Re: [PATCH v7 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

From: Daniel Kurtz
Date: Wed Jan 13 2016 - 19:31:40 EST

Hi Jitao,

On Tue, Jan 12, 2016 at 6:18 PM, Jitao Shi <jitao.shi@xxxxxxxxxxxx> wrote:
> This patch adds drm_bridge driver for parade DSI to eDP bridge chip.
>
> Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
> ---
> 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?

> - Add comments for each page client
> ---
> drivers/gpu/drm/bridge/Kconfig | 10 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> drivers/gpu/drm/bridge/parade-ps8640.c | 1106 ++++++++++++++++++++++++++++++++
> 3 files changed, 1117 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 6dddd39..dcfdbc9 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -41,4 +41,14 @@ config DRM_PARADE_PS8622
> ---help---
> Parade eDP-LVDS bridge chip driver.
>
> +config DRM_PARADE_PS8640
> + tristate "Parade PS8640 MIPI DSI to eDP Converter"
> + depends on OF

depends on I2C, too.

> + select DRM_KMS_HELPER
> + 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
> +
> endmenu
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index d4e28be..272e3c01 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw_hdmi.o
> obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw_hdmi-ahb-audio.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
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> new file mode 100644
> index 0000000..a18d8e9
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -0,0 +1,1106 @@
> +/*
> + * Copyright (c) 2014 MediaTek Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#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_crtc_helper.h>
> +#include <drm_crtc.h>
> +#include <drm_atomic_helper.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_REST 0xbc
> +#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 bridge_to_ps8640(e) container_of(e, struct ps8640, bridge)
> +#define connector_to_ps8640(e) container_of(e, struct ps8640, connector)
> +
> +struct ps8640_info {
> + u8 family_id;
> + u8 variant_id;
> + u16 version;
> +};
> +
> +struct ps8640 {
> + struct drm_connector connector;
> + struct drm_bridge bridge;
> + struct i2c_client *page[8];
> + struct ps8640_driver_data *driver_data;
> + struct regulator *pwr_1v2_supply;
> + struct regulator *pwr_3v3_supply;
> + 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 name */
> + bool in_fw_update;
> + char *fw_file;
> + struct ps8640_info info;
> +};
> +
> +static const u8 enc_ctrl_code[6] = {0xaa, 0x55, 0x50, 0x41, 0x52, 0x44};
> +
> +static int ps8640_regr(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,
> + }
> + };
> +
> + ret = i2c_transfer(client->adapter, msgs, 2);
> +
> + if (ret == 2)
> + return 0;
> + if (ret < 0)
> + return ret;
> + else
> + return -EIO;
> +}
> +
> +static int ps8640_regw(struct i2c_client *client, u8 reg, const u8 *data,
> + u16 data_len)
> +{
> + int ret, i;
> + struct i2c_msg msg;
> + u8 *buf;
> +
> + buf = devm_kzalloc(&client->dev, data_len + 1, GFP_KERNEL);

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@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 <jitao.shi@xxxxxxxxxxxx>");
> +MODULE_AUTHOR("CK Hu <ck.hu@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>