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SubjectRe: [PATCH v21 2/2] drm/bridge: Add I2C based driver for ps8640 bridge
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On Mon, 2019-12-16 at 14:58 +0100, Enric Balletbo i Serra wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
>
> This patch adds drm_bridge driver for parade DSI to eDP bridge chip.
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> [uli: followed API changes, removed FW update feature]
> Signed-off-by: Ulrich Hecht <uli@fpond.eu>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> ---
>
> 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>

Commented stuff should gone.

> +#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>

Ditto.

> +#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

Unused macro.

> +#define PAGE1_VDO_BDG 1
> +#define PAGE2_TOP_CNTL 2
> +#define PAGE3_DSI_CNTL1 3
> +#define PAGE4_MIPI_PHY 4

Ditto... maybe others as well?

> +#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;
> +};
> +
> +static const u8 enc_ctrl_code[6] = { 0xaa, 0x55, 0x50, 0x41, 0x52, 0x44 };
> +static const u8 hw_chip_id[4] = { 0x00, 0x0a, 0x00, 0x30 };
> +

More unused stuff. Left-overs?

> +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 };
> +

I was gonna say you should avoid transmitting data
in the stack, but then I noticed the I2C core doesn't
complaint about it (doesn't use object_is_on_stack).

Wolfram, does the I2C accept stacked (possibly non-DMA-able) objects?

> + 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[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]);

Hm, isn't this too verbose?

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

I believe it's cleaner to use this idiom:

unsigned long timeout = jiffies + msecs_to_jiffies(YOUR_DRIVER_TIMEOUT);

while (time_is_after_jiffies(timeout)) {
....
}

> +
> + msleep(50);
> +
> + ps8640_read(page1, PAGE1_VSTART, &vstart, 1);
> + DRM_INFO("PS8640 PAGE1.0x6B = 0x%x\n", vstart);
> +

Ditto, isn't this too verbose?

I stopped reviewing at this point. It sounds like this driver
could use some love. (Not sure how this driver stood twenty reviews :-))

Thanks,
Ezequiel

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