diff mbox

[V4,04/10] drm/panel: Add driver for lvds/edp based panels

Message ID 1402511228-18945-5-git-send-email-ajaykumar.rs@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ajay Kumar June 11, 2014, 6:27 p.m. UTC
This patch adds a simple driver to handle all the LCD and LED
powerup/down routines needed to support eDP/LVDS panels.

The LCD and LED units are usually powered up via regulators,
and almost on all boards, we will have a BACKLIGHT_EN pin to
enable/ disable the backlight.
Sometimes, we can have LCD_EN switches as well.

The routines in this driver can be used to control
panel power sequence on such boards.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
---
 .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
 drivers/gpu/drm/panel/Kconfig                      |   10 +
 drivers/gpu/drm/panel/Makefile                     |    1 +
 drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
 4 files changed, 323 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
 create mode 100644 drivers/gpu/drm/panel/panel-lvds.c

Comments

Ajay kumar June 20, 2014, 8:07 a.m. UTC | #1
ping.

On Wed, Jun 11, 2014 at 11:57 PM, Ajay Kumar <ajaykumar.rs@samsung.com> wrote:
> This patch adds a simple driver to handle all the LCD and LED
> powerup/down routines needed to support eDP/LVDS panels.
>
> The LCD and LED units are usually powered up via regulators,
> and almost on all boards, we will have a BACKLIGHT_EN pin to
> enable/ disable the backlight.
> Sometimes, we can have LCD_EN switches as well.
>
> The routines in this driver can be used to control
> panel power sequence on such boards.
>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
> ---
>  .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
>  drivers/gpu/drm/panel/Kconfig                      |   10 +
>  drivers/gpu/drm/panel/Makefile                     |    1 +
>  drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
>  4 files changed, 323 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
>  create mode 100644 drivers/gpu/drm/panel/panel-lvds.c
>
> diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> new file mode 100644
> index 0000000..7cb6084
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> @@ -0,0 +1,50 @@
> +panel interface for eDP/lvds panels
> +
> +Required properties:
> +  - compatible: "panel-lvds"
> +
> +Optional properties:
> +       -lcd-en-gpio:
> +               panel LCD poweron GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to powerup/enable the switch to the LCD panel.
> +       -led-en-gpio:
> +               panel LED enable GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to enable the backlight.
> +       -panel-prepare-delay:
> +               delay value in ms required for panel_prepare process
> +                       Delay in ms needed for the panel LCD unit to
> +                       powerup completely.
> +                       ex: delay needed till eDP panel throws HPD.
> +                           delay needed so that we cans tart reading edid.
> +       -panel-enable-delay:
> +               delay value in ms required for panel_enable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       to powerup, and delay needed between video_enable and
> +                       backlight_enable.
> +       -panel-disable-delay:
> +               delay value in ms required for panel_disable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       powerdown, and delay needed between backlight_disable
> +                       and video_disable.
> +       -panel-unprepare-delay:
> +               delay value in ms required for panel_post_disable process
> +                       Delay in ms needed for the panel LCD unit to
> +                       to powerdown completely, and the minimum delay needed
> +                       before powering it on again.
> +       -panel-width-mm: physical panel width [mm]
> +       -panel-height-mm: physical panel height [mm]
> +
> +Example:
> +
> +       panel-lvds {
> +               compatible = "panel-lvds";
> +               led-en-gpio = <&gpx3 0 1>;
> +               panel-prepare-delay = <40>;
> +               panel-enable-delay = <20>;
> +               panel-disable-delay = <20>;
> +               panel-unprepare-delay = <30>;
> +               panel-width-mm = <256>;
> +               panel-height-mm = <144>;
> +       };
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 4ec874d..8fe7ee5 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -30,4 +30,14 @@ config DRM_PANEL_S6E8AA0
>         select DRM_MIPI_DSI
>         select VIDEOMODE_HELPERS
>
> +config DRM_PANEL_EDP_LVDS
> +       tristate "support for eDP/LVDS panels"
> +       depends on OF && DRM_PANEL
> +       select VIDEOMODE_HELPERS
> +       help
> +         DRM panel driver for direct eDP panels or LVDS connected
> +         via DP bridges, that need at most a regulator for LCD unit,
> +         a regulator for LED unit and/or enable GPIOs for LCD or LED units.
> +         Delay values can also be specified to support powerup and
> +         powerdown process.
>  endmenu
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 8b92921..eaafa01 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -1,3 +1,4 @@
>  obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
>  obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
>  obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
> +obj-$(CONFIG_DRM_PANEL_EDP_LVDS) += panel-lvds.o
> diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
> new file mode 100644
> index 0000000..2124fcb
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-lvds.c
> @@ -0,0 +1,262 @@
> +/*
> + * panel driver for lvds and eDP panels
> + *
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd
> + *
> + * Ajay Kumar <ajaykumar.rs@samsung.com>
> + *
> + * 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.
> + */
> +
> +#include <linux/gpio.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/of_videomode.h>
> +#include <video/videomode.h>
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_panel.h>
> +
> +struct panel_lvds {
> +       struct drm_panel        base;
> +       struct regulator        *backlight_fet;
> +       struct regulator        *lcd_fet;
> +       struct videomode        vm;
> +       int                     width_mm;
> +       int                     height_mm;
> +       bool                    backlight_fet_enabled;
> +       bool                    lcd_fet_enabled;
> +       int                     led_en_gpio;
> +       int                     lcd_en_gpio;
> +       int                     panel_prepare_delay;
> +       int                     panel_enable_delay;
> +       int                     panel_disable_delay;
> +       int                     panel_unprepare_delay;
> +};
> +
> +static inline struct panel_lvds *to_panel(struct drm_panel *panel)
> +{
> +       return container_of(panel, struct panel_lvds, base);
> +}
> +
> +static int panel_lvds_prepare(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
> +               if (!lvds_panel->lcd_fet_enabled) {
> +                       if (regulator_enable(lvds_panel->lcd_fet))
> +                               DRM_ERROR("failed to enable LCD fet\n");
> +                       lvds_panel->lcd_fet_enabled = true;
> +               }
> +
> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
> +               gpio_set_value(lvds_panel->lcd_en_gpio, 1);
> +
> +       msleep(lvds_panel->panel_prepare_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_enable(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
> +               if (!lvds_panel->backlight_fet_enabled) {
> +                       if (regulator_enable(lvds_panel->backlight_fet))
> +                               DRM_ERROR("failed to enable LED fet\n");
> +                       lvds_panel->backlight_fet_enabled = true;
> +               }
> +
> +       msleep(lvds_panel->panel_enable_delay);
> +
> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
> +               gpio_set_value(lvds_panel->led_en_gpio, 1);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_disable(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
> +               gpio_set_value(lvds_panel->led_en_gpio, 0);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
> +               if (lvds_panel->backlight_fet_enabled) {
> +                       regulator_disable(lvds_panel->backlight_fet);
> +                       lvds_panel->backlight_fet_enabled = false;
> +               }
> +
> +       msleep(lvds_panel->panel_disable_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_unprepare(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
> +               gpio_set_value(lvds_panel->lcd_en_gpio, 0);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
> +               if (lvds_panel->lcd_fet_enabled) {
> +                       regulator_disable(lvds_panel->lcd_fet);
> +                       lvds_panel->lcd_fet_enabled = false;
> +               }
> +
> +       msleep(lvds_panel->panel_unprepare_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_get_modes(struct drm_panel *panel)
> +{
> +       struct drm_connector *connector = panel->connector;
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +       struct drm_display_mode *mode;
> +
> +       mode = drm_mode_create(connector->dev);
> +       if (!mode) {
> +               DRM_ERROR("failed to create a new display mode.\n");
> +               return 0;
> +       }
> +
> +       drm_display_mode_from_videomode(&lvds_panel->vm, mode);
> +       mode->width_mm = lvds_panel->width_mm;
> +       mode->height_mm = lvds_panel->height_mm;
> +       connector->display_info.width_mm = mode->width_mm;
> +       connector->display_info.height_mm = mode->height_mm;
> +
> +       mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +       drm_mode_set_name(mode);
> +       drm_mode_probed_add(connector, mode);
> +
> +       return 1;
> +}
> +
> +static const struct drm_panel_funcs panel_lvds_funcs = {
> +       .unprepare = panel_lvds_unprepare,
> +       .disable = panel_lvds_disable,
> +       .prepare = panel_lvds_prepare,
> +       .enable = panel_lvds_enable,
> +       .get_modes = panel_lvds_get_modes,
> +};
> +
> +static int panel_lvds_probe(struct platform_device *pdev)
> +{
> +       struct panel_lvds *panel;
> +       struct device *dev = &pdev->dev;
> +       struct device_node *node = dev->of_node;
> +       int ret;
> +
> +       panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
> +       if (!panel)
> +               return -ENOMEM;
> +
> +       ret = of_get_videomode(node, &panel->vm, 0);
> +       if (ret) {
> +               DRM_ERROR("failed: of_get_videomode() : %d\n", ret);
> +               return ret;
> +       }
> +
> +       panel->lcd_fet = devm_regulator_get_optional(dev, "lcd_vdd");
> +       if (IS_ERR(panel->lcd_fet))
> +               return -EPROBE_DEFER;
> +
> +       panel->backlight_fet = devm_regulator_get_optional(dev, "vcd_led");
> +       if (IS_ERR(panel->backlight_fet))
> +               return -EPROBE_DEFER;
> +
> +       panel->lcd_en_gpio = of_get_named_gpio(node, "lcd-en-gpio", 0);
> +       panel->led_en_gpio = of_get_named_gpio(node, "led-en-gpio", 0);
> +
> +       of_property_read_u32(node, "panel-width-mm", &panel->width_mm);
> +       of_property_read_u32(node, "panel-height-mm", &panel->height_mm);
> +
> +       of_property_read_u32(node, "panel-prepare-delay",
> +                                       &panel->panel_prepare_delay);
> +       of_property_read_u32(node, "panel-enable-delay",
> +                                       &panel->panel_enable_delay);
> +       of_property_read_u32(node, "panel-disable-delay",
> +                                       &panel->panel_disable_delay);
> +       of_property_read_u32(node, "panel-unprepare-delay",
> +                                       &panel->panel_unprepare_delay);
> +
> +       if (gpio_is_valid(panel->lcd_en_gpio)) {
> +               ret = devm_gpio_request_one(dev, panel->lcd_en_gpio,
> +                                       GPIOF_OUT_INIT_LOW, "lcd_en_gpio");
> +               if (ret) {
> +                       DRM_ERROR("failed to get lcd-en gpio [%d]\n", ret);
> +                       return 0;
> +               }
> +       } else {
> +               panel->lcd_en_gpio = -ENODEV;
> +       }
> +
> +       if (gpio_is_valid(panel->led_en_gpio)) {
> +               ret = devm_gpio_request_one(dev, panel->led_en_gpio,
> +                                       GPIOF_OUT_INIT_LOW, "led_en_gpio");
> +               if (ret) {
> +                       DRM_ERROR("failed to get led-en gpio [%d]\n", ret);
> +                       return 0;
> +               }
> +       } else {
> +               panel->led_en_gpio = -ENODEV;
> +       }
> +
> +       drm_panel_init(&panel->base);
> +       panel->base.dev = dev;
> +       panel->base.funcs = &panel_lvds_funcs;
> +
> +       ret = drm_panel_add(&panel->base);
> +       if (ret < 0)
> +               return ret;
> +
> +       dev_set_drvdata(dev, panel);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_remove(struct platform_device *pdev)
> +{
> +       struct panel_lvds *panel = dev_get_drvdata(&pdev->dev);
> +
> +       panel_lvds_disable(&panel->base);
> +       panel_lvds_unprepare(&panel->base);
> +
> +       drm_panel_remove(&panel->base);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id lvds_panel_dt_match[] = {
> +       { .compatible = "panel-lvds" },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, lvds_panel_dt_match);
> +
> +struct platform_driver lvds_panel_driver = {
> +       .driver = {
> +               .name = "panel_lvds",
> +               .owner = THIS_MODULE,
> +               .of_match_table = lvds_panel_dt_match,
> +       },
> +       .probe = panel_lvds_probe,
> +       .remove = panel_lvds_remove,
> +};
> +module_platform_driver(lvds_panel_driver);
> +
> +MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
> +MODULE_DESCRIPTION("lvds/eDP panel driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>
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Javier Martinez Canillas June 23, 2014, 3:30 p.m. UTC | #2
Hello Ajay,

Not an extensive review since I'm not familiar with the graphics stack
but a few things I noticed are commented below.

On Wed, Jun 11, 2014 at 8:27 PM, Ajay Kumar <ajaykumar.rs@samsung.com> wrote:
> This patch adds a simple driver to handle all the LCD and LED
> powerup/down routines needed to support eDP/LVDS panels.
>
> The LCD and LED units are usually powered up via regulators,
> and almost on all boards, we will have a BACKLIGHT_EN pin to
> enable/ disable the backlight.
> Sometimes, we can have LCD_EN switches as well.
>
> The routines in this driver can be used to control
> panel power sequence on such boards.
>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
> ---
>  .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
>  drivers/gpu/drm/panel/Kconfig                      |   10 +
>  drivers/gpu/drm/panel/Makefile                     |    1 +
>  drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
>  4 files changed, 323 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
>  create mode 100644 drivers/gpu/drm/panel/panel-lvds.c
>
> diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> new file mode 100644
> index 0000000..7cb6084
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> @@ -0,0 +1,50 @@
> +panel interface for eDP/lvds panels
> +
> +Required properties:
> +  - compatible: "panel-lvds"
> +
> +Optional properties:
> +       -lcd-en-gpio:
> +               panel LCD poweron GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to powerup/enable the switch to the LCD panel.
> +       -led-en-gpio:
> +               panel LED enable GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to enable the backlight.
> +       -panel-prepare-delay:
> +               delay value in ms required for panel_prepare process
> +                       Delay in ms needed for the panel LCD unit to
> +                       powerup completely.
> +                       ex: delay needed till eDP panel throws HPD.
> +                           delay needed so that we cans tart reading edid.
> +       -panel-enable-delay:
> +               delay value in ms required for panel_enable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       to powerup, and delay needed between video_enable and
> +                       backlight_enable.
> +       -panel-disable-delay:
> +               delay value in ms required for panel_disable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       powerdown, and delay needed between backlight_disable
> +                       and video_disable.
> +       -panel-unprepare-delay:
> +               delay value in ms required for panel_post_disable process
> +                       Delay in ms needed for the panel LCD unit to
> +                       to powerdown completely, and the minimum delay needed
> +                       before powering it on again.
> +       -panel-width-mm: physical panel width [mm]
> +       -panel-height-mm: physical panel height [mm]
> +
> +Example:
> +
> +       panel-lvds {
> +               compatible = "panel-lvds";
> +               led-en-gpio = <&gpx3 0 1>;
> +               panel-prepare-delay = <40>;
> +               panel-enable-delay = <20>;
> +               panel-disable-delay = <20>;
> +               panel-unprepare-delay = <30>;
> +               panel-width-mm = <256>;
> +               panel-height-mm = <144>;
> +       };

Recently it's considered a good practice to have the DT binding
documentation in a separate patch.

> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 4ec874d..8fe7ee5 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -30,4 +30,14 @@ config DRM_PANEL_S6E8AA0
>         select DRM_MIPI_DSI
>         select VIDEOMODE_HELPERS
>
> +config DRM_PANEL_EDP_LVDS
> +       tristate "support for eDP/LVDS panels"
> +       depends on OF && DRM_PANEL
> +       select VIDEOMODE_HELPERS
> +       help
> +         DRM panel driver for direct eDP panels or LVDS connected
> +         via DP bridges, that need at most a regulator for LCD unit,
> +         a regulator for LED unit and/or enable GPIOs for LCD or LED units.
> +         Delay values can also be specified to support powerup and
> +         powerdown process.
>  endmenu
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 8b92921..eaafa01 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -1,3 +1,4 @@
>  obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
>  obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
>  obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
> +obj-$(CONFIG_DRM_PANEL_EDP_LVDS) += panel-lvds.o
> diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
> new file mode 100644
> index 0000000..2124fcb
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-lvds.c
> @@ -0,0 +1,262 @@
> +/*
> + * panel driver for lvds and eDP panels
> + *
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd
> + *
> + * Ajay Kumar <ajaykumar.rs@samsung.com>
> + *
> + * 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.
> + */
> +
> +#include <linux/gpio.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/of_videomode.h>
> +#include <video/videomode.h>
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_panel.h>
> +
> +struct panel_lvds {
> +       struct drm_panel        base;
> +       struct regulator        *backlight_fet;
> +       struct regulator        *lcd_fet;
> +       struct videomode        vm;
> +       int                     width_mm;
> +       int                     height_mm;
> +       bool                    backlight_fet_enabled;
> +       bool                    lcd_fet_enabled;
> +       int                     led_en_gpio;
> +       int                     lcd_en_gpio;
> +       int                     panel_prepare_delay;
> +       int                     panel_enable_delay;
> +       int                     panel_disable_delay;
> +       int                     panel_unprepare_delay;
> +};
> +
> +static inline struct panel_lvds *to_panel(struct drm_panel *panel)
> +{
> +       return container_of(panel, struct panel_lvds, base);
> +}
> +
> +static int panel_lvds_prepare(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
> +               if (!lvds_panel->lcd_fet_enabled) {
> +                       if (regulator_enable(lvds_panel->lcd_fet))
> +                               DRM_ERROR("failed to enable LCD fet\n");
> +                       lvds_panel->lcd_fet_enabled = true;

If this is an expected condition then using DRM_INFO() instead? It
looks like an error to me though so maybe should return an error in
this case?

> +               }
> +
> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
> +               gpio_set_value(lvds_panel->lcd_en_gpio, 1);
> +
> +       msleep(lvds_panel->panel_prepare_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_enable(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
> +               if (!lvds_panel->backlight_fet_enabled) {
> +                       if (regulator_enable(lvds_panel->backlight_fet))
> +                               DRM_ERROR("failed to enable LED fet\n");
> +                       lvds_panel->backlight_fet_enabled = true;

Same here.

> +               }
> +
> +       msleep(lvds_panel->panel_enable_delay);
> +
> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
> +               gpio_set_value(lvds_panel->led_en_gpio, 1);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_disable(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
> +               gpio_set_value(lvds_panel->led_en_gpio, 0);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
> +               if (lvds_panel->backlight_fet_enabled) {
> +                       regulator_disable(lvds_panel->backlight_fet);
> +                       lvds_panel->backlight_fet_enabled = false;
> +               }
> +
> +       msleep(lvds_panel->panel_disable_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_unprepare(struct drm_panel *panel)
> +{
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +
> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
> +               gpio_set_value(lvds_panel->lcd_en_gpio, 0);
> +
> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
> +               if (lvds_panel->lcd_fet_enabled) {
> +                       regulator_disable(lvds_panel->lcd_fet);
> +                       lvds_panel->lcd_fet_enabled = false;
> +               }
> +
> +       msleep(lvds_panel->panel_unprepare_delay);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_get_modes(struct drm_panel *panel)
> +{
> +       struct drm_connector *connector = panel->connector;
> +       struct panel_lvds *lvds_panel = to_panel(panel);
> +       struct drm_display_mode *mode;
> +
> +       mode = drm_mode_create(connector->dev);
> +       if (!mode) {
> +               DRM_ERROR("failed to create a new display mode.\n");
> +               return 0;
> +       }
> +
> +       drm_display_mode_from_videomode(&lvds_panel->vm, mode);
> +       mode->width_mm = lvds_panel->width_mm;
> +       mode->height_mm = lvds_panel->height_mm;
> +       connector->display_info.width_mm = mode->width_mm;
> +       connector->display_info.height_mm = mode->height_mm;
> +
> +       mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +       drm_mode_set_name(mode);
> +       drm_mode_probed_add(connector, mode);
> +
> +       return 1;
> +}
> +
> +static const struct drm_panel_funcs panel_lvds_funcs = {
> +       .unprepare = panel_lvds_unprepare,
> +       .disable = panel_lvds_disable,
> +       .prepare = panel_lvds_prepare,
> +       .enable = panel_lvds_enable,
> +       .get_modes = panel_lvds_get_modes,
> +};
> +
> +static int panel_lvds_probe(struct platform_device *pdev)
> +{
> +       struct panel_lvds *panel;
> +       struct device *dev = &pdev->dev;
> +       struct device_node *node = dev->of_node;
> +       int ret;
> +
> +       panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
> +       if (!panel)
> +               return -ENOMEM;
> +
> +       ret = of_get_videomode(node, &panel->vm, 0);
> +       if (ret) {
> +               DRM_ERROR("failed: of_get_videomode() : %d\n", ret);
> +               return ret;
> +       }
> +
> +       panel->lcd_fet = devm_regulator_get_optional(dev, "lcd_vdd");
> +       if (IS_ERR(panel->lcd_fet))
> +               return -EPROBE_DEFER;
> +
> +       panel->backlight_fet = devm_regulator_get_optional(dev, "vcd_led");
> +       if (IS_ERR(panel->backlight_fet))
> +               return -EPROBE_DEFER;
> +
> +       panel->lcd_en_gpio = of_get_named_gpio(node, "lcd-en-gpio", 0);
> +       panel->led_en_gpio = of_get_named_gpio(node, "led-en-gpio", 0);
> +

The old integer-based GPIO API has been deprecated and new drivers
should use the new descriptor-based interface
(Documentation/gpio/consumer.txt) instead if possible.

> +       of_property_read_u32(node, "panel-width-mm", &panel->width_mm);
> +       of_property_read_u32(node, "panel-height-mm", &panel->height_mm);
> +
> +       of_property_read_u32(node, "panel-prepare-delay",
> +                                       &panel->panel_prepare_delay);
> +       of_property_read_u32(node, "panel-enable-delay",
> +                                       &panel->panel_enable_delay);
> +       of_property_read_u32(node, "panel-disable-delay",
> +                                       &panel->panel_disable_delay);
> +       of_property_read_u32(node, "panel-unprepare-delay",
> +                                       &panel->panel_unprepare_delay);
> +
> +       if (gpio_is_valid(panel->lcd_en_gpio)) {
> +               ret = devm_gpio_request_one(dev, panel->lcd_en_gpio,
> +                                       GPIOF_OUT_INIT_LOW, "lcd_en_gpio");
> +               if (ret) {
> +                       DRM_ERROR("failed to get lcd-en gpio [%d]\n", ret);
> +                       return 0;

The probe() function returning 0 means success to the driver core but
here is returning early due an error.

> +               }
> +       } else {
> +               panel->lcd_en_gpio = -ENODEV;
> +       }
> +
> +       if (gpio_is_valid(panel->led_en_gpio)) {
> +               ret = devm_gpio_request_one(dev, panel->led_en_gpio,
> +                                       GPIOF_OUT_INIT_LOW, "led_en_gpio");
> +               if (ret) {
> +                       DRM_ERROR("failed to get led-en gpio [%d]\n", ret);
> +                       return 0;

Same here, it should return an error code instead 0.

> +               }
> +       } else {
> +               panel->led_en_gpio = -ENODEV;
> +       }
> +
> +       drm_panel_init(&panel->base);
> +       panel->base.dev = dev;
> +       panel->base.funcs = &panel_lvds_funcs;
> +
> +       ret = drm_panel_add(&panel->base);
> +       if (ret < 0)
> +               return ret;
> +
> +       dev_set_drvdata(dev, panel);
> +
> +       return 0;
> +}
> +
> +static int panel_lvds_remove(struct platform_device *pdev)
> +{
> +       struct panel_lvds *panel = dev_get_drvdata(&pdev->dev);
> +
> +       panel_lvds_disable(&panel->base);
> +       panel_lvds_unprepare(&panel->base);
> +
> +       drm_panel_remove(&panel->base);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id lvds_panel_dt_match[] = {
> +       { .compatible = "panel-lvds" },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, lvds_panel_dt_match);
> +
> +struct platform_driver lvds_panel_driver = {
> +       .driver = {
> +               .name = "panel_lvds",
> +               .owner = THIS_MODULE,
> +               .of_match_table = lvds_panel_dt_match,
> +       },
> +       .probe = panel_lvds_probe,
> +       .remove = panel_lvds_remove,
> +};
> +module_platform_driver(lvds_panel_driver);
> +
> +MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
> +MODULE_DESCRIPTION("lvds/eDP panel driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.9.5
>

Best regards,
Javier
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Christian Gmeiner June 23, 2014, 4:55 p.m. UTC | #3
Hi


2014-06-11 20:27 GMT+02:00 Ajay Kumar <ajaykumar.rs@samsung.com>:
> This patch adds a simple driver to handle all the LCD and LED
> powerup/down routines needed to support eDP/LVDS panels.
>
> The LCD and LED units are usually powered up via regulators,
> and almost on all boards, we will have a BACKLIGHT_EN pin to
> enable/ disable the backlight.
> Sometimes, we can have LCD_EN switches as well.
>
> The routines in this driver can be used to control
> panel power sequence on such boards.
>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
> ---
>  .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
>  drivers/gpu/drm/panel/Kconfig                      |   10 +
>  drivers/gpu/drm/panel/Makefile                     |    1 +
>  drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
>  4 files changed, 323 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
>  create mode 100644 drivers/gpu/drm/panel/panel-lvds.c
>
> diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> new file mode 100644
> index 0000000..7cb6084
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
> @@ -0,0 +1,50 @@
> +panel interface for eDP/lvds panels
> +
> +Required properties:
> +  - compatible: "panel-lvds"
> +
> +Optional properties:
> +       -lcd-en-gpio:
> +               panel LCD poweron GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to powerup/enable the switch to the LCD panel.
> +       -led-en-gpio:
> +               panel LED enable GPIO.
> +                       Indicates which GPIO needs to be powered up as output
> +                       to enable the backlight.
> +       -panel-prepare-delay:
> +               delay value in ms required for panel_prepare process
> +                       Delay in ms needed for the panel LCD unit to
> +                       powerup completely.
> +                       ex: delay needed till eDP panel throws HPD.
> +                           delay needed so that we cans tart reading edid.
> +       -panel-enable-delay:
> +               delay value in ms required for panel_enable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       to powerup, and delay needed between video_enable and
> +                       backlight_enable.
> +       -panel-disable-delay:
> +               delay value in ms required for panel_disable process
> +                       Delay in ms needed for the panel backlight/LED unit
> +                       powerdown, and delay needed between backlight_disable
> +                       and video_disable.
> +       -panel-unprepare-delay:
> +               delay value in ms required for panel_post_disable process
> +                       Delay in ms needed for the panel LCD unit to
> +                       to powerdown completely, and the minimum delay needed
> +                       before powering it on again.
> +       -panel-width-mm: physical panel width [mm]
> +       -panel-height-mm: physical panel height [mm]
> +

For what are these two properties are needed?

If I find some time I will give this patch a try as I need something
like this for an imx6d based device.

greets
--
Christian Gmeiner, MSc

https://soundcloud.com/christian-gmeiner
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Ajay kumar June 24, 2014, 8:18 a.m. UTC | #4
Hi Javier,

Thanks for the review.

On Mon, Jun 23, 2014 at 11:30 AM, Javier Martinez Canillas
<javier@dowhile0.org> wrote:
> Hello Ajay,
>
> Not an extensive review since I'm not familiar with the graphics stack
> but a few things I noticed are commented below.
>
> On Wed, Jun 11, 2014 at 8:27 PM, Ajay Kumar <ajaykumar.rs@samsung.com> wrote:
>> This patch adds a simple driver to handle all the LCD and LED
>> powerup/down routines needed to support eDP/LVDS panels.
>>
>> The LCD and LED units are usually powered up via regulators,
>> and almost on all boards, we will have a BACKLIGHT_EN pin to
>> enable/ disable the backlight.
>> Sometimes, we can have LCD_EN switches as well.
>>
>> The routines in this driver can be used to control
>> panel power sequence on such boards.
>>
>> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
>> Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
>> ---
>>  .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
>>  drivers/gpu/drm/panel/Kconfig                      |   10 +
>>  drivers/gpu/drm/panel/Makefile                     |    1 +
>>  drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
>>  4 files changed, 323 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
>>  create mode 100644 drivers/gpu/drm/panel/panel-lvds.c
>>
>> diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
>> new file mode 100644
>> index 0000000..7cb6084
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
>> @@ -0,0 +1,50 @@
>> +panel interface for eDP/lvds panels
>> +
>> +Required properties:
>> +  - compatible: "panel-lvds"
>> +
>> +Optional properties:
>> +       -lcd-en-gpio:
>> +               panel LCD poweron GPIO.
>> +                       Indicates which GPIO needs to be powered up as output
>> +                       to powerup/enable the switch to the LCD panel.
>> +       -led-en-gpio:
>> +               panel LED enable GPIO.
>> +                       Indicates which GPIO needs to be powered up as output
>> +                       to enable the backlight.
>> +       -panel-prepare-delay:
>> +               delay value in ms required for panel_prepare process
>> +                       Delay in ms needed for the panel LCD unit to
>> +                       powerup completely.
>> +                       ex: delay needed till eDP panel throws HPD.
>> +                           delay needed so that we cans tart reading edid.
>> +       -panel-enable-delay:
>> +               delay value in ms required for panel_enable process
>> +                       Delay in ms needed for the panel backlight/LED unit
>> +                       to powerup, and delay needed between video_enable and
>> +                       backlight_enable.
>> +       -panel-disable-delay:
>> +               delay value in ms required for panel_disable process
>> +                       Delay in ms needed for the panel backlight/LED unit
>> +                       powerdown, and delay needed between backlight_disable
>> +                       and video_disable.
>> +       -panel-unprepare-delay:
>> +               delay value in ms required for panel_post_disable process
>> +                       Delay in ms needed for the panel LCD unit to
>> +                       to powerdown completely, and the minimum delay needed
>> +                       before powering it on again.
>> +       -panel-width-mm: physical panel width [mm]
>> +       -panel-height-mm: physical panel height [mm]
>> +
>> +Example:
>> +
>> +       panel-lvds {
>> +               compatible = "panel-lvds";
>> +               led-en-gpio = <&gpx3 0 1>;
>> +               panel-prepare-delay = <40>;
>> +               panel-enable-delay = <20>;
>> +               panel-disable-delay = <20>;
>> +               panel-unprepare-delay = <30>;
>> +               panel-width-mm = <256>;
>> +               panel-height-mm = <144>;
>> +       };
>
> Recently it's considered a good practice to have the DT binding
> documentation in a separate patch.
Ok, will remember this.

>> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
>> index 4ec874d..8fe7ee5 100644
>> --- a/drivers/gpu/drm/panel/Kconfig
>> +++ b/drivers/gpu/drm/panel/Kconfig
>> @@ -30,4 +30,14 @@ config DRM_PANEL_S6E8AA0
>>         select DRM_MIPI_DSI
>>         select VIDEOMODE_HELPERS
>>
>> +config DRM_PANEL_EDP_LVDS
>> +       tristate "support for eDP/LVDS panels"
>> +       depends on OF && DRM_PANEL
>> +       select VIDEOMODE_HELPERS
>> +       help
>> +         DRM panel driver for direct eDP panels or LVDS connected
>> +         via DP bridges, that need at most a regulator for LCD unit,
>> +         a regulator for LED unit and/or enable GPIOs for LCD or LED units.
>> +         Delay values can also be specified to support powerup and
>> +         powerdown process.
>>  endmenu
>> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
>> index 8b92921..eaafa01 100644
>> --- a/drivers/gpu/drm/panel/Makefile
>> +++ b/drivers/gpu/drm/panel/Makefile
>> @@ -1,3 +1,4 @@
>>  obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
>>  obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
>>  obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
>> +obj-$(CONFIG_DRM_PANEL_EDP_LVDS) += panel-lvds.o
>> diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
>> new file mode 100644
>> index 0000000..2124fcb
>> --- /dev/null
>> +++ b/drivers/gpu/drm/panel/panel-lvds.c
>> @@ -0,0 +1,262 @@
>> +/*
>> + * panel driver for lvds and eDP panels
>> + *
>> + * Copyright (c) 2014 Samsung Electronics Co., Ltd
>> + *
>> + * Ajay Kumar <ajaykumar.rs@samsung.com>
>> + *
>> + * 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.
>> + */
>> +
>> +#include <linux/gpio.h>
>> +#include <linux/module.h>
>> +#include <linux/of_gpio.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include <video/of_videomode.h>
>> +#include <video/videomode.h>
>> +
>> +#include <drm/drmP.h>
>> +#include <drm/drm_crtc.h>
>> +#include <drm/drm_panel.h>
>> +
>> +struct panel_lvds {
>> +       struct drm_panel        base;
>> +       struct regulator        *backlight_fet;
>> +       struct regulator        *lcd_fet;
>> +       struct videomode        vm;
>> +       int                     width_mm;
>> +       int                     height_mm;
>> +       bool                    backlight_fet_enabled;
>> +       bool                    lcd_fet_enabled;
>> +       int                     led_en_gpio;
>> +       int                     lcd_en_gpio;
>> +       int                     panel_prepare_delay;
>> +       int                     panel_enable_delay;
>> +       int                     panel_disable_delay;
>> +       int                     panel_unprepare_delay;
>> +};
>> +
>> +static inline struct panel_lvds *to_panel(struct drm_panel *panel)
>> +{
>> +       return container_of(panel, struct panel_lvds, base);
>> +}
>> +
>> +static int panel_lvds_prepare(struct drm_panel *panel)
>> +{
>> +       struct panel_lvds *lvds_panel = to_panel(panel);
>> +
>> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
>> +               if (!lvds_panel->lcd_fet_enabled) {
>> +                       if (regulator_enable(lvds_panel->lcd_fet))
>> +                               DRM_ERROR("failed to enable LCD fet\n");
>> +                       lvds_panel->lcd_fet_enabled = true;
>
> If this is an expected condition then using DRM_INFO() instead? It
> looks like an error to me though so maybe should return an error in
> this case?
Right, we should ideally return an error here.

>> +               }
>> +
>> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
>> +               gpio_set_value(lvds_panel->lcd_en_gpio, 1);
>> +
>> +       msleep(lvds_panel->panel_prepare_delay);
>> +
>> +       return 0;
>> +}
>> +
>> +static int panel_lvds_enable(struct drm_panel *panel)
>> +{
>> +       struct panel_lvds *lvds_panel = to_panel(panel);
>> +
>> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
>> +               if (!lvds_panel->backlight_fet_enabled) {
>> +                       if (regulator_enable(lvds_panel->backlight_fet))
>> +                               DRM_ERROR("failed to enable LED fet\n");
>> +                       lvds_panel->backlight_fet_enabled = true;
>
> Same here.
Ok.

>> +               }
>> +
>> +       msleep(lvds_panel->panel_enable_delay);
>> +
>> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
>> +               gpio_set_value(lvds_panel->led_en_gpio, 1);
>> +
>> +       return 0;
>> +}
>> +
>> +static int panel_lvds_disable(struct drm_panel *panel)
>> +{
>> +       struct panel_lvds *lvds_panel = to_panel(panel);
>> +
>> +       if (gpio_is_valid(lvds_panel->led_en_gpio))
>> +               gpio_set_value(lvds_panel->led_en_gpio, 0);
>> +
>> +       if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
>> +               if (lvds_panel->backlight_fet_enabled) {
>> +                       regulator_disable(lvds_panel->backlight_fet);
>> +                       lvds_panel->backlight_fet_enabled = false;
>> +               }
>> +
>> +       msleep(lvds_panel->panel_disable_delay);
>> +
>> +       return 0;
>> +}
>> +
>> +static int panel_lvds_unprepare(struct drm_panel *panel)
>> +{
>> +       struct panel_lvds *lvds_panel = to_panel(panel);
>> +
>> +       if (gpio_is_valid(lvds_panel->lcd_en_gpio))
>> +               gpio_set_value(lvds_panel->lcd_en_gpio, 0);
>> +
>> +       if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
>> +               if (lvds_panel->lcd_fet_enabled) {
>> +                       regulator_disable(lvds_panel->lcd_fet);
>> +                       lvds_panel->lcd_fet_enabled = false;
>> +               }
>> +
>> +       msleep(lvds_panel->panel_unprepare_delay);
>> +
>> +       return 0;
>> +}
>> +
>> +static int panel_lvds_get_modes(struct drm_panel *panel)
>> +{
>> +       struct drm_connector *connector = panel->connector;
>> +       struct panel_lvds *lvds_panel = to_panel(panel);
>> +       struct drm_display_mode *mode;
>> +
>> +       mode = drm_mode_create(connector->dev);
>> +       if (!mode) {
>> +               DRM_ERROR("failed to create a new display mode.\n");
>> +               return 0;
>> +       }
>> +
>> +       drm_display_mode_from_videomode(&lvds_panel->vm, mode);
>> +       mode->width_mm = lvds_panel->width_mm;
>> +       mode->height_mm = lvds_panel->height_mm;
>> +       connector->display_info.width_mm = mode->width_mm;
>> +       connector->display_info.height_mm = mode->height_mm;
>> +
>> +       mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
>> +       drm_mode_set_name(mode);
>> +       drm_mode_probed_add(connector, mode);
>> +
>> +       return 1;
>> +}
>> +
>> +static const struct drm_panel_funcs panel_lvds_funcs = {
>> +       .unprepare = panel_lvds_unprepare,
>> +       .disable = panel_lvds_disable,
>> +       .prepare = panel_lvds_prepare,
>> +       .enable = panel_lvds_enable,
>> +       .get_modes = panel_lvds_get_modes,
>> +};
>> +
>> +static int panel_lvds_probe(struct platform_device *pdev)
>> +{
>> +       struct panel_lvds *panel;
>> +       struct device *dev = &pdev->dev;
>> +       struct device_node *node = dev->of_node;
>> +       int ret;
>> +
>> +       panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
>> +       if (!panel)
>> +               return -ENOMEM;
>> +
>> +       ret = of_get_videomode(node, &panel->vm, 0);
>> +       if (ret) {
>> +               DRM_ERROR("failed: of_get_videomode() : %d\n", ret);
>> +               return ret;
>> +       }
>> +
>> +       panel->lcd_fet = devm_regulator_get_optional(dev, "lcd_vdd");
>> +       if (IS_ERR(panel->lcd_fet))
>> +               return -EPROBE_DEFER;
>> +
>> +       panel->backlight_fet = devm_regulator_get_optional(dev, "vcd_led");
>> +       if (IS_ERR(panel->backlight_fet))
>> +               return -EPROBE_DEFER;
>> +
>> +       panel->lcd_en_gpio = of_get_named_gpio(node, "lcd-en-gpio", 0);
>> +       panel->led_en_gpio = of_get_named_gpio(node, "led-en-gpio", 0);
>> +
>
> The old integer-based GPIO API has been deprecated and new drivers
> should use the new descriptor-based interface
> (Documentation/gpio/consumer.txt) instead if possible.
Ok, I just saw other panel drivers using the same.
Will change this.

>> +       of_property_read_u32(node, "panel-width-mm", &panel->width_mm);
>> +       of_property_read_u32(node, "panel-height-mm", &panel->height_mm);
>> +
>> +       of_property_read_u32(node, "panel-prepare-delay",
>> +                                       &panel->panel_prepare_delay);
>> +       of_property_read_u32(node, "panel-enable-delay",
>> +                                       &panel->panel_enable_delay);
>> +       of_property_read_u32(node, "panel-disable-delay",
>> +                                       &panel->panel_disable_delay);
>> +       of_property_read_u32(node, "panel-unprepare-delay",
>> +                                       &panel->panel_unprepare_delay);
>> +
>> +       if (gpio_is_valid(panel->lcd_en_gpio)) {
>> +               ret = devm_gpio_request_one(dev, panel->lcd_en_gpio,
>> +                                       GPIOF_OUT_INIT_LOW, "lcd_en_gpio");
>> +               if (ret) {
>> +                       DRM_ERROR("failed to get lcd-en gpio [%d]\n", ret);
>> +                       return 0;
>
> The probe() function returning 0 means success to the driver core but
> here is returning early due an error.
Right, will fix it.

>> +               }
>> +       } else {
>> +               panel->lcd_en_gpio = -ENODEV;
>> +       }
>> +
>> +       if (gpio_is_valid(panel->led_en_gpio)) {
>> +               ret = devm_gpio_request_one(dev, panel->led_en_gpio,
>> +                                       GPIOF_OUT_INIT_LOW, "led_en_gpio");
>> +               if (ret) {
>> +                       DRM_ERROR("failed to get led-en gpio [%d]\n", ret);
>> +                       return 0;
>
> Same here, it should return an error code instead 0.
Right, will fix it.

>> +               }
>> +       } else {
>> +               panel->led_en_gpio = -ENODEV;
>> +       }
>> +
>> +       drm_panel_init(&panel->base);
>> +       panel->base.dev = dev;
>> +       panel->base.funcs = &panel_lvds_funcs;
>> +
>> +       ret = drm_panel_add(&panel->base);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       dev_set_drvdata(dev, panel);
>> +
>> +       return 0;
>> +}
>> +
>> +static int panel_lvds_remove(struct platform_device *pdev)
>> +{
>> +       struct panel_lvds *panel = dev_get_drvdata(&pdev->dev);
>> +
>> +       panel_lvds_disable(&panel->base);
>> +       panel_lvds_unprepare(&panel->base);
>> +
>> +       drm_panel_remove(&panel->base);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct of_device_id lvds_panel_dt_match[] = {
>> +       { .compatible = "panel-lvds" },
>> +       {},
>> +};
>> +MODULE_DEVICE_TABLE(of, lvds_panel_dt_match);
>> +
>> +struct platform_driver lvds_panel_driver = {
>> +       .driver = {
>> +               .name = "panel_lvds",
>> +               .owner = THIS_MODULE,
>> +               .of_match_table = lvds_panel_dt_match,
>> +       },
>> +       .probe = panel_lvds_probe,
>> +       .remove = panel_lvds_remove,
>> +};
>> +module_platform_driver(lvds_panel_driver);
>> +
>> +MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
>> +MODULE_DESCRIPTION("lvds/eDP panel driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 1.7.9.5
>>
>
> Best regards,
> Javier
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Ajay kumar June 24, 2014, 8:22 a.m. UTC | #5
Hi Gmeiner,

On Mon, Jun 23, 2014 at 12:55 PM, Christian Gmeiner
<christian.gmeiner@gmail.com> wrote:
> Hi
>
>
> 2014-06-11 20:27 GMT+02:00 Ajay Kumar <ajaykumar.rs@samsung.com>:
>> This patch adds a simple driver to handle all the LCD and LED
>> powerup/down routines needed to support eDP/LVDS panels.
>>
>> The LCD and LED units are usually powered up via regulators,
>> and almost on all boards, we will have a BACKLIGHT_EN pin to
>> enable/ disable the backlight.
>> Sometimes, we can have LCD_EN switches as well.
>>
>> The routines in this driver can be used to control
>> panel power sequence on such boards.
>>
>> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
>> Signed-off-by: Rahul Sharma <Rahul.Sharma@samsung.com>
>> ---
>>  .../devicetree/bindings/panel/panel-lvds.txt       |   50 ++++
>>  drivers/gpu/drm/panel/Kconfig                      |   10 +
>>  drivers/gpu/drm/panel/Makefile                     |    1 +
>>  drivers/gpu/drm/panel/panel-lvds.c                 |  262 ++++++++++++++++++++
>>  4 files changed, 323 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/panel/panel-lvds.txt
>>  create mode 100644 drivers/gpu/drm/panel/panel-lvds.c
>>
>> diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
>> new file mode 100644
>> index 0000000..7cb6084
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
>> @@ -0,0 +1,50 @@
>> +panel interface for eDP/lvds panels
>> +
>> +Required properties:
>> +  - compatible: "panel-lvds"
>> +
>> +Optional properties:
>> +       -lcd-en-gpio:
>> +               panel LCD poweron GPIO.
>> +                       Indicates which GPIO needs to be powered up as output
>> +                       to powerup/enable the switch to the LCD panel.
>> +       -led-en-gpio:
>> +               panel LED enable GPIO.
>> +                       Indicates which GPIO needs to be powered up as output
>> +                       to enable the backlight.
>> +       -panel-prepare-delay:
>> +               delay value in ms required for panel_prepare process
>> +                       Delay in ms needed for the panel LCD unit to
>> +                       powerup completely.
>> +                       ex: delay needed till eDP panel throws HPD.
>> +                           delay needed so that we cans tart reading edid.
>> +       -panel-enable-delay:
>> +               delay value in ms required for panel_enable process
>> +                       Delay in ms needed for the panel backlight/LED unit
>> +                       to powerup, and delay needed between video_enable and
>> +                       backlight_enable.
>> +       -panel-disable-delay:
>> +               delay value in ms required for panel_disable process
>> +                       Delay in ms needed for the panel backlight/LED unit
>> +                       powerdown, and delay needed between backlight_disable
>> +                       and video_disable.
>> +       -panel-unprepare-delay:
>> +               delay value in ms required for panel_post_disable process
>> +                       Delay in ms needed for the panel LCD unit to
>> +                       to powerdown completely, and the minimum delay needed
>> +                       before powering it on again.
>> +       -panel-width-mm: physical panel width [mm]
>> +       -panel-height-mm: physical panel height [mm]
>> +
>
> For what are these two properties are needed?
Actually, these are needed to caluculate DPI(dots/pixels per inch).
That information will be used by the corresponding userspace to
deliver proper size fonts.
You can refer other panel drivers, even they too are using it!

Regards,
Ajay

> If I find some time I will give this patch a try as I need something
> like this for an imx6d based device.
That would be great, Thanks.

Ajay
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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/panel/panel-lvds.txt b/Documentation/devicetree/bindings/panel/panel-lvds.txt
new file mode 100644
index 0000000..7cb6084
--- /dev/null
+++ b/Documentation/devicetree/bindings/panel/panel-lvds.txt
@@ -0,0 +1,50 @@ 
+panel interface for eDP/lvds panels
+
+Required properties:
+  - compatible: "panel-lvds"
+
+Optional properties:
+	-lcd-en-gpio:
+		panel LCD poweron GPIO.
+			Indicates which GPIO needs to be powered up as output
+			to powerup/enable the switch to the LCD panel.
+	-led-en-gpio:
+		panel LED enable GPIO.
+			Indicates which GPIO needs to be powered up as output
+			to enable the backlight.
+	-panel-prepare-delay:
+		delay value in ms required for panel_prepare process
+			Delay in ms needed for the panel LCD unit to
+			powerup completely.
+			ex: delay needed till eDP panel throws HPD.
+			    delay needed so that we cans tart reading edid.
+	-panel-enable-delay:
+		delay value in ms required for panel_enable process
+			Delay in ms needed for the panel backlight/LED unit
+			to powerup, and delay needed between video_enable and
+			backlight_enable.
+	-panel-disable-delay:
+		delay value in ms required for panel_disable process
+			Delay in ms needed for the panel backlight/LED unit
+			powerdown, and delay needed between backlight_disable
+			and video_disable.
+	-panel-unprepare-delay:
+		delay value in ms required for panel_post_disable process
+			Delay in ms needed for the panel LCD unit to
+			to powerdown completely, and the minimum delay needed
+			before powering it on again.
+	-panel-width-mm: physical panel width [mm]
+	-panel-height-mm: physical panel height [mm]
+
+Example:
+
+	panel-lvds {
+		compatible = "panel-lvds";
+		led-en-gpio = <&gpx3 0 1>;
+		panel-prepare-delay = <40>;
+		panel-enable-delay = <20>;
+		panel-disable-delay = <20>;
+		panel-unprepare-delay = <30>;
+		panel-width-mm = <256>;
+		panel-height-mm = <144>;
+	};
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 4ec874d..8fe7ee5 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -30,4 +30,14 @@  config DRM_PANEL_S6E8AA0
 	select DRM_MIPI_DSI
 	select VIDEOMODE_HELPERS
 
+config DRM_PANEL_EDP_LVDS
+	tristate "support for eDP/LVDS panels"
+	depends on OF && DRM_PANEL
+	select VIDEOMODE_HELPERS
+	help
+	  DRM panel driver for direct eDP panels or LVDS connected
+	  via DP bridges, that need at most a regulator for LCD unit,
+	  a regulator for LED unit and/or enable GPIOs for LCD or LED units.
+	  Delay values can also be specified to support powerup and
+	  powerdown process.
 endmenu
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 8b92921..eaafa01 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,3 +1,4 @@ 
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
 obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
 obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
+obj-$(CONFIG_DRM_PANEL_EDP_LVDS) += panel-lvds.o
diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
new file mode 100644
index 0000000..2124fcb
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-lvds.c
@@ -0,0 +1,262 @@ 
+/*
+ * panel driver for lvds and eDP panels
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd
+ *
+ * Ajay Kumar <ajaykumar.rs@samsung.com>
+ *
+ * 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.
+ */
+
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/of_videomode.h>
+#include <video/videomode.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_panel.h>
+
+struct panel_lvds {
+	struct drm_panel	base;
+	struct regulator	*backlight_fet;
+	struct regulator	*lcd_fet;
+	struct videomode	vm;
+	int			width_mm;
+	int			height_mm;
+	bool			backlight_fet_enabled;
+	bool			lcd_fet_enabled;
+	int			led_en_gpio;
+	int			lcd_en_gpio;
+	int			panel_prepare_delay;
+	int			panel_enable_delay;
+	int			panel_disable_delay;
+	int			panel_unprepare_delay;
+};
+
+static inline struct panel_lvds *to_panel(struct drm_panel *panel)
+{
+	return container_of(panel, struct panel_lvds, base);
+}
+
+static int panel_lvds_prepare(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
+		if (!lvds_panel->lcd_fet_enabled) {
+			if (regulator_enable(lvds_panel->lcd_fet))
+				DRM_ERROR("failed to enable LCD fet\n");
+			lvds_panel->lcd_fet_enabled = true;
+		}
+
+	if (gpio_is_valid(lvds_panel->lcd_en_gpio))
+		gpio_set_value(lvds_panel->lcd_en_gpio, 1);
+
+	msleep(lvds_panel->panel_prepare_delay);
+
+	return 0;
+}
+
+static int panel_lvds_enable(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
+		if (!lvds_panel->backlight_fet_enabled) {
+			if (regulator_enable(lvds_panel->backlight_fet))
+				DRM_ERROR("failed to enable LED fet\n");
+			lvds_panel->backlight_fet_enabled = true;
+		}
+
+	msleep(lvds_panel->panel_enable_delay);
+
+	if (gpio_is_valid(lvds_panel->led_en_gpio))
+		gpio_set_value(lvds_panel->led_en_gpio, 1);
+
+	return 0;
+}
+
+static int panel_lvds_disable(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (gpio_is_valid(lvds_panel->led_en_gpio))
+		gpio_set_value(lvds_panel->led_en_gpio, 0);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->backlight_fet))
+		if (lvds_panel->backlight_fet_enabled) {
+			regulator_disable(lvds_panel->backlight_fet);
+			lvds_panel->backlight_fet_enabled = false;
+		}
+
+	msleep(lvds_panel->panel_disable_delay);
+
+	return 0;
+}
+
+static int panel_lvds_unprepare(struct drm_panel *panel)
+{
+	struct panel_lvds *lvds_panel = to_panel(panel);
+
+	if (gpio_is_valid(lvds_panel->lcd_en_gpio))
+		gpio_set_value(lvds_panel->lcd_en_gpio, 0);
+
+	if (!IS_ERR_OR_NULL(lvds_panel->lcd_fet))
+		if (lvds_panel->lcd_fet_enabled) {
+			regulator_disable(lvds_panel->lcd_fet);
+			lvds_panel->lcd_fet_enabled = false;
+		}
+
+	msleep(lvds_panel->panel_unprepare_delay);
+
+	return 0;
+}
+
+static int panel_lvds_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct panel_lvds *lvds_panel = to_panel(panel);
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_create(connector->dev);
+	if (!mode) {
+		DRM_ERROR("failed to create a new display mode.\n");
+		return 0;
+	}
+
+	drm_display_mode_from_videomode(&lvds_panel->vm, mode);
+	mode->width_mm = lvds_panel->width_mm;
+	mode->height_mm = lvds_panel->height_mm;
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+	drm_mode_set_name(mode);
+	drm_mode_probed_add(connector, mode);
+
+	return 1;
+}
+
+static const struct drm_panel_funcs panel_lvds_funcs = {
+	.unprepare = panel_lvds_unprepare,
+	.disable = panel_lvds_disable,
+	.prepare = panel_lvds_prepare,
+	.enable = panel_lvds_enable,
+	.get_modes = panel_lvds_get_modes,
+};
+
+static int panel_lvds_probe(struct platform_device *pdev)
+{
+	struct panel_lvds *panel;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+
+	panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
+	if (!panel)
+		return -ENOMEM;
+
+	ret = of_get_videomode(node, &panel->vm, 0);
+	if (ret) {
+		DRM_ERROR("failed: of_get_videomode() : %d\n", ret);
+		return ret;
+	}
+
+	panel->lcd_fet = devm_regulator_get_optional(dev, "lcd_vdd");
+	if (IS_ERR(panel->lcd_fet))
+		return -EPROBE_DEFER;
+
+	panel->backlight_fet = devm_regulator_get_optional(dev, "vcd_led");
+	if (IS_ERR(panel->backlight_fet))
+		return -EPROBE_DEFER;
+
+	panel->lcd_en_gpio = of_get_named_gpio(node, "lcd-en-gpio", 0);
+	panel->led_en_gpio = of_get_named_gpio(node, "led-en-gpio", 0);
+
+	of_property_read_u32(node, "panel-width-mm", &panel->width_mm);
+	of_property_read_u32(node, "panel-height-mm", &panel->height_mm);
+
+	of_property_read_u32(node, "panel-prepare-delay",
+					&panel->panel_prepare_delay);
+	of_property_read_u32(node, "panel-enable-delay",
+					&panel->panel_enable_delay);
+	of_property_read_u32(node, "panel-disable-delay",
+					&panel->panel_disable_delay);
+	of_property_read_u32(node, "panel-unprepare-delay",
+					&panel->panel_unprepare_delay);
+
+	if (gpio_is_valid(panel->lcd_en_gpio)) {
+		ret = devm_gpio_request_one(dev, panel->lcd_en_gpio,
+					GPIOF_OUT_INIT_LOW, "lcd_en_gpio");
+		if (ret) {
+			DRM_ERROR("failed to get lcd-en gpio [%d]\n", ret);
+			return 0;
+		}
+	} else {
+		panel->lcd_en_gpio = -ENODEV;
+	}
+
+	if (gpio_is_valid(panel->led_en_gpio)) {
+		ret = devm_gpio_request_one(dev, panel->led_en_gpio,
+					GPIOF_OUT_INIT_LOW, "led_en_gpio");
+		if (ret) {
+			DRM_ERROR("failed to get led-en gpio [%d]\n", ret);
+			return 0;
+		}
+	} else {
+		panel->led_en_gpio = -ENODEV;
+	}
+
+	drm_panel_init(&panel->base);
+	panel->base.dev = dev;
+	panel->base.funcs = &panel_lvds_funcs;
+
+	ret = drm_panel_add(&panel->base);
+	if (ret < 0)
+		return ret;
+
+	dev_set_drvdata(dev, panel);
+
+	return 0;
+}
+
+static int panel_lvds_remove(struct platform_device *pdev)
+{
+	struct panel_lvds *panel = dev_get_drvdata(&pdev->dev);
+
+	panel_lvds_disable(&panel->base);
+	panel_lvds_unprepare(&panel->base);
+
+	drm_panel_remove(&panel->base);
+
+	return 0;
+}
+
+static const struct of_device_id lvds_panel_dt_match[] = {
+	{ .compatible = "panel-lvds" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, lvds_panel_dt_match);
+
+struct platform_driver lvds_panel_driver = {
+	.driver = {
+		.name = "panel_lvds",
+		.owner = THIS_MODULE,
+		.of_match_table = lvds_panel_dt_match,
+	},
+	.probe = panel_lvds_probe,
+	.remove = panel_lvds_remove,
+};
+module_platform_driver(lvds_panel_driver);
+
+MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
+MODULE_DESCRIPTION("lvds/eDP panel driver");
+MODULE_LICENSE("GPL v2");