Hi Jitao,

On Tue, Jan 12, 2016 at 6:18 PM, Jitao Shi [off-list ref] wrote:

This patch adds drm_bridge driver for parade DSI to eDP bridge chip.

Signed-off-by: Jitao Shi <redacted>
---
Changes since v6:
 - Add ps8640 firmware update function
 - Change i2c to i2c_transfer from i2c_master_recv/i2c_master_send

Thank you for using i2c_transfer.
Did you notice any improvement during i2c-intesive operations (eg.,
mode set or suspend/resume) by doing so?

depends on I2C, too.

This devm_kzalloc() is really bad, since it just sits here and
accumulates buffers on every transaction for the life of the device
instance.

There are only 3 calls to ps8640_regw().
We should be able to refactor things to avoid this devm_kzalloc.

Two of these calls transfer a fixed 2 bytes, each of these can be
handled by a custom helper function that takes the two values as
parameters.

The third is the firmware page buffer, which can also be implemented
using a fixed 257 byte buffer, with a 0 followed by memcpy'ed 256
bytes of data.

+       /* i2c page size is 256 bytes, so limit the data_len 256 */
+       if (data_len > 256) {
+               dev_err(&client->dev, "data_len must under 256: len = %d\n",
+                       data_len);
+               return -EIO;
+       }

In any case, you definitely do not need this runtime error checking,
since you are just checking your own code...

+       for (i = 0; i < data_len + 1; i++)
+               buf[i] = (i == 0) ? reg : data[i - 1];
+
+       msg.addr = client->addr;
+       msg.flags = 0;
+       msg.len = data_len + 1;
+       msg.buf = buf;
+
+       ret = i2c_transfer(client->adapter, &msg, 1);
+       if (ret == 1)
+               return 0;
+       if (ret < 0)
+               return ret;
+       else
+               return -EIO;
+}
+
+static int ps8640_regw_byte(struct i2c_client *client, u8 reg,  u8 data)
+{
+       int ret;
+       struct i2c_msg msg;
+       u8 buf[] = {reg, data};
+
+       msg.addr = client->addr;
+       msg.flags = 0;
+       msg.len = sizeof(buf);
+       msg.buf = buf;
+
+       ret = i2c_transfer(client->adapter, &msg, 1);
+       if (ret == 1)
+               return 0;
+       if (ret < 0)
+               return ret;
+       else
+               return -EIO;
+}
+
+static int ps8640_check_valid_id(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[4];
+       u8 chip_id[4];
+
+       ps8640_regr(client, PAGE4_REV_L, chip_id, 4);
+
+       if ((chip_id[0] == 0x00) && (chip_id[1] == 0x0a) &&
+           (chip_id[2] == 0x00) && (chip_id[3] == 0x30))

nit: the inner () are not needed.

+               return 0;
+
+       return -ENODEV;
+}
+
+static void ps8640_show_mcu_fw_version(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[5];
+       u8 fw_ver[2];
+
+       ps8640_regr(client, 0x4, fw_ver, 2);
+       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_bdg_enable(struct ps8640 *ps_bridge)

What is "bdg_enable"?
If it is "bridge_enable", please spell it out:
 ps8640_bridge_enable()

+{
+       struct i2c_client *client = ps_bridge->page[3];
+       int ret;
+       u8 vdo_ctrl[2] = {VDO_CTL_ADD, VDO_EN};
+
+       ret = ps8640_check_valid_id(ps_bridge);

Why are we doing this check here?
I think we should only do this once, in probe.
If the ps8640 is not valid, we shouldn't even get this far.

+       if (ret) {
+               DRM_ERROR("ps8640 not valid: %d\n", ret);
+               return ret;
+       }
+
+       ret = ps8640_regw(client, PAGE3_SET_ADD, vdo_ctrl, 2);
+       return ret;
+}
+
+static bool ps8640_in_bootloader(struct ps8640 *ps_bridge)

This function doesn't seem very useful.  Just check the variable directly.

+{
+       return ps_bridge->in_fw_update;
+}
+
+static void ps8640_prepare(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[2];
+       int err, retry_cnt = 0;
+       u8 set_vdo_done;
+
+       if (ps8640_in_bootloader(ps_bridge))
+               return;
+
+       if (ps_bridge->enabled)
+               return;
+
+       err = drm_panel_prepare(ps_bridge->panel);
+       if (err < 0) {
+               DRM_ERROR("failed to prepare panel: %d\n", err);
+               return;
+       }
+
+       /* delay for power stable */
+       usleep_range(500, 700);

What is this "power stable" delay for?  The panel?
Shouldn't that be handled in drm_panel_prepare()?

+
+       err = regulator_enable(ps_bridge->pwr_1v2_supply);
+       if (err < 0) {
+               DRM_ERROR("failed to enable vdd12-supply: %d\n", err);
+               goto err_panel_unprepare;
+       }
+
+       err = regulator_enable(ps_bridge->pwr_3v3_supply);
+       if (err < 0) {
+               DRM_ERROR("failed to enable vdd33-supply: %d\n", err);
+               goto err_regulator_1v2_disable;
+       }
+
+       gpiod_set_value(ps_bridge->gpio_slp_n, 1);
+       gpiod_set_value(ps_bridge->gpio_rst_n, 0);

Shouldn't we setup these GPIO before enabling the regulators?

+       usleep_range(500, 700);
+       gpiod_set_value(ps_bridge->gpio_rst_n, 1);
+
+       /* wait for the ps8640 embed mcu ready
+         * first wait 200ms and then check the mcu ready flag every 20ms
+       */

Please fix multi-line comment indentation.

+       msleep(200);
+       do {
+               err = ps8640_regr(client, PAGE2_GPIO_H, &set_vdo_done, 1);
+               if (err < 0) {
+                       DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", err);
+                       goto err_regulator_1v2_disable;
+               }
+               msleep(20);
+       } while ((retry_cnt++ < 10) && ((set_vdo_done & PS_GPIO9) != PS_GPIO9));
+
+       ps8640_show_mcu_fw_version(ps_bridge);

Why do you need to read this on every prepare?
We only print it once anyway.

+       ps8640_regw_byte(client, PAGE2_I2C_BYPASS, I2C_BYPASS_EN);

What does this do?

+       ps_bridge->enabled = true;
+
+       return;
+
+err_regulator_1v2_disable:
+       regulator_disable(ps_bridge->pwr_1v2_supply);
+err_panel_unprepare:
+       drm_panel_unprepare(ps_bridge->panel);
+}
+
+static void ps8640_pre_enable(struct drm_bridge *bridge)
+{
+       struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
+
+       ps8640_prepare(ps_bridge);

The order looks strange to me:

AFAICT, we are preparing the ps8640 before the panel, however, we also
*disable* the ps8640 before the panel.

Shouldn't we enable/disable in opposite order, like:

 ps8640_prepare
 ps8640_bdg_enable
 drm_panel_enable

 drm_panel_disable
 ps8640_bdg_disable
 ps8640_unprepare

+}
+
+static void ps8640_enable(struct drm_bridge *bridge)
+{
+       struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
+       int err;
+
+       err = ps8640_bdg_enable(ps_bridge);
+       if (err)
+               DRM_ERROR("failed to enable unmutevideo: %d\n", err);
+
+       err = drm_panel_enable(ps_bridge->panel);
+       if (err < 0)
+               DRM_ERROR("failed to enable panel: %d\n", err);
+}
+
+static void ps8640_disable(struct drm_bridge *bridge)
+{
+       struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
+       int err;
+
+       if (ps8640_in_bootloader(ps_bridge))
+               return;
+
+       if (!ps_bridge->enabled)
+               return;
+
+       ps_bridge->enabled = false;
+
+       err = drm_panel_disable(ps_bridge->panel);
+       if (err < 0)
+               DRM_ERROR("failed to disable panel: %d\n", err);
+
+       gpiod_set_value(ps_bridge->gpio_rst_n, 0);
+       gpiod_set_value(ps_bridge->gpio_slp_n, 0);
+       regulator_disable(ps_bridge->pwr_3v3_supply);
+       regulator_disable(ps_bridge->pwr_1v2_supply);
+}
+
+static void ps8640_post_disable(struct drm_bridge *bridge)
+{
+       struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
+       int err;
+
+       err = drm_panel_unprepare(ps_bridge->panel);
+       if (err)
+               DRM_ERROR("failed to unprepare panel: %d\n", err);
+}
+
+static int ps8640_get_modes(struct drm_connector *connector)
+{
+       struct ps8640 *ps_bridge = connector_to_ps8640(connector);
+
+       ps8640_prepare(ps_bridge);

Hmm, is this needed?
Shouldn't we unprepare after getting the modes?

+
+       return drm_panel_get_modes(ps_bridge->panel);
+}
+
+static struct drm_encoder *ps8640_best_encoder(struct drm_connector *connector)
+{
+       struct ps8640 *ps_bridge;
+
+       ps_bridge = connector_to_ps8640(connector);
+       return ps_bridge->bridge.encoder;
+}
+
+static const struct drm_connector_helper_funcs ps8640_connector_helper_funcs = {
+       .get_modes = ps8640_get_modes,
+       .best_encoder = ps8640_best_encoder,
+};
+
+static enum drm_connector_status ps8640_detect(struct drm_connector *connector,
+                                              bool force)
+{
+       return connector_status_connected;
+}
+
+static void ps8640_connector_destroy(struct drm_connector *connector)
+{
+       drm_connector_unregister(connector);
+       drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs ps8640_connector_funcs = {
+       .dpms = drm_atomic_helper_connector_dpms,
+       .fill_modes = drm_helper_probe_single_connector_modes,
+       .detect = ps8640_detect,
+       .destroy = ps8640_connector_destroy,
+       .reset = drm_atomic_helper_connector_reset,
+       .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+int ps8640_bridge_attach(struct drm_bridge *bridge)
+{
+       struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
+       int ret;
+
+       if (!bridge->encoder) {

Hmm, how is this possible?

+               DRM_ERROR("Parent encoder object not found");
+               return -ENODEV;
+       }
+
+       ret = drm_connector_init(bridge->dev, &ps_bridge->connector,
+                                &ps8640_connector_funcs,
+                                DRM_MODE_CONNECTOR_eDP);
+
+       if (ret) {
+               DRM_ERROR("Failed to initialize connector with drm: %d\n", ret);
+               return ret;
+       }
+
+       drm_connector_helper_add(&ps_bridge->connector,
+                                &ps8640_connector_helper_funcs);
+       drm_connector_register(&ps_bridge->connector);
+
+       ps_bridge->connector.dpms = DRM_MODE_DPMS_ON;
+       drm_mode_connector_attach_encoder(&ps_bridge->connector,
+                                         bridge->encoder);
+
+       if (ps_bridge->panel)
+               drm_panel_attach(ps_bridge->panel, &ps_bridge->connector);
+
+       return ret;
+}
+
+static bool ps8640_bridge_mode_fixup(struct drm_bridge *bridge,
+                                    const struct drm_display_mode *mode,
+                                    struct drm_display_mode *adjusted_mode)
+{
+       return true;
+}
+
+static const struct drm_bridge_funcs ps8640_bridge_funcs = {
+       .attach = ps8640_bridge_attach,
+       .mode_fixup = ps8640_bridge_mode_fixup,
+       .disable = ps8640_disable,
+       .post_disable = ps8640_post_disable,
+       .pre_enable = ps8640_pre_enable,
+       .enable = ps8640_enable,
+};
+
+static ssize_t ps8640_fw_file_show(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+       struct ps8640 *ps_bridge = dev_get_drvdata(dev);
+
+       return scnprintf(buf, PAGE_SIZE, "%s\n", ps_bridge->fw_file);
+}
+
+static int ps8640_update_file_name(struct device *dev, char **file_name,
+                                  const char *buf, size_t count)
+{
+       char *new_file_name;
+
+       /* Simple sanity check */
+       if (count > 64) {
+               dev_warn(dev, "File name too long\n");
+               return -EINVAL;
+       }
+
+       new_file_name = devm_kmalloc(dev, count + 1, GFP_KERNEL);
+       if (!new_file_name)
+               return -ENOMEM;
+
+       memcpy(new_file_name, buf, count + 1);
+
+       /* Echo into the sysfs entry may append newline at the end of buf */
+       if (new_file_name[count - 1] == '\n')
+               count--;
+
+       new_file_name[count] = '\0';
+
+       if (*file_name)
+               devm_kfree(dev, *file_name);
+
+       *file_name = new_file_name;
+
+       return 0;
+}
+
+static ssize_t ps8640_fw_file_store(struct device *dev,
+                                   struct device_attribute *attr,
+                                   const char *buf, size_t count)

Hmm. Why do we need to make the firmware file name changeable?
Can't we just mandate a ps8640 file name, and use a symlink if
necessary to select from a set of files if necessary?

+{
+       struct ps8640 *ps_bridge = dev_get_drvdata(dev);
+       int ret;
+
+       ret = ps8640_update_file_name(dev, &ps_bridge->fw_file, buf, count);
+       if (ret)
+               return ret;
+
+       return count;
+}
+
+/* Firmware Version is returned as Major.Minor.Build */
+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);
+}
+
+/* Hardware Version is returned as FamilyID.VariantID */
+static ssize_t ps8640_hw_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, "ps%u.%u\n", info->family_id,
+                        info->variant_id);
+}
+
+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;
+       int ret;
+
+       ret = ps8640_regw_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_regw_byte(client, PAGE2_SWSPI_WDATA, cmd[i]);
+               if (ret)
+                       goto err;
+       }
+       /*      command length */
+       ret = ps8640_regw_byte(client, PAGE2_SWSPI_LEN, cmd_len - 1);
+       if (ret)
+               goto err;
+       /*      trigger read */
+       ret = ps8640_regw_byte(client, PAGE2_SWSPI_CTL, TRIGGER_NO_READBACK);
+       if (ret)
+               goto err;
+
+       ret = ps8640_regw_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
+       if (ret)
+               goto err;
+
+       return 0;
+
+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, retry_cnt = 0;
+
+       do {
+               ps8640_regr(client, PAGE2_SPI_STATUS, &spi_rdy_st, 1);
+               msleep(20);
+               if ((retry_cnt == SPI_MAX_RETRY_CNT) &&
+                   ((spi_rdy_st & 0x0c) != 0x0c)) {
+                       dev_err(&client->dev, "wait spi ready timeout\n");
+                       return -EBUSY;
+               }
+       } while ((retry_cnt++ < SPI_MAX_RETRY_CNT) &&
+                (spi_rdy_st & 0x0c) == 0x0c);
+
+       return 0;
+}
+
+static int ps8640_wait_spi_nobusy(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[2];
+       u8 spi_status, retry_cnt = 0;
+       int ret;
+
+       do {
+               /*  0x05 RDSR; Read-Status-Register */
+               ret = ps8640_regw_byte(client, PAGE2_SWSPI_WDATA, 0x05);
+               if (ret)
+                       goto err_send_cmd_exit;
+
+               /*  command length */
+               ret = ps8640_regw_byte(client, PAGE2_SWSPI_LEN, 0x00);
+               if (ret)
+                       goto err_send_cmd_exit;
+
+               /*  trigger read */
+               ret = ps8640_regw_byte(client, PAGE2_SWSPI_CTL,
+                                      TRIGGER_READBACK);
+               if (ret)
+                       goto err_send_cmd_exit;
+
+               /* delay for cmd send */
+               usleep_range(100, 300);
+               /* wait for SPI ROM until not busy */
+               ret = ps8640_regr(client, PAGE2_SWSPI_RDATA, &spi_status, 1);
+               if (ret)
+                       goto err_send_cmd_exit;
+       } while ((retry_cnt++ < SPI_MAX_RETRY_CNT) &&
+                (spi_status & 0x0c) == 0x0c);
+
+       if ((retry_cnt > SPI_MAX_RETRY_CNT) && (spi_status & 0x0c) != 0x0c) {
+               ret = -EBUSY;
+               dev_err(&client->dev, "wait spi no busy timeout: %d\n", ret);
+               goto err_timeout;
+       }
+
+       return 0;
+
+err_send_cmd_exit:
+       dev_err(&client->dev, "send command err: %d\n", ret);
+
+err_timeout:
+       return ret;
+}
+
+static int ps8640_wait_rom_idle(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[0];
+       int ret;
+
+       ret = ps8640_regw_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
+       if (ret)
+               goto exit;
+
+       ret = ps8640_wait_spi_ready(ps_bridge);
+       if (ret)
+               goto exit;
+
+       ret = ps8640_wait_spi_nobusy(ps_bridge);
+       if (ret)
+               goto exit;
+
+       ret = ps8640_regw_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
+       if (ret)
+               goto exit;
+
+exit:
+       if (ret)
+               dev_err(&client->dev, "wait ps8640 rom idle fail: %d\n", ret);
+
+       return ret;
+}
+
+static int ps8640_spi_dl_mode(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[2];
+       int ret;
+
+       /* switch ps8640 mode to spi dl mode */
+       gpiod_set_value(ps_bridge->gpio_mode_sel_n, 0);
+
+       /* reset spi interface */
+       ret = ps8640_regw_byte(client, PAGE2_SW_REST, 0xc0);
+       if (ret)
+               goto exit;
+
+       ret = ps8640_regw_byte(client, PAGE2_SW_REST, 0x40);
+       if (ret)
+               goto exit;
+
+exit:
+       if (ret)
+               dev_err(&client->dev, "fail reset spi interface: %d\n", ret);
+
+       return ret;
+}
+
+static int ps8640_rom_prepare(struct ps8640 *ps_bridge)
+{
+       struct i2c_client *client = ps_bridge->page[2];
+       struct device *dev = &client->dev;
+       u8 i, cmd[2];
+       int ret;
+
+       /*      Enable-Write-Status-Register */
+       cmd[0] = 0x06;
+       ret = ps8640_spi_send_cmd(ps_bridge, cmd, 1);
+       if (ret) {
+               dev_err(dev, "failed enable-write-status-register: %d\n", ret);
+               return ret;
+       }
+
+       /* disable all protection */
+       cmd[0] = 0x01;
+       cmd[1] = 0x00;
+       ret = ps8640_spi_send_cmd(ps_bridge, cmd, 2);
+       if (ret) {
+               dev_err(dev, "fail disable all protection: %d\n", ret);
+               return ret;
+       }
+
+       /* wait for SPI module ready */
+       ret = ps8640_wait_rom_idle(ps_bridge);
+       if (ret) {
+               dev_err(dev, "fail wait rom idle: %d\n", ret);
+               return ret;
+       }
+
+       ps8640_regw_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
+       for (i = 0; i < 6; i++)
+               ps8640_regw_byte(client, PAGE2_ENCTLSPI_WR, enc_ctrl_code[i]);
+       ps8640_regw_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
+
+       /*      Enable-Write-Status-Register */
+       cmd[0] = 0x06;
+       ret = ps8640_spi_send_cmd(ps_bridge, cmd, 1);
+       if (ret) {
+               dev_err(dev, "fail enable-write-status-register: %d\n", ret);
+               return ret;
+       }
+
+       /* chip erase command */
+       cmd[0] = 0xc7;
+       ret = ps8640_spi_send_cmd(ps_bridge, cmd, 1);
+       if (ret) {
+               dev_err(dev, "fail disable all protection: %d\n", ret);
+               return ret;
+       }
+
+       ret = ps8640_wait_rom_idle(ps_bridge);
+       if (ret) {
+               dev_err(dev, "fail wait rom idle: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int ps8640_validate_firmware(struct ps8640 *ps_bridge,
+                                   const struct firmware *fw)
+{
+       struct i2c_client *client = ps_bridge->page[0];
+       struct ps8640_info *info = &ps_bridge->info;
+       u16 fw_chip_id, fw_version_id;
+
+       /*
+        * Get the chip_id from the firmware. Make sure that it is the
+        * right controller to do the firmware and config update.
+        */
+       fw_chip_id = get_unaligned_le16(fw->data + FW_CHIP_ID_OFFSET);
+
+       if (fw_chip_id != 0x8640) {
+               dev_err(&client->dev,
+                       "chip id mismatch: fw 0x%x vs. chip 0x8640\n",
+                       fw_chip_id);
+               return -ENODEV;
+       }
+
+       fw_version_id = get_unaligned_le16(fw->data + FW_VERSION_OFFSET);
+
+       if (fw_chip_id != info->version) {
+               dev_err(&client->dev,
+                       "fw version mismatch: fw %d.%d vs. chip %d.%d\n",
+                       fw_version_id >> 8, fw_version_id & 0xff,
+                       info->version >> 8, info->version & 0xff);
+               return -ENODEV;
+       }
+
+       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;
+       u8 progress_cnt, rom_page_id[2];
+       int ret;
+
+       ps8640_regw_byte(client2, PAGE2_SPI_CFG3, I2C_TO_SPI_RESET);
+       msleep(100);
+       ps8640_regw_byte(client2, PAGE2_SPI_CFG3, 0x00);
+
+       while (pos < fw->size) {
+               rom_page_id[0] = (pos >> 8) & 0xFF;
+               rom_page_id[1] = (pos >> 16) & 0xFF;

nit: kernel usually uses lowercase hex.  At the very least, be
consistent in the driver (other hex constants are lowercase).

+               ret = ps8640_regw(client2, PAGE2_ROMADD_BYTE1, rom_page_id, 2);
+               if (ret)
+                       goto error;
+               ret = ps8640_regw(client7, 0, fw->data + pos, 256);
+               if (ret)
+                       goto error;
+
+               pos += 256;
+               if (progress_cnt != (pos * 100) / fw->size) {
+                       progress_cnt = (pos * 100) / fw->size;
+                       dev_info(dev, "fw update progress percent %d\n",
+                                progress_cnt);

Please don't spam dmesg.  Use dev_dbg().
Also, it might be more straightforward as:
  dev_dbg(dev, "fw update completed %u / %u bytes\n", pos, fw->size);

+               }
+       }
+       return 0;
+
+error:
+       dev_err(dev, "failed write extenal flash, %d\n", ret);
+       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] = 0x06;
+       ps8640_spi_send_cmd(ps_bridge, cmd, 1);
+
+       /* protect BPL/BP0/BP1 */
+       cmd[0] = 0x01;
+       cmd[1] = 0x8c;
+       ps8640_spi_send_cmd(ps_bridge, cmd, 2);
+
+       /* wait for SPI rom ready */
+       ps8640_wait_rom_idle(ps_bridge);
+
+     /* disable PS8640 mapping function */

Indent w/ tabs everywhere.

+       ps8640_regw_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)
+{
+       int ret;
+
+       ret = ps8640_spi_dl_mode(ps_bridge);
+       if (ret)
+               return ret;
+
+       ps_bridge->in_fw_update = true;
+       return 0;
+}
+
+static void ps8640_exit_bl(struct ps8640 *ps_bridge, const struct firmware *fw)
+{
+       ps_bridge->in_fw_update = false;
+       ps8640_spi_normal_mode(ps_bridge);
+}
+
+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;
+
+       if (!ps8640_in_bootloader(ps_bridge)) {
+               if (!ps8640_status_backup)
+                       ps8640_prepare(ps_bridge);
+
+               ret = ps8640_enter_bl(ps_bridge);
+               if (ret)
+                       goto exit;
+       }
+
+       ret = ps8640_validate_firmware(ps_bridge, fw);
+       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_disable(&ps_bridge->bridge);
+       return ret;
+}
+
+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_bridge->fw_file, dev);
+       if (error) {
+               dev_err(dev, "Unable to open firmware %s: %d\n",
+                       ps_bridge->fw_file, 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;
+}
+
+static DEVICE_ATTR(fw_file, S_IRUGO | S_IWUSR, ps8640_fw_file_show,
+                  ps8640_fw_file_store);
+static DEVICE_ATTR(fw_version, S_IRUGO, ps8640_fw_version_show, NULL);
+static DEVICE_ATTR(hw_version, S_IRUGO, ps8640_hw_version_show, NULL);
+static DEVICE_ATTR(update_fw, S_IWUSR, NULL, ps8640_update_fw_store);
+
+static struct attribute *ps8640_attrs[] = {
+       &dev_attr_fw_file.attr,
+       &dev_attr_fw_version.attr,
+       &dev_attr_hw_version.attr,
+       &dev_attr_update_fw.attr,
+       NULL
+};
+
+static const struct attribute_group ps8640_attr_group = {
+       .attrs = ps8640_attrs,
+};
+
+static void ps8640_remove_sysfs_group(void *data)
+{
+       struct ps8640 *ps_bridge = data;
+
+       sysfs_remove_group(&ps_bridge->page[0]->dev.kobj, &ps8640_attr_group);
+}
+
+/* for fireware update end */

/* firmware update end */
... or, just remove this comment

+
+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;
+
+       ps_bridge = devm_kzalloc(dev, sizeof(*ps_bridge), GFP_KERNEL);
+       if (!ps_bridge) {
+               ret = -ENOMEM;
+               goto exit;
+       }
+       /* port at 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) {
+                       ret = -EPROBE_DEFER;
+                       goto exit;
+               }
+       }
+
+       ps_bridge->pwr_3v3_supply = devm_regulator_get(dev, "vdd33");
+       if (IS_ERR(ps_bridge->pwr_3v3_supply)) {
+               ret = PTR_ERR(ps_bridge->pwr_3v3_supply);
+               dev_err(dev, "cannot get vdd33 supply: %d\n", ret);
+               goto exit;
+       }
+
+       ps_bridge->pwr_1v2_supply = devm_regulator_get(dev, "vdd12");
+       if (IS_ERR(ps_bridge->pwr_1v2_supply)) {
+               ret = PTR_ERR(ps_bridge->pwr_1v2_supply);
+               dev_err(dev, "cannot get vdd12 supply: %d\n", ret);
+               goto exit;
+       }
+
+       ps_bridge->gpio_mode_sel_n = devm_gpiod_get(&client->dev, "mode-sel",
+                                                   GPIOD_OUT_HIGH);
+       if (IS_ERR(ps_bridge->gpio_mode_sel_n)) {
+               ret = PTR_ERR(ps_bridge->gpio_mode_sel_n);
+               dev_err(dev, "cannot get gpio_mode_sel_n %d\n", ret);
+               goto exit;
+       }
+
+       ps_bridge->gpio_slp_n = devm_gpiod_get(&client->dev, "sleep",
+                                              GPIOD_OUT_HIGH);
+       if (IS_ERR(ps_bridge->gpio_slp_n)) {
+               ret = PTR_ERR(ps_bridge->gpio_slp_n);
+               dev_err(dev, "cannot get gpio_slp_n: %d\n", ret);
+               goto exit;
+       }
+
+       ps_bridge->gpio_rst_n = devm_gpiod_get(&client->dev, "reset",
+                                              GPIOD_OUT_HIGH);
+       if (IS_ERR(ps_bridge->gpio_rst_n)) {
+               ret = PTR_ERR(ps_bridge->gpio_rst_n);
+               dev_err(dev, "cannot get gpio_rst_n: %d\n", ret);
+               goto exit;
+       }
+
+       ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
+       ps_bridge->bridge.of_node = dev->of_node;
+       ret = drm_bridge_add(&ps_bridge->bridge);
+       if (ret) {
+               dev_err(dev, "Failed to add bridge: %d\n", ret);
+               goto exit;
+       }
+
+       ret = ps8640_update_file_name(&client->dev, &ps_bridge->fw_file,
+                                     PS_FW_NAME, strlen(PS_FW_NAME));
+       if (ret) {
+               dev_err(dev, "failed to update file name: %d\n", ret);
+               goto exit;

goto exit_drm_bridge_remove:

+       }
+
+       ps_bridge->page[0] = client;
+
+       /* 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) {
+               ps8640_remove_sysfs_group(ps_bridge);
+               dev_err(dev, "failed to add sysfs cleanup action: %d\n", ret);
+               goto exit_dummy;

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]);
+
+exit:

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++)
+               if (ps_bridge->page[i])

This will always be true and can be skipped.

+                       i2c_unregister_device(ps_bridge->page[i]);
+

exit_drm_bridge_remove:

+       drm_bridge_remove(&ps_bridge->bridge);
+
+       return 0;
+}
+
+static const struct i2c_device_id ps8640_i2c_table[] = {
+       {"parade,ps8640", 0},
+       {},
+};
+MODULE_DEVICE_TABLE(i2c, ps8640_i2c_table);
+
+static const struct of_device_id ps8640_match[] = {
+       { .compatible = "parade,ps8640" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, ps8640_match);
+
+static struct i2c_driver ps8640_driver = {
+       .id_table = ps8640_i2c_table,
+       .probe = ps8640_probe,
+       .remove = ps8640_remove,
+       .driver = {
+               .name = "parade,ps8640",
+               .of_match_table = ps8640_match,
+       },
+};
+module_i2c_driver(ps8640_driver);
+
+MODULE_AUTHOR("Jitao Shi [off-list ref]");
+MODULE_AUTHOR("CK Hu [off-list ref]");
+MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5