Re: [PATCH v22 2/2] drm/bridge: Add I2C based driver for ps8640 bridge

[Ezequiel Garcia]

Hi Enric,

Note that this series is marked as v22, but it's really the 23th.
Some minor comments below, it's looking really now.

Reviewed-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>

On Mon, 2019-12-23 at 15:35 +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>
> [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>
> Tested-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> ---
> One of the reviews from Laurent was to use 'i2c_new_ancillary_device'. I
> didn't change this for two reasons.
> 1) It doesn't have a devm version, so the remove path is more simple
> using the devm_i2c_new_dummy_device family.
> 2) IIUC the ancillary function is useful when you want to retrieve the
> address from the firmware or DT, that's not really the case here, as we
> have a base address and fixed offset to the base address which I think
> is not configurable.
> 
> Let me know if you still think that I should use the ancillary call.
> 
> Changes in v23:
> - Merge mute/unmute functions into one (Nicolas Boichat)
> - Use enum for ENABLE/DISABLE instead of bool (Ezequiel Garcia)
> - Rename mute/unmute to vdo_control and fix error messages (Nicolas Boichat and Enric)
> - Add space between address and address parameter 'address%02x' (Nicolas Boichat)
> - Add Tested-by Hsin-Yi
> - Added me as author after the refactor
> 
> Changes in v22:
> - Remove sysfs attributes because are not really used (Enric Balletbo)
> - Use enum for address page offsets (Ezequiel Garcia)
> - Remove enable tracking (Enric Balletbo)
> - Use panel_bridge API (Laurent Pinchart)
> - Do not use kernel-doc format for non kernel-doc formatted commands (Enric Balletbo)
> - Remove verbose message for PAGE1_VSTART command (Ezequiel Garcia)
> - Use time_is_after_jiffies idiom (Ezequiel Garcia)
> - Remove unused macros (Ezequiel Garcia)
> - Fix weird alignment in dsi->mode_flags (Laurent Pinchart)
> - Use drm_of_find_panel_or_bridge helper (Laurent Pinchart)
> - Remove mode-sel-gpios as is not used (Laurent Pinchart)
> - Remove error messages to get gpios as the core will already report it (Enric Balletbo)
> - Remove redundant message getting the regulators (Laurent Pinchart)
> - Rename sleep-gpios to powerdown-gpios (Laurent Pinchart)
> - Use ARRAY_SIZE(ps_bridge->page) instead of MAX_DEV when possible (Laurent Pinchart)
> - Fix race with userspace accessing the sysfs attributes (Laurent Pinchart)
> - Remove id_table as is only used on DR platforms (Laurent Pinchart)
> - Convert to new i2c device probe() (Laurent Pinchart)
> - Use i2c_smbus_read/write helpers instead of open coding it (Laurent Pinchart)
> - Remove unnused global variables (Laurent Pinchart)
> - Remove unnused fields in ps8640 struct (Laurent Pinchart)
> - Remove commented-out headers (Laurent Pinchart)
> 
> 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 | 348 +++++++++++++++++++++++++
>  3 files changed, 360 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"

Not a showstopper, but perhaps later you can amend the other
Parade bridge menuconfig entry. Right now it's
"Parade eDP/LVDS bridge". It would be nice to have
consistency between Parade bridges.

> +	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..646ac649d175
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -0,0 +1,348 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2016 MediaTek Inc.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.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 <drm/drm_bridge.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +#define PAGE2_GPIO_H		0xa7
> +#define PS_GPIO9		BIT(1)
> +#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 VDO_CTL_ADD		0x13
> +#define VDO_DIS			0x18
> +#define VDO_EN			0x1c
> +
> +/*
> + * PS8640 uses multiple addresses:
> + * 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
> + */
> +enum page_addr_offset {
> +	PAGE0_DP_CNTL = 0,
> +	PAGE1_VDO_BDG,
> +	PAGE2_TOP_CNTL,
> +	PAGE3_DSI_CNTL1,
> +	PAGE4_MIPI_PHY,
> +	PAGE5_VPLL,
> +	PAGE6_DSI_CNTL2,
> +	PAGE7_SPI_CNTL,
> +	MAX_DEVS
> +};
> +
> +enum ps8640_vdo_control {
> +	DISABLE = VDO_DIS,
> +	ENABLE = VDO_EN,
> +};
> +
> +struct ps8640 {
> +	struct drm_bridge bridge;
> +	struct drm_bridge *panel_bridge;
> +	struct mipi_dsi_device *dsi;
> +	struct i2c_client *page[MAX_DEVS];
> +	struct regulator_bulk_data supplies[2];
> +	struct gpio_desc *gpio_reset;
> +	struct gpio_desc *gpio_powerdown;
> +};
> +
> +static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e)
> +{
> +	return container_of(e, struct ps8640, bridge);
> +}
> +
> +static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge,
> +				     const enum ps8640_vdo_control ctrl)
> +{
> +	struct i2c_client *client = ps_bridge->page[PAGE3_DSI_CNTL1];
> +	u8 vdo_ctrl_buf[] = { VDO_CTL_ADD, ctrl };
> +	int ret;
> +
> +	ret = i2c_smbus_write_i2c_block_data(client, PAGE3_SET_ADD,
> +					     sizeof(vdo_ctrl_buf),
> +					     vdo_ctrl_buf);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +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];
> +	unsigned long timeout;
> +	int ret, status;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies),
> +				    ps_bridge->supplies);
> +	if (ret < 0) {
> +		DRM_ERROR("cannot enable regulators %d\n", ret);
> +		return;
> +	}
> +
> +	gpiod_set_value(ps_bridge->gpio_powerdown, 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 embedded MCU to be ready
> +	 * First wait 200ms and then check the MCU ready flag every 20ms
> +	 */
> +	msleep(200);
> +
> +	timeout = jiffies + msecs_to_jiffies(200) + 1;
> +
> +	while (time_is_after_jiffies(timeout)) {
> +		status = i2c_smbus_read_byte_data(client, PAGE2_GPIO_H);
> +		if (status < 0) {
> +			DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", status);
> +			goto err_regulators_disable;
> +		}
> +		if ((status & PS_GPIO9) == PS_GPIO9)
> +			break;
> +
> +		msleep(20);
> +	}
> +
> +	msleep(50);
> +
> +	/*
> +	 * 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.
> +	 */
> +	status = i2c_smbus_read_byte_data(client, PAGE2_MCS_EN);
> +	if (status < 0) {
> +		DRM_ERROR("failed read PAGE2_MCS_EN: %d\n", status);
> +		goto err_regulators_disable;
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(client, PAGE2_MCS_EN,
> +					status & ~MCS_EN);
> +	if (ret < 0) {
> +		DRM_ERROR("failed write PAGE2_MCS_EN: %d\n", ret);
> +		goto err_regulators_disable;
> +	}
> +
> +	ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE);

That's much better than mute/unmute!

> +	if (ret) {
> +		DRM_ERROR("failed to enable VDO: %d\n", ret);
> +		goto err_regulators_disable;
> +	}
> +
> +	/* Switch access edp panel's edid through i2c */
> +	ret = i2c_smbus_write_byte_data(client, PAGE2_I2C_BYPASS,
> +					I2C_BYPASS_EN);
> +	if (ret < 0) {
> +		DRM_ERROR("failed write PAGE2_I2C_BYPASS: %d\n", ret);
> +		goto err_regulators_disable;
> +	}
> +
> +	return;
> +
> +err_regulators_disable:
> +	regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
> +			       ps_bridge->supplies);
> +}
> +
> +static void ps8640_post_disable(struct drm_bridge *bridge)
> +{
> +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> +	int ret;
> +
> +	ret = ps8640_bridge_vdo_control(ps_bridge, DISABLE);
> +	if (ret < 0)
> +		DRM_ERROR("failed to disable VDO: %d\n", ret);
> +
> +	gpiod_set_value(ps_bridge->gpio_reset, 0);
> +	gpiod_set_value(ps_bridge->gpio_powerdown, 0);
> +	ret = regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
> +				     ps_bridge->supplies);
> +	if (ret < 0)
> +		DRM_ERROR("cannot disable regulators %d\n", ret);
> +}
> +
> +int ps8640_bridge_attach(struct drm_bridge *bridge)

Compiling this with static analyzers says this should be 'static'.

> +{
> +	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
> +	struct device *dev = &ps_bridge->page[0]->dev;
> +	struct device_node *in_ep, *dsi_node;
> +	struct mipi_dsi_device *dsi;
> +	struct mipi_dsi_host *host;
> +	int ret;
> +	const struct mipi_dsi_device_info info = { .type = "ps8640",
> +						   .channel = 0,
> +						   .node = NULL,
> +						 };
> +	/* port@0 is ps8640 dsi input port */
> +	in_ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
> +	if (!in_ep)
> +		return -ENODEV;
> +
> +	dsi_node = of_graph_get_remote_port_parent(in_ep);
> +	of_node_put(in_ep);
> +	if (!dsi_node)
> +		return -ENODEV;
> +
> +	host = of_find_mipi_dsi_host_by_node(dsi_node);
> +	of_node_put(dsi_node);
> +	if (!host)
> +		return -ENODEV;
> +
> +	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);
> +		return ret;
> +	}
> +
> +	ps_bridge->dsi = dsi;
> +
> +	dsi->host = host;
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
> +			  MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->lanes = 4;

I'm not an expert here, so maybe this makes no sense:
are you sure you don't need to take the number of lanes from the
device-tree?

>From the yaml spec:

"""
The device accepts a single channel of
MIPI DSI v1.1, with up to four lanes [..]
"""

If it's OK to hardcode to 4, maybe use a macro for clarity?

> +	ret = mipi_dsi_attach(dsi);
> +	if (ret)
> +		goto err_dsi_attach;
> +
> +	/* Attach the panel-bridge to the dsi bridge */
> +	return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge,
> +				 &ps_bridge->bridge);
> +
> +err_dsi_attach:
> +	mipi_dsi_device_unregister(dsi);
> +	return ret;
> +}
> +
> +static const struct drm_bridge_funcs ps8640_bridge_funcs = {
> +	.attach = ps8640_bridge_attach,
> +	.post_disable = ps8640_post_disable,
> +	.pre_enable = ps8640_pre_enable,
> +};
> +
> +static int ps8640_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct device_node *np = dev->of_node;
> +	struct ps8640 *ps_bridge;
> +	struct drm_panel *panel;
> +	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 */

Hm, regarding my comment on patch 1/2 about required port@0,
perhaps this really requires both port@0 and port@1.

> +	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
> +	if (ret < 0)
> +		return ret;
> +	if (!panel)
> +		return -ENODEV;
> +
> +	panel->connector_type = DRM_MODE_CONNECTOR_eDP;
> +
> +	ps_bridge->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> +	if (IS_ERR(ps_bridge->panel_bridge))
> +		return PTR_ERR(ps_bridge->panel_bridge);
> +
> +	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)
> +		return ret;
> +
> +	ps_bridge->gpio_powerdown = devm_gpiod_get(&client->dev, "powerdown",
> +						   GPIOD_OUT_LOW);
> +	if (IS_ERR(ps_bridge->gpio_powerdown))
> +		return PTR_ERR(ps_bridge->gpio_powerdown);
> +
> +	/*
> +	 * 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))
> +		return PTR_ERR(ps_bridge->gpio_reset);
> +
> +	ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
> +	ps_bridge->bridge.of_node = dev->of_node;
> +
> +	ps_bridge->page[PAGE0_DP_CNTL] = client;
> +
> +	for (i = 1; i < ARRAY_SIZE(ps_bridge->page); i++) {
> +		ps_bridge->page[i] = devm_i2c_new_dummy_device(&client->dev,
> +							     client->adapter,
> +							     client->addr + i);
> +		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);
> +
> +	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 of_device_id ps8640_match[] = {
> +	{ .compatible = "parade,ps8640" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, ps8640_match);
> +
> +static struct i2c_driver ps8640_driver = {
> +	.probe_new = ps8640_probe,
> +	.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_AUTHOR("Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("PARADE ps8640 DSI-eDP converter driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.20.1
> 
>