Re: [v17 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

[Archit Taneja]

Hi Jitao,

I couldn't locate the original mail, so posting on this thread instead.
Some comments below.

On 11/10/2016 10:09 PM, Enric Balletbo Serra wrote:
> Hi Jitao,
>
> 2016-08-27 8:44 GMT+02:00 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>
> > ---
> > Changes since v16:
> >  - Disable ps8640 DSI MCS Function.
> >  - Rename gpios name more clearly.
> >  - Tune the ps8640 power on sequence.
> >
> > Changes since 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 since 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 since 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 since v12:
> >  - fix hw_chip_id build warning
> >
> > Changes since 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         |   12 +
> >  drivers/gpu/drm/bridge/Makefile        |    1 +
> >  drivers/gpu/drm/bridge/parade-ps8640.c | 1077 ++++++++++++++++++++++++++++++++
> >  3 files changed, 1090 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 b590e67..c59d043 100644
> > --- a/drivers/gpu/drm/bridge/Kconfig
> > +++ b/drivers/gpu/drm/bridge/Kconfig
> > @@ -50,6 +50,18 @@ 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 DRM
> > +       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_SII902X
> >         tristate "Silicon Image sii902x RGB/HDMI bridge"
> >         depends on OF
> > diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> > index efdb07e..3360537 100644
> > --- a/drivers/gpu/drm/bridge/Makefile
> > +++ b/drivers/gpu/drm/bridge/Makefile
> > @@ -5,6 +5,7 @@ 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-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
> >  obj-$(CONFIG_DRM_SII902X) += sii902x.o
> >  obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o
> >  obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/
> > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> > new file mode 100644
> > index 0000000..7d67431
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> > @@ -0,0 +1,1077 @@
> > +/*
> > + * Copyright (c) 2016 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>

Not needed.

> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_gpio.h>

The above 2 aren't needed.

> > +#include <linux/of_graph.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <asm/unaligned.h>
> > +#include <drm/drm_panel.h>
> > +
> > +#include <drmP.h>
> > +#include <drm_atomic_helper.h>
> > +#include <drm_crtc_helper.h>
> > +#include <drm_crtc.h>

Not needed.

> > +#include <drm_edid.h>
> > +#include <drm_mipi_dsi.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
> > +
> > +/* Firmware */
> > +#define PS_FW_NAME             "ps864x_fw.bin"
> > +
>
> About the firmware discussion I think that if you want to maintain the
> upgrade firmware thing you should also include this patch in the
> series.
>
>  https://chromium-review.googlesource.com/#/c/317221/
>
> Otherwise, if this is not really needed I think that remove this from
> the driver is the best. Just an opinion, this is something the
> maintainer should decide.

Was there a conclusion on this? As Daniel Kurtz suggested, can we drop
the update firmware stuff for now and try to get the functional part
for 4.10?

> > +#define FW_CHIP_ID_OFFSET      0
> > +#define FW_VERSION_OFFSET      2
> > +#define EDID_I2C_ADDR          0x50
> > +
> > +#define WRITE_STATUS_REG_CMD   0x01
> > +#define READ_STATUS_REG_CMD    0x05
> > +#define BUSY                   BIT(0)
> > +#define CLEAR_ALL_PROTECT      0x00
> > +#define BLK_PROTECT_BITS       0x0c
> > +#define STATUS_REG_PROTECT     BIT(7)
> > +#define WRITE_ENABLE_CMD       0x06
> > +#define CHIP_ERASE_CMD         0xc7
> > +#define 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 i2c_client *ddc_i2c;
> > +       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;
> > +};
> > +
> > +static const u8 enc_ctrl_code[6] = { 0xaa, 0x55, 0x50, 0x41, 0x52, 0x44 };
> > +static const u8 hw_chip_id[4] = { 0x00, 0x0a, 0x00, 0x30 };
> > +
> > +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;
> > +}
> > +
> > +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));
> > +}
> > +
> > +static void ps8640_get_mcu_fw_version(struct ps8640 *ps_bridge)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[5];
> > +       u8 fw_ver[2];
> > +
> > +       ps8640_read(client, 0x4, fw_ver, 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[3];
> > +       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[3];
> > +       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[2];
> > +       struct i2c_client *page1 = ps_bridge->page[1];

It's a bit hard to follow what page[3] or page[5] means without going to the
bottom and reading the dummy devices comment. It would be nice to have some
macros here.

> > +       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->ddc_i2c->adapter);

See comments related to this in ps8640_probe.

> > +       if (!edid)
> > +               goto out;
> > +
> > +       ps_bridge->edid = edid;
> > +       drm_mode_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 struct drm_encoder *ps8640_best_encoder(struct drm_connector *connector)
> > +{
> > +       struct ps8640 *ps_bridge = connector_to_ps8640(connector);
> > +
> > +       return ps_bridge->bridge.encoder;
> > +}

We can drop the above func.

> > +
> > +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 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,
> > +       .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 *port, *in_ep;
> > +       struct device_node *dsi_node = NULL;
> > +       struct mipi_dsi_host *host = NULL;
> > +       int ret;
> > +
> > +       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_mode_connector_attach_encoder(&ps_bridge->connector,
> > +                                         bridge->encoder);
> > +
> > +       if (ps_bridge->panel)
> > +               drm_panel_attach(ps_bridge->panel, &ps_bridge->connector);
> > +
> > +       /* port@0 is ps8640 dsi input port */
> > +       port = of_graph_get_port_by_id(dev->of_node, 0);
> > +       if (port) {
> > +               in_ep = of_get_child_by_name(port, "endpoint");
> > +               of_node_put(port);

The above 2 funcs can be done by a single func: of_graph_get_endpoint_by_regs().

> > +               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;
> > +               }
> > +       }
> > +

We haven't created a DSI device for this yet. Don't we need to call
mipi_dsi_device_register_full() here?

> > +       ps_bridge->dsi.host = host;

The code above proceeds even if we don't find a dsi host. In that
case, the host would be a NULL pointer. We shouldn't call
mipi_dsi_attach() with a NULL host. We should have returned earlier with
an error.

> > +       ps_bridge->dsi.mode_flags = MIPI_DSI_MODE_VIDEO |
> > +                                    MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
> > +       ps_bridge->dsi.format = MIPI_DSI_FMT_RGB888;
> > +       ps_bridge->dsi.lanes = 4;
> > +       ret = mipi_dsi_attach(&ps_bridge->dsi);
> > +       if (ret)
> > +               goto err;
> > +
> > +       return 0;
> > +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 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, buf[3] = { PAGE2_SWSPI_LEN, cmd_len - 1, TRIGGER_NO_READBACK };
> > +       int ret;
> > +
> > +       ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
> > +       if (ret)
> > +               goto err;
> > +
> > +       /* write command in write port */
> > +       for (i = 0; i < cmd_len; i++) {
> > +               ret = ps8640_write_byte(client, PAGE2_SWSPI_WDATA, cmd[i]);
> > +               if (ret)
> > +                       goto err_irom_disable;
> > +       }
> > +
> > +       ret = ps8640_write_bytes(client, buf, sizeof(buf));
> > +       if (ret)
> > +               goto err_irom_disable;
> > +
> > +       ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +       if (ret)
> > +               goto err;
> > +
> > +       return 0;
> > +err_irom_disable:
> > +       ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +err:
> > +       dev_err(&client->dev, "send command err: %d\n", ret);
> > +       return ret;
> > +}
> > +
> > +static int ps8640_wait_spi_ready(struct ps8640 *ps_bridge)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[2];
> > +       u8 spi_rdy_st;
> > +       ktime_t timeout;
> > +
> > +       timeout = ktime_add_ms(ktime_get(), 200);
> > +       for (;;) {
> > +               ps8640_read(client, PAGE2_SPI_STATUS, &spi_rdy_st, 1);
> > +               if ((spi_rdy_st & SPI_READY) != SPI_READY)
> > +                       break;
> > +
> > +               if (ktime_compare(ktime_get(), timeout) > 0) {
> > +                       dev_err(&client->dev, "wait spi ready timeout\n");
> > +                       return -EBUSY;
> > +               }
> > +
> > +               msleep(20);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int ps8640_wait_spi_nobusy(struct ps8640 *ps_bridge)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[2];
> > +       u8 spi_status, buf[3] = { PAGE2_SWSPI_LEN, 0, TRIGGER_READBACK };
> > +       int ret;
> > +       ktime_t timeout;
> > +
> > +       timeout = ktime_add_ms(ktime_get(), 500);
> > +       for (;;) {
> > +               /* 0x05 RDSR; Read-Status-Register */
> > +               ret = ps8640_write_byte(client, PAGE2_SWSPI_WDATA,
> > +                                       READ_STATUS_REG_CMD);
> > +               if (ret)
> > +                       goto err_send_cmd_exit;
> > +
> > +               ret = ps8640_write_bytes(client, buf, 3);
> > +               if (ret)
> > +                       goto err_send_cmd_exit;
> > +
> > +               /* delay for cmd send */
> > +               usleep_range(300, 500);
> > +               /* wait for SPI ROM until not busy */
> > +               ret = ps8640_read(client, PAGE2_SWSPI_RDATA, &spi_status, 1);
> > +               if (ret)
> > +                       goto err_send_cmd_exit;
> > +
> > +               if (!(spi_status & BUSY))
> > +                       break;
> > +
> > +               if (ktime_compare(ktime_get(), timeout) > 0) {
> > +                       dev_err(&client->dev, "wait spi no busy timeout: %d\n",
> > +                               ret);
> > +                       return -EBUSY;
> > +               }
> > +       }
> > +
> > +       return 0;
> > +
> > +err_send_cmd_exit:
> > +       dev_err(&client->dev, "send command err: %d\n", ret);
> > +       return ret;
> > +}
> > +
> > +static int ps8640_wait_rom_idle(struct ps8640 *ps_bridge)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[0];
> > +       int ret;
> > +
> > +       ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
> > +       if (ret)
> > +               goto exit;
> > +
> > +       ret = ps8640_wait_spi_ready(ps_bridge);
> > +       if (ret)
> > +               goto err_spi;
> > +
> > +       ret = ps8640_wait_spi_nobusy(ps_bridge);
> > +       if (ret)
> > +               goto err_spi;
> > +
> > +       ret = ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +       if (ret)
> > +               goto exit;
> > +
> > +       return 0;
> > +
> > +err_spi:
> > +       ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +exit:
> > +       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 */
> > +       if (ps_bridge->gpio_mode_sel)
> > +               gpiod_set_value(ps_bridge->gpio_mode_sel, 0);
> > +
> > +       /* reset spi interface */
> > +       ret = ps8640_write_byte(client, PAGE2_SW_RESET,
> > +                               SPI_SW_RESET | MPU_SW_RESET);
> > +       if (ret)
> > +               goto exit;
> > +
> > +       ret = ps8640_write_byte(client, PAGE2_SW_RESET, MPU_SW_RESET);
> > +       if (ret)
> > +               goto exit;
> > +
> > +       return 0;
> > +
> > +exit:
> > +       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;
> > +
> > +       cmd[0] = WRITE_ENABLE_CMD;
> > +       ret = ps8640_spi_send_cmd(ps_bridge, cmd, 1);
> > +       if (ret) {
> > +               dev_err(dev, "failed enable-write-status-register: %d\n", ret);
> > +               return ret;
> > +       }
> > +
> > +       cmd[0] = WRITE_STATUS_REG_CMD;
> > +       cmd[1] = CLEAR_ALL_PROTECT;
> > +       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_write_byte(client, PAGE2_IROM_CTRL, IROM_ENABLE);
> > +       for (i = 0; i < ARRAY_SIZE(enc_ctrl_code); i++)
> > +               ps8640_write_byte(client, PAGE2_ENCTLSPI_WR, enc_ctrl_code[i]);
> > +       ps8640_write_byte(client, PAGE2_IROM_CTRL, IROM_DISABLE);
> > +
> > +       /* Enable-Write-Status-Register */
> > +       cmd[0] = WRITE_ENABLE_CMD;
> > +       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] = CHIP_ERASE_CMD;
> > +       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_check_chip_id(struct ps8640 *ps_bridge)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[4];
> > +       u8 buf[4];
> > +
> > +       ps8640_read(client, PAGE4_REV_L, buf, 4);
> > +       return memcmp(buf, hw_chip_id, sizeof(buf));
> > +}
> > +
> > +static int ps8640_validate_firmware(struct ps8640 *ps_bridge,
> > +                                   const struct firmware *fw)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[0];
> > +       u16 fw_chip_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 && ps8640_check_chip_id(ps_bridge) == 0) {
> > +               dev_err(&client->dev,
> > +                       "chip id mismatch: fw 0x%x vs. chip 0x8640\n",
> > +                       fw_chip_id);
> > +               return -EINVAL;
> > +       }
> > +
> > +       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];
> > +       size_t pos, cpy_len;
> > +       u8 buf[257];
> > +       int ret;
> > +
> > +       ps8640_write_byte(client2, PAGE2_SPI_CFG3, I2C_TO_SPI_RESET);
> > +       msleep(100);
> > +       ps8640_write_byte(client2, PAGE2_SPI_CFG3, 0x00);
> > +
> > +       for (pos = 0; pos < fw->size; pos += cpy_len) {
> > +               buf[0] = PAGE2_ROMADD_BYTE1;
> > +               buf[1] = pos >> 8;
> > +               buf[2] = pos >> 16;
> > +               ret = ps8640_write_bytes(client2, buf, 3);
> > +               if (ret)
> > +                       goto error;
> > +               cpy_len = fw->size >= 256 + pos ? 256 : fw->size - pos;
> > +               buf[0] = 0;
> > +               memcpy(buf + 1, fw->data + pos, cpy_len);
> > +               ret = ps8640_write_bytes(client7, buf, cpy_len + 1);
> > +               if (ret)
> > +                       goto error;
> > +
> > +               dev_dbg(dev, "fw update completed %zu / %zu bytes\n", pos,
> > +                       fw->size);
> > +       }
> > +       return 0;
> > +
> > +error:
> > +       dev_err(dev, "failed write external 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] = WRITE_ENABLE_CMD;
> > +       ps8640_spi_send_cmd(ps_bridge, cmd, 1);
> > +
> > +       /* protect BPL/BP0/BP1 */
> > +       cmd[0] = WRITE_STATUS_REG_CMD;
> > +       cmd[1] = BLK_PROTECT_BITS | STATUS_REG_PROTECT;
> > +       ps8640_spi_send_cmd(ps_bridge, cmd, 2);
> > +
> > +       /* wait for SPI rom ready */
> > +       ps8640_wait_rom_idle(ps_bridge);
> > +
> > +       /* disable PS8640 mapping function */
> > +       ps8640_write_byte(client, PAGE2_ENCTLSPI_WR, 0x00);
> > +
> > +       if (ps_bridge->gpio_mode_sel)
> > +               gpiod_set_value(ps_bridge->gpio_mode_sel, 1);
> > +       return 0;
> > +}
> > +
> > +static int ps8640_enter_bl(struct ps8640 *ps_bridge)
> > +{
> > +       ps_bridge->in_fw_update = true;
> > +       return ps8640_spi_dl_mode(ps_bridge);
> > +}
> > +
> > +static void ps8640_exit_bl(struct ps8640 *ps_bridge, const struct firmware *fw)
> > +{
> > +       ps8640_spi_normal_mode(ps_bridge);
> > +       ps_bridge->in_fw_update = false;
> > +}
> > +
> > +static int ps8640_load_fw(struct ps8640 *ps_bridge, const struct firmware *fw)
> > +{
> > +       struct i2c_client *client = ps_bridge->page[0];
> > +       struct device *dev = &client->dev;
> > +       int ret;
> > +       bool ps8640_status_backup = ps_bridge->enabled;
> > +
> > +       ret = ps8640_validate_firmware(ps_bridge, fw);
> > +       if (ret)
> > +               return ret;
> > +
> > +       mutex_lock(&ps_bridge->fw_mutex);
> > +       if (!ps_bridge->in_fw_update) {
> > +               if (!ps8640_status_backup)
> > +                       ps8640_pre_enable(&ps_bridge->bridge);
> > +
> > +               ret = ps8640_enter_bl(ps_bridge);
> > +               if (ret)
> > +                       goto exit;
> > +       }
> > +
> > +       ret = ps8640_rom_prepare(ps_bridge);
> > +       if (ret)
> > +               goto exit;
> > +
> > +       ret = ps8640_write_rom(ps_bridge, fw);
> > +
> > +exit:
> > +       if (ret)
> > +               dev_err(dev, "Failed to load firmware, %d\n", ret);
> > +
> > +       ps8640_exit_bl(ps_bridge, fw);
> > +       if (!ps8640_status_backup)
> > +               ps8640_post_disable(&ps_bridge->bridge);
> > +       mutex_unlock(&ps_bridge->fw_mutex);
> > +       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_FW_NAME, dev);
> > +       if (error) {
> > +               dev_err(dev, "Unable to open firmware %s: %d\n",
> > +                       PS_FW_NAME, error);
> > +               return error;
> > +       }
> > +
> > +       error = ps8640_load_fw(ps_bridge, fw);
> > +       if (error)
> > +               dev_err(dev, "The firmware update failed(%d)\n", error);
> > +       else
> > +               dev_info(dev, "The firmware update succeeded\n");
> > +
> > +       release_firmware(fw);
> > +       return error ? error : count;
> > +}
> > +
> > +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_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);
> > +}
> > +
> > +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 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 (!ps_bridge->panel)
> > +                       return -EPROBE_DEFER;
> > +       }
> > +
> > +       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);
> > +               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);
> > +               return ret;
> > +       }
> > +
> > +       ps_bridge->gpio_power_down = devm_gpiod_get(&client->dev, "sleep",
> > +                                              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
> > +        */
> > +       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;
> > +       ps_bridge->ddc_i2c = i2c_new_dummy(client->adapter, EDID_I2C_ADDR);

I don't see why we need to create this dummy client. The drm edid helper
drm_get_edid() just needs the i2c adapter to which the client is connected.
It will internally initiate a read form the address EDID_I2C_ADDR.

I guess "drm_get_edid(connector, ps_bridge->page[0]->adapter)" should work.

> > +       if (!ps_bridge->ddc_i2c) {
> > +               dev_err(dev, "failed ddc_i2c dummy device, address%02x\n",
> > +                       EDID_I2C_ADDR);
> > +               return -EBUSY;
> > +       }
> > +       /*
> > +        * 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

Does this chip support 2 DSI inputs, and we're just exposing one for now?
If so, we should probably revisit the DT bindings, so that port@2 doesn't
need to represent the 2nd DSI link.

Thanks,
Archit

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