Re: [PATCH v14 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

[Jitao Shi]

On Thu, 2016-04-14 at 16:28 +0200, Thierry Reding wrote:
> On Sun, Apr 03, 2016 at 12:20:45PM +0800, Jitao Shi wrote:
> [...]
> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> > new file mode 100644
> > index 0000000..87f8bc7
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> > @@ -0,0 +1,1066 @@
> > +/*
> > + * Copyright (c) 2014 MediaTek Inc.
> 
> Presumably the copyright here should be updated?

Thanks for your review. I'll update it next version.

> 
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/firmware.h>
> > +#include <linux/gpio.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_gpio.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <asm/unaligned.h>
> > +#include <drm/drm_panel.h>
> > +
> > +#include <drmP.h>
> > +#include <drm_atomic_helper.h>
> > +#include <drm_crtc_helper.h>
> > +#include <drm_crtc.h>
> > +#include <drm_edid.h>
> > +#include <drm_mipi_dsi.h>
> > +
> > +#define PAGE2_SPI_CFG3		0x82
> > +#define I2C_TO_SPI_RESET	0x20
> > +#define PAGE2_ROMADD_BYTE1	0x8e
> > +#define PAGE2_ROMADD_BYTE2	0x8f
> > +#define PAGE2_SWSPI_WDATA	0x90
> > +#define PAGE2_SWSPI_RDATA	0x91
> > +#define PAGE2_SWSPI_LEN		0x92
> > +#define PAGE2_SWSPI_CTL		0x93
> > +#define TRIGGER_NO_READBACK	0x05
> > +#define TRIGGER_READBACK	0x01
> > +#define PAGE2_SPI_STATUS	0x9e
> > +#define PAGE2_GPIO_L		0xa6
> > +#define PAGE2_GPIO_H		0xa7
> > +#define PS_GPIO9		BIT(1)
> > +#define PAGE2_IROM_CTRL		0xb0
> > +#define IROM_ENABLE		0xc0
> > +#define IROM_DISABLE		0x80
> > +#define PAGE2_SW_RESET		0xbc
> > +#define SPI_SW_RESET		BIT(7)
> > +#define MPU_SW_RESET		BIT(6)
> > +#define PAGE2_ENCTLSPI_WR	0xda
> > +#define PAGE2_I2C_BYPASS	0xea
> > +#define I2C_BYPASS_EN		0xd0
> > +#define PAGE3_SET_ADD		0xfe
> > +#define PAGE3_SET_VAL		0xff
> > +#define VDO_CTL_ADD		0x13
> > +#define VDO_DIS			0x18
> > +#define VDO_EN			0x1c
> > +#define PAGE4_REV_L		0xf0
> > +#define PAGE4_REV_H		0xf1
> > +#define PAGE4_CHIP_L		0xf2
> > +#define PAGE4_CHIP_H		0xf3
> > +
> > +/* Firmware */
> > +#define SPI_MAX_RETRY_CNT	8
> > +#define PS_FW_NAME		"ps864x_fw.bin"
> > +
> > +#define FW_CHIP_ID_OFFSET	0
> > +#define FW_VERSION_OFFSET	2
> > +#define EDID_I2C_ADDR		0x50
> > +
> > +#define WRITE_STATUS_REG_CMD	0x01
> > +#define READ_STATUS_REG_CMD	0x05
> > +#define BUSY			BIT(0)
> > +#define CLEAR_ALL_PROTECT	0x00
> > +#define BLK_PROTECT_BITS	0x0c
> > +#define STATUS_REG_PROTECT	BIT(7)
> > +#define WRITE_ENABLE_CMD	0x06
> > +#define CHIP_ERASE_CMD		0xc7
> > +
> > +#define bridge_to_ps8640(e)	container_of(e, struct ps8640, bridge)
> > +#define connector_to_ps8640(e)	container_of(e, struct ps8640, connector)
> 
> I'd prefer these to be static inline functions.
I'll update it next version.
Thanks
> 
> > +
> > +struct ps8640_info {
> > +	u8 family_id;
> > +	u8 variant_id;
> > +	u16 version;
> > +};
> > +
> > +struct ps8640 {
> > +	struct drm_connector connector;
> > +	struct drm_bridge bridge;
> > +	struct edid *edid;
> > +	struct mipi_dsi_device dsi;
> > +	struct i2c_client *page[8];
> > +	struct i2c_client *ddc_i2c;
> > +	struct regulator_bulk_data supplies[2];
> > +	struct drm_panel *panel;
> > +	struct gpio_desc *gpio_rst_n;
> > +	struct gpio_desc *gpio_slp_n;
> > +	struct gpio_desc *gpio_mode_sel_n;
> > +	bool enabled;
> > +
> > +	/* firmware file info */
> > +	bool in_fw_update;
> > +	struct ps8640_info info;
> > +};
> > +
> > +static const u8 enc_ctrl_code[6] = {0xaa, 0x55, 0x50, 0x41, 0x52, 0x44};
> > +static const u8 hw_chip_id[4] = {0x00, 0x0a, 0x00, 0x30};
> 
> Spaces after { and before }, please.

I'll fix them next version, thanks.

> > +
> > +static int ps8640_read(struct i2c_client *client, u8 reg, u8 *data,
> > +		       u16 data_len)
> > +{
> > +	int ret;
> > +	struct i2c_msg msgs[] = {
> > +		{
> > +		 .addr = client->addr,
> > +		 .flags = 0,
> > +		 .len = 1,
> > +		 .buf = &reg,
> > +		 },
> > +		{
> > +		 .addr = client->addr,
> > +		 .flags = I2C_M_RD,
> > +		 .len = data_len,
> > +		 .buf = data,
> > +		 }
> 
> Please indent properly here. This uses a weird mix of tabs and spaces,
> where it should be tabs only.

I'll fix it next version.
Thanks
> 
> > +	};
> > +
> > +	ret = i2c_transfer(client->adapter, msgs, 2);
> > +
> > +	if (ret == 2)
> > +		return 0;
> > +	if (ret < 0)
> > +		return ret;
> > +	else
> > +		return -EIO;
> > +}
> > +
> > +static int ps8640_write_bytes(struct i2c_client *client, const u8 *data,
> > +			      u16 data_len)
> > +{
> > +	int ret;
> > +	struct i2c_msg msg;
> > +
> > +	msg.addr = client->addr;
> > +	msg.flags = 0;
> > +	msg.len = data_len;
> > +	msg.buf = (u8 *)data;
> > +
> > +	ret = i2c_transfer(client->adapter, &msg, 1);
> > +	if (ret == 1)
> > +		return 0;
> > +	if (ret < 0)
> > +		return ret;
> > +	else
> > +		return -EIO;
> > +}
> > +
> > +static int ps8640_write_byte(struct i2c_client *client, u8 reg,  u8 data)
> > +{
> > +	u8 buf[] = {reg, data};
> 
> Spaces after { and before }, please. There are a bunch more of those
> below, please fix those up as well.

I'll fix them next version.
Thanks

> 
> > +
> > +	return ps8640_write_bytes(client, buf, sizeof(buf));
> > +}
> > +
> > +static void ps8640_get_mcu_fw_version(struct ps8640 *ps_bridge)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[5];
> > +	u8 fw_ver[2];
> > +
> > +	ps8640_read(client, 0x4, fw_ver, 2);
> 
> sizeof(fw_ver) perhaps and check for errors?
I'll fix it next version.
Thanks
> 
> > +	ps_bridge->info.version = (fw_ver[0] << 8) | fw_ver[1];
> > +
> > +	DRM_INFO_ONCE("ps8640 rom fw version %d.%d\n", fw_ver[0], fw_ver[1]);
> > +}
> > +
> > +static int ps8640_bridge_enable(struct ps8640 *ps_bridge)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[3];
> > +	u8 vdo_ctrl_buf[3] = {PAGE3_SET_ADD, VDO_CTL_ADD, VDO_EN};
> > +
> > +	return ps8640_write_bytes(client, vdo_ctrl_buf, 3);
> 
> sizeof(vdo_ctrl_buf)? There are more of these in a couple of places.
I'll fix it next version.
Thanks
> 
> > +static void ps8640_post_disable(struct drm_bridge *bridge)
> > +{
> > +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> > +	int err;
> > +
> > +	if (ps_bridge->in_fw_update)
> > +		return;
> 
> I don't like how this is handled. Consider what happens if you are in
> the process of updating the firmware. The above code along with that in
> other parts of the driver will silently ignore all operations on the
> bridge during an update. I think these places should be updated to
> return an error code (-EAGAIN, -EBUSY or the like) or they should block
> all operations (perhaps via a mutex) until the firmware update is
> complete.
> 

I'll add mutex when firmware update next version. 

> > +static int ps8640_get_modes(struct drm_connector *connector)
> > +{
> > +	struct ps8640 *ps_bridge = connector_to_ps8640(connector);
> > +	struct device *dev = &ps_bridge->page[0]->dev;
> > +	u8 *edid;
> > +	int ret, num_modes = 0;
> > +	bool power_off;
> > +
> > +	if (ps_bridge->edid)
> > +		return drm_add_edid_modes(connector, ps_bridge->edid);
> > +
> > +	power_off = !ps_bridge->enabled;
> > +	ps8640_pre_enable(&ps_bridge->bridge);
> > +
> > +	edid = devm_kmalloc(dev, EDID_LENGTH, GFP_KERNEL);
> > +	if (!edid) {
> > +		DRM_ERROR("Failed to allocate EDID\n");
> > +		return 0;
> > +	}
> > +
> > +	ret = ps8640_read(ps_bridge->ddc_i2c, 0, edid, EDID_LENGTH);
> > +	if (ret)
> > +		goto out;
> 
> This should be using the standard EDID helpers.

I'll fix it next version.
Thanks
> 
> > +/* Firmware Version is returned as Major.Minor.Build */
> 
> No, it isn't. The below returns "x.y" (which I assume is "major.minor").
> 
I'll fix it next version.
Thanks

> > +static ssize_t ps8640_fw_version_show(struct device *dev,
> > +				      struct device_attribute *attr, char *buf)
> > +{
> > +	struct ps8640 *ps_bridge = dev_get_drvdata(dev);
> > +	struct ps8640_info *info = &ps_bridge->info;
> > +
> > +	return scnprintf(buf, PAGE_SIZE, "%u.%u\n", info->version >> 8,
> > +			 info->version & 0xff);
> > +}
> [...]
> > +static int ps8640_spi_send_cmd(struct ps8640 *ps_bridge, u8 *cmd, u8 cmd_len)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[2];
> > +	u8 i, buf[3] = {PAGE2_SWSPI_LEN, cmd_len - 1, TRIGGER_NO_READBACK};
> > +	int ret;
> > +
> > +	ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
> > +	if (ret)
> > +		goto err;
> > +
> > +	/* write command in write port */
> > +	for (i = 0; i < cmd_len; i++) {
> > +		ret = ps8640_write_byte(client, PAGE2_SWSPI_WDATA, cmd[i]);
> > +		if (ret) {
> > +			ps8640_write_byte(client, PAGE2_IROM_CTRL,
> > +					  IROM_DISABLE);
> > +			goto err;
> 
> Can't this simply be "goto err_irom_disable;"?

I'll fix it next version.
Thanks
> 
> > +		}
> > +	}
> > +
> > +	ret = ps8640_write_bytes(client, buf, 3);
> > +	if (ret)
> > +		goto err_irom_disable;
> > +
> > +	ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +	if (ret)
> > +		goto err;
> > +
> > +	return 0;
> > +err_irom_disable:
> > +	ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +err:
> > +	dev_err(&client->dev, "send command err: %d\n", ret);
> > +	return ret;
> > +}
> > +
> > +static int ps8640_wait_spi_ready(struct ps8640 *ps_bridge)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[2];
> > +	u8 spi_rdy_st;
> > +	ktime_t timeout;
> > +
> > +	timeout = ktime_add_ms(ktime_get(), 200);
> > +	for (;;) {
> > +		ps8640_read(client, PAGE2_SPI_STATUS, &spi_rdy_st, 1);
> > +		if ((spi_rdy_st & 0x0c) != 0x0c)
> 
> Can we get symbolic names for 0x0c, please?
I'll fix it next version.
Thanks
> 
> > +			break;
> > +
> > +		if (ktime_compare(ktime_get(), timeout) > 0) {
> > +			dev_err(&client->dev, "wait spi ready timeout\n");
> > +			return -EBUSY;
> > +		}
> > +
> > +		msleep(20);
> > +	}
> > +
> > +	return 0;
> > +}
> [...]
> > +static int ps8640_write_rom(struct ps8640 *ps_bridge, const struct firmware *fw)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[0];
> > +	struct device *dev = &client->dev;
> > +	struct i2c_client *client2 = ps_bridge->page[2];
> > +	struct i2c_client *client7 = ps_bridge->page[7];
> > +	unsigned int pos = 0;
> 
> Make this size_t since you compare it to fw->size, which is size_t as
> well.

I'll fix it next version.
Thanks
> 
> > +	u8 buf[257], rom_page_id_buf[3];
> > +	int ret;
> > +	u16 cpy_len;
> > +
> > +	ps8640_write_byte(client2, PAGE2_SPI_CFG3, I2C_TO_SPI_RESET);
> > +	msleep(100);
> > +	ps8640_write_byte(client2, PAGE2_SPI_CFG3, 0x00);
> > +
> > +	for (pos = 0; pos < fw->size; pos += cpy_len) {
> > +		rom_page_id_buf[0] = PAGE2_ROMADD_BYTE1;
> > +		rom_page_id_buf[1] = pos >> 8;
> > +		rom_page_id_buf[2] = pos >> 16;
> > +		ret = ps8640_write_bytes(client2, rom_page_id_buf, 3);
> > +		if (ret)
> > +			goto error;
> > +		cpy_len = fw->size >= 256 + pos ? 256 : fw->size - pos;
> > +		buf[0] = 0;
> > +		memcpy(buf + 1, fw->data + pos, cpy_len);
> > +		ret = ps8640_write_bytes(client7, buf, cpy_len + 1);
> > +		if (ret)
> > +			goto error;
> > +
> > +		dev_dbg(dev, "fw update completed %u / %zu bytes\n", pos,
> > +			fw->size);
> > +	}
> > +	return 0;
> > +
> > +error:
> > +	dev_err(dev, "failed write extenal flash, %d\n", ret);
> 
> "external"
I'll fix it next version.
Thanks
> 
> > +	return ret;
> > +}
> > +
> > +static int ps8640_spi_normal_mode(struct ps8640 *ps_bridge)
> > +{
> > +	u8 cmd[2];
> > +	struct i2c_client *client = ps_bridge->page[2];
> > +
> > +	/* Enable-Write-Status-Register */
> > +	cmd[0] = WRITE_ENABLE_CMD;
> > +	ps8640_spi_send_cmd(ps_bridge, cmd, 1);
> > +
> > +	/* protect BPL/BP0/BP1 */
> > +	cmd[0] = WRITE_STATUS_REG_CMD;
> > +	cmd[1] = BLK_PROTECT_BITS | STATUS_REG_PROTECT;
> > +	ps8640_spi_send_cmd(ps_bridge, cmd, 2);
> > +
> > +	/* wait for SPI rom ready */
> > +	ps8640_wait_rom_idle(ps_bridge);
> > +
> > +	/* disable PS8640 mapping function */
> > +	ps8640_write_byte(client, PAGE2_ENCTLSPI_WR, 0x00);
> > +
> > +	gpiod_set_value(ps_bridge->gpio_mode_sel_n, 1);
> > +	return 0;
> > +}
> > +
> > +static int ps8640_enter_bl(struct ps8640 *ps_bridge)
> > +{
> > +	ps_bridge->in_fw_update = true;
> 
> Besides my other comments on this, I think you'll need proper locking
> here, otherwise you might end up in a situation where you can still
> power off the chip during firmware update. Consider the case where you
> power off the chip, pass the in_fw_update check but then immediately
> trigger the firmware update via sysfs and start updating while the chip
> is being shut down.
> 

I'll fix it next version. I'll add mutex whole firmware updating to
protect.
Thanks

> > +	return ps8640_spi_dl_mode(ps_bridge);
> > +}
> > +
> > +static void ps8640_exit_bl(struct ps8640 *ps_bridge, const struct firmware *fw)
> > +{
> > +	ps8640_spi_normal_mode(ps_bridge);
> > +	ps_bridge->in_fw_update = false;
> > +}
> > +
> > +static int ps8640_load_fw(struct ps8640 *ps_bridge, const struct firmware *fw)
> > +{
> > +	struct i2c_client *client = ps_bridge->page[0];
> > +	struct device *dev = &client->dev;
> > +	int ret;
> > +	bool ps8640_status_backup = ps_bridge->enabled;
> > +
> > +	ret = ps8640_validate_firmware(ps_bridge, fw);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (!ps_bridge->in_fw_update) {
> > +		if (!ps8640_status_backup)
> > +			ps8640_pre_enable(&ps_bridge->bridge);
> > +
> > +		ret = ps8640_enter_bl(ps_bridge);
> > +		if (ret)
> > +			goto exit;
> > +	}
> > +
> > +	ret = ps8640_rom_prepare(ps_bridge);
> > +	if (ret)
> > +		goto exit;
> > +
> > +	ret = ps8640_write_rom(ps_bridge, fw);
> > +
> > +exit:
> > +	if (ret)
> > +		dev_err(dev, "Failed to load firmware, %d\n", ret);
> > +
> > +	ps8640_exit_bl(ps_bridge, fw);
> > +	if (!ps8640_status_backup)
> > +		ps8640_post_disable(&ps_bridge->bridge);
> > +	return ret;
> 
> Taking a mutex around all of this code might be the easiest way to
> achieve this.

I'll fix it next version. I'll add mutex when firmware updating
Thanks
> 
> > +}
> > +
> > +static ssize_t ps8640_update_fw_store(struct device *dev,
> > +				      struct device_attribute *attr,
> > +				      const char *buf, size_t count)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct ps8640 *ps_bridge = i2c_get_clientdata(client);
> > +	const struct firmware *fw;
> > +	int error;
> > +
> > +	error = request_firmware(&fw, PS_FW_NAME, dev);
> > +	if (error) {
> > +		dev_err(dev, "Unable to open firmware %s: %d\n",
> > +			PS_FW_NAME, error);
> > +		return error;
> > +	}
> > +
> > +	error = ps8640_load_fw(ps_bridge, fw);
> > +	if (error)
> > +		dev_err(dev, "The firmware update failed(%d)\n", error);
> > +	else
> > +		dev_info(dev, "The firmware update succeeded\n");
> > +
> > +	release_firmware(fw);
> > +	return error ? error : count;
> > +}
> 
> This sysfs interface is somewhat unintuitive because it triggers no
> matter what you write to the file. I find it also a little unusual that
> you would trigger a firmware update through sysfs, but then go through
> the request_firmware() to obtain it. Is this a common method, or do
> other drivers do something different?
> 


Thanks, i think it is a common method.
Other drivers are same ex. the drivers\input\mouse\elan_i2c_core.c


> > +static int ps8640_probe(struct i2c_client *client,
> > +			const struct i2c_device_id *id)
> > +{
> > +	struct device *dev = &client->dev;
> > +	struct ps8640 *ps_bridge;
> > +	struct device_node *np = dev->of_node;
> > +	struct device_node *port, *out_ep;
> > +	struct device_node *panel_node = NULL;
> > +	int i, ret;
> 
> i could be unsigned.

I'll fix it next version.
Thanks
> 
> > +
> > +	ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
> > +	if (!ps_bridge)
> > +		return -ENOMEM;
> > +
> > +	/* port@1 is ps8640 output port */
> > +	port = of_graph_get_port_by_id(np, 1);
> > +	if (port) {
> > +		out_ep = of_get_child_by_name(port, "endpoint");
> > +		of_node_put(port);
> > +		if (out_ep) {
> > +			panel_node = of_graph_get_remote_port_parent(out_ep);
> > +			of_node_put(out_ep);
> > +		}
> > +	}
> > +	if (panel_node) {
> > +		ps_bridge->panel = of_drm_find_panel(panel_node);
> > +		of_node_put(panel_node);
> > +		if (!ps_bridge->panel)
> > +			return -EPROBE_DEFER;
> > +	}
> > +
> > +	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) {
> > +		dev_info(dev, "failed to get regulators: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ps_bridge->gpio_mode_sel_n = devm_gpiod_get(&client->dev, "mode-sel",
> > +						    GPIOD_OUT_HIGH);
> 
> This GPIO is used to enable programming mode. Perhaps it should be made
> optional, and the programming mode refuse to run if it isn't specified?

I'll fix it next version.
Thanks
> 
> > +	if (IS_ERR(ps_bridge->gpio_mode_sel_n)) {
> > +		ret = PTR_ERR(ps_bridge->gpio_mode_sel_n);
> > +		dev_err(dev, "cannot get mode-sel %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ps_bridge->gpio_slp_n = devm_gpiod_get(&client->dev, "sleep",
> > +					       GPIOD_OUT_LOW);
> > +	if (IS_ERR(ps_bridge->gpio_slp_n)) {
> > +		ret = PTR_ERR(ps_bridge->gpio_slp_n);
> > +		dev_err(dev, "cannot get sleep: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	/*
> > +	 * Request the reset pin low to avoid the bridge being
> > +	 * initialized prematurely
> > +	 */
> > +	ps_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
> > +					       GPIOD_OUT_LOW);
> > +	if (IS_ERR(ps_bridge->gpio_rst_n)) {
> > +		ret = PTR_ERR(ps_bridge->gpio_rst_n);
> > +		dev_err(dev, "cannot get reset: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
> > +	ps_bridge->bridge.of_node = dev->of_node;
> > +	ret = drm_bridge_add(&ps_bridge->bridge);
> 
> Perhaps postpone the call to drm_bridge_add() until everything has been
> properly set up? That way you don't have to undo it again if something
> goes wrong in the more likely places.

I'll fix it next version.
Thanks
> 
> > +	if (ret) {
> > +		dev_err(dev, "Failed to add bridge: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	ps_bridge->page[0] = client;
> > +	ps_bridge->ddc_i2c = i2c_new_dummy(client->adapter, EDID_I2C_ADDR);
> > +	if (!ps_bridge->ddc_i2c) {
> > +		dev_err(dev, "failed ddc_i2c dummy device, address%02x\n",
> > +			EDID_I2C_ADDR);
> > +		ret = -EBUSY;
> > +		goto exit_ddc_i2c_dummy;
> > +	}
> > +	/*
> > +	 * ps8640 uses multiple addresses, use dummy devices for them
> > +	 * 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
> > +	 */
> > +	for (i = 1; i < 8; i++) {
> > +		ps_bridge->page[i] = i2c_new_dummy(client->adapter,
> > +						   client->addr + i);
> > +		if (!ps_bridge->page[i]) {
> > +			dev_err(dev, "failed i2c dummy device, address%02x\n",
> > +				client->addr + i);
> > +			ret = -EBUSY;
> > +			goto exit_dummy;
> > +		}
> > +	}
> > +	i2c_set_clientdata(client, ps_bridge);
> > +
> > +	ret = sysfs_create_group(&client->dev.kobj, &ps8640_attr_group);
> > +	if (ret) {
> > +		dev_err(dev, "failed to create sysfs entries: %d\n", ret);
> > +		goto exit_dummy;
> > +	}
> > +
> > +	ret = devm_add_action(dev, ps8640_remove_sysfs_group, ps_bridge);
> > +	if (ret) {
> > +		dev_err(dev, "failed to add sysfs cleanup action: %d\n", ret);
> > +		goto exit_remove_sysfs;
> > +	}
> > +	return 0;
> > +
> > +exit_remove_sysfs:
> > +	sysfs_remove_group(&ps_bridge->page[0]->dev.kobj, &ps8640_attr_group);
> > +exit_dummy:
> > +	for (i = 1; i < 8; i++)
> > +		if (ps_bridge->page[i])
> > +			i2c_unregister_device(ps_bridge->page[i]);
> 
> Might be better to make this into something like:
> 
> 	while (--i)
> 		i2c_unregister_device(ps_bridge->page[i]);
> 
> That way you can omit the check for valid page because you only
> unregister the ones you've successfully registered before.
> 

Got it, I'll fix it next version.
Thanks

> > +	i2c_unregister_device(ps_bridge->ddc_i2c);
> > +exit_ddc_i2c_dummy:
> > +	drm_bridge_remove(&ps_bridge->bridge);
> > +	return ret;
> > +}
> > +
> > +static int ps8640_remove(struct i2c_client *client)
> > +{
> > +	struct ps8640 *ps_bridge = i2c_get_clientdata(client);
> > +	int i;
> > +
> > +	for (i = 1; i < 8; i++)
> > +		i2c_unregister_device(ps_bridge->page[i]);
> > +
> > +	i2c_unregister_device(ps_bridge->ddc_i2c);
> > +	drm_bridge_remove(&ps_bridge->bridge);
> > +
> > +	return 0;
> > +}
> 
> The ordering here should be the reverse of that in ->probe().
> 

I'll fix it next version.
Thanks

> > +
> > +static const struct i2c_device_id ps8640_i2c_table[] = {
> > +	{"parade,ps8640", 0},
> > +	{},
> 
> Spaces after { and before }. Also is this really correct? I thought for
> I2C device IDs we didn't need a vendor prefix.
> 
I refer other i2c device, they also contain the vendor prefix.

> Thierry