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

From: Jitao Shi
Date: Mon Nov 14 2016 - 08:50:42 EST

Dear Archit,

Thanks a lot for your reviewing.
I have sent a new patchset for those review items.

On Fri, 2016-11-11 at 11:32 +0530, Archit Taneja wrote:
> 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.
>

PS8640 has only one dsi input.
DSI Link Control1 and DSI Link Control2 just two parts of the DSI
controller.


> Thanks,
> Archit
>