATCH v4 2/2] media: Add a driver for the ov7251 camera sensor

[Todor Tomov]

The ov7251 sensor is a 1/7.5-Inch B VGA (640x480) CMOS Digital Image
Sensor from Omnivision.

The driver supports the following modes:
- 640x480 30fps
- 640x480 60fps
- 640x480 90fps

Output format is 10bit B RAW - MEDIA_BUS_FMT_Y10_1X10.

The driver supports configuration via user controls for:
- exposure and gain;
- horizontal and vertical flip;
- test pattern.

Signed-off-by: Todor Tomov 
Reviewed-by: Jacopo Mondi 
---
 drivers/media/i2c/Kconfig  |   12 +
 drivers/media/i2c/Makefile |1 +
 drivers/media/i2c/ov7251.c | 1503 
 3 files changed, 1516 insertions(+)
 create mode 100644 drivers/media/i2c/ov7251.c

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 541f0d28..3dd16c6 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -688,6 +688,18 @@ config VIDEO_OV5695
  To compile this driver as a module, choose M here: the
  module will be called ov5695.
 
+config VIDEO_OV7251
+   tristate "OmniVision OV7251 sensor support"
+   depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
+   depends on MEDIA_CAMERA_SUPPORT
+   select V4L2_FWNODE
+   help
+ This is a Video4Linux2 sensor-level driver for the OmniVision
+ OV7251 camera.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ov7251.
+
 config VIDEO_OV772X
tristate "OmniVision OV772x sensor support"
depends on I2C && VIDEO_V4L2
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index ea34aee..c8585b1 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
 obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
 obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
 obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
+obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
 obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
 obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
 obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
new file mode 100644
index 000..c05a9de
--- /dev/null
+++ b/drivers/media/i2c/ov7251.c
@@ -0,0 +1,1503 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the OV7251 camera sensor.
+ *
+ * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017-2018, Linaro Ltd.
+ */
+
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#define OV7251_SC_MODE_SELECT  0x0100
+#define OV7251_SC_MODE_SELECT_SW_STANDBY   0x0
+#define OV7251_SC_MODE_SELECT_STREAMING0x1
+
+#define OV7251_CHIP_ID_HIGH0x300a
+#define OV7251_CHIP_ID_HIGH_BYTE   0x77
+#define OV7251_CHIP_ID_LOW 0x300b
+#define OV7251_CHIP_ID_LOW_BYTE0x50
+#define OV7251_SC_GP_IO_IN10x3029
+#define OV7251_AEC_EXPO_0  0x3500
+#define OV7251_AEC_EXPO_1  0x3501
+#define OV7251_AEC_EXPO_2  0x3502
+#define OV7251_AEC_AGC_ADJ_0   0x350a
+#define OV7251_AEC_AGC_ADJ_1   0x350b
+#define OV7251_TIMING_FORMAT1  0x3820
+#define OV7251_TIMING_FORMAT1_VFLIPBIT(2)
+#define OV7251_TIMING_FORMAT2  0x3821
+#define OV7251_TIMING_FORMAT2_MIRROR   BIT(2)
+#define OV7251_PRE_ISP_00  0x5e00
+#define OV7251_PRE_ISP_00_TEST_PATTERN BIT(7)
+
+struct reg_value {
+   u16 reg;
+   u8 val;
+};
+
+struct ov7251_mode_info {
+   u32 width;
+   u32 height;
+   const struct reg_value *data;
+   u32 data_size;
+   u32 pixel_clock;
+   u32 link_freq;
+   u16 exposure_max;
+   u16 exposure_def;
+   struct v4l2_fract timeperframe;
+};
+
+struct ov7251 {
+   struct i2c_client *i2c_client;
+   struct device *dev;
+   struct v4l2_subdev sd;
+   struct media_pad pad;
+   struct v4l2_fwnode_endpoint ep;
+   struct v4l2_mbus_framefmt fmt;
+   struct v4l2_rect crop;
+   struct clk *xclk;
+   u32 xclk_freq;
+
+   struct regulator *io_regulator;
+   struct regulator *core_regulator;
+   struct regulator *analog_regulator;
+
+   const struct ov7251_mode_info *current_mode;
+
+   struct v4l2_ctrl_handler ctrls;
+   struct v4l2_ctrl *pixel_clock;
+   struct v4l2_ctrl *link_freq;
+   struct v4l2_ctrl *exposure;
+   struct v4l2_ctrl *gain;
+
+   /* Cached register values */
+   u8 aec_pk_manual;
+   u8 pre_isp_00;
+   u8 timing_format1;
+   u8 timing_format2;
+
+   struct mutex lock; /* lock to protect power state, ctrls and mode */
+   bool power_on;
+
+   struct gpio_desc *enable_gpio;
+};
+
+static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
+{
+   return container_of(sd, struct ov7251, sd);
+}
+
+static const struct reg_value ov7251_global_init_setting[] = {
+