Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 1 Mar 2022 10:31:07 +0100
From:   Jacopo Mondi <jacopo@jmondi.org>
To:     Krzysztof =?utf-8?Q?Ha=C5=82asa?= <khalasa@piap.pl>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Sakari Ailus <sakari.ailus@iki.fi>,
        Joe Perches <joe@perches.com>
Subject: Re: [PATCH v8 2/2] On Semi AR0521 sensor driver
Message-ID: <20220301093107.ihokyp4xptkzpbpc@uno.localdomain>
References: <m3pmn66pie.fsf@t19.piap.pl>
 <m3h78i6p4t.fsf@t19.piap.pl>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <m3h78i6p4t.fsf@t19.piap.pl>
Precedence: bulk

Hi Krzysztof

In subject

"media: i2c:"

Same for 1/2 where permutation of "media: dt-bindings: i2c:" are used
when adding bindings for media i2c drivers.

On Tue, Mar 01, 2022 at 09:41:38AM +0100, Krzysztof Hałasa wrote:
> The driver has been extensively tested in an i.MX6-based system.
> AR0521 is a 5.7 mm x 4.3 mm, 5 MPix RGGB MIPI/HiSPi BSI CMOS sensor
> from On Semiconductor.
>
> Signed-off-by: Krzysztof Hałasa <khalasa@piap.pl>
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 83d27b57016f8..fb78f871e6e6b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1401,6 +1401,13 @@ S:	Supported
>  W:	http://www.aquantia.com
>  F:	drivers/net/ethernet/aquantia/atlantic/aq_ptp*
>
> +AR0521 ON SEMICONDUCTOR CAMERA SENSOR DRIVER
> +M:	Krzysztof Hałasa <khalasa@piap.pl>
> +L:	linux-media@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/media/i2c/onnn,ar0521.yaml
> +F:	drivers/media/i2c/ar0521.c
> +
>  ARASAN NAND CONTROLLER DRIVER
>  M:	Miquel Raynal <miquel.raynal@bootlin.com>
>  M:	Naga Sureshkumar Relli <nagasure@xilinx.com>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index fe66093b8849e..b92af4c02d6ac 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -733,6 +733,19 @@ config VIDEO_APTINA_PLL
>  config VIDEO_CCS_PLL
>  	tristate
>
> +config VIDEO_AR0521
> +	tristate "ON Semiconductor AR0521 sensor support"
> +	depends on I2C && VIDEO_V4L2
> +	select MEDIA_CONTROLLER
> +	select VIDEO_V4L2_SUBDEV_API
> +	select V4L2_FWNODE
> +	help
> +	  This is a Video4Linux2 sensor driver for the ON Semiconductor
> +	  AR0521 camera.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ar0521.
> +
>  config VIDEO_HI556
>  	tristate "Hynix Hi-556 sensor support"
>  	depends on I2C && VIDEO_V4L2
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index f6b80ef6f41d7..72d5d310ca23c 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -119,6 +119,7 @@ obj-$(CONFIG_VIDEO_I2C)		+= video-i2c.o
>  obj-$(CONFIG_VIDEO_ML86V7667)	+= ml86v7667.o
>  obj-$(CONFIG_VIDEO_OV2659)	+= ov2659.o
>  obj-$(CONFIG_VIDEO_TC358743)	+= tc358743.o
> +obj-$(CONFIG_VIDEO_AR0521)	+= ar0521.o
>  obj-$(CONFIG_VIDEO_HI556)	+= hi556.o
>  obj-$(CONFIG_VIDEO_HI846)	+= hi846.o
>  obj-$(CONFIG_VIDEO_HI847)	+= hi847.o
> diff --git a/drivers/media/i2c/ar0521.c b/drivers/media/i2c/ar0521.c
> new file mode 100644
> index 0000000000000..1cce512ff62b0
> --- /dev/null
> +++ b/drivers/media/i2c/ar0521.c
> @@ -0,0 +1,1059 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2021 Sieć Badawcza Łukasiewicz
> + * - Przemysłowy Instytut Automatyki i Pomiarów PIAP
> + * Written by Krzysztof Hałasa
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/pm_runtime.h>
> +
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +/* External clock (extclk) frequencies */
> +#define AR0521_EXTCLK_MIN	  (10 * 1000 * 1000)
> +#define AR0521_EXTCLK_MAX	  (48 * 1000 * 1000)
> +
> +/* PLL and PLL2 */
> +#define AR0521_PLL_MIN		 (320 * 1000 * 1000)
> +#define AR0521_PLL_MAX		(1280 * 1000 * 1000)
> +
> +/* Effective pixel clocks, the registers may be DDR */
> +#define AR0521_PIXEL_CLOCK_RATE	 (184 * 1000 * 1000)
> +#define AR0521_PIXEL_CLOCK_MIN	 (168 * 1000 * 1000)
> +#define AR0521_PIXEL_CLOCK_MAX	 (414 * 1000 * 1000)
> +
> +#define AR0521_WIDTH_MIN	       8u
> +#define AR0521_WIDTH_MAX	    2608u
> +#define AR0521_HEIGHT_MIN	       8u
> +#define AR0521_HEIGHT_MAX	    1958u
> +
> +#define AR0521_WIDTH_BLANKING_MIN     572u
> +#define AR0521_HEIGHT_BLANKING_MIN     38u /* must be even */
> +#define AR0521_TOTAL_WIDTH_MIN	     2968u
> +
> +/* AR0521 registers */
> +#define AR0521_REG_VT_PIX_CLK_DIV		0x0300
> +#define AR0521_REG_FRAME_LENGTH_LINES		0x0340
> +
> +#define AR0521_REG_CHIP_ID			0x3000
> +#define AR0521_REG_COARSE_INTEGRATION_TIME	0x3012
> +#define AR0521_REG_ROW_SPEED			0x3016
> +#define AR0521_REG_EXTRA_DELAY			0x3018
> +#define AR0521_REG_RESET			0x301A
> +#define   AR0521_REG_RESET_DEFAULTS		  0x0238
> +#define   AR0521_REG_RESET_GROUP_PARAM_HOLD	  0x8000
> +#define   AR0521_REG_RESET_STREAM		  BIT(2)
> +#define   AR0521_REG_RESET_RESTART		  BIT(1)
> +#define   AR0521_REG_RESET_INIT			  BIT(0)
> +
> +#define AR0521_REG_GREEN1_GAIN			0x3056
> +#define AR0521_REG_BLUE_GAIN			0x3058
> +#define AR0521_REG_RED_GAIN			0x305A
> +#define AR0521_REG_GREEN2_GAIN			0x305C
> +#define AR0521_REG_GLOBAL_GAIN			0x305E
> +
> +#define AR0521_REG_HISPI_TEST_MODE		0x3066
> +#define AR0521_REG_HISPI_TEST_MODE_LP11		  0x0004
> +
> +#define AR0521_REG_TEST_PATTERN_MODE		0x3070
> +
> +#define AR0521_REG_SERIAL_FORMAT		0x31AE
> +#define AR0521_REG_SERIAL_FORMAT_MIPI		  0x0200
> +
> +#define AR0521_REG_HISPI_CONTROL_STATUS		0x31C6
> +#define AR0521_REG_HISPI_CONTROL_STATUS_FRAMER_TEST_MODE_ENABLE 0x80
> +
> +#define be		cpu_to_be16
> +
> +static const char * const ar0521_supply_names[] = {
> +	"vdd_io",	/* I/O (1.8V) supply */
> +	"vdd",		/* Core, PLL and MIPI (1.2V) supply */
> +	"vaa",		/* Analog (2.7V) supply */
> +};
> +
> +struct ar0521_ctrls {
> +	struct v4l2_ctrl_handler handler;
> +	struct {
> +		struct v4l2_ctrl *gain;
> +		struct v4l2_ctrl *red_balance;
> +		struct v4l2_ctrl *blue_balance;
> +	};
> +	struct {
> +		struct v4l2_ctrl *hblank;
> +		struct v4l2_ctrl *vblank;
> +	};
> +	struct v4l2_ctrl *pixrate;
> +	struct v4l2_ctrl *exposure;
> +	struct v4l2_ctrl *test_pattern;
> +};
> +
> +struct ar0521_dev {
> +	struct i2c_client *i2c_client;
> +	struct v4l2_subdev sd;
> +	struct media_pad pad;
> +	struct clk *extclk;
> +	u32 extclk_freq;
> +
> +	struct regulator *supplies[ARRAY_SIZE(ar0521_supply_names)];
> +	struct gpio_desc *reset_gpio;
> +
> +	/* lock to protect all members below */
> +	struct mutex lock;
> +
> +	struct v4l2_mbus_framefmt fmt;
> +	struct ar0521_ctrls ctrls;
> +	unsigned int lane_count;
> +	u16 total_width;
> +	u16 total_height;
> +	u16 pll_pre;
> +	u16 pll_mult;
> +	u16 pll_pre2;
> +	u16 pll_mult2;
> +	bool streaming;
> +};
> +
> +static inline struct ar0521_dev *to_ar0521_dev(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct ar0521_dev, sd);
> +}
> +
> +static inline struct v4l2_subdev *ctrl_to_sd(struct v4l2_ctrl *ctrl)
> +{
> +	return &container_of(ctrl->handler, struct ar0521_dev,
> +			     ctrls.handler)->sd;
> +}
> +
> +static u32 div64_round(u64 v, u32 d)
> +{
> +	return div_u64(v + (d >> 1), d);
> +}
> +
> +static u32 div64_round_up(u64 v, u32 d)
> +{
> +	return div_u64(v + d - 1, d);
> +}
> +
> +/* Data must be BE16, the first value is the register address */
> +static int ar0521_write_regs(struct ar0521_dev *sensor, const __be16 *data,
> +			     unsigned int count)
> +{
> +	struct i2c_client *client = sensor->i2c_client;
> +	struct i2c_msg msg;
> +	int ret;
> +
> +	msg.addr = client->addr;
> +	msg.flags = client->flags;
> +	msg.buf = (u8 *)data;
> +	msg.len = count * sizeof(*data);
> +
> +	ret = i2c_transfer(client->adapter, &msg, 1);
> +
> +	if (ret < 0) {
> +		v4l2_err(&sensor->sd, "%s: I2C write error\n", __func__);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ar0521_write_reg(struct ar0521_dev *sensor, u16 reg, u16 val)
> +{
> +	__be16 buf[2] = {be(reg), be(val)};
> +
> +	return ar0521_write_regs(sensor, buf, 2);
> +}
> +
> +static int ar0521_set_geometry(struct ar0521_dev *sensor)
> +{
> +	/* All dimensions are unsigned 12-bit integers */
> +	u16 x = (AR0521_WIDTH_MAX - sensor->fmt.width) / 2;
> +	u16 y = ((AR0521_HEIGHT_MAX - sensor->fmt.height) / 2) & ~1;
> +	__be16 regs[] = {
> +		be(AR0521_REG_FRAME_LENGTH_LINES),
> +		be(sensor->total_height),
> +		be(sensor->total_width),
> +		be(x),
> +		be(y),
> +		be(x + sensor->fmt.width - 1),
> +		be(y + sensor->fmt.height - 1),
> +		be(sensor->fmt.width),
> +		be(sensor->fmt.height)
> +	};
> +
> +	return ar0521_write_regs(sensor, regs, ARRAY_SIZE(regs));
> +}
> +
> +static int ar0521_set_gains(struct ar0521_dev *sensor)
> +{
> +	int green = sensor->ctrls.gain->val;
> +	int red = max(green + sensor->ctrls.red_balance->val, 0);
> +	int blue = max(green + sensor->ctrls.blue_balance->val, 0);
> +	unsigned int gain = min(red, min(green, blue));
> +	unsigned int analog = min(gain, 64u); /* range is 0 - 127 */
> +	__be16 regs[5];
> +
> +	red   = min(red   - analog + 64, 511u);
> +	green = min(green - analog + 64, 511u);
> +	blue  = min(blue  - analog + 64, 511u);
> +	regs[0] = be(AR0521_REG_GREEN1_GAIN);
> +	regs[1] = be(green << 7 | analog);
> +	regs[2] = be(blue  << 7 | analog);
> +	regs[3] = be(red   << 7 | analog);
> +	regs[4] = be(green << 7 | analog);
> +
> +	return ar0521_write_regs(sensor, regs, ARRAY_SIZE(regs));
> +}
> +
> +static u32 calc_pll(struct ar0521_dev *sensor, int num, u32 freq, u16 *pre_ptr,
> +		    u16 *mult_ptr)
> +{
> +	u16 pre = 1, mult = 1, new_pre;
> +	u32 pll = AR0521_PLL_MAX + 1;
> +
> +	for (new_pre = 1; new_pre < 64; new_pre++) {
> +		u32 new_pll;
> +		u32 new_mult = div64_round_up((u64)freq * new_pre,
> +					      sensor->extclk_freq);
> +
> +		if (new_mult < 32)
> +			continue; /* Minimum value */
> +		if (new_mult > 254)
> +			break; /* Maximum, larger pre won't work either */
> +		if (sensor->extclk_freq * (u64)new_mult < AR0521_PLL_MIN *
> +		    new_pre)
> +			continue;
> +		if (sensor->extclk_freq * (u64)new_mult > AR0521_PLL_MAX *
> +		    new_pre)
> +			break; /* Larger pre won't work either */
> +		new_pll = div64_round_up(sensor->extclk_freq * (u64)new_mult,
> +					 new_pre);
> +		if (new_pll < pll) {
> +			pll = new_pll;
> +			pre = new_pre;
> +			mult = new_mult;
> +		}
> +	}
> +
> +	pll = div64_round(sensor->extclk_freq * (u64)mult, pre);
> +	*pre_ptr = pre;
> +	*mult_ptr = mult;
> +	return pll;
> +}
> +
> +#define DIV 4
> +static void ar0521_calc_mode(struct ar0521_dev *sensor)
> +{
> +	unsigned int speed_mod = 4 / sensor->lane_count; /* 1 with 4 DDR lanes */
> +	u16 total_width = max(sensor->fmt.width + AR0521_WIDTH_BLANKING_MIN,
> +			      AR0521_TOTAL_WIDTH_MIN);
> +	u16 total_height = sensor->fmt.height + AR0521_HEIGHT_BLANKING_MIN;
> +
> +	/* Calculate approximate pixel clock first */
> +	u64 pix_clk = AR0521_PIXEL_CLOCK_RATE;
> +
> +	/* PLL1 drives pixel clock - dual rate */
> +	pix_clk = calc_pll(sensor, 1, pix_clk * (DIV / 2), &sensor->pll_pre,
> +			   &sensor->pll_mult);
> +	pix_clk = div64_round(pix_clk, (DIV / 2));
> +	calc_pll(sensor, 2, pix_clk * (DIV / 2) * speed_mod, &sensor->pll_pre2,
> +		 &sensor->pll_mult2);
> +
> +	sensor->total_width = total_width;
> +	sensor->total_height = total_height;
> +}
> +
> +static int ar0521_write_mode(struct ar0521_dev *sensor)
> +{
> +	__be16 pll_regs[] = {
> +		be(AR0521_REG_VT_PIX_CLK_DIV),
> +		/* 0x300 */ be(4), /* vt_pix_clk_div = number of bits / 2 */
> +		/* 0x302 */ be(1), /* vt_sys_clk_div */
> +		/* 0x304 */ be((sensor->pll_pre2 << 8) | sensor->pll_pre),
> +		/* 0x306 */ be((sensor->pll_mult2 << 8) | sensor->pll_mult),
> +		/* 0x308 */ be(8), /* op_pix_clk_div = 2 * vt_pix_clk_div */
> +		/* 0x30A */ be(1)  /* op_sys_clk_div */
> +	};
> +	int ret;
> +
> +	/* Stop streaming for just a moment */
> +	ret = ar0521_write_reg(sensor, AR0521_REG_RESET,
> +			       AR0521_REG_RESET_DEFAULTS);
> +	if (ret)
> +		return ret;
> +
> +	ret = ar0521_set_geometry(sensor);
> +	if (ret)
> +		return ret;
> +
> +	ret = ar0521_write_regs(sensor, pll_regs, ARRAY_SIZE(pll_regs));
> +	if (ret)
> +		return ret;
> +
> +	ret = ar0521_write_reg(sensor, AR0521_REG_COARSE_INTEGRATION_TIME,
> +			       sensor->ctrls.exposure->val);
> +	if (ret)
> +		return ret;
> +
> +	ret = ar0521_write_reg(sensor, AR0521_REG_RESET,
> +			       AR0521_REG_RESET_DEFAULTS |
> +			       AR0521_REG_RESET_STREAM);
> +	if (ret)
> +		return ret;
> +
> +	ret = ar0521_write_reg(sensor, AR0521_REG_TEST_PATTERN_MODE,
> +			       sensor->ctrls.test_pattern->val);
> +	return ret;
> +}
> +
> +static int ar0521_set_stream(struct ar0521_dev *sensor, bool on)
> +{
> +	int ret;
> +
> +	if (on) {
> +		ret = pm_runtime_resume_and_get(&sensor->i2c_client->dev);
> +		if (ret < 0)
> +			return ret;
> +
> +		ar0521_calc_mode(sensor);
> +		ret = ar0521_write_mode(sensor);
> +		if (ret)
> +			goto err;
> +
> +		ret = ar0521_set_gains(sensor);
> +		if (ret)
> +			goto err;
> +
> +		/* Exit LP-11 mode on clock and data lanes */
> +		ret = ar0521_write_reg(sensor, AR0521_REG_HISPI_CONTROL_STATUS,
> +				       0);
> +		if (ret)
> +			goto err;
> +
> +		/* Start streaming */
> +		ret = ar0521_write_reg(sensor, AR0521_REG_RESET,
> +				       AR0521_REG_RESET_DEFAULTS |
> +				       AR0521_REG_RESET_STREAM);
> +		if (ret)
> +			goto err;
> +
> +		return 0;
> +
> +err:
> +		pm_runtime_put(&sensor->i2c_client->dev);
> +		return ret;
> +
> +	} else {
> +		/* Reset gain, the sensor may produce all white pixels without
> +		   this */
> +		ret = ar0521_write_reg(sensor, AR0521_REG_GLOBAL_GAIN, 0x2000);
> +		if (ret)
> +			return ret;
> +
> +		/* Stop streaming */
> +		ret = ar0521_write_reg(sensor, AR0521_REG_RESET,
> +				       AR0521_REG_RESET_DEFAULTS);
> +		if (ret)
> +			return ret;
> +
> +		pm_runtime_put(&sensor->i2c_client->dev);
> +		return 0;
> +	}
> +}
> +
> +static void ar0521_adj_fmt(struct v4l2_mbus_framefmt *fmt)
> +{
> +	fmt->width = clamp(ALIGN(fmt->width, 4), AR0521_WIDTH_MIN,
> +			   AR0521_WIDTH_MAX);
> +	fmt->height = clamp(ALIGN(fmt->height, 4), AR0521_HEIGHT_MIN,
> +			    AR0521_HEIGHT_MAX);
> +	fmt->code = MEDIA_BUS_FMT_SGRBG8_1X8;
> +	fmt->field = V4L2_FIELD_NONE;
> +	fmt->colorspace = V4L2_COLORSPACE_SRGB;
> +	fmt->ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> +	fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
> +	fmt->xfer_func = V4L2_XFER_FUNC_DEFAULT;
> +}
> +
> +static int ar0521_get_fmt(struct v4l2_subdev *sd,
> +			  struct v4l2_subdev_state *sd_state,
> +			  struct v4l2_subdev_format *format)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	struct v4l2_mbus_framefmt *fmt;
> +
> +	mutex_lock(&sensor->lock);
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> +		fmt = v4l2_subdev_get_try_format(&sensor->sd, sd_state, 0
> +						 /* pad */);
> +	else
> +		fmt = &sensor->fmt;
> +
> +	format->format = *fmt;
> +
> +	mutex_unlock(&sensor->lock);
> +	return 0;
> +}
> +
> +static int ar0521_set_fmt(struct v4l2_subdev *sd,
> +			  struct v4l2_subdev_state *sd_state,
> +			  struct v4l2_subdev_format *format)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	int ret = 0;
> +
> +	ar0521_adj_fmt(&format->format);
> +
> +	mutex_lock(&sensor->lock);
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
> +		struct v4l2_mbus_framefmt *fmt;
> +
> +		fmt = v4l2_subdev_get_try_format(sd, sd_state, 0 /* pad */);
> +		*fmt = format->format;
> +	} else {
> +		sensor->fmt = format->format;
> +		ar0521_calc_mode(sensor);
> +	}
> +
> +	mutex_unlock(&sensor->lock);
> +	return ret;
> +}
> +
> +static int ar0521_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	int ret;
> +
> +	/* v4l2_ctrl_lock() locks our own mutex */
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_HBLANK:
> +	case V4L2_CID_VBLANK:
> +		sensor->total_width = sensor->fmt.width +
> +			sensor->ctrls.hblank->val;
> +		sensor->total_height = sensor->fmt.width +
> +			sensor->ctrls.vblank->val;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	/* access the sensor only if it's powered up */
> +	if (!pm_runtime_get_if_in_use(&sensor->i2c_client->dev))
> +		return 0;
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_HBLANK:
> +	case V4L2_CID_VBLANK:
> +		ret = ar0521_set_geometry(sensor);
> +		break;
> +	case V4L2_CID_GAIN:
> +	case V4L2_CID_RED_BALANCE:
> +	case V4L2_CID_BLUE_BALANCE:
> +		ret = ar0521_set_gains(sensor);
> +		break;
> +	case V4L2_CID_EXPOSURE:
> +		ret = ar0521_write_reg(sensor,
> +				       AR0521_REG_COARSE_INTEGRATION_TIME,
> +				       ctrl->val);
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ar0521_write_reg(sensor, AR0521_REG_TEST_PATTERN_MODE,
> +				       ctrl->val);
> +		break;
> +	}
> +
> +	pm_runtime_put(&sensor->i2c_client->dev);
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ar0521_ctrl_ops = {
> +	.s_ctrl = ar0521_s_ctrl,
> +};
> +
> +static const char * const test_pattern_menu[] = {
> +	"Disabled",
> +	"Solid color",
> +	"Color bars",
> +	"Faded color bars"
> +};
> +
> +static int ar0521_init_controls(struct ar0521_dev *sensor)
> +{
> +	const struct v4l2_ctrl_ops *ops = &ar0521_ctrl_ops;
> +	struct ar0521_ctrls *ctrls = &sensor->ctrls;
> +	struct v4l2_ctrl_handler *hdl = &ctrls->handler;
> +	int ret;
> +
> +	v4l2_ctrl_handler_init(hdl, 32);
> +
> +	/* We can use our own mutex for the ctrl lock */
> +	hdl->lock = &sensor->lock;
> +
> +	/* Manual gain */
> +	ctrls->gain = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAIN, 0, 511, 1, 0);
> +	ctrls->red_balance = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_RED_BALANCE,
> +					       -512, 511, 1, 0);
> +	ctrls->blue_balance = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BLUE_BALANCE,
> +						-512, 511, 1, 0);
> +	v4l2_ctrl_cluster(3, &ctrls->gain);
> +
> +	ctrls->hblank = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_HBLANK,
> +					  AR0521_WIDTH_BLANKING_MIN, 4094, 1,
> +					  AR0521_WIDTH_BLANKING_MIN);
> +	ctrls->vblank = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_VBLANK,
> +					  AR0521_HEIGHT_BLANKING_MIN, 4094, 2,
> +					  AR0521_HEIGHT_BLANKING_MIN);
> +	v4l2_ctrl_cluster(2, &ctrls->hblank);
> +
> +	/* Read-only */
> +	ctrls->pixrate = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_PIXEL_RATE,
> +					   AR0521_PIXEL_CLOCK_MIN,
> +					   AR0521_PIXEL_CLOCK_MAX, 1,
> +					   AR0521_PIXEL_CLOCK_RATE);
> +
> +	/* Manual exposure time */
> +	ctrls->exposure = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_EXPOSURE, 0,
> +					    65535, 1, 360);
> +
> +	ctrls->test_pattern = v4l2_ctrl_new_std_menu_items(hdl, ops,
> +					V4L2_CID_TEST_PATTERN,
> +					ARRAY_SIZE(test_pattern_menu) - 1,
> +					0, 0, test_pattern_menu);
> +
> +	if (hdl->error) {
> +		ret = hdl->error;
> +		goto free_ctrls;
> +	}
> +
> +	sensor->sd.ctrl_handler = hdl;
> +	return 0;
> +
> +free_ctrls:
> +	v4l2_ctrl_handler_free(hdl);
> +	return ret;
> +}
> +
> +#define REGS_ENTRY(a)	{(a), ARRAY_SIZE(a)}
> +#define REGS(...)	REGS_ENTRY(((const __be16[]){__VA_ARGS__}))
> +
> +static const struct initial_reg {
> +	const __be16 *data; /* data[0] is register address */
> +	unsigned int count;
> +} initial_regs[] = {
> +	REGS(be(0x0112), be(0x0808)), /* 8-bit/8-bit mode */
> +
> +	/* PEDESTAL+2 :+2 is a workaround for 10bit mode +0.5 rounding */
> +	REGS(be(0x301E), be(0x00AA)),
> +
> +	/* corrections_recommended_bayer */
> +	REGS(be(0x3042),
> +	     be(0x0004),  /* 3042: RNC: enable b/w rnc mode */
> +	     be(0x4580)), /* 3044: RNC: enable row noise correction */
> +
> +	REGS(be(0x30D2),
> +	     be(0x0000),  /* 30D2: CRM/CC: enable crm on Visible and CC rows */
> +	     be(0x0000),  /* 30D4: CC: CC enabled with 16 samples per column */
> +	     /* 30D6: CC: bw mode enabled/12 bit data resolution/bw mode */
> +	     be(0x2FFF)),
> +
> +	REGS(be(0x30DA),
> +	     be(0x0FFF),  /* 30DA: CC: column correction clip level 2 is 0 */
> +	     be(0x0FFF),  /* 30DC: CC: column correction clip level 3 is 0 */
> +	     be(0x0000)), /* 30DE: CC: Group FPN correction */
> +
> +	/* RNC: rnc scaling factor = * 54 / 64 (32 / 38 * 64 = 53.9) */
> +	REGS(be(0x30EE), be(0x1136)),
> +	REGS(be(0x30FA), be(0xFD00)), /* GPIO0 = flash, GPIO1 = shutter */
> +	REGS(be(0x3120), be(0x0005)), /* p1 dither enabled for 10bit mode */
> +	REGS(be(0x3172), be(0x0206)), /* txlo clk divider options */
> +	/* FDOC:fdoc settings with fdoc every frame turned of */
> +	REGS(be(0x3180), be(0x9434)),
> +
> +	REGS(be(0x31B0),
> +	     be(0x008B),  /* 31B0: frame_preamble - FIXME check WRT lanes# */
> +	     be(0x0050)), /* 31B2: line_preamble - FIXME check WRT lanes# */
> +
> +	/* don't use continuous clock mode while shut down */
> +	REGS(be(0x31BC), be(0x068C)),
> +	REGS(be(0x31E0), be(0x0781)), /* Fuse/2DDC: enable 2ddc */
> +
> +	/* analog_setup_recommended_10bit */
> +	REGS(be(0x341A), be(0x4735)), /* Samp&Hold pulse in ADC */
> +	REGS(be(0x3420), be(0x4735)), /* Samp&Hold pulse in ADC */
> +	REGS(be(0x3426), be(0x8A1A)), /* ADC offset distribution pulse */
> +	REGS(be(0x342A), be(0x0018)), /* pulse_config */
> +
> +	/* pixel_timing_recommended */
> +	REGS(be(0x3D00),
> +	     /* 3D00 */ be(0x043E), be(0x4760), be(0xFFFF), be(0xFFFF),
> +	     /* 3D08 */ be(0x8000), be(0x0510), be(0xAF08), be(0x0252),
> +	     /* 3D10 */ be(0x486F), be(0x5D5D), be(0x8056), be(0x8313),
> +	     /* 3D18 */ be(0x0087), be(0x6A48), be(0x6982), be(0x0280),
> +	     /* 3D20 */ be(0x8359), be(0x8D02), be(0x8020), be(0x4882),
> +	     /* 3D28 */ be(0x4269), be(0x6A95), be(0x5988), be(0x5A83),
> +	     /* 3D30 */ be(0x5885), be(0x6280), be(0x6289), be(0x6097),
> +	     /* 3D38 */ be(0x5782), be(0x605C), be(0xBF18), be(0x0961),
> +	     /* 3D40 */ be(0x5080), be(0x2090), be(0x4390), be(0x4382),
> +	     /* 3D48 */ be(0x5F8A), be(0x5D5D), be(0x9C63), be(0x8063),
> +	     /* 3D50 */ be(0xA960), be(0x9757), be(0x8260), be(0x5CFF),
> +	     /* 3D58 */ be(0xBF10), be(0x1681), be(0x0802), be(0x8000),
> +	     /* 3D60 */ be(0x141C), be(0x6000), be(0x6022), be(0x4D80),
> +	     /* 3D68 */ be(0x5C97), be(0x6A69), be(0xAC6F), be(0x4645),
> +	     /* 3D70 */ be(0x4400), be(0x0513), be(0x8069), be(0x6AC6),
> +	     /* 3D78 */ be(0x5F95), be(0x5F70), be(0x8040), be(0x4A81),
> +	     /* 3D80 */ be(0x0300), be(0xE703), be(0x0088), be(0x4A83),
> +	     /* 3D88 */ be(0x40FF), be(0xFFFF), be(0xFD70), be(0x8040),
> +	     /* 3D90 */ be(0x4A85), be(0x4FA8), be(0x4F8C), be(0x0070),
> +	     /* 3D98 */ be(0xBE47), be(0x8847), be(0xBC78), be(0x6B89),
> +	     /* 3DA0 */ be(0x6A80), be(0x6986), be(0x6B8E), be(0x6B80),
> +	     /* 3DA8 */ be(0x6980), be(0x6A88), be(0x7C9F), be(0x866B),
> +	     /* 3DB0 */ be(0x8765), be(0x46FF), be(0xE365), be(0xA679),
> +	     /* 3DB8 */ be(0x4A40), be(0x4580), be(0x44BC), be(0x7000),
> +	     /* 3DC0 */ be(0x8040), be(0x0802), be(0x10EF), be(0x0104),
> +	     /* 3DC8 */ be(0x3860), be(0x5D5D), be(0x5682), be(0x1300),
> +	     /* 3DD0 */ be(0x8648), be(0x8202), be(0x8082), be(0x598A),
> +	     /* 3DD8 */ be(0x0280), be(0x2048), be(0x3060), be(0x8042),
> +	     /* 3DE0 */ be(0x9259), be(0x865A), be(0x8258), be(0x8562),
> +	     /* 3DE8 */ be(0x8062), be(0x8560), be(0x9257), be(0x8221),
> +	     /* 3DF0 */ be(0x10FF), be(0xB757), be(0x9361), be(0x1019),
> +	     /* 3DF8 */ be(0x8020), be(0x9043), be(0x8E43), be(0x845F),
> +	     /* 3E00 */ be(0x835D), be(0x805D), be(0x8163), be(0x8063),
> +	     /* 3E08 */ be(0xA060), be(0x9157), be(0x8260), be(0x5CFF),
> +	     /* 3E10 */ be(0xFFFF), be(0xFFE5), be(0x1016), be(0x2048),
> +	     /* 3E18 */ be(0x0802), be(0x1C60), be(0x0014), be(0x0060),
> +	     /* 3E20 */ be(0x2205), be(0x8120), be(0x908F), be(0x6A80),
> +	     /* 3E28 */ be(0x6982), be(0x5F9F), be(0x6F46), be(0x4544),
> +	     /* 3E30 */ be(0x0005), be(0x8013), be(0x8069), be(0x6A80),
> +	     /* 3E38 */ be(0x7000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E40 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E48 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E50 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E58 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E60 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E68 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E70 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E78 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E80 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E88 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E90 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3E98 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3EA0 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3EA8 */ be(0x0000), be(0x0000), be(0x0000), be(0x0000),
> +	     /* 3EB0 */ be(0x0000), be(0x0000), be(0x0000)),
> +
> +	REGS(be(0x3EB6), be(0x004C)), /* ECL */
> +
> +	REGS(be(0x3EBA),
> +	     be(0xAAAD),  /* 3EBA */
> +	     be(0x0086)), /* 3EBC: Bias currents for FSC/ECL */
> +
> +	REGS(be(0x3EC0),
> +	     be(0x1E00),  /* 3EC0: SFbin/SH mode settings */
> +	     be(0x100A),  /* 3EC2: CLK divider for ramp for 10 bit 400MH */
> +	     /* 3EC4: FSC clamps for HDR mode and adc comp power down co */
> +	     be(0x3300),
> +	     be(0xEA44),  /* 3EC6: VLN and clk gating controls */
> +	     be(0x6F6F),  /* 3EC8: Txl0 and Txlo1 settings for normal mode */
> +	     be(0x2F4A),  /* 3ECA: CDAC/Txlo2/RSTGHI/RSTGLO settings */
> +	     be(0x0506),  /* 3ECC: RSTDHI/RSTDLO/CDAC/TXHI settings */
> +	     /* 3ECE: Ramp buffer settings and Booster enable (bits 0-5) */
> +	     be(0x203B),
> +	     be(0x13F0),  /* 3ED0: TXLO from atest/sf bin settings */
> +	     be(0xA53D),  /* 3ED2: Ramp offset */
> +	     be(0x862F),  /* 3ED4: TXLO open loop/row driver settings */
> +	     be(0x4081),  /* 3ED6: Txlatch fr cfpn rows/vln bias */
> +	     be(0x8003),  /* 3ED8: Ramp step setting for 10 bit 400 Mhz */
> +	     be(0xA580),  /* 3EDA: Ramp Offset */
> +	     be(0xC000),  /* 3EDC: over range for rst and under range for sig */
> +	     be(0xC103)), /* 3EDE: over range for sig and col dec clk settings */
> +
> +	/* corrections_recommended_bayer */
> +	REGS(be(0x3F00),
> +	     be(0x0017),  /* 3F00: BM_T0 */
> +	     be(0x02DD),  /* 3F02: BM_T1 */
> +	     /* 3F04: if Ana_gain less than 2, use noise_floor0, multipl */
> +	     be(0x0020),
> +	     /* 3F06: if Ana_gain between 4 and 7, use noise_floor2 and */
> +	     be(0x0040),
> +	     /* 3F08: if Ana_gain between 4 and 7, use noise_floor2 and */
> +	     be(0x0070),
> +	     /* 3F0A: Define noise_floor0(low address) and noise_floor1 */
> +	     be(0x0101),
> +	     be(0x0302)), /* 3F0C: Define noise_floor2 and noise_floor3 */
> +
> +	REGS(be(0x3F10),
> +	     be(0x0505),  /* 3F10: single k factor 0 */
> +	     be(0x0505),  /* 3F12: single k factor 1 */
> +	     be(0x0505),  /* 3F14: single k factor 2 */
> +	     be(0x01FF),  /* 3F16: cross factor 0 */
> +	     be(0x01FF),  /* 3F18: cross factor 1 */
> +	     be(0x01FF),  /* 3F1A: cross factor 2 */
> +	     be(0x0022)), /* 3F1E */
> +
> +	/* GTH_THRES_RTN: 4max,4min filtered out of every 46 samples and */
> +	REGS(be(0x3F2C), be(0x442E)),
> +
> +	REGS(be(0x3F3E),
> +	     be(0x0000),  /* 3F3E: Switch ADC from 12 bit to 10 bit mode */
> +	     be(0x1511),  /* 3F40: couple k factor 0 */
> +	     be(0x1511),  /* 3F42: couple k factor 1 */
> +	     be(0x0707)), /* 3F44: couple k factor 2 */
> +};
> +
> +static int ar0521_power_off(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	int i;
> +
> +	clk_disable_unprepare(sensor->extclk);
> +
> +	if (sensor->reset_gpio)
> +		gpiod_set_value(sensor->reset_gpio, 1); /* assert RESET signal */
> +
> +	for (i = ARRAY_SIZE(ar0521_supply_names) - 1; i >= 0; i--) {
> +		if (sensor->supplies[i])
> +			regulator_disable(sensor->supplies[i]);
> +	}
> +	return 0;
> +}
> +
> +static int ar0521_power_on(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	unsigned int cnt;
> +	int ret;
> +
> +	for (cnt = 0; cnt < ARRAY_SIZE(ar0521_supply_names); cnt++)
> +		if (sensor->supplies[cnt]) {
> +			ret = regulator_enable(sensor->supplies[cnt]);
> +			if (ret < 0)
> +				goto off;
> +
> +			usleep_range(1000, 1500); /* min 1 ms */
> +		}
> +
> +	ret = clk_prepare_enable(sensor->extclk);
> +	if (ret < 0) {
> +		v4l2_err(&sensor->sd, "error enabling sensor clock\n");
> +		goto off;
> +	}
> +	usleep_range(1000, 1500); /* min 1 ms */
> +
> +	if (sensor->reset_gpio)
> +		/* deassert RESET signal */
> +		gpiod_set_value(sensor->reset_gpio, 0);
> +	usleep_range(4500, 5000); /* min 45000 clocks */
> +
> +	for (cnt = 0; cnt < ARRAY_SIZE(initial_regs); cnt++)
> +		if (ar0521_write_regs(sensor, initial_regs[cnt].data,
> +				      initial_regs[cnt].count))
> +			goto off;
> +
> +	ret = ar0521_write_reg(sensor, AR0521_REG_SERIAL_FORMAT,
> +			       AR0521_REG_SERIAL_FORMAT_MIPI |
> +			       sensor->lane_count);
> +	if (ret)
> +		goto off;
> +
> +	/* set MIPI test mode - disabled for now */
> +	ret = ar0521_write_reg(sensor, AR0521_REG_HISPI_TEST_MODE,
> +			       ((0x40 << sensor->lane_count) - 0x40) |
> +			       AR0521_REG_HISPI_TEST_MODE_LP11);
> +	if (ret)
> +		goto off;
> +
> +	ret = ar0521_write_reg(sensor, AR0521_REG_ROW_SPEED, 0x110 |
> +			       4 / sensor->lane_count);
> +	if (ret)
> +		goto off;
> +
> +	return 0;
> +off:
> +	ar0521_power_off(dev);
> +	return ret;
> +}
> +
> +static int ar0521_enum_mbus_code(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_state *sd_state,
> +				 struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +
> +	if (code->index)
> +		return -EINVAL;
> +
> +	code->code = sensor->fmt.code;
> +	return 0;
> +}
> +
> +static int ar0521_pre_streamon(struct v4l2_subdev *sd, u32 flags)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	int ret;
> +
> +	if (!(flags & V4L2_SUBDEV_PRE_STREAMON_FL_MANUAL_LP))
> +		return -EACCES;
> +
> +	ret = pm_runtime_resume_and_get(&sensor->i2c_client->dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Set LP-11 on clock and data lanes */
> +	ret = ar0521_write_reg(sensor, AR0521_REG_HISPI_CONTROL_STATUS,
> +			AR0521_REG_HISPI_CONTROL_STATUS_FRAMER_TEST_MODE_ENABLE);
> +	if (ret)
> +		goto err;
> +
> +	/* Start streaming LP-11 */
> +	ret = ar0521_write_reg(sensor, AR0521_REG_RESET,
> +			       AR0521_REG_RESET_DEFAULTS |
> +			       AR0521_REG_RESET_STREAM);
> +	if (ret)
> +		goto err;
> +	return 0;
> +
> +err:
> +	pm_runtime_put(&sensor->i2c_client->dev);
> +	return ret;
> +}
> +
> +static int ar0521_post_streamoff(struct v4l2_subdev *sd)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +
> +	pm_runtime_put(&sensor->i2c_client->dev);
> +	return 0;
> +}
> +
> +static int ar0521_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +	int ret;
> +
> +	mutex_lock(&sensor->lock);
> +
> +	ret = ar0521_set_stream(sensor, enable);
> +	if (!ret)
> +		sensor->streaming = enable;
> +
> +	mutex_unlock(&sensor->lock);
> +	return ret;
> +}
> +
> +static const struct v4l2_subdev_core_ops ar0521_core_ops = {
> +	.log_status = v4l2_ctrl_subdev_log_status,
> +};
> +
> +static const struct v4l2_subdev_video_ops ar0521_video_ops = {
> +	.s_stream = ar0521_s_stream,
> +	.pre_streamon = ar0521_pre_streamon,
> +	.post_streamoff = ar0521_post_streamoff,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ar0521_pad_ops = {
> +	.enum_mbus_code = ar0521_enum_mbus_code,
> +	.get_fmt = ar0521_get_fmt,
> +	.set_fmt = ar0521_set_fmt,
> +};
> +
> +static const struct v4l2_subdev_ops ar0521_subdev_ops = {
> +	.core = &ar0521_core_ops,
> +	.video = &ar0521_video_ops,
> +	.pad = &ar0521_pad_ops,
> +};
> +
> +static int __maybe_unused ar0521_suspend(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +
> +	if (sensor->streaming)
> +		ar0521_set_stream(sensor, 0);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused ar0521_resume(struct device *dev)
> +{
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +
> +	if (sensor->streaming)
> +		return ar0521_set_stream(sensor, 1);
> +
> +	return 0;
> +}
> +
> +static int ar0521_probe(struct i2c_client *client)
> +{
> +	struct v4l2_fwnode_endpoint ep = {
> +		.bus_type = V4L2_MBUS_CSI2_DPHY
> +	};
> +	struct device *dev = &client->dev;
> +	struct fwnode_handle *endpoint;
> +	struct ar0521_dev *sensor;
> +	unsigned int cnt;
> +	int ret;
> +
> +	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
> +	if (!sensor)
> +		return -ENOMEM;
> +
> +	sensor->i2c_client = client;
> +	sensor->fmt.width = AR0521_WIDTH_MAX;
> +	sensor->fmt.height = AR0521_HEIGHT_MAX;
> +
> +	endpoint = fwnode_graph_get_endpoint_by_id(dev_fwnode(dev), 0, 0,
> +						   FWNODE_GRAPH_ENDPOINT_NEXT);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &ep);
> +	fwnode_handle_put(endpoint);
> +	if (ret) {
> +		dev_err(dev, "could not parse endpoint\n");
> +		return ret;
> +	}
> +
> +	if (ep.bus_type != V4L2_MBUS_CSI2_DPHY) {
> +		dev_err(dev, "invalid bus type, must be MIPI CSI2\n");
> +		return -EINVAL;
> +	}
> +
> +	sensor->lane_count = ep.bus.mipi_csi2.num_data_lanes;
> +	switch (sensor->lane_count) {
> +	case 1:
> +	case 2:
> +	case 4:
> +		break;
> +	default:
> +		dev_err(dev, "invalid number of MIPI data lanes\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Get master clock (extclk) */
> +	sensor->extclk = devm_clk_get(dev, "extclk");
> +	if (IS_ERR(sensor->extclk)) {
> +		dev_err(dev, "failed to get extclk\n");
> +		return PTR_ERR(sensor->extclk);
> +	}
> +
> +	sensor->extclk_freq = clk_get_rate(sensor->extclk);
> +
> +	if (sensor->extclk_freq < AR0521_EXTCLK_MIN ||
> +	    sensor->extclk_freq > AR0521_EXTCLK_MAX) {
> +		dev_err(dev, "extclk frequency out of range: %u Hz\n",
> +			sensor->extclk_freq);
> +		return -EINVAL;
> +	}
> +
> +	/* Request optional reset pin (usually active low) and assert it */
> +	sensor->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> +						     GPIOD_OUT_HIGH);
> +
> +	v4l2_i2c_subdev_init(&sensor->sd, client, &ar0521_subdev_ops);
> +
> +	sensor->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	sensor->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	sensor->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +	ret = media_entity_pads_init(&sensor->sd.entity, 1, &sensor->pad);
> +	if (ret)
> +		return ret;
> +
> +	for (cnt = 0; cnt < ARRAY_SIZE(ar0521_supply_names); cnt++) {
> +		struct regulator *supply = devm_regulator_get(dev,
> +						ar0521_supply_names[cnt]);
> +
> +		if (IS_ERR(supply)) {
> +			dev_info(dev, "no %s regulator found: %li\n",
> +				 ar0521_supply_names[cnt], PTR_ERR(supply));
> +			return PTR_ERR(supply);
> +		}
> +		sensor->supplies[cnt] = supply;
> +	}
> +
> +	mutex_init(&sensor->lock);
> +
> +	ret = ar0521_init_controls(sensor);
> +	if (ret)
> +		goto entity_cleanup;
> +
> +	ar0521_adj_fmt(&sensor->fmt);
> +
> +	ret = v4l2_async_register_subdev(&sensor->sd);
> +	if (ret)
> +		goto free_ctrls;
> +
> +	/* Turn on the device and enable runtime PM */
> +	ret = ar0521_power_on(&client->dev);
> +	if (ret)
> +		goto disable;
> +	pm_runtime_set_active(&client->dev);
> +	pm_runtime_enable(&client->dev);
> +	pm_runtime_idle(&client->dev);

Do you have an _idle() callback ? This seems a no-op to me, or am I
mistaken ? (runtime_pm is still cryptic to me sometimes)

Can't you just remove power_on() if it's not needed ?

There still are a few checkpatch warnings which might be worth
considering  but nothing huge.

Apart from that, all other comments I had are now resolved.
With the above _idle question clarified:
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
   j

> +	return 0;
> +
> +disable:
> +	v4l2_async_unregister_subdev(&sensor->sd);
> +	media_entity_cleanup(&sensor->sd.entity);
> +free_ctrls:
> +	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
> +entity_cleanup:
> +	media_entity_cleanup(&sensor->sd.entity);
> +	mutex_destroy(&sensor->lock);
> +	return ret;
> +}
> +
> +static int ar0521_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ar0521_dev *sensor = to_ar0521_dev(sd);
> +
> +	v4l2_async_unregister_subdev(&sensor->sd);
> +	media_entity_cleanup(&sensor->sd.entity);
> +	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
> +	pm_runtime_disable(&client->dev);
> +	if (!pm_runtime_status_suspended(&client->dev))
> +		ar0521_power_off(&client->dev);
> +	pm_runtime_set_suspended(&client->dev);
> +	mutex_destroy(&sensor->lock);
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ar0521_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(ar0521_suspend, ar0521_resume)
> +	SET_RUNTIME_PM_OPS(ar0521_power_off, ar0521_power_on, NULL)
> +};
> +static const struct of_device_id ar0521_dt_ids[] = {
> +	{.compatible = "onnn,ar0521"},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ar0521_dt_ids);
> +
> +static struct i2c_driver ar0521_i2c_driver = {
> +	.driver = {
> +		.name  = "ar0521",
> +		.pm = &ar0521_pm_ops,
> +		.of_match_table = ar0521_dt_ids,
> +	},
> +	.probe_new = ar0521_probe,
> +	.remove = ar0521_remove,
> +};
> +
> +module_i2c_driver(ar0521_i2c_driver);
> +
> +MODULE_DESCRIPTION("AR0521 MIPI Camera subdev driver");
> +MODULE_AUTHOR("Krzysztof Hałasa <khalasa@piap.pl>");
> +MODULE_LICENSE("GPL v2");
>
> --
> Krzysztof "Chris" Hałasa
>
> Sieć Badawcza Łukasiewicz
> Przemysłowy Instytut Automatyki i Pomiarów PIAP
> Al. Jerozolimskie 202, 02-486 Warszawa