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Subject: Re: [PATCH v22 2/2] drm/bridge: Add I2C based driver for ps8640
 bridge
To:     Ezequiel Garcia <ezequiel@collabora.com>,
        linux-kernel@vger.kernel.org
Cc:     Collabora Kernel ML <kernel@collabora.com>, matthias.bgg@gmail.com,
        drinkcat@chromium.org, hsinyi@chromium.org,
        Jitao Shi <jitao.shi@mediatek.com>,
        Daniel Kurtz <djkurtz@chromium.org>,
        Ulrich Hecht <uli@fpond.eu>,
        linux-arm-kernel@lists.infradead.org,
        Andrzej Hajda <a.hajda@samsung.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        dri-devel@lists.freedesktop.org,
        Neil Armstrong <narmstrong@baylibre.com>,
        linux-mediatek@lists.infradead.org,
        David Airlie <airlied@linux.ie>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Daniel Vetter <daniel@ffwll.ch>
References: <20191223143538.20327-1-enric.balletbo@collabora.com>
 <20191223143538.20327-3-enric.balletbo@collabora.com>
 <c7dd37a21c0b43d1b05242f6077102414a3d81d9.camel@collabora.com>
From:   Enric Balletbo i Serra <enric.balletbo@collabora.com>
Message-ID: <85e9054f-aa69-71a7-e5af-299ef77bc547@collabora.com>
Date:   Fri, 27 Dec 2019 11:08:50 +0100
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Hi Ezequiel,

On 26/12/19 17:38, Ezequiel Garcia wrote:
> Hi Enric,
> 
> Note that this series is marked as v22, but it's really the 23th.
> Some minor comments below, it's looking really now.
> 
> Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
> 
> On Mon, 2019-12-23 at 15:35 +0100, Enric Balletbo i Serra wrote:
>> From: Jitao Shi <jitao.shi@mediatek.com>
>>
>> This patch adds drm_bridge driver for parade DSI to eDP bridge chip.
>>
>> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
>> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
>> [uli: followed API changes, removed FW update feature]
>> Signed-off-by: Ulrich Hecht <uli@fpond.eu>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
>> ---
>> One of the reviews from Laurent was to use 'i2c_new_ancillary_device'. I
>> didn't change this for two reasons.
>> 1) It doesn't have a devm version, so the remove path is more simple
>> using the devm_i2c_new_dummy_device family.
>> 2) IIUC the ancillary function is useful when you want to retrieve the
>> address from the firmware or DT, that's not really the case here, as we
>> have a base address and fixed offset to the base address which I think
>> is not configurable.
>>
>> Let me know if you still think that I should use the ancillary call.
>>
>> Changes in v23:
>> - Merge mute/unmute functions into one (Nicolas Boichat)
>> - Use enum for ENABLE/DISABLE instead of bool (Ezequiel Garcia)
>> - Rename mute/unmute to vdo_control and fix error messages (Nicolas Boichat and Enric)
>> - Add space between address and address parameter 'address%02x' (Nicolas Boichat)
>> - Add Tested-by Hsin-Yi
>> - Added me as author after the refactor
>>
>> Changes in v22:
>> - Remove sysfs attributes because are not really used (Enric Balletbo)
>> - Use enum for address page offsets (Ezequiel Garcia)
>> - Remove enable tracking (Enric Balletbo)
>> - Use panel_bridge API (Laurent Pinchart)
>> - Do not use kernel-doc format for non kernel-doc formatted commands (Enric Balletbo)
>> - Remove verbose message for PAGE1_VSTART command (Ezequiel Garcia)
>> - Use time_is_after_jiffies idiom (Ezequiel Garcia)
>> - Remove unused macros (Ezequiel Garcia)
>> - Fix weird alignment in dsi->mode_flags (Laurent Pinchart)
>> - Use drm_of_find_panel_or_bridge helper (Laurent Pinchart)
>> - Remove mode-sel-gpios as is not used (Laurent Pinchart)
>> - Remove error messages to get gpios as the core will already report it (Enric Balletbo)
>> - Remove redundant message getting the regulators (Laurent Pinchart)
>> - Rename sleep-gpios to powerdown-gpios (Laurent Pinchart)
>> - Use ARRAY_SIZE(ps_bridge->page) instead of MAX_DEV when possible (Laurent Pinchart)
>> - Fix race with userspace accessing the sysfs attributes (Laurent Pinchart)
>> - Remove id_table as is only used on DR platforms (Laurent Pinchart)
>> - Convert to new i2c device probe() (Laurent Pinchart)
>> - Use i2c_smbus_read/write helpers instead of open coding it (Laurent Pinchart)
>> - Remove unnused global variables (Laurent Pinchart)
>> - Remove unnused fields in ps8640 struct (Laurent Pinchart)
>> - Remove commented-out headers (Laurent Pinchart)
>>
>> Changes in v21:
>>  - Use devm_i2c_new_dummy_device and fix build issue using deprecated i2c_new_dummy
>>  - Fix build issue due missing drm_bridge.h
>>  - Do not remove in ps8640_remove device managed resources
>>
>> Changes in v19:
>>  - fixed return value of ps8640_probe() when no panel is found
>>
>> Changes in v18:
>>  - followed DRM API changes
>>  - use DEVICE_ATTR_RO()
>>  - remove firmware update code
>>  - add SPDX identifier
>>
>> Changes in v17:
>>  - remove some unused head files.
>>  - add macros for ps8640 pages.
>>  - remove ddc_i2c client
>>  - add mipi_dsi_device_register_full
>>  - remove the manufacturer from the name and i2c_device_id
>>
>> Changes in v16:
>>  - Disable ps8640 DSI MCS Function.
>>  - Rename gpios name more clearly.
>>  - Tune the ps8640 power on sequence.
>>
>> Changes in v15:
>>  - Drop drm_connector_(un)register calls from parade ps8640.
>>    The main DRM driver mtk_drm_drv now calls
>>    drm_connector_register_all() after drm_dev_register() in the
>>    mtk_drm_bind() function. That function should iterate over all
>>    connectors and call drm_connector_register() for each of them.
>>    So, remove drm_connector_(un)register calls from parade ps8640.
>>
>> Changes in v14:
>>  - update copyright info.
>>  - change bridge_to_ps8640 and connector_to_ps8640 to inline function.
>>  - fix some coding style.
>>  - use sizeof as array counter.
>>  - use drm_get_edid when read edid.
>>  - add mutex when firmware updating.
>>
>> Changes in v13:
>>  - add const on data, ps8640_write_bytes(struct i2c_client *client, const u8 *data, u16 data_len)
>>  - fix PAGE2_SW_REST tyro.
>>  - move the buf[3] init to entrance of the function.
>>
>> Changes in v12:
>>  - fix hw_chip_id build warning
>>
>> Changes in v11:
>>  - Remove depends on I2C, add DRM depends
>>  - Reuse ps8640_write_bytes() in ps8640_write_byte()
>>  - Use timer check for polling like the routines in <linux/iopoll.h>
>>  - Fix no drm_connector_unregister/drm_connector_cleanup when ps8640_bridge_attach fail
>>  - Check the ps8640 hardware id in ps8640_validate_firmware
>>  - Remove fw_version check
>>  - Move ps8640_validate_firmware before ps8640_enter_bl
>>  - Add ddc_i2c unregister when probe fail and ps8640_remove
>>
>>  drivers/gpu/drm/bridge/Kconfig         |  11 +
>>  drivers/gpu/drm/bridge/Makefile        |   1 +
>>  drivers/gpu/drm/bridge/parade-ps8640.c | 348 +++++++++++++++++++++++++
>>  3 files changed, 360 insertions(+)
>>  create mode 100644 drivers/gpu/drm/bridge/parade-ps8640.c
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 4734f6993858..3e0a63011723 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -101,6 +101,17 @@ config DRM_PARADE_PS8622
>>  	---help---
>>  	  Parade eDP-LVDS bridge chip driver.
>>  
>> +config DRM_PARADE_PS8640
>> +	tristate "Parade PS8640 MIPI DSI to eDP Converter"
> 
> Not a showstopper, but perhaps later you can amend the other
> Parade bridge menuconfig entry. Right now it's
> "Parade eDP/LVDS bridge". It would be nice to have
> consistency between Parade bridges.
> 
>> +	depends on OF
>> +	select DRM_KMS_HELPER
>> +	select DRM_MIPI_DSI
>> +	select DRM_PANEL
>> +	help
>> +	  Choose this option if you have PS8640 for display
>> +	  The PS8640 is a high-performance and low-power
>> +	  MIPI DSI to eDP converter
>> +
>>  config DRM_SIL_SII8620
>>  	tristate "Silicon Image SII8620 HDMI/MHL bridge"
>>  	depends on OF
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index 1c0c92667ac4..91490c595b38 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o
>>  obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
>>  obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>  obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> +obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
>>  obj-$(CONFIG_DRM_SIL_SII8620) += sil-sii8620.o
>>  obj-$(CONFIG_DRM_SII902X) += sii902x.o
>>  obj-$(CONFIG_DRM_SII9234) += sii9234.o
>> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
>> new file mode 100644
>> index 000000000000..646ac649d175
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
>> @@ -0,0 +1,348 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2016 MediaTek Inc.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_print.h>
>> +
>> +#define PAGE2_GPIO_H		0xa7
>> +#define PS_GPIO9		BIT(1)
>> +#define PAGE2_I2C_BYPASS	0xea
>> +#define I2C_BYPASS_EN		0xd0
>> +#define PAGE2_MCS_EN		0xf3
>> +#define MCS_EN			BIT(0)
>> +#define PAGE3_SET_ADD		0xfe
>> +#define VDO_CTL_ADD		0x13
>> +#define VDO_DIS			0x18
>> +#define VDO_EN			0x1c
>> +
>> +/*
>> + * PS8640 uses multiple addresses:
>> + * page[0]: for DP control
>> + * page[1]: for VIDEO Bridge
>> + * page[2]: for control top
>> + * page[3]: for DSI Link Control1
>> + * page[4]: for MIPI Phy
>> + * page[5]: for VPLL
>> + * page[6]: for DSI Link Control2
>> + * page[7]: for SPI ROM mapping
>> + */
>> +enum page_addr_offset {
>> +	PAGE0_DP_CNTL = 0,
>> +	PAGE1_VDO_BDG,
>> +	PAGE2_TOP_CNTL,
>> +	PAGE3_DSI_CNTL1,
>> +	PAGE4_MIPI_PHY,
>> +	PAGE5_VPLL,
>> +	PAGE6_DSI_CNTL2,
>> +	PAGE7_SPI_CNTL,
>> +	MAX_DEVS
>> +};
>> +
>> +enum ps8640_vdo_control {
>> +	DISABLE = VDO_DIS,
>> +	ENABLE = VDO_EN,
>> +};
>> +
>> +struct ps8640 {
>> +	struct drm_bridge bridge;
>> +	struct drm_bridge *panel_bridge;
>> +	struct mipi_dsi_device *dsi;
>> +	struct i2c_client *page[MAX_DEVS];
>> +	struct regulator_bulk_data supplies[2];
>> +	struct gpio_desc *gpio_reset;
>> +	struct gpio_desc *gpio_powerdown;
>> +};
>> +
>> +static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e)
>> +{
>> +	return container_of(e, struct ps8640, bridge);
>> +}
>> +
>> +static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge,
>> +				     const enum ps8640_vdo_control ctrl)
>> +{
>> +	struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
>> +	u8 vdo_ctrl_buf[] = { VDO_CTL_ADD, ctrl };
>> +	int ret;
>> +
>> +	ret = i2c_smbus_write_i2c_block_data(client, PAGE3_SET_ADD,
>> +					     sizeof(vdo_ctrl_buf),
>> +					     vdo_ctrl_buf);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return 0;
>> +}
>> +
>> +static void ps8640_pre_enable(struct drm_bridge *bridge)
>> +{
>> +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> +	struct i2c_client *client = ps_bridge->page[PAGE2_TOP_CNTL];
>> +	unsigned long timeout;
>> +	int ret, status;
>> +
>> +	ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies),
>> +				    ps_bridge->supplies);
>> +	if (ret < 0) {
>> +		DRM_ERROR("cannot enable regulators %d\n", ret);
>> +		return;
>> +	}
>> +
>> +	gpiod_set_value(ps_bridge->gpio_powerdown, 1);
>> +	gpiod_set_value(ps_bridge->gpio_reset, 0);
>> +	usleep_range(2000, 2500);
>> +	gpiod_set_value(ps_bridge->gpio_reset, 1);
>> +
>> +	/*
>> +	 * Wait for the ps8640 embedded MCU to be ready
>> +	 * First wait 200ms and then check the MCU ready flag every 20ms
>> +	 */
>> +	msleep(200);
>> +
>> +	timeout = jiffies + msecs_to_jiffies(200) + 1;
>> +
>> +	while (time_is_after_jiffies(timeout)) {
>> +		status = i2c_smbus_read_byte_data(client, PAGE2_GPIO_H);
>> +		if (status < 0) {
>> +			DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", status);
>> +			goto err_regulators_disable;
>> +		}
>> +		if ((status & PS_GPIO9) == PS_GPIO9)
>> +			break;
>> +
>> +		msleep(20);
>> +	}
>> +
>> +	msleep(50);
>> +
>> +	/*
>> +	 * The Manufacturer Command Set (MCS) is a device dependent interface
>> +	 * intended for factory programming of the display module default
>> +	 * parameters. Once the display module is configured, the MCS shall be
>> +	 * disabled by the manufacturer. Once disabled, all MCS commands are
>> +	 * ignored by the display interface.
>> +	 */
>> +	status = i2c_smbus_read_byte_data(client, PAGE2_MCS_EN);
>> +	if (status < 0) {
>> +		DRM_ERROR("failed read PAGE2_MCS_EN: %d\n", status);
>> +		goto err_regulators_disable;
>> +	}
>> +
>> +	ret = i2c_smbus_write_byte_data(client, PAGE2_MCS_EN,
>> +					status & ~MCS_EN);
>> +	if (ret < 0) {
>> +		DRM_ERROR("failed write PAGE2_MCS_EN: %d\n", ret);
>> +		goto err_regulators_disable;
>> +	}
>> +
>> +	ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE);
> 
> That's much better than mute/unmute!
> 
>> +	if (ret) {
>> +		DRM_ERROR("failed to enable VDO: %d\n", ret);
>> +		goto err_regulators_disable;
>> +	}
>> +
>> +	/* Switch access edp panel's edid through i2c */
>> +	ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS,
>> +					I2C_BYPASS_EN);
>> +	if (ret < 0) {
>> +		DRM_ERROR("failed write PAGE2_I2C_BYPASS: %d\n", ret);
>> +		goto err_regulators_disable;
>> +	}
>> +
>> +	return;
>> +
>> +err_regulators_disable:
>> +	regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> +			       ps_bridge->supplies);
>> +}
>> +
>> +static void ps8640_post_disable(struct drm_bridge *bridge)
>> +{
>> +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> +	int ret;
>> +
>> +	ret = ps8640_bridge_vdo_control(ps_bridge, DISABLE);
>> +	if (ret < 0)
>> +		DRM_ERROR("failed to disable VDO: %d\n", ret);
>> +
>> +	gpiod_set_value(ps_bridge->gpio_reset, 0);
>> +	gpiod_set_value(ps_bridge->gpio_powerdown, 0);
>> +	ret = regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> +				     ps_bridge->supplies);
>> +	if (ret < 0)
>> +		DRM_ERROR("cannot disable regulators %d\n", ret);
>> +}
>> +
>> +int ps8640_bridge_attach(struct drm_bridge *bridge)
> 
> Compiling this with static analyzers says this should be 'static'.
> 

Ack, done in next version.

>> +{
>> +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> +	struct device *dev = &ps_bridge->page[0]->dev;
>> +	struct device_node *in_ep, *dsi_node;
>> +	struct mipi_dsi_device *dsi;
>> +	struct mipi_dsi_host *host;
>> +	int ret;
>> +	const struct mipi_dsi_device_info info = { .type = "ps8640",
>> +						   .channel = 0,
>> +						   .node = NULL,
>> +						 };
>> +	/* port@0 is ps8640 dsi input port */
>> +	in_ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
>> +	if (!in_ep)
>> +		return -ENODEV;
>> +
>> +	dsi_node = of_graph_get_remote_port_parent(in_ep);
>> +	of_node_put(in_ep);
>> +	if (!dsi_node)
>> +		return -ENODEV;
>> +
>> +	host = of_find_mipi_dsi_host_by_node(dsi_node);
>> +	of_node_put(dsi_node);
>> +	if (!host)
>> +		return -ENODEV;
>> +
>> +	dsi = mipi_dsi_device_register_full(host, &info);
>> +	if (IS_ERR(dsi)) {
>> +		dev_err(dev, "failed to create dsi device\n");
>> +		ret = PTR_ERR(dsi);
>> +		return ret;
>> +	}
>> +
>> +	ps_bridge->dsi = dsi;
>> +
>> +	dsi->host = host;
>> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
>> +			  MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
>> +	dsi->format = MIPI_DSI_FMT_RGB888;
>> +	dsi->lanes = 4;
> 
> I'm not an expert here, so maybe this makes no sense:
> are you sure you don't need to take the number of lanes from the
> device-tree?
> 

For the comment below looks like it might be configurable, yes, but like you I
don't have the datasheet so I can't really answer.

> From the yaml spec:
> 
> """
> The device accepts a single channel of
> MIPI DSI v1.1, with up to four lanes [..]
> """
> 
> If it's OK to hardcode to 4, maybe use a macro for clarity?
> 

Ok, I'll wait for if anyone can confirm, and if not I'll hardcode the value as
is known to workand the use case I can test.

>> +	ret = mipi_dsi_attach(dsi);
>> +	if (ret)
>> +		goto err_dsi_attach;
>> +
>> +	/* Attach the panel-bridge to the dsi bridge */
>> +	return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge,
>> +				 &ps_bridge->bridge);
>> +
>> +err_dsi_attach:
>> +	mipi_dsi_device_unregister(dsi);
>> +	return ret;
>> +}
>> +
>> +static const struct drm_bridge_funcs ps8640_bridge_funcs = {
>> +	.attach = ps8640_bridge_attach,
>> +	.post_disable = ps8640_post_disable,
>> +	.pre_enable = ps8640_pre_enable,
>> +};
>> +
>> +static int ps8640_probe(struct i2c_client *client)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct device_node *np = dev->of_node;
>> +	struct ps8640 *ps_bridge;
>> +	struct drm_panel *panel;
>> +	int ret;
>> +	u32 i;
>> +
>> +	ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
>> +	if (!ps_bridge)
>> +		return -ENOMEM;
>> +
>> +	/* port@1 is ps8640 output port */
> 
> Hm, regarding my comment on patch 1/2 about required port@0,
> perhaps this really requires both port@0 and port@1.
> 

As I commented on patch 1/2 to your question, I am not sure about if port@1 is
required or not. My understanding is that no, but I might be wrong. What is true
is that the code below only covers the case where a panel is connected and fails
otherwise. You can also have another bridge (not covered by the below code), or
just a connector so I am not sure whether I should support all the possible
cases or just support the ones I can test for now.

Will wait for the DRM experts here to know how to proceed.

Thanks,
 Enric

>> +	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
>> +	if (ret < 0)
>> +		return ret;
>> +	if (!panel)
>> +		return -ENODEV;
>> +
>> +	panel->connector_type = DRM_MODE_CONNECTOR_eDP;
>> +
>> +	ps_bridge->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
>> +	if (IS_ERR(ps_bridge->panel_bridge))
>> +		return PTR_ERR(ps_bridge->panel_bridge);
>> +
>> +	ps_bridge->supplies[0].supply = "vdd33";
>> +	ps_bridge->supplies[1].supply = "vdd12";
>> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ps_bridge->supplies),
>> +				      ps_bridge->supplies);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ps_bridge->gpio_powerdown = devm_gpiod_get(&client->dev, "powerdown",
>> +						   GPIOD_OUT_LOW);
>> +	if (IS_ERR(ps_bridge->gpio_powerdown))
>> +		return PTR_ERR(ps_bridge->gpio_powerdown);
>> +
>> +	/*
>> +	 * Request the reset pin low to avoid the bridge being
>> +	 * initialized prematurely
>> +	 */
>> +	ps_bridge->gpio_reset = devm_gpiod_get(&client->dev, "reset",
>> +					       GPIOD_OUT_LOW);
>> +	if (IS_ERR(ps_bridge->gpio_reset))
>> +		return PTR_ERR(ps_bridge->gpio_reset);
>> +
>> +	ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
>> +	ps_bridge->bridge.of_node = dev->of_node;
>> +
>> +	ps_bridge->page[PAGE0_DP_CNTL] = client;
>> +
>> +	for (i = 1; i < ARRAY_SIZE(ps_bridge->page); i++) {
>> +		ps_bridge->page[i] = devm_i2c_new_dummy_device(&client->dev,
>> +							     client->adapter,
>> +							     client->addr + i);
>> +		if (IS_ERR(ps_bridge->page[i])) {
>> +			dev_err(dev, "failed i2c dummy device, address %02x\n",
>> +				client->addr + i);
>> +			return PTR_ERR(ps_bridge->page[i]);
>> +		}
>> +	}
>> +
>> +	i2c_set_clientdata(client, ps_bridge);
>> +
>> +	drm_bridge_add(&ps_bridge->bridge);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ps8640_remove(struct i2c_client *client)
>> +{
>> +	struct ps8640 *ps_bridge = i2c_get_clientdata(client);
>> +
>> +	drm_bridge_remove(&ps_bridge->bridge);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id ps8640_match[] = {
>> +	{ .compatible = "parade,ps8640" },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, ps8640_match);
>> +
>> +static struct i2c_driver ps8640_driver = {
>> +	.probe_new = ps8640_probe,
>> +	.remove = ps8640_remove,
>> +	.driver = {
>> +		.name = "ps8640",
>> +		.of_match_table = ps8640_match,
>> +	},
>> +};
>> +module_i2c_driver(ps8640_driver);
>> +
>> +MODULE_AUTHOR("Jitao Shi <jitao.shi@mediatek.com>");
>> +MODULE_AUTHOR("CK Hu <ck.hu@mediatek.com>");
>> +MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@collabora.com>");
>> +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.20.1
>>
>>
> 
>