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Date:   Wed, 9 Oct 2019 14:30:32 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Xin Ji <xji@analogixsemi.com>
Cc:     "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Nicolas Boichat <drinkcat@chromium.org>,
        Jonas Karlman <jonas@kwiboo.se>,
        David Airlie <airlied@linux.ie>,
        Neil Armstrong <narmstrong@baylibre.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        Sheng Pan <span@analogixsemi.com>,
        Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH v2 2/2] drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to
 DP bridge driver
Message-ID: <20191009113032.GL25098@kadam>
References: <cover.1570588741.git.xji@analogixsemi.com>
 <6ad16e52cd7591d320001a842fc357d976006ef7.1570588741.git.xji@analogixsemi.com>
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In-Reply-To: <6ad16e52cd7591d320001a842fc357d976006ef7.1570588741.git.xji@analogixsemi.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-kernel-owner@vger.kernel.org
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Are you sure you sent the correct patch?  This has many of the same
style issues I mentioned in the previous email.  The error handling
in edid_read() is wrong.  probe() will still crash if allocating the
work queue fails.

On Wed, Oct 09, 2019 at 09:28:02AM +0000, Xin Ji wrote:
> The ANX7625 is an ultra-low power 4K Mobile HD Transmitter designed
> for portable device. It converts MIPI DSI/DPI to DisplayPort 1.3 4K.
> 
> The ANX7625 can support both USB Type-C PD feature and MIPI DSI/DPI
> to DP feature. This driver only enabled MIPI DSI/DPI to DP feature.
> 
> Signed-off-by: Xin Ji <xji@analogixsemi.com>
> ---
>  drivers/gpu/drm/bridge/Makefile           |    2 +-
>  drivers/gpu/drm/bridge/analogix/Kconfig   |    6 +
>  drivers/gpu/drm/bridge/analogix/Makefile  |    1 +
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 2132 +++++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/analogix/anx7625.h |  405 ++++++
>  5 files changed, 2545 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/bridge/analogix/anx7625.c
>  create mode 100644 drivers/gpu/drm/bridge/analogix/anx7625.h
> 
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 4934fcf..bcd388a 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -12,8 +12,8 @@ obj-$(CONFIG_DRM_SII9234) += sii9234.o
>  obj-$(CONFIG_DRM_THINE_THC63LVD1024) += thc63lvd1024.o
>  obj-$(CONFIG_DRM_TOSHIBA_TC358764) += tc358764.o
>  obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
> -obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
>  obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
>  obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
>  obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
> +obj-y += analogix/
>  obj-y += synopsys/
> diff --git a/drivers/gpu/drm/bridge/analogix/Kconfig b/drivers/gpu/drm/bridge/analogix/Kconfig
> index e930ff9..b2f127e 100644
> --- a/drivers/gpu/drm/bridge/analogix/Kconfig
> +++ b/drivers/gpu/drm/bridge/analogix/Kconfig
> @@ -2,3 +2,9 @@
>  config DRM_ANALOGIX_DP
>  	tristate
>  	depends on DRM
> +
> +config ANALOGIX_ANX7625
> +	tristate "Analogix MIPI to DP interface support"
> +	help
> +		ANX7625 is an ultra-low power 4K mobile HD transmitter designed
> +		for portable devices. It converts MIPI/DPI to DisplayPort1.3 4K.
> diff --git a/drivers/gpu/drm/bridge/analogix/Makefile b/drivers/gpu/drm/bridge/analogix/Makefile
> index fdbf3fd..8a52867 100644
> --- a/drivers/gpu/drm/bridge/analogix/Makefile
> +++ b/drivers/gpu/drm/bridge/analogix/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_ANALOGIX_ANX7625) += anx7625.o
>  analogix_dp-objs := analogix_dp_core.o analogix_dp_reg.o
>  obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix_dp.o
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> new file mode 100644
> index 0000000..7bb4e17
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -0,0 +1,2132 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright(c) 2016, Analogix Semiconductor. All rights reserved.
> + *
> + */
> +#include <linux/extcon.h>
> +#include <linux/gcd.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/workqueue.h>
> +
> +#include <linux/of_gpio.h>
> +#include <linux/of_graph.h>
> +#include <linux/of_platform.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_dp_helper.h>
> +#include <drm/drm_edid.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +#include <drm/drm_probe_helper.h>
> +
> +#include <video/display_timing.h>
> +
> +#include "anx7625.h"
> +
> +/*
> + * there is a sync issue while access I2C register between AP(CPU) and
> + * internal firmware(OCM), to avoid the race condition, AP should access
> + * the reserved slave address before slave address occurs changes.
> + */
> +static int i2c_access_workaround(struct anx7625_data *ctx,
> +				 struct i2c_client *client)
> +{
> +	u8 offset;
> +	struct device *dev = &client->dev;
> +	struct i2c_client *last_client = ctx->last_client;
> +	int ret = 0;
> +
> +	if (client != last_client) {


Please reverse this condition.

	if (client == ctx->last_client)
		return 0;

Get rid of the last_client variable.


> +		ctx->last_client = client;
> +
> +		if (client == ctx->i2c.tcpc_client)
> +			offset = RSVD_00_ADDR;
> +		else if (client == ctx->i2c.tx_p0_client)
> +			offset = RSVD_D1_ADDR;
> +		else if (client == ctx->i2c.tx_p1_client)
> +			offset = RSVD_60_ADDR;
> +		else if (client == ctx->i2c.rx_p0_client)
> +			offset = RSVD_39_ADDR;
> +		else if (client == ctx->i2c.rx_p1_client)
> +			offset = RSVD_7F_ADDR;
> +		else
> +			offset = RSVD_00_ADDR;
> +
> +		ret = i2c_smbus_write_byte_data(client, offset, 0x00);
> +		if (ret < 0)
> +			DRM_DEV_ERROR(dev,
> +				      "failed to access i2c id=%x\n:%x",
> +				      client->addr, offset);
> +	}
> +
> +	return ret;
> +}
> +
> +static int anx7625_reg_read(struct anx7625_data *ctx,
> +			    struct i2c_client *client, u8 reg_addr)
> +{
> +	int ret;
> +	struct device *dev = &client->dev;
> +
> +	i2c_access_workaround(ctx, client);
> +
> +	ret = i2c_smbus_read_byte_data(client, reg_addr);
> +	if (ret < 0)
> +		DRM_DEV_ERROR(dev, "read i2c failed id=%x:%x\n",
> +			      client->addr, reg_addr);
> +
> +	return ret;
> +}
> +
> +static int anx7625_reg_block_read(struct anx7625_data *ctx,
> +				  struct i2c_client *client,
> +				  u8 reg_addr, u8 len, u8 *buf)
> +{
> +	int ret;
> +	struct device *dev = &client->dev;
> +
> +	i2c_access_workaround(ctx, client);
> +
> +	ret = i2c_smbus_read_i2c_block_data(client, reg_addr, len, buf);
> +	if (ret < 0)
> +		DRM_DEV_ERROR(dev, "read i2c block failed id=%x:%x\n",
> +			      client->addr, reg_addr);
> +
> +	return ret;
> +}
> +
> +static int anx7625_reg_write(struct anx7625_data *ctx,
> +			     struct i2c_client *client,
> +			     u8 reg_addr, u8 reg_val)
> +{
> +	int ret;
> +	struct device *dev = &client->dev;
> +
> +	i2c_access_workaround(ctx, client);
> +
> +	ret = i2c_smbus_write_byte_data(client, reg_addr, reg_val);
> +
> +	if (ret < 0)
> +		DRM_DEV_ERROR(dev, "failed to write i2c id=%x\n:%x",
> +			      client->addr, reg_addr);
> +
> +	return ret;
> +}
> +
> +static int anx7625_write_or(struct anx7625_data *ctx,
> +			    struct i2c_client *client,
> +			    u8 offset, u8 mask)
> +{
> +	int val = anx7625_reg_read(ctx, client, offset);
> +
> +	return (val < 0) ? val :
> +		anx7625_reg_write(ctx, client, offset, (val | (mask)));


Please write it like this:

static int anx7625_write_or(struct anx7625_data *ctx,
			    struct i2c_client *client,
			    u8 offset, u8 mask)
{
	int val;

	val = anx7625_reg_read(ctx, client, offset);
	if (val < 0)
		return val;

	return anx7625_reg_write(ctx, client, offset, (val | (mask)));
}

> +}
> +
> +static int anx7625_write_and(struct anx7625_data *ctx,
> +			     struct i2c_client *client,
> +			     u8 offset, u8 mask)
> +{
> +	int val = anx7625_reg_read(ctx, client, offset);
> +
> +	return (val < 0) ? val :
> +		anx7625_reg_write(ctx, client, offset, (val & (mask)));

Same.

> +}
> +
> +static int anx7625_write_and_or(struct anx7625_data *ctx,
> +				struct i2c_client *client,
> +				u8 offset, u8 and_mask, u8 or_mask)
> +{
> +	int val = anx7625_reg_read(ctx, client, offset);
> +
> +	return (val < 0) ? val :
> +		anx7625_reg_write(ctx, client, offset,
> +				  (val & and_mask) | (or_mask));

Same.

> +}
> +
> +static int anx7625_config_bit_matrix(struct anx7625_data *ctx)
> +{
> +	int i, ret;
> +
> +	ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				AUDIO_CONTROL_REGISTER, 0x80);
> +	for (i = 0; i < 13; i++)
> +		ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +					 VIDEO_BIT_MATRIX_12 + i,
> +					 0x18 + i);
> +
> +	return ret;
> +}
> +
> +static int anx7625_read_ctrl_status_p0(struct anx7625_data *ctx)
> +{
> +	return anx7625_reg_read(ctx, ctx->i2c.rx_p0_client, AP_AUX_CTRL_STATUS);
> +}
> +
> +static int wait_aux_op_finish(struct anx7625_data *ctx)
> +{
> +	int val;
> +	int ret;
> +	struct device *dev = &ctx->client->dev;
> +
> +	ret = readx_poll_timeout(anx7625_read_ctrl_status_p0,
> +				 ctx, val,
> +				 (!(val & AP_AUX_CTRL_OP_EN) || (val < 0)),
> +				 2000,
> +				 2000 * 150);
> +	if (ret) {
> +		DRM_DEV_ERROR(dev, "aux operation failed!\n");
> +		val = -EIO;

Return directly here:

		return -EIO;

> +	} else {
> +		val = anx7625_reg_read(ctx, ctx->i2c.rx_p0_client,
> +				       AP_AUX_CTRL_STATUS);
> +		if (val < 0 || (val & 0x0F)) {
> +			DRM_DEV_ERROR(dev, "aux status %02x\n", val);
> +			val = -EIO;
> +		}
> +	}
> +
> +	return val;
> +}
> +
> +static int write_dpcd_addr(struct anx7625_data *ctx,
> +			   u8 addrh, u8 addrm, u8 addrl)
> +{
> +	int ret;
> +
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_ADDR_7_0, (u8)addrl);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_ADDR_15_8, (u8)addrm);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_ADDR_19_16, (u8)addrh);
> +
> +	return ret;
> +}
> +
> +static int sp_tx_aux_dpcdread_bytes(struct anx7625_data *ctx,
> +				    u8 addrh, u8 addrm,
> +				    u8 addrl, u8 count,
> +				    u8 *buf)
> +{
> +	u8 c;
> +	int ret;
> +	struct device *dev = &ctx->client->dev;
> +
> +	if (WARN_ON(count > (size_t)MAX_DPCD_BUFFER_SIZE))

No need for this cast.

> +		return -E2BIG;
> +
> +	/* command and length */
> +	c = ((count - 1) << 4) | 0x09;

If count == 0 this would cause a problem.  But count is never invalid
so that's okay.

> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, AP_AUX_COMMAND, c);
> +	/* address */
> +	ret |= write_dpcd_addr(ctx, addrh, addrm, addrl);
> +	/* aux en */
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client, AP_AUX_CTRL_STATUS,
> +				AP_AUX_CTRL_OP_EN);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(dev, "aux enable failed.\n");
> +		return ret;
> +	}
> +
> +	usleep_range(2000, 2100);
> +
> +	ret = wait_aux_op_finish(ctx);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(dev, "aux read failed\n");
> +		return ret;
> +	}
> +
> +	return anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> +			AP_AUX_BUFF_START, count, buf);
> +}
> +
> +static int anx7625_video_mute_control(struct anx7625_data *ctx,
> +				      u8 status)
> +{
> +	int ret;
> +
> +	if (status) { /* mute on */
> +		/* set mute flag */
> +		ret = anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +				       AP_AV_STATUS, AP_MIPI_MUTE);
> +		/* clear mipi RX en */
> +		ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +					 AP_AV_STATUS, (u8)~AP_MIPI_RX_EN);
> +	} else { /* mute off */
> +		/* clear mute flag */
> +		ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +					AP_AV_STATUS, (u8)~AP_MIPI_MUTE);
> +		/* set MIPI RX EN */
> +		ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +					AP_AV_STATUS, AP_MIPI_RX_EN);
> +	}
> +
> +	return ret;
> +}
> +
> +static int anx7625_config_audio_input(struct anx7625_data *ctx)
> +{
> +	int ret;
> +
> +	/* channel num */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				AUDIO_CHANNEL_STATUS_6, I2S_CH_2 << 5);
> +	/* layout */
> +	/* as I2S channel is 2, no need to set layout */
> +
> +	/* FS */
> +	ret |= anx7625_write_and_or(ctx, ctx->i2c.tx_p2_client,
> +				    AUDIO_CHANNEL_STATUS_4,
> +				    0xf0, AUDIO_FS_48K);
> +	/* word length */
> +	ret |= anx7625_write_and_or(ctx, ctx->i2c.tx_p2_client,
> +				    AUDIO_CHANNEL_STATUS_5,
> +				    0xf0, AUDIO_W_LEN_24_24MAX);
> +	/* I2S */
> +	ret |= anx7625_write_or(ctx, ctx->i2c.tx_p2_client,
> +				AUDIO_CHANNEL_STATUS_6, I2S_SLAVE_MODE);
> +	ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client,
> +				 AUDIO_CONTROL_REGISTER, ~TDM_TIMING_MODE);
> +	/* audio change flag */
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +				AP_AV_STATUS, AP_AUDIO_CHG);
> +
> +	if (ret < 0)
> +		DRM_ERROR("failed to config audio.\n");
> +
> +	return ret;
> +}
> +
> +/* reduction of fraction a/b */
> +static void anx7625_reduction_of_a_fraction(unsigned long *a, unsigned long *b)
> +{
> +	unsigned long gcd_num;
> +	unsigned long tmp_a, tmp_b;
> +	u32 i = 1;
> +
> +	gcd_num = gcd(*a, *b);
> +	*a /= gcd_num;
> +	*b /= gcd_num;
> +
> +	tmp_a = *a;
> +	tmp_b = *b;
> +
> +	while ((*a > MAX_UNSIGNED_24BIT) || (*b > MAX_UNSIGNED_24BIT)) {
> +		i++;
> +		*a = tmp_a / i;
> +		*b = tmp_b / i;
> +	}
> +
> +	/*
> +	 * in the end, make a, b larger to have higher ODFC PLL
> +	 * output frequency accuracy
> +	 */
> +	while ((*a < MAX_UNSIGNED_24BIT) && (*b < MAX_UNSIGNED_24BIT)) {
> +		*a <<= 1;
> +		*b <<= 1;
> +	}
> +
> +	*a >>= 1;
> +	*b >>= 1;
> +}
> +
> +static int anx7625_calculate_m_n(u32 pixelclock,
> +				 unsigned long *m,
> +				 unsigned long *n,
> +				 u8 *post_divider)
> +{
> +	if (pixelclock > PLL_OUT_FREQ_ABS_MAX / POST_DIVIDER_MIN) {
> +		/* pixel clock frequency is too high */
> +		DRM_ERROR("pixelclock too high, act(%d), maximum(%lu)\n",
> +			  pixelclock,
> +			  PLL_OUT_FREQ_ABS_MAX / POST_DIVIDER_MIN);
> +		return -EDOM;

Why -EDOM instead of -EINVAL?

> +	}
> +
> +	if (pixelclock < PLL_OUT_FREQ_ABS_MIN / POST_DIVIDER_MAX) {
> +		/* pixel clock frequency is too low */
> +		DRM_ERROR("pixelclock too low, act(%d), maximum(%lu)\n",
> +			  pixelclock,
> +			  PLL_OUT_FREQ_ABS_MIN / POST_DIVIDER_MAX);
> +		return -EDOM;
> +	}
> +
> +	*post_divider = 1;
        ^^^^^^^^^^^^^^^^^
Delete.

> +
> +	for (*post_divider = 1;
             ^^^^^^^^^^^^^^^^^
Duplicate.

> +		pixelclock < (PLL_OUT_FREQ_MIN / (*post_divider));)
> +		*post_divider += 1;
> +
> +	if (*post_divider > POST_DIVIDER_MAX) {
> +		for (*post_divider = 1;
> +			(pixelclock <
> +			 (PLL_OUT_FREQ_ABS_MIN / (*post_divider)));)
> +			*post_divider += 1;
> +
> +		if (*post_divider > POST_DIVIDER_MAX) {
> +			DRM_ERROR("cannot find property post_divider(%d)\n",
> +				  *post_divider);
> +			return -EDOM;
> +		}
> +	}
> +
> +	/* patch to improve the accuracy */
> +	if (*post_divider == 7) {
> +		/* 27,000,000 is not divisible by 7 */
> +		*post_divider = 8;
> +	} else if (*post_divider == 11) {
> +		/* 27,000,000 is not divisible by 11 */
> +		*post_divider = 12;
> +	} else if ((*post_divider == 13) || (*post_divider == 14)) {
> +		/*27,000,000 is not divisible by 13 or 14*/
> +		*post_divider = 15;
> +	}
> +
> +	if (pixelclock * (*post_divider) > PLL_OUT_FREQ_ABS_MAX) {
> +		DRM_ERROR("act clock(%u) large than maximum(%lu)\n",
> +			  pixelclock * (*post_divider),
> +			  PLL_OUT_FREQ_ABS_MAX);
> +		return -EDOM;
> +	}
> +
> +	*m = pixelclock;
> +	*n = XTAL_FRQ / (*post_divider);
> +
> +	anx7625_reduction_of_a_fraction(m, n);
> +
> +	return 0;
> +}
> +
> +static int anx7625_odfc_config(struct anx7625_data *ctx,
> +			       u8 post_divider)
> +{
> +	int ret;
> +
> +	/* config input reference clock frequency 27MHz/19.2MHz */
> +	ret = anx7625_write_and(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_16,
> +				~(REF_CLK_27000KHZ << MIPI_FREF_D_IND));
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_16,
> +				(REF_CLK_27000KHZ << MIPI_FREF_D_IND));
> +	/* post divider */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_DIGITAL_PLL_8, 0x0f);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_8,
> +				post_divider << 4);
> +
> +	/* add patch for MIS2-125 (5pcs ANX7625 fail ATE MBIST test) */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_7,
> +				 ~MIPI_PLL_VCO_TUNE_REG_VAL);
> +
> +	/* reset ODFC PLL */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_7,
> +				 ~MIPI_PLL_RESET_N);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_7,
> +				MIPI_PLL_RESET_N);
> +
> +	if (ret < 0)
> +		DRM_ERROR("IO error.\n");
> +
> +	return ret;
> +}
> +
> +static int anx7625_dsi_video_timing_config(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +	unsigned long m, n;
> +	u16 htotal;
> +	int ret;
> +	u8 post_divider = 0;
> +
> +	ret = anx7625_calculate_m_n(ctx->dt.pixelclock.min * 1000,
> +				    &m, &n, &post_divider);
> +
> +	if (ret != 0) {

if (ret) {

> +		DRM_ERROR("cannot get property m n value.\n");
> +		return -EINVAL;
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "compute M(%lu), N(%lu), divider(%d).\n",
> +			     m, n, post_divider);
> +
> +	/* configure pixel clock */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, PIXEL_CLOCK_L,
> +				(ctx->dt.pixelclock.min / 1000) & 0xFF);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, PIXEL_CLOCK_H,
> +				 (ctx->dt.pixelclock.min / 1000) >> 8);
> +	/* lane count */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_LANE_CTRL_0, 0xfc);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client,
> +				MIPI_LANE_CTRL_0, 3);
> +
> +	/* Htotal */
> +	htotal = ctx->dt.hactive.min + ctx->dt.hfront_porch.min +
> +		ctx->dt.hback_porch.min + ctx->dt.hsync_len.min;
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_TOTAL_PIXELS_L, htotal & 0xFF);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_TOTAL_PIXELS_H, htotal >> 8);
> +	/* Hactive */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_ACTIVE_PIXELS_L, ctx->dt.hactive.min & 0xFF);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_ACTIVE_PIXELS_H, ctx->dt.hactive.min >> 8);
> +	/* HFP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_FRONT_PORCH_L, ctx->dt.hfront_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_FRONT_PORCH_H,
> +			ctx->dt.hfront_porch.min >> 8);
> +	/* HWS */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_SYNC_WIDTH_L, ctx->dt.hsync_len.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_SYNC_WIDTH_H, ctx->dt.hsync_len.min >> 8);
> +	/* HBP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_BACK_PORCH_L, ctx->dt.hback_porch.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			HORIZONTAL_BACK_PORCH_H, ctx->dt.hback_porch.min >> 8);
> +	/* Vactive */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_L,
> +			ctx->dt.vactive.min);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client, ACTIVE_LINES_H,
> +			ctx->dt.vactive.min >> 8);
> +	/* VFP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			VERTICAL_FRONT_PORCH, ctx->dt.vfront_porch.min);
> +	/* VWS */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			VERTICAL_SYNC_WIDTH, ctx->dt.vsync_len.min);
> +	/* VBP */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p2_client,
> +			VERTICAL_BACK_PORCH, ctx->dt.vback_porch.min);
> +	/* M value */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_PLL_M_NUM_23_16, (m >> 16) & 0xff);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_PLL_M_NUM_15_8, (m >> 8) & 0xff);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_PLL_M_NUM_7_0, (m & 0xff));
> +	/* N value */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_PLL_N_NUM_23_16, (n >> 16) & 0xff);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_PLL_N_NUM_15_8, (n >> 8) & 0xff);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client, MIPI_PLL_N_NUM_7_0,
> +			(n & 0xff));
> +	/* diff */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +			MIPI_DIGITAL_ADJ_1, 0x37);
> +
> +	ret |= anx7625_odfc_config(ctx, post_divider - 1);
> +
> +	if (ret < 0)
> +		DRM_ERROR("mipi dsi setup IO error.\n");
> +
> +	return ret;
> +}
> +
> +static int anx7625_swap_dsi_lane3(struct anx7625_data *ctx)
> +{
> +	int val;
> +
> +	/* swap MIPI-DSI data lane 3 P and N */
> +	val = anx7625_reg_read(ctx, ctx->i2c.rx_p1_client, MIPI_SWAP);
> +	if (val < 0) {
> +		DRM_ERROR("IO error : access MIPI_SWAP.\n");
> +		return -EIO;
> +	}
> +
> +	val |= (1 << MIPI_SWAP_CH3);
> +	return anx7625_reg_write(ctx, ctx->i2c.rx_p1_client, MIPI_SWAP, val);
> +}
> +
> +static int anx7625_api_dsi_config(struct anx7625_data *ctx)
> +
> +{
> +	int val, ret;
> +
> +	/* swap MIPI-DSI data lane 3 P and N */
> +	ret = anx7625_swap_dsi_lane3(ctx);
> +	if (ret < 0) {
> +		DRM_ERROR("IO error : swap dsi lane 3 failed.\n");
> +		return ret;
> +	}
> +
> +	/* DSI clock settings */
> +	val = (0 << MIPI_HS_PWD_CLK)		|
> +		(0 << MIPI_HS_RT_CLK)		|
> +		(0 << MIPI_PD_CLK)		|
> +		(1 << MIPI_CLK_RT_MANUAL_PD_EN)	|
> +		(1 << MIPI_CLK_HS_MANUAL_PD_EN)	|
> +		(0 << MIPI_CLK_DET_DET_BYPASS)	|
> +		(0 << MIPI_CLK_MISS_CTRL)	|
> +		(0 << MIPI_PD_LPTX_CH_MANUAL_PD_EN);
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				MIPI_PHY_CONTROL_3, val);
> +
> +	/*
> +	 * Decreased HS prepare timing delay from 160ns to 80ns work with
> +	 *     a) Dragon board 810 series (Qualcomm AP)
> +	 *     b) Moving Pixel DSI source (PG3A pattern generator +
> +	 *	P332 D-PHY Probe) default D-PHY timing
> +	 *	5ns/step
> +	 */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_TIME_HS_PRPR, 0x10);
> +
> +	/* enable DSI mode*/
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_18,
> +				SELECT_DSI << MIPI_DPI_SELECT);
> +
> +	ret |= anx7625_dsi_video_timing_config(ctx);
> +	if (ret < 0) {
> +		DRM_ERROR("dsi video timing config failed\n");
> +		return ret;
> +	}
> +
> +	/* toggle m, n ready */
> +	ret = anx7625_write_and(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_6,
> +				~(MIPI_M_NUM_READY | MIPI_N_NUM_READY));
> +	usleep_range(1000, 1100);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, MIPI_DIGITAL_PLL_6,
> +				MIPI_M_NUM_READY | MIPI_N_NUM_READY);
> +
> +	/* configure integer stable register */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_VIDEO_STABLE_CNT, 0x02);
> +	/* power on MIPI RX */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_LANE_CTRL_10, 0x00);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_LANE_CTRL_10, 0x80);
> +
> +	if (ret < 0)
> +		DRM_ERROR("IO error : mipi dsi enable init failed.\n");
> +
> +	return ret;
> +}
> +
> +static int anx7625_dsi_config(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "config dsi.\n");
> +
> +	/* DSC disable */
> +	ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +				R_DSC_CTRL_0, ~DSC_EN);
> +
> +	ret |= anx7625_api_dsi_config(ctx);
> +
> +	if (ret < 0) {
> +		DRM_ERROR("IO error : api dsi config error.\n");

return ret;

> +	} else {
> +		/* set MIPI RX EN */
> +		ret = anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +				       AP_AV_STATUS, AP_MIPI_RX_EN);
> +		/* clear mute flag */
> +		ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +					 AP_AV_STATUS, (u8)~AP_MIPI_MUTE);
> +		if (ret < 0)
> +			DRM_ERROR("IO error : enable mipi rx failed.\n");
> +		else
> +			DRM_DEV_DEBUG_DRIVER(dev, "success to config DSI\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static int anx7625_api_dpi_config(struct anx7625_data *ctx)
> +{
> +	u16 freq = ctx->dt.pixelclock.min / 1000;
> +	int ret;
> +
> +	/* configure pixel clock */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				PIXEL_CLOCK_L, freq & 0xFF);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 PIXEL_CLOCK_H, (freq >> 8));
> +
> +	/* set DPI mode */
> +	/* set to DPI PLL module sel */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_DIGITAL_PLL_9, 0x20);
> +	/* power down MIPI */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_LANE_CTRL_10, 0x08);
> +	/* enable DPI mode */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p1_client,
> +				 MIPI_DIGITAL_PLL_18, 0x1C);
> +	/* set first edge */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.tx_p2_client,
> +				 VIDEO_CONTROL_0, 0x05);
> +	if (ret < 0)
> +		DRM_ERROR("IO error : dpi phy set failed.\n");
> +
> +	return ret;
> +}
> +
> +static int anx7625_dpi_config(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "config dpi\n");
> +
> +	/* DSC disable */
> +	ret = anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +				R_DSC_CTRL_0, ~DSC_EN);
> +	if (ret < 0) {
> +		DRM_ERROR("IO error : disable dsc failed.\n");
> +		return ret;
> +	}
> +
> +	ret = anx7625_config_bit_matrix(ctx);
> +	if (ret < 0) {
> +		DRM_ERROR("config bit matrix failed.\n");
> +		return ret;
> +	}
> +
> +	ret = anx7625_api_dpi_config(ctx);
> +	if (ret < 0) {
> +		DRM_ERROR("mipi phy(dpi) setup failed.\n");
> +		return ret;
> +	}
> +
> +	/* set MIPI RX EN */
> +	ret = anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +			       AP_AV_STATUS, AP_MIPI_RX_EN);
> +	/* clear mute flag */
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AV_STATUS, (u8)~AP_MIPI_MUTE);
> +	if (ret < 0)
> +		DRM_ERROR("IO error : enable mipi rx failed.\n");
> +
> +	return ret;
> +}
> +
> +const u8 ANX_OUI[3] = { 0x00, 0x22, 0xB9 };
> +static int is_anx_dongle(struct anx7625_data *ctx)
> +{
> +	u8 buf[3];
> +
> +	/* 0x0500~0x0502: BRANCH_IEEE_OUI */
> +	sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x05, 0x00, sizeof(buf), buf);
> +	if (memcmp(buf, ANX_OUI, sizeof(buf)) == 0)
> +		return 0;
> +
> +	return -ENXIO;
> +}
> +
> +static void sp_tx_get_rx_bw(struct anx7625_data *ctx, u8 *bw)
> +{
> +	u8 data_buf[4];
> +	/*
> +	 * When ANX dongle connected, if CHIP_ID = 0x7750, bandwidth is 6.75G,
> +	 * because ANX7750 DPCD 0x052x was not available.
> +	 */
> +	if (!is_anx_dongle(ctx)) {
> +		sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x05, 0x03, 0x04, data_buf);
> +		if (data_buf[0] == 0x37 && data_buf[1] == 0x37 &&
> +		    data_buf[2] == 0x35 && data_buf[3] == 0x30) {
> +			/* 0x19 : 6.75G */
> +			*bw = 0x19;
> +		} else {
> +			sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x05, 0x21, 1, bw);
> +			/*
> +			 * some ANX dongle read out value 0,
> +			 * retry standard register.
> +			 */
> +			if (((*bw) == 0) || ((*bw) == 0xff))
> +				sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x00,
> +							 DPCD_MAX_LINK_RATE,
> +							 1, bw);
> +		}
> +	} else {
> +		sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x00,
> +					 DPCD_MAX_LINK_RATE, 1, bw);
> +	}
> +}
> +
> +static void anx7625_dp_start(struct anx7625_data *ctx)
> +{
> +	int ret;
> +
> +	if (!ctx->display_timing_valid) {
> +		DRM_ERROR("mipi drm haven't set display timing yet.\n");
> +		return;
> +	}
> +
> +	ret = anx7625_config_audio_input(ctx);
> +	if (ret < 0)
> +		DRM_ERROR("config audio input failed.\n");
> +
> +	if (ctx->pdata.dsi_supported)
> +		ret = anx7625_dsi_config(ctx);
> +	else
> +		ret = anx7625_dpi_config(ctx);
> +
> +	if (ret < 0)
> +		DRM_ERROR("MIPI phy setup error.\n");
> +}
> +
> +static void anx7625_dp_stop(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "stop dp output\n");
> +
> +	/*
> +	 * video disable: 0x72:08 bit 7 = 0;
> +	 * audio disable: 0x70:87 bit 0 = 0;
> +	 */
> +	ret = anx7625_write_and(ctx, ctx->i2c.tx_p0_client, 0x87, 0xfe);
> +	ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client, 0x08, 0x7f);
> +
> +	ret |= anx7625_video_mute_control(ctx, 1);
> +	if (ret < 0)
> +		DRM_ERROR("IO error : mute video failed\n");
> +}
> +
> +static int sp_tx_rst_aux(struct anx7625_data *ctx)
> +{
> +	int ret;
> +
> +	ret = anx7625_write_or(ctx, ctx->i2c.tx_p2_client, RST_CTRL2,
> +			       AUX_RST);
> +	ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client, RST_CTRL2,
> +				 ~AUX_RST);
> +	return ret;
> +}
> +
> +static int sp_tx_aux_wr(struct anx7625_data *ctx, u8 offset)
> +{
> +	int ret;
> +
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_BUFF_START, offset);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_COMMAND, 0x04);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_CTRL_STATUS, AP_AUX_CTRL_OP_EN);
> +	return (ret | wait_aux_op_finish(ctx));
> +}
> +
> +static int sp_tx_aux_rd(struct anx7625_data *ctx, u8 len_cmd)
> +{
> +	int ret;
> +
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_COMMAND, len_cmd);
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_CTRL_STATUS, AP_AUX_CTRL_OP_EN);
> +	return (ret | wait_aux_op_finish(ctx));
> +}
> +
> +static int sp_tx_get_edid_block(struct anx7625_data *ctx)
> +{
> +	int c = 0;
> +	struct device *dev = &ctx->client->dev;
> +
> +	sp_tx_aux_wr(ctx, 0x7e);
> +	sp_tx_aux_rd(ctx, 0x01);
> +	c = anx7625_reg_read(ctx, ctx->i2c.rx_p0_client, AP_AUX_BUFF_START);
> +	if (c < 0) {
> +		DRM_ERROR("IO error : access AUX BUFF.\n");
> +		return -EIO;
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, " EDID Block = %d\n", c + 1);
> +
> +	if (c > 3)

Replace magic number 3 with a define.

> +		c = 1;
> +
> +	return c;
> +}
> +
> +static int edid_read(struct anx7625_data *ctx,
> +		     u8 offset, u8 *pblock_buf)
> +{
> +	u8 c, cnt = 0;
              ^^^^^^^
No need.

> +	struct device *dev = &ctx->client->dev;
> +
> +	c = 0;
> +	for (cnt = 0; cnt < 3; cnt++) {
> +		sp_tx_aux_wr(ctx, offset);
> +		/* set I2C read com 0x01 mot = 0 and read 16 bytes */
> +		c = sp_tx_aux_rd(ctx, 0xf1);

c needs to be an int because this returns negative error codes.

> +
> +		if (c == 1) {

What does 1 mean in this context?  It seems like a magic number.  Make
it a define.

> +			sp_tx_rst_aux(ctx);
> +			DRM_DEV_DEBUG_DRIVER(dev, "edid read failed, reset!\n");
> +			cnt++;
> +		} else {
> +			anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> +					       AP_AUX_BUFF_START,
> +					       MAX_DPCD_BUFFER_SIZE,
> +					       pblock_buf);
> +			return 0;

Why do we do this read?  It's weird that we don't check for errors.

> +		}
> +	}
> +
> +	return -EIO;
> +}
> +
> +static int segments_edid_read(struct anx7625_data *ctx,
> +			      u8 segment, u8 *buf, u8 offset)
> +{
> +	u8 c, cnt = 0;
> +	int ret;
> +	struct device *dev = &ctx->client->dev;
> +
> +	/* write address only */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_ADDR_7_0, 0x30);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_COMMAND, 0x04);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_CTRL_STATUS,
> +				 AP_AUX_CTRL_ADDRONLY | AP_AUX_CTRL_OP_EN);
> +
> +	ret |= wait_aux_op_finish(ctx);
> +	/* write segment address */
> +	ret |= sp_tx_aux_wr(ctx, segment);
> +	/* data read */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_ADDR_7_0, 0x50);
> +	if (ret < 0) {
> +		DRM_ERROR("IO error : aux initial failed.\n");
> +		return ret;
> +	}
> +
> +	for (cnt = 0; cnt < 3; cnt++) {
> +		sp_tx_aux_wr(ctx, offset);
> +		/* set I2C read com 0x01 mot = 0 and read 16 bytes */
> +		c = sp_tx_aux_rd(ctx, 0xf1);
> +
> +		if (c == 1) {

Same.

> +			ret = sp_tx_rst_aux(ctx);
> +			DRM_DEV_ERROR(dev, "segment read failed, reset!\n");
> +			cnt++;
> +		} else {
> +			ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> +						     AP_AUX_BUFF_START,
> +						     MAX_DPCD_BUFFER_SIZE, buf);
> +			return ret;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int sp_tx_edid_read(struct anx7625_data *ctx,
> +			   u8 *pedid_blocks_buf)
> +{
> +	u8 offset, edid_pos;
> +	int count, blocks_num;
> +	u8 pblock_buf[MAX_DPCD_BUFFER_SIZE];
> +	u8 i, j;
> +	u8 g_edid_break = 0;
> +	int ret;
> +	struct device *dev = &ctx->client->dev;
> +
> +	/* address initial */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				AP_AUX_ADDR_7_0, 0x50);
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_ADDR_15_8, 0);
> +	ret |= anx7625_write_and(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AUX_ADDR_19_16, 0xf0);
> +	if (ret < 0) {
> +		DRM_ERROR("access aux channel IO error.\n");
> +		return -EIO;
> +	}
> +
> +	blocks_num = sp_tx_get_edid_block(ctx);
> +	if (blocks_num < 0)
> +		return blocks_num;
> +
> +	count = 0;
> +
> +	do {
> +		switch (count) {
> +		case 0:
> +		case 1:
> +			for (i = 0; i < 8; i++) {
> +				offset = (i + count * 8) * MAX_DPCD_BUFFER_SIZE;
> +				g_edid_break = edid_read(ctx, offset,
> +							 pblock_buf);
> +
> +				if (g_edid_break)
> +					break;
> +
> +				memcpy(&pedid_blocks_buf[offset],
> +				       pblock_buf,
> +				       MAX_DPCD_BUFFER_SIZE);
> +			}
> +
> +			break;
> +		case 2:
> +			offset = 0x00;
> +
> +			for (j = 0; j < 8; j++) {
> +				edid_pos = (j + count * 8) *
> +					MAX_DPCD_BUFFER_SIZE;
> +
> +				if (g_edid_break == 1)
> +					break;
> +
> +				segments_edid_read(ctx, count / 2,
> +						   pblock_buf, offset);
> +				memcpy(&pedid_blocks_buf[edid_pos],
> +				       pblock_buf,
> +				       MAX_DPCD_BUFFER_SIZE);
> +				offset = offset + 0x10;
> +			}
> +
> +			break;
> +		case 3:
> +			offset = 0x80;
> +
> +			for (j = 0; j < 8; j++) {
> +				edid_pos = (j + count * 8) *
> +					MAX_DPCD_BUFFER_SIZE;
> +				if (g_edid_break == 1)
> +					break;
> +
> +				segments_edid_read(ctx, count / 2,
> +						   pblock_buf, offset);
> +				memcpy(&pedid_blocks_buf[edid_pos],
> +				       pblock_buf,
> +				       MAX_DPCD_BUFFER_SIZE);
> +				offset = offset + 0x10;
> +			}
> +
> +			break;
> +		default:
> +			break;
> +		}
> +
> +		count++;
> +
> +	} while (blocks_num >= count);
> +
> +	/* check edid data */
> +	if (drm_edid_is_valid((struct edid *)pedid_blocks_buf) == false)

if (!drm_edid_is_valid((struct edid *)pedid_blocks_buf))

Shouldn't this return a negative error?

> +		DRM_DEV_ERROR(dev, "WARNING! edid check failed!\n");
> +
> +	/* reset aux channel */
> +	sp_tx_rst_aux(ctx);
> +
> +	return (blocks_num + 1);
> +}
> +
> +static void anx7625_power_on(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +
> +	if (ctx->pdata.low_power_mode) {

Reverse this condition

	if (!ctx->pdata.low_power_mode) {
		DRM_DEV_DEBUG_DRIVER(dev, "Anx7625 not low power mode!\n");
		return;
	}

> +		/* power on pin enable */
> +		gpiod_set_value(ctx->pdata.gpio_p_on, 1);
> +		usleep_range(10000, 11000);
> +		/* power reset pin enable */
> +		gpiod_set_value(ctx->pdata.gpio_reset, 1);
> +		usleep_range(10000, 11000);
> +
> +		DRM_DEV_DEBUG_DRIVER(dev, "Anx7625 power on !\n");
> +	} else {
> +		DRM_DEV_DEBUG_DRIVER(dev, "Anx7625 not low power mode!\n");
> +	}
> +}
> +
> +static void anx7625_power_standby(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +
> +	if (ctx->pdata.low_power_mode) {

Same

> +		gpiod_set_value(ctx->pdata.gpio_reset, 0);
> +		usleep_range(1000, 1100);
> +		gpiod_set_value(ctx->pdata.gpio_p_on, 0);
> +		usleep_range(1000, 1100);
> +		DRM_DEV_DEBUG_DRIVER(dev, "anx7625 power down\n");
> +	} else {
> +		DRM_DEV_DEBUG_DRIVER(dev, "anx7625 not low power mode!\n");
> +	}
> +}
> +
> +/* basic configurations of ANX7625 */
> +static void anx7625_config(struct anx7625_data *ctx)
> +{
> +	anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +			  XTAL_FRQ_SEL, XTAL_FRQ_27M);
> +}
> +
> +static void anx7625_disable_pd_protocol(struct anx7625_data *ctx)
> +{
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	/* reset main ocm */
> +	ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 0x88, 0x40);
> +	/* Disable PD */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				 AP_AV_STATUS, AP_DISABLE_PD);
> +	/* release main ocm */
> +	ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 0x88, 0x00);
> +
> +	if (ret < 0)
> +		DRM_DEV_DEBUG_DRIVER(dev, "disable PD feature failed.\n");
> +	else
> +		DRM_DEV_DEBUG_DRIVER(dev, "disable PD feature succeeded.\n");
> +}
> +
> +static void anx7625_power_on_init(struct anx7625_data *ctx)
> +{
> +	int retry_count, i;
> +	int ret = 0;
> +	struct device *dev = &ctx->client->dev;
> +
> +	for (retry_count = 0; retry_count < 3; retry_count++) {
> +		anx7625_power_on(ctx);
> +		anx7625_config(ctx);
> +
> +		for (i = 0; i < OCM_LOADING_TIME; i++) {
> +			/* check interface workable */
> +			ret = anx7625_reg_read(ctx, ctx->i2c.rx_p0_client,
> +					       FLASH_LOAD_STA);
> +			if (ret < 0) {
> +				DRM_ERROR("IO error : access flash load.\n");
> +				return;
> +			}
> +			if ((ret & FLASH_LOAD_STA_CHK) == FLASH_LOAD_STA_CHK) {
> +				anx7625_disable_pd_protocol(ctx);
> +				DRM_DEV_DEBUG_DRIVER(dev,
> +						     "Firmware ver %02x%02x,",
> +					anx7625_reg_read(ctx,
> +							 ctx->i2c.rx_p0_client,
> +							 OCM_FW_VERSION),
> +					anx7625_reg_read(ctx,
> +							 ctx->i2c.rx_p0_client,
> +							 OCM_FW_REVERSION));
> +				DRM_DEV_DEBUG_DRIVER(dev, "Driver version %s\n",
> +						     ANX7625_DRV_VERSION);
> +
> +				return;
> +			}
> +			usleep_range(1000, 1100);
> +		}
> +		anx7625_power_standby(ctx);
> +	}
> +}
> +
> +static int anx7625_extcon_notifier(struct notifier_block *nb,
> +				   unsigned long event, void *ptr)
> +{
> +	struct anx7625_data *ctx =
> +		container_of(nb, struct anx7625_data, event_nb);
> +
> +	schedule_work(&ctx->extcon_wq);
> +	return NOTIFY_DONE;
> +}
> +
> +static void anx7625_chip_control(struct anx7625_data *ctx, int state)
> +{
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "before set, power_state(%d).\n",
> +			     atomic_read(&ctx->power_status));
> +	if (ctx->pdata.low_power_mode) {

Revserse this condition:

	if (!ctx->pdata.low_power_mode)
		return;

> +		if (state) {
> +			atomic_inc(&ctx->power_status);
> +			if (atomic_read(&ctx->power_status) == 1)
> +				anx7625_power_on_init(ctx);
> +		} else {
> +			if (atomic_read(&ctx->power_status)) {
> +				atomic_dec(&ctx->power_status);
> +
> +				if (atomic_read(&ctx->power_status) == 0)
> +					anx7625_power_standby(ctx);
> +			}
> +		}
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "after set, power_state(%d).\n",
> +			     atomic_read(&ctx->power_status));
> +}
> +
> +static void anx7625_extcon_work(struct work_struct *work)
> +{
> +	struct anx7625_data *ctx =
> +		container_of(work, struct anx7625_data, extcon_wq);
> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_DP);
> +
> +	mutex_lock(&ctx->lock);
> +	anx7625_chip_control(ctx, state);
> +	mutex_unlock(&ctx->lock);
> +}
> +
> +static int anx7625_extcon_notifier_init(struct anx7625_data *ctx)
> +{
> +	int ret;
> +	struct device *dev = &ctx->client->dev;
> +
> +	ctx->event_nb.notifier_call = anx7625_extcon_notifier;
> +	INIT_WORK(&ctx->extcon_wq, anx7625_extcon_work);
> +	ret = devm_extcon_register_notifier(&ctx->client->dev, ctx->extcon,
> +					    EXTCON_DISP_DP, &ctx->event_nb);
> +	if (ret) {
> +		DRM_DEV_ERROR(dev, "failed to register notifier for DP");
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static void anx7625_init_gpio(struct anx7625_data *platform)
> +{
> +	struct device *dev = &platform->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "anx7625 init gpio\n");
> +
> +	/* gpio for chip power enable */
> +	platform->pdata.gpio_p_on =
> +		devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
> +	/* gpio for chip reset */
> +	platform->pdata.gpio_reset =
> +		devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> +
> +	if (platform->pdata.gpio_p_on && platform->pdata.gpio_reset) {
> +		platform->pdata.low_power_mode = 1;
> +		DRM_DEV_DEBUG_DRIVER(dev, "low power mode, pon %d, reset %d.\n",
> +				     desc_to_gpio(platform->pdata.gpio_p_on),
> +				     desc_to_gpio(platform->pdata.gpio_reset));
> +	} else {
> +		platform->pdata.low_power_mode = 0;
> +		DRM_DEV_DEBUG_DRIVER(dev, "not low power mode.\n");
> +	}
> +
> +	platform->pdata.gpio_intr_hpd =
> +		devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "hpd gpio %d.\n",
> +			     (!platform->pdata.gpio_intr_hpd) ? 0 :
> +			     desc_to_gpio(platform->pdata.gpio_intr_hpd));
> +}
> +
> +static void anx7625_stop_dp_work(struct anx7625_data *ctx)
> +{
> +	ctx->hpd_status = 0;
> +	ctx->hpd_high_cnt = 0;
> +	ctx->display_timing_valid = 0;
> +
> +	ctx->slimport_edid_p.edid_block_num = -1;
> +
> +	if (ctx->pdata.low_power_mode == 0)
> +		anx7625_disable_pd_protocol(ctx);
> +}
> +
> +static void anx7625_start_dp_work(struct anx7625_data *ctx)
> +{
> +	int ret;
> +	u8 buf[MAX_DPCD_BUFFER_SIZE];
> +	u8 hdcp_cap;
> +	struct device *dev = &ctx->client->dev;
> +

Delete this blank line.

> +	u8 sp_tx_bw; /* linktraining banwidth */
> +	u8 sp_tx_lane_count; /* link training lane count */
> +
> +	if (ctx->hpd_high_cnt >= 2) {
> +		DRM_DEV_DEBUG_DRIVER(dev, "anx7625 filter useless HPD\n");
> +		return;
> +	}
> +
> +	ctx->hpd_high_cnt++;
> +
> +	sp_tx_get_rx_bw(ctx, &sp_tx_bw);
> +
> +	sp_tx_aux_dpcdread_bytes(ctx, 0x00, 0x00, DPCD_MAX_LANE_COUNT,
> +				 1, &sp_tx_lane_count);
> +
> +	sp_tx_lane_count = sp_tx_lane_count & 0x1f;
> +	sp_tx_aux_dpcdread_bytes(ctx, 0x06, 0x80, 0x28, 1, buf);/* read Bcap */
> +
> +	hdcp_cap = buf[0] & 0x01;
> +
> +	/* not support HDCP */
> +	ret = anx7625_write_and(ctx, ctx->i2c.rx_p1_client, 0xee, 0x9f);
> +
> +	if (hdcp_cap == 0x01)
> +		DRM_DEV_DEBUG_DRIVER(dev, "HDCP1.4\n");
> +
> +	/* try auth flag */
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xec, 0x10);
> +	/* interrupt for DRM */
> +	ret |= anx7625_write_or(ctx, ctx->i2c.rx_p1_client, 0xff, 0x01);
> +	if (ret < 0)
> +		return;
> +	DRM_DEV_DEBUG_DRIVER(dev, "MAX BW=%02x, MAX Lane cnt=%02x, HDCP=%02x\n",
> +			     (u32)sp_tx_bw,
> +			     (u32)sp_tx_lane_count,
> +			     (u32)hdcp_cap);
> +
> +	ret = anx7625_reg_read(ctx, ctx->i2c.rx_p1_client, 0x86);
> +	if (ret < 0)
> +		return;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "Secure OCM version=%02x\n", ret);
> +}
> +
> +static int anx7625_read_hpd_status_p0(struct anx7625_data *ctx)
> +{
> +	return anx7625_reg_read(ctx, ctx->i2c.rx_p0_client, SYSTEM_STSTUS);
> +}
> +
> +static void anx7625_hpd_polling(struct anx7625_data *ctx)
> +{
> +	int ret, val;
> +	struct device *dev = &ctx->client->dev;
> +
> +	if (atomic_read(&ctx->power_status) != 1) {
> +		DRM_DEV_DEBUG_DRIVER(dev, "No need to poling HPD status.\n");
> +		return;
> +	}
> +
> +	ret = readx_poll_timeout(anx7625_read_hpd_status_p0,
> +				 ctx, val,
> +				 ((val & HPD_STATUS) || (val < 0)),
> +				 5000,
> +				 5000 * 100);
> +	if (ret) {
> +		DRM_DEV_ERROR(dev, "HPD polling timeout!\n");
> +	} else {
> +		DRM_DEV_DEBUG_DRIVER(dev, "HPD raise up.\n");
> +		anx7625_reg_write(ctx, ctx->i2c.tcpc_client,
> +				  INTR_ALERT_1, 0xFF);
> +		anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				  INTERFACE_CHANGE_INT, 0);
> +	}
> +
> +	anx7625_start_dp_work(ctx);
> +}
> +
> +static void anx7625_disconnect_check(struct anx7625_data *ctx)
> +{
> +	if (atomic_read(&ctx->power_status) == 0)
> +		anx7625_stop_dp_work(ctx);
> +}
> +
> +static void anx7625_low_power_mode_check(struct anx7625_data *ctx,
> +					 int state)
> +{
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "low power mode check, state(%d).\n", state);
> +
> +	if (ctx->pdata.low_power_mode) {
> +		anx7625_chip_control(ctx, state);
> +		if (state)
> +			anx7625_hpd_polling(ctx);
> +		else
> +			anx7625_disconnect_check(ctx);
> +	}
> +}
> +
> +static void dp_hpd_change_handler(struct anx7625_data *ctx, bool on)
> +{
> +	struct device *dev = &ctx->client->dev;
> +
> +	/* hpd changed */
> +	DRM_DEV_DEBUG_DRIVER(dev, "dp_hpd_change_default_func: %d\n",
> +			     (u32)on);
> +
> +	if (on == 0) {
> +		DRM_DEV_DEBUG_DRIVER(dev, " HPD low\n");
> +		anx7625_stop_dp_work(ctx);
> +	} else {
> +		DRM_DEV_DEBUG_DRIVER(dev, " HPD high\n");
> +		anx7625_start_dp_work(ctx);
> +	}
> +
> +	ctx->hpd_status = 1;
> +}
> +
> +static int anx7625_hpd_change_detect(struct anx7625_data *ctx)
> +{
> +	int intr_vector, status;
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "power_status=%d\n",
> +			     (u32)atomic_read(&ctx->power_status));
> +
> +	status = anx7625_reg_write(ctx, ctx->i2c.tcpc_client,
> +				   INTR_ALERT_1, 0xFF);
> +	if (status < 0) {
> +		DRM_ERROR("IO error : clear alert register.\n");
> +		return status;
> +	}
> +
> +	intr_vector = anx7625_reg_read(ctx, ctx->i2c.rx_p0_client,
> +				       INTERFACE_CHANGE_INT);
> +	if (intr_vector < 0) {
> +		DRM_ERROR("IO error : access interrupt change register.\n");
> +		return intr_vector;
> +	}
> +	DRM_DEV_DEBUG_DRIVER(dev, "0x7e:0x44=%x\n", intr_vector);
> +	status = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> +				   INTERFACE_CHANGE_INT,
> +				   intr_vector & (~intr_vector));
> +	if (status < 0) {
> +		DRM_ERROR("IO error : clear interrupt change register.\n");
> +		return status;
> +	}
> +
> +	if (intr_vector & HPD_STATUS_CHANGE) {

Reverse this condition.  We always want the normal/success path
indented one tab and the weird/error path indented two tabs.

	if (status < 0) {
		DRM_ERROR("IO error : clear interrupt change register.\n");
		return status;
	}
	if (!(intr_vector & HPD_STATUS_CHANGE))
		return -ENOENT;

> +		status = anx7625_reg_read(ctx, ctx->i2c.rx_p0_client,
> +					  SYSTEM_STSTUS);
> +		if (status < 0) {
> +			DRM_ERROR("IO error : clear interrupt status.\n");
> +			return status;
> +		}
> +
> +		DRM_DEV_DEBUG_DRIVER(dev, "0x7e:0x45=%x\n", status);
> +		dp_hpd_change_handler(ctx, status & HPD_STATUS);
> +		return 0;
> +	}
> +
> +	return -ENOENT;
> +}
> +
> +static void anx7625_work_func(struct work_struct *work)
> +{
> +	int event;
> +	struct anx7625_data *ctx = container_of(work,
> +						struct anx7625_data, work);
> +
> +	mutex_lock(&ctx->lock);
> +	event = anx7625_hpd_change_detect(ctx);
> +	mutex_unlock(&ctx->lock);
> +
> +	if (event < 0)
> +		return;
> +
> +	if (ctx->bridge_attached)
> +		drm_helper_hpd_irq_event(ctx->connector.dev);
> +}
> +
> +static irqreturn_t anx7625_intr_hpd_isr(int irq, void *data)
> +{
> +	struct anx7625_data *ctx = (struct anx7625_data *)data;
> +
> +	if (atomic_read(&ctx->power_status) != 1)
> +		return IRQ_NONE;
> +
> +	queue_work(ctx->workqueue, &ctx->work);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +#ifdef CONFIG_OF
> +static int anx7625_parse_dt(struct device *dev,
> +			    struct anx7625_platform_data *pdata)
> +{
> +	struct device_node *np = dev->of_node;
> +	struct device_node *mipi_host_node;
> +	struct device_node *panel_node, *out_ep;
> +
> +	pdata->node.mipi_dsi_host_node = of_graph_get_remote_node(np, 0, 0);
> +	if (pdata->node.mipi_dsi_host_node) {
> +		of_node_put(pdata->node.mipi_dsi_host_node);
> +		pdata->dsi_supported = 1;
> +		mipi_host_node = pdata->node.mipi_dsi_host_node;
> +	} else {
> +		pdata->node.mipi_dpi_host_node =
> +			of_graph_get_remote_node(np, 1, 0);
> +		if (!pdata->node.mipi_dpi_host_node)
> +			DRM_ERROR("cannot resolve any MIPI host node.\n");
> +		else
> +			of_node_put(pdata->node.mipi_dpi_host_node);
> +
> +		mipi_host_node = pdata->node.mipi_dpi_host_node;
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "dsi_supported : %d\n", pdata->dsi_supported);
> +	DRM_DEV_DEBUG_DRIVER(dev, "mipi host node %s exist\n",
> +			     (!mipi_host_node) ? "not" : " ");

This debug message is pointles because if mipi_host_node is NULL then
we already printed an error message.  Delete the mipi_host_node variable
as well.

> +
> +	pdata->node.extcon_node = of_graph_get_port_by_id(np, 2);
> +	pdata->node.internal_panel_node = of_graph_get_port_by_id(np, 3);
> +	pdata->node.edp_node = of_graph_get_port_by_id(np, 4);
> +	if (pdata->node.extcon_node)
> +		pdata->extcon_supported = 1;
> +
> +	if (pdata->node.internal_panel_node) {
> +		pdata->internal_panel = 1;
> +		of_node_put(pdata->node.internal_panel_node);
> +		out_ep = of_get_child_by_name(pdata->node.internal_panel_node,
> +					      "endpoint");
> +		if (out_ep) {

Reverse this condition.  Error path is indented, success path is not.

> +			panel_node = of_graph_get_remote_port_parent(out_ep);
> +			of_node_put(out_ep);
> +
> +			pdata->panel = of_drm_find_panel(panel_node);
> +			DRM_DEV_DEBUG_DRIVER(dev, "get panel node.\n");
> +			of_node_put(panel_node);
> +			if (IS_ERR_OR_NULL(pdata->panel))
> +				return -EPROBE_DEFER;
> +		} else {
> +			DRM_DEV_DEBUG_DRIVER(dev, "cannot get endpoint.\n");
> +			return -EPROBE_DEFER;
> +		}
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "%s support extcon, %s internal panel\n",
> +			     pdata->extcon_supported ? "" : "not",
> +			     pdata->internal_panel ? "has" : "no");
> +
> +	return 0;
> +}
> +#else
> +static int anx7625_parse_dt(struct device *dev,
> +			    struct anx7625_platform_data *pdata)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
> +static inline struct anx7625_data *connector_to_anx7625(struct drm_connector *c)
> +{
> +	return container_of(c, struct anx7625_data, connector);
> +}
> +
> +static inline struct anx7625_data *bridge_to_anx7625(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct anx7625_data, bridge);
> +}
> +
> +static void anx7625_post_disable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "post disable\n");
> +	if (ctx->pdata.panel) {

Reverse.

> +		ret = drm_panel_unprepare(ctx->pdata.panel);
> +		if (ret)
> +			DRM_ERROR("failed to unprepare panel: %d\n", ret);
> +		else
> +			DRM_DEV_DEBUG_DRIVER(dev, "backlight unprepared.\n");
> +
> +		atomic_set(&ctx->panel_power, 0);
> +	}
> +}
> +
> +static void anx7625_pre_enable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "pre enable\n");
> +	if (ctx->pdata.panel) {

Reverse.

> +		ret = drm_panel_prepare(ctx->pdata.panel);
> +		if (ret < 0)
> +			DRM_ERROR("failed to prepare panel: %d\n", ret);
> +		else
> +			DRM_DEV_DEBUG_DRIVER(dev, "backlight prepared.\n");
> +		atomic_set(&ctx->panel_power, 1);
> +	}
> +}
> +
> +static int anx7625_get_modes(struct drm_connector *connector)
> +{
> +	struct anx7625_data *ctx = connector_to_anx7625(connector);
> +	int err, num_modes = 0;
> +	int turn_off_flag = 0;
> +	struct s_edid_data *p_edid = &ctx->slimport_edid_p;
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm get modes\n");
> +
> +	if (ctx->slimport_edid_p.edid_block_num > 0)
> +		goto out;
> +
> +	mutex_lock(&ctx->lock);
> +
> +	if (ctx->pdata.panel && atomic_read(&ctx->panel_power) == 0) {
> +		turn_off_flag = 1;
> +		anx7625_pre_enable(&ctx->bridge);
> +	}
> +
> +	anx7625_low_power_mode_check(ctx, 1);
> +
> +	p_edid->edid_block_num = sp_tx_edid_read(ctx, p_edid->edid_raw_data);
> +
> +	err = -EIO;
> +	if (p_edid->edid_block_num < 0) {
> +		DRM_ERROR("Failed to read EDID.\n");
> +		goto fail;
> +	}
> +
> +	err = drm_connector_update_edid_property(connector,
> +						 (struct edid *)
> +						 &p_edid->edid_raw_data);
> +
> +	if (err)
> +		DRM_ERROR("Failed to update EDID property: %d\n", err);
> +
> +fail:
> +	mutex_unlock(&ctx->lock);
> +	anx7625_low_power_mode_check(ctx, 0);
> +	if (ctx->pdata.panel && turn_off_flag == 1)
> +		anx7625_post_disable(&ctx->bridge);
> +
> +	if (err)
> +		return err;
> +
> +out:
> +	num_modes = drm_add_edid_modes(connector,
> +				       (struct edid *)&p_edid->edid_raw_data);
> +	DRM_DEV_DEBUG_DRIVER(dev, "num_modes(%d)\n", num_modes);
> +
> +	return num_modes;
> +}
> +
> +static enum drm_mode_status
> +anx7625_connector_mode_valid(struct drm_connector *connector,
> +			     struct drm_display_mode *mode)
> +{
> +	struct anx7625_data *ctx = connector_to_anx7625(connector);
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm modes valid verify\n");
> +
> +	if (mode->clock > 300000)

Make all the references to 300000 a define.

> +		return MODE_CLOCK_HIGH;
> +
> +	return MODE_OK;
> +}
> +
> +static struct drm_connector_helper_funcs anx7625_connector_helper_funcs = {
> +	.get_modes = anx7625_get_modes,
> +	.mode_valid = anx7625_connector_mode_valid,
> +};
> +
> +static enum drm_connector_status anx7625_detect(struct drm_connector *connector,
> +						bool force)
> +{
> +	struct anx7625_data *ctx = connector_to_anx7625(connector);
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm detect\n");
> +
> +	if (ctx->pdata.internal_panel)
> +		return connector_status_connected;
> +
> +	if (!ctx->hpd_status)
> +		return connector_status_disconnected;
> +
> +	return connector_status_connected;
> +}
> +
> +static const struct drm_connector_funcs anx7625_connector_funcs = {
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.detect = anx7625_detect,
> +	.destroy = drm_connector_cleanup,
> +	.reset = drm_atomic_helper_connector_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +};
> +
> +static void anx7625_attach_dsi(struct anx7625_data *ctx)
> +{
> +	struct mipi_dsi_host *host;
> +	struct mipi_dsi_device *dsi;
> +	struct device_node *mipi_host_node;
> +	struct device *dev = &ctx->client->dev;
> +	const struct mipi_dsi_device_info info = {
> +		.type = "anx7625",
> +		.channel = 0,
> +		.node = NULL,
> +	};
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "attach dsi\n");
> +
> +	if (ctx->pdata.dsi_supported)
> +		mipi_host_node = ctx->pdata.node.mipi_dsi_host_node;
> +	else
> +		mipi_host_node = ctx->pdata.node.mipi_dpi_host_node;
> +
> +	if (!mipi_host_node) {
> +		DRM_ERROR("dsi host is not configured.\n");
> +		return;
> +	}
> +
> +	host = of_find_mipi_dsi_host_by_node(mipi_host_node);
> +	if (!host) {
> +		DRM_ERROR("failed to find dsi host.\n");
> +		return;
> +	}
> +
> +	dsi = mipi_dsi_device_register_full(host, &info);
> +	if (IS_ERR(dsi)) {
> +		DRM_ERROR("failed to create dsi device.\n");
> +		return;
> +	}
> +
> +	dsi->lanes = 4;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO	|
> +		MIPI_DSI_MODE_VIDEO_SYNC_PULSE	|
> +		MIPI_DSI_MODE_EOT_PACKET	|
> +		MIPI_DSI_MODE_VIDEO_HSE;
> +
> +	if (mipi_dsi_attach(dsi) < 0) {
> +		DRM_ERROR("failed to attach dsi to host.\n");
> +		mipi_dsi_device_unregister(dsi);
> +		return;
> +	}
> +
> +	ctx->dsi = dsi;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "attach dsi succeeded.\n");
> +}
> +
> +static void anx7625_detach_dsi(struct anx7625_data *ctx)
> +{
> +	if (ctx->dsi) {
> +		mipi_dsi_detach(ctx->dsi);
> +		mipi_dsi_device_unregister(ctx->dsi);
> +	}
> +}
> +
> +static int anx7625_bridge_attach(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	int err;
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm attach\n");
> +	if (!bridge->encoder) {
> +		DRM_ERROR("Parent encoder object not found");
> +		return -ENODEV;
> +	}
> +
> +	err = drm_connector_init(bridge->dev, &ctx->connector,
> +				 &anx7625_connector_funcs,
> +				 DRM_MODE_CONNECTOR_DisplayPort);
> +	if (err) {
> +		DRM_ERROR("Failed to initialize connector: %d\n", err);
> +		return err;
> +	}
> +
> +	drm_connector_helper_add(&ctx->connector,
> +				 &anx7625_connector_helper_funcs);
> +
> +	err = drm_connector_register(&ctx->connector);
> +	if (err) {
> +		DRM_ERROR("Failed to register connector: %d\n", err);
> +		return err;
> +	}
> +
> +	ctx->connector.polled = DRM_CONNECTOR_POLL_HPD;
> +
> +	err = drm_connector_attach_encoder(&ctx->connector, bridge->encoder);
> +	if (err) {
> +		DRM_ERROR("Failed to link up connector to encoder: %d\n", err);
> +		drm_connector_unregister(&ctx->connector);
> +		return err;
> +	}
> +
> +	anx7625_attach_dsi(ctx);
> +
> +	ctx->bridge_attached = 1;
> +
> +	return 0;
> +}
> +
> +static enum drm_mode_status
> +anx7625_bridge_mode_valid(struct drm_bridge *bridge,
> +			  const struct drm_display_mode *mode)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm mode checking\n");
> +
> +	/* Max 1200p at 5.4 Ghz, one lane, pixel clock 300M */
> +	if (mode->clock > 300000) {
> +		DRM_DEV_DEBUG_DRIVER(dev,
> +				     "drm mode invalid, pixelclock too high.\n");
> +		return MODE_CLOCK_HIGH;
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm mode valid.\n");
> +
> +	return MODE_OK;
> +}
> +
> +static void anx7625_bridge_mode_set(struct drm_bridge *bridge,
> +				    const struct drm_display_mode *old_mode,
> +				    const struct drm_display_mode *mode)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm mode set\n");
> +
> +	mutex_lock(&ctx->lock);
> +
> +	ctx->dt.pixelclock.min = mode->clock;
> +	ctx->dt.hactive.min = mode->hdisplay;
> +	ctx->dt.hsync_len.min = mode->hsync_end - mode->hsync_start;
> +	ctx->dt.hfront_porch.min = mode->hsync_start - mode->hdisplay;
> +	ctx->dt.hback_porch.min = mode->htotal - mode->hsync_end;
> +	ctx->dt.vactive.min = mode->vdisplay;
> +	ctx->dt.vsync_len.min = mode->vsync_end - mode->vsync_start;
> +	ctx->dt.vfront_porch.min = mode->vsync_start - mode->vdisplay;
> +	ctx->dt.vback_porch.min = mode->vtotal - mode->vsync_end;
> +
> +	ctx->display_timing_valid = 1;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "pixelclock(%d).\n", ctx->dt.pixelclock.min);
> +	DRM_DEV_DEBUG_DRIVER(dev, "hactive(%d), hsync(%d), hfp(%d), hbp(%d)\n",
> +			     ctx->dt.hactive.min,
> +			     ctx->dt.hsync_len.min,
> +			     ctx->dt.hfront_porch.min,
> +			     ctx->dt.hback_porch.min);
> +	DRM_DEV_DEBUG_DRIVER(dev, "vactive(%d), vsync(%d), vfp(%d), vbp(%d)\n",
> +			     ctx->dt.vactive.min,
> +			     ctx->dt.vsync_len.min,
> +			     ctx->dt.vfront_porch.min,
> +			     ctx->dt.vback_porch.min);
> +	DRM_DEV_DEBUG_DRIVER(dev, "hdisplay(%d),hsync_start(%d).\n",
> +			     mode->hdisplay,
> +			     mode->hsync_start);
> +	DRM_DEV_DEBUG_DRIVER(dev, "hsync_end(%d),htotal(%d).\n",
> +			     mode->hsync_end,
> +			     mode->htotal);
> +	DRM_DEV_DEBUG_DRIVER(dev, "vdisplay(%d),vsync_start(%d).\n",
> +			     mode->vdisplay,
> +			     mode->vsync_start);
> +	DRM_DEV_DEBUG_DRIVER(dev, "vsync_end(%d),vtotal(%d).\n",
> +			     mode->vsync_end,
> +			     mode->vtotal);
> +
> +	mutex_unlock(&ctx->lock);
> +}
> +
> +static void anx7625_bridge_enable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm enable\n");
> +
> +	anx7625_low_power_mode_check(ctx, 1);
> +
> +	if (WARN_ON(!atomic_read(&ctx->power_status)))
> +		return;
> +
> +	if (ctx->pdata.panel) {
> +		ret = drm_panel_enable(ctx->pdata.panel);
> +		if (ret < 0) {
> +			DRM_ERROR("failed to enable panel: %d.\n", ret);
> +			return;
> +		}
> +	}
> +
> +	mutex_lock(&ctx->lock);
> +	anx7625_dp_start(ctx);
> +	mutex_unlock(&ctx->lock);
> +}
> +
> +static void anx7625_bridge_disable(struct drm_bridge *bridge)
> +{
> +	struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +	struct device *dev = &ctx->client->dev;
> +	int ret;
> +
> +	if (WARN_ON(!atomic_read(&ctx->power_status)))
> +		return;
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm disable\n");
> +
> +	if (ctx->pdata.panel) {
> +		ret = drm_panel_disable(ctx->pdata.panel);
> +		if (ret < 0)
> +			DRM_ERROR("failed to disable panel: %d.\n", ret);
> +	}
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "drm disable\n");
> +	mutex_lock(&ctx->lock);
> +
> +	anx7625_dp_stop(ctx);
> +
> +	anx7625_low_power_mode_check(ctx, 0);
> +
> +	mutex_unlock(&ctx->lock);
> +}
> +
> +static const struct drm_bridge_funcs anx7625_bridge_funcs = {
> +	.attach = anx7625_bridge_attach,
> +	.disable = anx7625_bridge_disable,
> +	.post_disable = anx7625_post_disable,
> +	.pre_enable = anx7625_pre_enable,
> +	.mode_valid = anx7625_bridge_mode_valid,
> +	.mode_set = anx7625_bridge_mode_set,
> +	.enable = anx7625_bridge_enable,
> +};
> +
> +static int anx7625_register_i2c_dummy_clients(struct anx7625_data *ctx,
> +					      struct i2c_client *client)
> +{
> +	ctx->i2c.tx_p0_client = i2c_new_dummy(client->adapter,
> +					      TX_P0_ADDR >> 1);
> +	ctx->i2c.tx_p1_client = i2c_new_dummy(client->adapter,
> +					      TX_P1_ADDR >> 1);
> +	ctx->i2c.tx_p2_client = i2c_new_dummy(client->adapter,
> +					      TX_P2_ADDR >> 1);
> +
> +	ctx->i2c.rx_p0_client = i2c_new_dummy(client->adapter,
> +					      RX_P0_ADDR >> 1);
> +	ctx->i2c.rx_p1_client = i2c_new_dummy(client->adapter,
> +					      RX_P1_ADDR >> 1);
> +	ctx->i2c.rx_p2_client = i2c_new_dummy(client->adapter,
> +					      RX_P2_ADDR >> 1);
> +
> +	ctx->i2c.tcpc_client = i2c_new_dummy(client->adapter,
> +					     TCPC_INTERFACE_ADDR >> 1);
> +
> +	if ((!ctx->i2c.tx_p0_client |
> +	     !ctx->i2c.tx_p1_client |
> +	     !ctx->i2c.tx_p2_client |
> +	     !ctx->i2c.rx_p0_client |
> +	     !ctx->i2c.rx_p1_client |
> +	     !ctx->i2c.rx_p2_client |
> +	     !ctx->i2c.tcpc_client) != 0)

!= 0 is a double negative.  Only != 0 and == 0 when you are talking
numbers or strcmp().

	if (nr == 0) {
	if (strcmp(foo, bar) == 0) {

Don't use it for pointers or error codes.  There is no reason to do
a bitwise OR instead of a logical OR here.  Just say:


	if (!ctx->i2c.tx_p0_client ||
	    !ctx->i2c.tx_p1_client ||
	    !ctx->i2c.tx_p2_client ||
	    !ctx->i2c.rx_p0_client ||
	    !ctx->i2c.rx_p1_client ||
	    !ctx->i2c.rx_p2_client ||
	    !ctx->i2c.tcpc_client)
		return -EIO;

It wouldn't be that hard to write this without the memory leaks, btw.
Just use "Free the most recent allocation" style.

	ctx->i2c.tx_p0_client = i2c_new_dummy(client->adapter,
					      TX_P0_ADDR >> 1);
	if (!ctx->i2c.tx_p0_client)
		return -ENOMEM;

	ctx->i2c.tx_p1_client = i2c_new_dummy(client->adapter,
					      TX_P1_ADDR >> 1);
	if (!ctx->i2c.tx_p1_client)
		goto free_tx_p0;

	ctx->i2c.tx_p2_client = i2c_new_dummy(client->adapter,
					      TX_P2_ADDR >> 1);
	if (!ctx->i2c.tx_p2_client)
		goto free_tx_p1;


	ctx->i2c.rx_p0_client = i2c_new_dummy(client->adapter,
					      RX_P0_ADDR >> 1);
	if (!ctx->i2c.rx_p0_client)
		goto free_tx_p2;

	ctx->i2c.rx_p1_client = i2c_new_dummy(client->adapter,
					      RX_P1_ADDR >> 1);
	if (!ctx->i2c.rx_p1_client)
		goto free_rx_p0;

	ctx->i2c.rx_p2_client = i2c_new_dummy(client->adapter,
					      RX_P2_ADDR >> 1);
	if (!ctx->i2c.rx_p2_client)
		goto free_rx_p1;


	ctx->i2c.tcpc_client = i2c_new_dummy(client->adapter,
					     TCPC_INTERFACE_ADDR >> 1);
	if (!ctx->i2c.tcpc_client)
		goto free_rx_p2;

	return 0;

free_rx_p2:
	i2c_unregister_device(ctx->i2c.rx_p2_client);
free_rx_p1:
	i2c_unregister_device(ctx->i2c.rx_p1_client);
free_rx_p0:
	i2c_unregister_device(ctx->i2c.rx_p0_client);
free_tx_p2:
	i2c_unregister_device(ctx->i2c.tx_p2_client);
free_tx_p1:
	i2c_unregister_device(ctx->i2c.tx_p1_client);
free_tx_p0:
	i2c_unregister_device(ctx->i2c.tx_p0_client);

	return -ENOMEM;

It's a little bit extra work, but I have done it so I know how hard it
is.  Also now static analysis tools won't complain about the leaks.


> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +static void anx7625_unregister_i2c_dummy_clients(struct anx7625_data *ctx)
> +{
> +	i2c_unregister_device(ctx->i2c.tx_p0_client);
> +	i2c_unregister_device(ctx->i2c.tx_p1_client);
> +	i2c_unregister_device(ctx->i2c.tx_p2_client);
> +	i2c_unregister_device(ctx->i2c.rx_p1_client);
> +	i2c_unregister_device(ctx->i2c.rx_p2_client);
> +	i2c_unregister_device(ctx->i2c.rx_p3_client);

Delete the ctx->i2c.rx_p3_client because it's never used.

> +	i2c_unregister_device(ctx->i2c.tcpc_client);


The other advantage of the "Free the last resource style" is that you
can just add a:

	i2c_unregister_device(ctx->i2c.tcpc_client);

and delete the error labels and you have an
anx7625_unregister_i2c_dummy_clients() function.

There is another bug here because we forgot to free "i2c.rx_p0_client".

> +}
> +
> +static int anx7625_i2c_probe(struct i2c_client *client,
> +			     const struct i2c_device_id *id)
> +{
> +	struct anx7625_data *platform;
> +	struct anx7625_platform_data *pdata;
> +	int ret = 0;
> +	struct device *dev = &client->dev;
> +
> +	if (!i2c_check_functionality(client->adapter,
> +				     I2C_FUNC_SMBUS_I2C_BLOCK)) {
> +		DRM_DEV_ERROR(dev, "anx7625's i2c bus doesn't support\n");
> +		ret = -ENODEV;
> +		goto exit;

Return directly, please.  "goto exit" is less readable than
return -ENODEV;

> +	}
> +
> +	platform = kzalloc(sizeof(*platform), GFP_KERNEL);
> +	if (!platform) {
> +		DRM_DEV_ERROR(dev, "failed to allocate driver data\n");
> +		ret = -ENOMEM;
> +		goto exit;

return -ENOMEM;

> +	}
> +
> +	pdata = &platform->pdata;
> +
> +	/* device tree parsing function call */
> +	ret = anx7625_parse_dt(&client->dev, pdata);
> +	if (ret != 0)	/* if occurs error */
> +		goto err0;

!= 0 is double negative.  Choose better label names.  Remove the obvious
comment.

if (ret)
	goto free_platform;

> +
> +	anx7625_init_gpio(platform);
> +
> +	/* to access global platform data */
> +	platform->client = client;
> +	i2c_set_clientdata(client, platform);
> +
> +	if (platform->pdata.extcon_supported) {
> +		/* get extcon device from DTS */
> +		platform->extcon = extcon_get_edev_by_phandle(&client->dev, 0);
> +		if (PTR_ERR(platform->extcon) == -EPROBE_DEFER)
> +			goto err0;

Preserve the error code.

> +		if (IS_ERR(platform->extcon)) {
> +			DRM_DEV_ERROR(&client->dev,
> +				      "can not get extcon device!");
> +			goto err0;

Prerve the error code.

> +		}
> +
> +		ret = anx7625_extcon_notifier_init(platform);
> +		if (ret < 0)
> +			goto err0;
> +	}
> +
> +	atomic_set(&platform->power_status, 0);
> +
> +	mutex_init(&platform->lock);
> +
> +	if (platform->pdata.gpio_intr_hpd) {
> +		INIT_WORK(&platform->work, anx7625_work_func);
> +		platform->workqueue = create_workqueue("anx7625_work");
> +		if (!platform->workqueue) {
> +			DRM_DEV_ERROR(dev, "failed to create work queue\n");
> +			ret = -ENOMEM;
> +			goto err1;

This goto will crash.  Because you have forgotten what the most recently
allocated resource was.  It should be "goto free_platform;" still.

> +		}
> +
> +		platform->pdata.hpd_irq =
> +			gpiod_to_irq(platform->pdata.gpio_intr_hpd);
> +		if (platform->pdata.hpd_irq < 0) {
> +			DRM_DEV_ERROR(dev, "failed to get gpio irq\n");
> +			goto err1;

goto free_wq;

> +		}
> +
> +		ret = request_threaded_irq(platform->pdata.hpd_irq,
> +					   NULL, anx7625_intr_hpd_isr,
> +					   IRQF_TRIGGER_FALLING |
> +					   IRQF_TRIGGER_RISING |
> +					   IRQF_ONESHOT,
> +					   "anx7625-hpd", platform);
> +		if (ret < 0) {
> +			DRM_DEV_ERROR(dev, "failed to request irq\n");
> +			goto err1;
> +		}
> +
> +		ret = irq_set_irq_wake(platform->pdata.hpd_irq, 1);
> +		if (ret < 0) {
> +			DRM_DEV_ERROR(dev, "Request irq for hpd");
> +			DRM_DEV_ERROR(dev, "interrupt wake set fail\n");
> +			goto err1;
> +		}
> +
> +		ret = enable_irq_wake(platform->pdata.hpd_irq);
> +		if (ret < 0) {
> +			DRM_DEV_ERROR(dev, "Enable irq for HPD");
> +			DRM_DEV_ERROR(dev, "interrupt wake enable fail\n");
> +			goto err1;
> +		}
> +	}
> +
> +	if (anx7625_register_i2c_dummy_clients(platform, client) != 0) {

Preserve the error code.

	ret = anx7625_register_i2c_dummy_clients();
	if (ret)
		goto free_platform;

Ugh...  The err2 is a layering violation.  Every function should free
its own partially allocated memory.  It should either succeed or fail
and it shouldn't expect the caller to clean up partially allocated
resources for it.


> +		ret = -ENOMEM;
> +		DRM_ERROR("Failed to reserve I2C bus.\n");
> +		goto err2;
> +	}
> +
> +	if (platform->pdata.low_power_mode == 0) {
> +		anx7625_disable_pd_protocol(platform);
> +		atomic_set(&platform->power_status, 1);
> +	}
> +
> +	/* add work function */
> +	if (platform->pdata.gpio_intr_hpd)
> +		queue_work(platform->workqueue, &platform->work);
> +
> +	platform->bridge.funcs = &anx7625_bridge_funcs;
> +#if IS_ENABLED(CONFIG_OF)
> +	platform->bridge.of_node = client->dev.of_node;
> +#endif
> +	drm_bridge_add(&platform->bridge);
> +
> +	DRM_DEV_DEBUG_DRIVER(dev, "probe done\n");
> +	goto exit;

return 0;

> +
> +err2:
> +	anx7625_unregister_i2c_dummy_clients(platform);
> +err1:
> +	if (platform->pdata.gpio_intr_hpd)
> +		destroy_workqueue(platform->workqueue);
> +err0:
> +	kfree(platform);
> +exit:
> +	return ret;
> +}
> +

regards,
dan carpenter