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From: Sakari Ailus <sakari.ailus@iki.fi>
To: Todor Tomov <todor.tomov@linaro.org>
Cc: mchehab@kernel.org, hverkuil@xs4all.nl,
	laurent.pinchart@ideasonboard.com, linux-media@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] media: Add a driver for the ov7251 camera sensor
Date: Wed, 25 Apr 2018 13:54:48 +0300	[thread overview]
Message-ID: <20180425105447.z35h44ep3rqjmfaz@valkosipuli.retiisi.org.uk> (raw)
In-Reply-To: <1524582067-28585-3-git-send-email-todor.tomov@linaro.org>

Hi Todor,

Thanks for the update. Just a few minor comments below.

On Tue, Apr 24, 2018 at 06:01:07PM +0300, Todor Tomov wrote:
> The ov7251 sensor is a 1/7.5-Inch B&W 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&W 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 <todor.tomov@linaro.org>
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  drivers/media/i2c/Kconfig  |   13 +
>  drivers/media/i2c/Makefile |    1 +
>  drivers/media/i2c/ov7251.c | 1501 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1515 insertions(+)
>  create mode 100644 drivers/media/i2c/ov7251.c
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 541f0d28..1ff7aaf 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -688,6 +688,19 @@ 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 OF

I think you could drop OF dependency.

> +	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 0000000..69e70a0
> --- /dev/null
> +++ b/drivers/media/i2c/ov7251.c
> @@ -0,0 +1,1501 @@
> +// 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 <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define OV7251_SC_MODE_SELECT		0x0100
> +#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
> +#define OV7251_SC_MODE_SELECT_STREAMING		0x1
> +
> +#define OV7251_CHIP_ID_HIGH		0x300a
> +#define OV7251_CHIP_ID_HIGH_BYTE	0x77
> +#define OV7251_CHIP_ID_LOW		0x300b
> +#define OV7251_CHIP_ID_LOW_BYTE		0x50
> +#define OV7251_SC_GP_IO_IN1		0x3029
> +#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_VFLIP	BIT(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[] = {
> +	{ 0x0103, 0x01 },
> +	{ 0x303b, 0x02 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_30fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0xf0 },
> +	{ 0x3017, 0xf0 },
> +	{ 0x3018, 0xf0 },
> +	{ 0x301a, 0xf0 },
> +	{ 0x301b, 0xf0 },
> +	{ 0x301c, 0xf0 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x06 }, /* total vertical timing high */
> +	{ 0x380f, 0xbc }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_60fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x03 }, /* total vertical timing high */
> +	{ 0x380f, 0x5c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_90fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x02 }, /* total vertical timing high */
> +	{ 0x380f, 0x3c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const s64 link_freq[] = {
> +	240000000,
> +};
> +
> +static const struct ov7251_mode_info ov7251_mode_info_data[] = {
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_30fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 1704,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 3000
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_60fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 840,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 6014
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_90fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 552,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 9043
> +		}
> +	},
> +};
> +
> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	/* OV7251 power up sequence requires core regulator
> +	 * to be enabled not earlier than io regulator
> +	 */
> +
> +	ret = regulator_enable(ov7251->io_regulator);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "set io voltage failed\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(ov7251->analog_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set analog voltage failed\n");
> +		goto err_disable_io;
> +	}
> +
> +	ret = regulator_enable(ov7251->core_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set core voltage failed\n");
> +		goto err_disable_analog;
> +	}
> +
> +	return 0;
> +
> +err_disable_analog:
> +	regulator_disable(ov7251->analog_regulator);

A newline would be nice here (before a label).

> +err_disable_io:
> +	regulator_disable(ov7251->io_regulator);
> +
> +	return ret;
> +}
> +
> +static void ov7251_regulators_disable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = regulator_disable(ov7251->core_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "core regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->analog_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "analog regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->io_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "io regulator disable failed\n");
> +}
> +
> +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;
> +}
> +
> +static int ov7251_write_seq_regs(struct ov7251 *ov7251, u16 reg, u8 *val,
> +				 u8 num)
> +{
> +	u8 *regbuf;
> +	u8 nregbuf = sizeof(reg) + num * sizeof(*val);
> +	int ret = 0;
> +	int i;
> +
> +	regbuf = kzalloc(nregbuf, GFP_KERNEL);
> +	if (!regbuf)
> +		return -ENOMEM;

num is either 2 or 3. Could you allocate from the stack instead, and return
an error if num exceeds the reserved space?

> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +
> +	for (i = 0; i < num; i++)
> +		regbuf[2 + i] = val[i];

You could use memcpy for this.

> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, nregbuf);
> +	kfree(regbuf);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write seq regs error %d: first reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
> +{
> +	u8 regbuf[2];
> +	int ret;
> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
> +{
> +	u16 reg;
> +	u8 val[3];
> +
> +	reg = OV7251_AEC_EXPO_0;
> +	val[0] = (exposure & 0xf000) >> 12; /* goes to OV7251_AEC_EXPO_0 */
> +	val[1] = (exposure & 0x0ff0) >> 4;  /* goes to OV7251_AEC_EXPO_1 */
> +	val[2] = (exposure & 0x000f) << 4;  /* goes to OV7251_AEC_EXPO_2 */
> +
> +	return ov7251_write_seq_regs(ov7251, reg, val, 3);
> +}
> +
> +static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
> +{
> +	u16 reg;
> +	u8 val[2];
> +
> +	reg = OV7251_AEC_AGC_ADJ_0;
> +	val[0] = (gain & 0x0300) >> 8; /* goes to OV7251_AEC_AGC_ADJ_0 */
> +	val[1] = gain & 0xff;          /* goes to OV7251_AEC_AGC_ADJ_1 */
> +
> +	return ov7251_write_seq_regs(ov7251, reg, val, 2);
> +}
> +
> +static int ov7251_set_register_array(struct ov7251 *ov7251,
> +				     const struct reg_value *settings,
> +				     unsigned int num_settings)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < num_settings; ++i, ++settings) {
> +		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_power_on(struct ov7251 *ov7251)
> +{
> +	int ret;
> +	u32 wait_us;
> +
> +	ret = ov7251_regulators_enable(ov7251);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = clk_prepare_enable(ov7251->xclk);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "clk prepare enable failed\n");
> +		ov7251_regulators_disable(ov7251);
> +		return ret;
> +	}
> +
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
> +
> +	/* wait at least 65536 external clock cycles */
> +	wait_us = (65536 * 1000) / (ov7251->xclk_freq / 1000);

Nice. But should you round upwards, i.e. DIV_ROUND_UP()?

> +	usleep_range(wait_us, wait_us + 1000);
> +
> +	return 0;
> +}
> +
> +static void ov7251_set_power_off(struct ov7251 *ov7251)
> +{
> +	clk_disable_unprepare(ov7251->xclk);
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
> +	ov7251_regulators_disable(ov7251);
> +}
> +
> +static int ov7251_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	int ret = 0;
> +
> +	mutex_lock(&ov7251->lock);
> +
> +	/* If the power state is not modified - no work to do. */
> +	if (ov7251->power_on == !!on)
> +		goto exit;
> +
> +	if (on) {
> +		ret = ov7251_set_power_on(ov7251);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = ov7251_set_register_array(ov7251,
> +					ov7251_global_init_setting,
> +					ARRAY_SIZE(ov7251_global_init_setting));
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not set init registers\n");
> +			ov7251_set_power_off(ov7251);
> +			goto exit;
> +		}
> +
> +		ov7251->power_on = true;
> +	} else {
> +		ov7251_set_power_off(ov7251);
> +		ov7251->power_on = false;
> +	}
> +
> +exit:
> +	mutex_unlock(&ov7251->lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format2;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT2_MIRROR;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT2_MIRROR;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
> +	if (!ret)
> +		ov7251->timing_format2 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format1;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT1_VFLIP;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT1_VFLIP;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
> +	if (!ret)
> +		ov7251->timing_format1 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->pre_isp_00;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_PRE_ISP_00_TEST_PATTERN;
> +	else
> +		val &= ~OV7251_PRE_ISP_00_TEST_PATTERN;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
> +	if (!ret)
> +		ov7251->pre_isp_00 = val;
> +
> +	return ret;
> +}
> +
> +static const char * const ov7251_test_pattern_menu[] = {
> +	"Disabled",
> +	"Vertical Pattern Bars",
> +};
> +
> +static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ov7251 *ov7251 = container_of(ctrl->handler,
> +					     struct ov7251, ctrls);
> +	int ret;
> +
> +	/* v4l2_ctrl_lock() locks our mutex */
> +
> +	if (!ov7251->power_on)
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_EXPOSURE:
> +		ret = ov7251_set_exposure(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_GAIN:
> +		ret = ov7251_set_gain(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_HFLIP:
> +		ret = ov7251_set_hflip(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_VFLIP:
> +		ret = ov7251_set_vflip(ov7251, ctrl->val);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
> +	.s_ctrl = ov7251_s_ctrl,
> +};
> +
> +static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_pad_config *cfg,
> +				 struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_Y10_1X10;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	if (fse->code != MEDIA_BUS_FMT_Y10_1X10)
> +		return -EINVAL;
> +
> +	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
> +		return -EINVAL;
> +
> +	fse->min_width = ov7251_mode_info_data[fse->index].width;
> +	fse->max_width = ov7251_mode_info_data[fse->index].width;
> +	fse->min_height = ov7251_mode_info_data[fse->index].height;
> +	fse->max_height = ov7251_mode_info_data[fse->index].height;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_interval_enum *fie)
> +{
> +	int index = fie->index;
> +	int i;

unsigned int for both?

> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		if (fie->width != ov7251_mode_info_data[i].width ||
> +		    fie->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		if (index-- == 0) {
> +			fie->interval = ov7251_mode_info_data[i].timeperframe;
> +			return 0;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static struct v4l2_mbus_framefmt *
> +__ov7251_get_pad_format(struct ov7251 *ov7251,
> +			struct v4l2_subdev_pad_config *cfg,
> +			unsigned int pad,
> +			enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->fmt;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int ov7251_get_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	mutex_lock(&ov7251->lock);
> +	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
> +						  format->which);
> +	mutex_unlock(&ov7251->lock);
> +
> +	return 0;
> +}
> +
> +static struct v4l2_rect *
> +__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
> +		      unsigned int pad, enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->crop;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static inline u32 avg_fps(const struct v4l2_fract *t)
> +{
> +	return (t->denominator + (t->numerator >> 1)) / t->numerator;
> +}
> +
> +static const struct ov7251_mode_info *
> +ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
> +{
> +	const struct ov7251_mode_info *mode = ov7251->current_mode;
> +	int fps_req = avg_fps(timeperframe);
> +	unsigned int max_dist_match = (unsigned int) -1;
> +	int i, n = 0;

unsigned int?

> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		unsigned int dist;
> +		int fps_tmp;
> +
> +		if (mode->width != ov7251_mode_info_data[i].width ||
> +		    mode->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		fps_tmp = avg_fps(&ov7251_mode_info_data[i].timeperframe);
> +
> +		dist = abs(fps_req - fps_tmp);
> +
> +		if (dist < max_dist_match) {
> +			n = i;
> +			max_dist_match = dist;
> +		}
> +	}
> +
> +	return &ov7251_mode_info_data[n];
> +}
> +
> +static int ov7251_set_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	struct v4l2_mbus_framefmt *__format;
> +	struct v4l2_rect *__crop;
> +	const struct ov7251_mode_info *new_mode;
> +	int ret = 0;
> +
> +	mutex_lock(&ov7251->lock);
> +
> +	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad, format->which);
> +
> +	new_mode = v4l2_find_nearest_size(ov7251_mode_info_data,
> +				ARRAY_SIZE(ov7251_mode_info_data),
> +				width, height,
> +				format->format.width, format->format.height);
> +
> +	__crop->width = new_mode->width;
> +	__crop->height = new_mode->height;
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		ret = __v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					       new_mode->pixel_clock);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +					 new_mode->link_freq);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_modify_range(ov7251->exposure,
> +					       1, new_mode->exposure_max,
> +					       1, new_mode->exposure_def);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->exposure,
> +					 new_mode->exposure_def);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
> +					   format->which);
> +	__format->width = __crop->width;
> +	__format->height = __crop->height;
> +	__format->code = MEDIA_BUS_FMT_Y10_1X10;
> +	__format->field = V4L2_FIELD_NONE;
> +	__format->colorspace = V4L2_COLORSPACE_SRGB;
> +	__format->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(__format->colorspace);
> +	__format->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
> +				__format->colorspace, __format->ycbcr_enc);
> +	__format->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(__format->colorspace);
> +
> +	format->format = *__format;
> +
> +exit:
> +	mutex_unlock(&ov7251->lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg)
> +{
> +	struct v4l2_subdev_format fmt = { 0 };
> +
> +	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
> +	fmt.format.width = 640;
> +	fmt.format.height = 480;

You could assign all these in variable declaration.

> +
> +	ov7251_set_format(subdev, cfg, &fmt);
> +
> +	return 0;
> +}
> +
> +static int ov7251_get_selection(struct v4l2_subdev *sd,
> +				struct v4l2_subdev_pad_config *cfg,
> +				struct v4l2_subdev_selection *sel)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	if (sel->target != V4L2_SEL_TGT_CROP)
> +		return -EINVAL;
> +
> +	mutex_lock(&ov7251->lock);
> +	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
> +					sel->which);
> +	mutex_unlock(&ov7251->lock);
> +
> +	return 0;
> +}
> +
> +static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	int ret;
> +
> +	mutex_lock(&ov7251->lock);
> +
> +	if (enable) {
> +		ret = ov7251_set_register_array(ov7251,
> +					ov7251->current_mode->data,
> +					ov7251->current_mode->data_size);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not set mode %dx%d\n",
> +				ov7251->current_mode->width,
> +				ov7251->current_mode->height);
> +			goto exit;
> +		}
> +		ret = __v4l2_ctrl_handler_setup(&ov7251->ctrls);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
> +			goto exit;
> +		}
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_STREAMING);
> +	} else {
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_SW_STANDBY);
> +	}
> +
> +exit:
> +	mutex_unlock(&ov7251->lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +
> +	mutex_lock(&ov7251->lock);
> +	fi->interval = ov7251->current_mode->timeperframe;
> +	mutex_unlock(&ov7251->lock);
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	const struct ov7251_mode_info *new_mode;
> +	int ret = 0;
> +
> +	mutex_lock(&ov7251->lock);
> +	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
> +
> +	if (new_mode != ov7251->current_mode) {
> +		ret = __v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					       new_mode->pixel_clock);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +					 new_mode->link_freq);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_modify_range(ov7251->exposure,
> +					       1, new_mode->exposure_max,
> +					       1, new_mode->exposure_def);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->exposure,
> +					 new_mode->exposure_def);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ret = __v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			goto exit;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	fi->interval = ov7251->current_mode->timeperframe;
> +
> +exit:
> +	mutex_unlock(&ov7251->lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_core_ops ov7251_core_ops = {
> +	.s_power = ov7251_s_power,
> +};
> +
> +static const struct v4l2_subdev_video_ops ov7251_video_ops = {
> +	.s_stream = ov7251_s_stream,
> +	.g_frame_interval = ov7251_get_frame_interval,
> +	.s_frame_interval = ov7251_set_frame_interval,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
> +	.init_cfg = ov7251_entity_init_cfg,
> +	.enum_mbus_code = ov7251_enum_mbus_code,
> +	.enum_frame_size = ov7251_enum_frame_size,
> +	.enum_frame_interval = ov7251_enum_frame_ival,
> +	.get_fmt = ov7251_get_format,
> +	.set_fmt = ov7251_set_format,
> +	.get_selection = ov7251_get_selection,
> +};
> +
> +static const struct v4l2_subdev_ops ov7251_subdev_ops = {
> +	.core = &ov7251_core_ops,
> +	.video = &ov7251_video_ops,
> +	.pad = &ov7251_subdev_pad_ops,
> +};
> +
> +static int ov7251_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct fwnode_handle *endpoint;
> +	struct ov7251 *ov7251;
> +	u8 chip_id_high, chip_id_low, chip_rev;
> +	int ret;
> +
> +	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
> +	if (!ov7251)
> +		return -ENOMEM;
> +
> +	ov7251->i2c_client = client;
> +	ov7251->dev = dev;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
> +	fwnode_handle_put(endpoint);
> +	if (ret < 0) {
> +		dev_err(dev, "parsing endpoint node failed\n");
> +		return ret;
> +	}
> +
> +	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
> +		dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
> +			ov7251->ep.bus_type, V4L2_MBUS_CSI2);
> +		return -EINVAL;
> +	}
> +
> +	/* get system clock (xclk) */
> +	ov7251->xclk = devm_clk_get(dev, "xclk");
> +	if (IS_ERR(ov7251->xclk)) {
> +		dev_err(dev, "could not get xclk");
> +		return PTR_ERR(ov7251->xclk);
> +	}
> +
> +	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
> +				       &ov7251->xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	/* external clock must be 24MHz, allow 1% tolerance */
> +	if (ov7251->xclk_freq < 23760000 || ov7251->xclk_freq > 24240000) {
> +		dev_err(dev, "external clock frequency %u is not supported\n",
> +			ov7251->xclk_freq);
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_set_rate(ov7251->xclk, ov7251->xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not set xclk frequency\n");
> +		return ret;
> +	}
> +
> +	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
> +	if (IS_ERR(ov7251->io_regulator)) {
> +		dev_err(dev, "cannot get io regulator\n");
> +		return PTR_ERR(ov7251->io_regulator);
> +	}
> +
> +	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
> +	if (IS_ERR(ov7251->core_regulator)) {
> +		dev_err(dev, "cannot get core regulator\n");
> +		return PTR_ERR(ov7251->core_regulator);
> +	}
> +
> +	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
> +	if (IS_ERR(ov7251->analog_regulator)) {
> +		dev_err(dev, "cannot get analog regulator\n");
> +		return PTR_ERR(ov7251->analog_regulator);
> +	}
> +
> +	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ov7251->enable_gpio)) {
> +		dev_err(dev, "cannot get enable gpio\n");
> +		return PTR_ERR(ov7251->enable_gpio);
> +	}
> +
> +	mutex_init(&ov7251->lock);
> +
> +	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
> +	ov7251->ctrls.lock = &ov7251->lock;
> +
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_HFLIP, 0, 1, 1, 0);
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_VFLIP, 0, 1, 1, 0);
> +	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
> +	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					 V4L2_CID_GAIN, 16, 1023, 1, 16);
> +	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
> +				     V4L2_CID_TEST_PATTERN,
> +				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
> +				     0, 0, ov7251_test_pattern_menu);
> +	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
> +						&ov7251_ctrl_ops,
> +						V4L2_CID_PIXEL_RATE,
> +						1, INT_MAX, 1, 1);
> +	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
> +						   &ov7251_ctrl_ops,
> +						   V4L2_CID_LINK_FREQ,
> +						   ARRAY_SIZE(link_freq) - 1,
> +						   0, link_freq);
> +	if (ov7251->link_freq)
> +		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	ov7251->sd.ctrl_handler = &ov7251->ctrls;
> +
> +	if (ov7251->ctrls.error) {
> +		dev_err(dev, "%s: control initialization error %d\n",
> +			__func__, ov7251->ctrls.error);
> +		ret = ov7251->ctrls.error;
> +		goto free_ctrl;
> +	}
> +
> +	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
> +	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	ov7251->sd.dev = &client->dev;
> +	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +
> +	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register media entity\n");
> +		goto free_ctrl;
> +	}
> +
> +	ret = ov7251_s_power(&ov7251->sd, true);
> +	if (ret < 0) {
> +		dev_err(dev, "could not power up OV7251\n");
> +		goto free_entity;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
> +	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
> +		dev_err(dev, "could not read ID high\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
> +	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
> +		dev_err(dev, "could not read ID low\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read revision\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	chip_rev >>= 4;
> +
> +	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
> +		 chip_rev,
> +		 chip_rev == 0x4 ? "1A / 1B" :
> +		 chip_rev == 0x5 ? "1C / 1D" :
> +		 chip_rev == 0x6 ? "1E" :
> +		 chip_rev == 0x7 ? "1F" : "unknown",
> +		 client->addr);
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
> +			      &ov7251->pre_isp_00);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read test pattern value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
> +			      &ov7251->timing_format1);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read vflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
> +			      &ov7251->timing_format2);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read hflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ov7251_s_power(&ov7251->sd, false);
> +
> +	ret = v4l2_async_register_subdev(&ov7251->sd);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register v4l2 device\n");
> +		goto free_entity;
> +	}
> +
> +	ov7251_entity_init_cfg(&ov7251->sd, NULL);
> +
> +	return 0;
> +
> +power_down:
> +	ov7251_s_power(&ov7251->sd, false);
> +free_entity:
> +	media_entity_cleanup(&ov7251->sd.entity);
> +free_ctrl:
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	v4l2_async_unregister_subdev(&ov7251->sd);
> +	media_entity_cleanup(&ov7251->sd.entity);
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->lock);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id ov7251_of_match[] = {
> +	{ .compatible = "ovti,ov7251" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
> +
> +static struct i2c_driver ov7251_i2c_driver = {
> +	.driver = {
> +		.of_match_table = ov7251_of_match,
> +		.name  = "ov7251",
> +	},
> +	.probe_new  = ov7251_probe,
> +	.remove = ov7251_remove,
> +};
> +
> +module_i2c_driver(ov7251_i2c_driver);
> +
> +MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
> +MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
> +MODULE_LICENSE("GPL v2");

-- 
Kind regards,

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

  reply	other threads:[~2018-04-25 10:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-24 15:01 [PATCH v3 0/2] Add support for " Todor Tomov
2018-04-24 15:01 ` [PATCH v3 1/2] dt-bindings: media: Binding document for OV7251 " Todor Tomov
2018-04-24 15:01 ` [PATCH v3 2/2] media: Add a driver for the ov7251 " Todor Tomov
2018-04-25 10:54   ` Sakari Ailus [this message]
2018-04-25 15:56     ` Todor Tomov

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