Re: [PATCH v21 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

From: Enric Balletbo i Serra
Date: Wed Dec 18 2019 - 07:14:35 EST

Hi Laurent,

Many thanks for the quick response and the review. Just preparing a new version
to send.

On 16/12/19 17:32, Laurent Pinchart wrote:
> Hello Enric and Jitao,
>
> Thank you for the patch.
>
> On Mon, Dec 16, 2019 at 02:58:34PM +0100, Enric Balletbo i Serra wrote:
>> From: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
>>
>> This patch adds drm_bridge driver for parade DSI to eDP bridge chip.
>>
>> Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
>> Reviewed-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
>> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
>> [uli: followed API changes, removed FW update feature]
>> Signed-off-by: Ulrich Hecht <uli@xxxxxxxx>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
>> ---
>>
>> 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 | 655 +++++++++++++++++++++++++
>> 3 files changed, 667 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"
>> + 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..ab896ceb1a42
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
>> @@ -0,0 +1,655 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2016 MediaTek Inc.
>> + */
>> +
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +//#include <linux/firmware.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 <asm/unaligned.h>
>
> Please remove commented-out headers.
>

Removed, sorry about that.

>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_crtc_helper.h>
>> +#include <drm/drm_edid.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_print.h>
>> +#include <drm/drm_probe_helper.h>
>> +
>> +#define PAGE1_VSTART 0x6b
>> +#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 SPI_READY 0x0c
>> +#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 PAGE2_MCS_EN 0xf3
>> +#define MCS_EN BIT(0)
>> +#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
>> +
>> +#define PAGE0_DP_CNTL 0
>> +#define PAGE1_VDO_BDG 1
>> +#define PAGE2_TOP_CNTL 2
>> +#define PAGE3_DSI_CNTL1 3
>> +#define PAGE4_MIPI_PHY 4
>> +#define PAGE5_VPLL 5
>> +#define PAGE6_DSI_CNTL2 6
>> +#define PAGE7_SPI_CNTL 7
>> +#define MAX_DEVS 0x8
>> +
>> +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[MAX_DEVS];
>> + struct regulator_bulk_data supplies[2];
>> + struct drm_panel *panel;
>> + struct gpio_desc *gpio_reset;
>> + struct gpio_desc *gpio_power_down;
>> + struct gpio_desc *gpio_mode_sel;
>> + bool enabled;
>> +
>> + /* firmware file info */
>> + struct ps8640_info info;
>> + bool in_fw_update;
>> + /* for firmware update protect */
>> + struct mutex fw_mutex;
>
> The last two fields are not used.
>

Right, removed in next version.

>> +};
>> +
>> +static const u8 enc_ctrl_code[6] = { 0xaa, 0x55, 0x50, 0x41, 0x52, 0x44 };
>> +static const u8 hw_chip_id[4] = { 0x00, 0x0a, 0x00, 0x30 };
>
> Those two variables are not used.
>

And removed too in next version.

>> +
>> +static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e)
>> +{
>> + return container_of(e, struct ps8640, bridge);
>> +}
>> +
>> +static inline struct ps8640 *connector_to_ps8640(struct drm_connector *e)
>> +{
>> + return container_of(e, struct ps8640, connector);
>> +}
>> +
>> +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,
>> + }
>> + };
>> +
>> + ret = i2c_transfer(client->adapter, msgs, 2);
>> +
>> + if (ret == 2)
>> + return 0;
>> + if (ret < 0)
>> + return ret;
>> + else
>> + return -EIO;
>> +}
>
> Isn't this equivalent to i2c_smbus_read_i2c_block_data() ?

Yes, so moved all to use the i2c_smbus read/write helpers.

>> +
>> +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 };
>> +
>> + return ps8640_write_bytes(client, buf, sizeof(buf));
>> +}
>
> And this to i2c_smbus_write_byte_data() ?
>

Done

>> +
>> +static void ps8640_get_mcu_fw_version(struct ps8640 *ps_bridge)
>> +{
>> + struct i2c_client *client = ps_bridge->page[PAGE5_VPLL];
>> + u8 fw_ver[2];
>> +
>> + ps8640_read(client, 0x4, fw_ver, sizeof(fw_ver));
>> + 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_unmute(struct ps8640 *ps_bridge)
>> +{
>> + struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
>> + u8 vdo_ctrl_buf[3] = { PAGE3_SET_ADD, VDO_CTL_ADD, VDO_EN };
>> +
>> + return ps8640_write_bytes(client, vdo_ctrl_buf, sizeof(vdo_ctrl_buf));
>> +}
>> +
>> +static int ps8640_bridge_mute(struct ps8640 *ps_bridge)
>> +{
>> + struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
>> + u8 vdo_ctrl_buf[3] = { PAGE3_SET_ADD, VDO_CTL_ADD, VDO_DIS };
>> +
>> + return ps8640_write_bytes(client, vdo_ctrl_buf, sizeof(vdo_ctrl_buf));
>> +}
>> +
>> +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];
>> + struct i2c_client *page1 = ps_bridge->page[PAGE1_VDO_BDG];
>> + int err;
>> + u8 set_vdo_done, mcs_en, vstart;
>> + ktime_t timeout;
>> +
>> + if (ps_bridge->in_fw_update)
>> + 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;
>> + }
>> +
>> + err = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> + if (err < 0) {
>> + DRM_ERROR("cannot enable regulators %d\n", err);
>> + goto err_panel_unprepare;
>> + }
>> +
>> + gpiod_set_value(ps_bridge->gpio_power_down, 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 embed mcu ready
>> + * First wait 200ms and then check the mcu ready flag every 20ms
>> + */
>> + msleep(200);
>> +
>> + timeout = ktime_add_ms(ktime_get(), 200);
>> + for (;;) {
>> + err = ps8640_read(client, PAGE2_GPIO_H, &set_vdo_done, 1);
>> + if (err < 0) {
>> + DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", err);
>> + goto err_regulators_disable;
>> + }
>> + if ((set_vdo_done & PS_GPIO9) == PS_GPIO9)
>> + break;
>> + if (ktime_compare(ktime_get(), timeout) > 0)
>> + break;
>> + msleep(20);
>> + }
>> +
>> + msleep(50);
>> +
>> + ps8640_read(page1, PAGE1_VSTART, &vstart, 1);
>> + DRM_INFO("PS8640 PAGE1.0x6B = 0x%x\n", vstart);
>> +
>> + /**
>> + * 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.
>> + */
>> + ps8640_read(client, PAGE2_MCS_EN, &mcs_en, 1);
>> + ps8640_write_byte(client, PAGE2_MCS_EN, mcs_en & ~MCS_EN);
>> +
>> + if (ps_bridge->info.version == 0)
>> + ps8640_get_mcu_fw_version(ps_bridge);
>> +
>> + err = ps8640_bridge_unmute(ps_bridge);
>> + if (err)
>> + DRM_ERROR("failed to enable unmutevideo: %d\n", err);
>> +
>> + /* Switch access edp panel's edid through i2c */
>> + ps8640_write_byte(client, PAGE2_I2C_BYPASS, I2C_BYPASS_EN);
>> + ps_bridge->enabled = true;
>> +
>> + return;
>> +
>> +err_regulators_disable:
>> + regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> +err_panel_unprepare:
>> + drm_panel_unprepare(ps_bridge->panel);
>> +}
>> +
>> +static void ps8640_enable(struct drm_bridge *bridge)
>> +{
>> + struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
>> + int 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;
>> +
>> + err = drm_panel_disable(ps_bridge->panel);
>> + if (err < 0)
>> + DRM_ERROR("failed to disable panel: %d\n", err);
>> +}
>> +
>> +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;
>> +
>> + if (!ps_bridge->enabled)
>> + return;
>> +
>> + ps_bridge->enabled = false;
>> +
>> + err = ps8640_bridge_mute(ps_bridge);
>> + if (err < 0)
>> + DRM_ERROR("failed to unmutevideo: %d\n", err);
>> +
>> + gpiod_set_value(ps_bridge->gpio_reset, 0);
>> + gpiod_set_value(ps_bridge->gpio_power_down, 0);
>> + err = regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
>> + ps_bridge->supplies);
>> + if (err < 0)
>> + DRM_ERROR("cannot disable regulators %d\n", 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);
>> + struct edid *edid;
>> + int 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 = drm_get_edid(connector, ps_bridge->page[0]->adapter);
>> + if (!edid)
>> + goto out;
>> +
>> + ps_bridge->edid = edid;
>> + drm_connector_update_edid_property(connector, ps_bridge->edid);
>> + num_modes = drm_add_edid_modes(connector, ps_bridge->edid);
>> +
>> +out:
>> + if (power_off)
>> + ps8640_post_disable(&ps_bridge->bridge);
>> +
>> + return num_modes;
>> +}
>> +
>> +static const struct drm_connector_helper_funcs ps8640_connector_helper_funcs = {
>> + .get_modes = ps8640_get_modes,
>> +};
>> +
>> +static enum drm_connector_status ps8640_detect(struct drm_connector *connector,
>> + bool force)
>> +{
>> + return connector_status_connected;
>> +}
>> +
>> +static const struct drm_connector_funcs ps8640_connector_funcs = {
>> + .fill_modes = drm_helper_probe_single_connector_modes,
>> + .detect = ps8640_detect,
>> + .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);
>> + struct device *dev = &ps_bridge->page[0]->dev;
>> + struct device_node *in_ep, *dsi_node = NULL;
>> + struct mipi_dsi_device *dsi;
>> + struct mipi_dsi_host *host = NULL;
>> + int ret;
>> + const struct mipi_dsi_device_info info = { .type = "ps8640",
>> + .channel = 0,
>> + .node = NULL,
>> + };
>> +
>> + 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);
>> +
>> + ps_bridge->connector.dpms = DRM_MODE_DPMS_ON;
>> + drm_connector_attach_encoder(&ps_bridge->connector,
>> + bridge->encoder);
>> +
>> + if (ps_bridge->panel)
>> + drm_panel_attach(ps_bridge->panel, &ps_bridge->connector);
>
> It would be nice if you could use the panel bridge API to let the bridge
> core handle the panel enable/disable automatically.
>

Ok, will try to do that.

>> +
>> + /* port@0 is ps8640 dsi input port */
>> + in_ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
>> + if (in_ep) {
>> + dsi_node = of_graph_get_remote_port_parent(in_ep);
>> + of_node_put(in_ep);
>> + }
>> +
>> + if (dsi_node) {
>> + host = of_find_mipi_dsi_host_by_node(dsi_node);
>> + of_node_put(dsi_node);
>> + if (!host) {
>> + ret = -ENODEV;
>> + goto err;
>> + }
>> + }
>> +
>
> If !in_ep you will end up here with host == NULL and crash. How about
> getting the DSI host at probe time to ensure that the DT is correct, and
> register the device here ?
>

Right, fixed in next version.

>> + 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);
>> + goto err;
>> + }
>> +
>> + ps_bridge->dsi = dsi;
>> +
>> + dsi->host = host;
>> + dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
>> + MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
>
> That's a weird alignment.
>

Fixed

>> + dsi->format = MIPI_DSI_FMT_RGB888;
>> + dsi->lanes = 4;
>> + ret = mipi_dsi_attach(dsi);
>> + if (ret)
>> + goto err_dsi_attach;
>> +
>> + return 0;
>> +
>> +err_dsi_attach:
>> + mipi_dsi_device_unregister(dsi);
>> +err:
>> + if (ps_bridge->panel)
>> + drm_panel_detach(ps_bridge->panel);
>> + drm_connector_cleanup(&ps_bridge->connector);
>> + return ret;
>> +}
>> +
>> +static const struct drm_bridge_funcs ps8640_bridge_funcs = {
>> + .attach = ps8640_bridge_attach,
>> + .disable = ps8640_disable,
>> + .post_disable = ps8640_post_disable,
>> + .pre_enable = ps8640_pre_enable,
>> + .enable = ps8640_enable,
>> +};
>> +
>> +/* Firmware Version is returned as Major.Minor */
>> +static ssize_t 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 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 DEVICE_ATTR_RO(fw_version);
>> +static DEVICE_ATTR_RO(hw_version);
>> +
>> +static struct attribute *ps8640_attrs[] = {
>> + &dev_attr_fw_version.attr,
>> + &dev_attr_hw_version.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);
>> +}
>> +
>> +static int ps8640_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct device *dev = &client->dev;
>> + struct device_node *np = dev->of_node;
>> + struct device_node *panel_node = NULL;
>> + struct device_node *port, *out_ep;
>> + struct ps8640 *ps_bridge;
>> + 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 */
>> + 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 (IS_ERR(ps_bridge->panel))
>> + return PTR_ERR(ps_bridge->panel);
>> + }
>
> How about replacing all that with
>
> ret = drm_of_find_panel_or_bridge(np, 1, 0, &ps_bridge->panel, NULL);
> if (ret < 0)
> return ret;
>

Done.

>> +
>> + mutex_init(&ps_bridge->fw_mutex);
>> + 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);
>
> You may want to condition this line with ret != -EPROBE_DEFER to avoid
> flooding the kernel log with messages related to probe deferral.
>

The core will already print an error, so I think that I can just remove this.

>> + return ret;
>> + }
>> +
>> + ps_bridge->gpio_mode_sel = devm_gpiod_get_optional(&client->dev,
>> + "mode-sel",
>> + GPIOD_OUT_HIGH);
>> + if (IS_ERR(ps_bridge->gpio_mode_sel)) {
>> + ret = PTR_ERR(ps_bridge->gpio_mode_sel);
>> + dev_err(dev, "cannot get mode-sel %d\n", ret);
>
> Same here and for the other GPIOs below.
>

Removed the errors as the core will already complain about it.

> By the way what is mode-sel used for ? It's not documented properly in
> the DT bindings (I think it should, but I can't reply to the bindings
> patch as it hasn't reached my mailbox yet for some reason), and isn't
> used in the driver except here.
>

This pin can be used to boot from spi-nor to use the embedded FW, or make it
fully controllable via I2C. We're not using this now, so I think I can just
remove that code.

>> + return ret;
>> + }
>> +
>> + ps_bridge->gpio_power_down = devm_gpiod_get(&client->dev, "sleep",
>
> I wonder if the bindings should name the GPIO "powerdown".
>

Indeed seems more common. Also is called sleep which is a bit confusing. So I'll
change here and in the bindings.

>> + GPIOD_OUT_LOW);
>> + if (IS_ERR(ps_bridge->gpio_power_down)) {
>> + ret = PTR_ERR(ps_bridge->gpio_power_down);
>> + dev_err(dev, "cannot get sleep: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + /*
>> + * Request the reset pin low to avoid the bridge being
>> + * initialized prematurely
>
> The polarity is wrong in DT then. Requesting the GPIO low should
> deassert reset, in drivers all GPIO descriptors should be handled as
> active high. Same for the sleep GPIO.
>
>> + */
>> + ps_bridge->gpio_reset = devm_gpiod_get(&client->dev, "reset",
>> + GPIOD_OUT_LOW);
>> + if (IS_ERR(ps_bridge->gpio_reset)) {
>> + ret = PTR_ERR(ps_bridge->gpio_reset);
>> + 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;
>> +
>> + 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 < MAX_DEVS; i++) {
>
> Maybe ARRAY_SIZE(ps_bridge->page) instead of MAX_DEVS ?
>

Done

>> + ps_bridge->page[i] = devm_i2c_new_dummy_device(&client->dev,
>> + client->adapter,
>> + client->addr + i);
>
> I think i2c_new_ancillary_device() is now preferred over the new dummy
> device function.
>



>> + 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);
>> +
>> + ret = sysfs_create_group(&client->dev.kobj, &ps8640_attr_group);
>> + if (ret) {
>> + dev_err(dev, "failed to create sysfs entries: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + 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);
>> + return ret;
>> + }
>
> How about calling ps8640_remove_sysfs_group() in ps8640_remove() instead
> ? Otherwise the sysfs group will be removed after ps8640_remove()
> returns, which could race with userspace accessing the sysfs attributes.
>

Done

>> +
>> + 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 i2c_device_id ps8640_i2c_table[] = {
>> + { "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,
>
> If the device is only used on DT platforms (I can't judge that) you can
> drop this and only specify the of_match_table.
>

id_table removed as is only used on DT platforms

>> + .probe = ps8640_probe,
>
> You should use .probe_new, that's the recommended way forward for I2C
> drivers.
>

Done

>> + .remove = ps8640_remove,
>> + .driver = {
>> + .name = "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");
>