[PATCH 2/2 v4] drm/panel: Add a driver for the TPO TPG110

[Sam Ravnborg]

Hi Linus

On Thu, Nov 01, 2018 at 10:32:56PM +0100, Linus Walleij wrote:
> The TPO (Toppoly) TPG110 is a pretty generic display driver
> similar in vein to the Ilitek 93xx devices. It is not a panel
> per se but a driver used with several low-cost noname panels.
> 
> This is used on the Nomadik NHK15 combined with a OSD
> OSD057VA01CT display for WVGA 800x480.
> 
> The driver is pretty minimalistic right now but can be
> extended to handle non-default polarities, gamma correction
> etc.
> 
> The driver is based on the baked-in code in
> drivers/video/fbdev/amba-clcd-nomadik.c which will be
> decomissioned once this us upstream.
> 
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> ChangeLog v3->v4:
> - Tag on the SPI_3WIRE_HIZ flag to the SPI slave mode.
> ChangeLog v2->v3:
> - Rewrite as an SPI child device.
> ---
>  MAINTAINERS                              |   7 +
>  drivers/gpu/drm/panel/Kconfig            |  10 +
>  drivers/gpu/drm/panel/Makefile           |   1 +
>  drivers/gpu/drm/panel/panel-tpo-tpg110.c | 506 +++++++++++++++++++++++
>  4 files changed, 524 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-tpo-tpg110.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 690c2f68a401..c3ca56c2a7a6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4746,6 +4746,13 @@ DRM DRIVER FOR TDFX VIDEO CARDS
>  S:	Orphan / Obsolete
>  F:	drivers/gpu/drm/tdfx/
>  
> +DRM DRIVER FOR TPO TPG110 PANELS
> +M:	Linus Walleij <linus.walleij at linaro.org>
> +T:	git git://anongit.freedesktop.org/drm/drm-misc
> +S:	Maintained
> +F:	drivers/gpu/drm/panel/panel-tpo-tpg110.c
> +F:	Documentation/devicetree/bindings/display/panel/tpo,tpg110.txt
> +
>  DRM DRIVER FOR USB DISPLAYLINK VIDEO ADAPTERS
>  M:	Dave Airlie <airlied at redhat.com>
>  R:	Sean Paul <sean at poorly.run>
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 6020c30a33b3..b2c8b02894b1 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -186,4 +186,14 @@ config DRM_PANEL_SITRONIX_ST7789V
>  	  Say Y here if you want to enable support for the Sitronix
>  	  ST7789V controller for 240x320 LCD panels
>  
> +config DRM_PANEL_TPO_TPG110
> +	tristate "TPO TPG 800x400 panel"
> +	depends on OF && SPI && GPIOLIB
> +	depends on BACKLIGHT_CLASS_DEVICE
> +	select VIDEOMODE_HELPERS
> +	help
> +	  Say Y here if you want to enable support for TPO TPG110
> +	  400CH LTPS TFT LCD Single Chip Digital Driver for up to
> +	  800x400 LCD panels.
> +
>  endmenu
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 5ccaaa9d13af..9b3a0629d255 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -19,3 +19,4 @@ obj-$(CONFIG_DRM_PANEL_SEIKO_43WVF1G) += panel-seiko-43wvf1g.o
>  obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
>  obj-$(CONFIG_DRM_PANEL_SHARP_LS043T1LE01) += panel-sharp-ls043t1le01.o
>  obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
> +obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o
> diff --git a/drivers/gpu/drm/panel/panel-tpo-tpg110.c b/drivers/gpu/drm/panel/panel-tpo-tpg110.c
> new file mode 100644
> index 000000000000..8e517ea5e73b
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-tpo-tpg110.c
> @@ -0,0 +1,506 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Panel driver for the TPO TPG110 400CH LTPS TFT LCD Single Chip
> + * Digital Driver.
> + *
> + * This chip drives a TFT LCD, so it does not know what kind of
> + * display is actually connected to it, so the width and height of that
> + * display needs to be supplied from the machine configuration.
> + *
> + * Author:
> + * Linus Walleij <linus.wallei at linaro.org>
> + */
> +#include <drm/drmP.h>
> +#include <drm/drm_panel.h>
> +
> +#include <linux/backlight.h>
> +#include <linux/bitops.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/spi/spi.h>
> +
> +#include <video/of_videomode.h>
> +#include <video/videomode.h>
> +
> +#define TPG110_TEST			0x00
> +#define TPG110_CHIPID			0x01
> +#define TPG110_CTRL1			0x02
> +#define TPG110_RES_MASK			GENMASK(2, 0)
> +#define TPG110_RES_800X480		0x07
> +#define TPG110_RES_640X480		0x06
> +#define TPG110_RES_480X272		0x05
> +#define TPG110_RES_480X640		0x04
> +#define TPG110_RES_480X272_D		0x01 /* Dual scan: outputs 800x480 */
> +#define TPG110_RES_400X240_D		0x00 /* Dual scan: outputs 800x480 */
> +#define TPG110_CTRL2			0x03
> +#define TPG110_CTRL2_PM			BIT(0)
> +#define TPG110_CTRL2_RES_PM_CTRL	BIT(7)
> +
> +/**
> + * struct tpg110_panel_mode - lookup struct for the supported modes
> + */
> +struct tpg110_panel_mode {
> +	/**
> +	 * @name: the name of this panel
> +	 */
> +	const char *name;
> +	/**
> +	 * @magic: the magic value from the detection register
> +	 */
> +	u32 magic;
> +	/**
> +	 * @mode: the DRM display mode for this panel
> +	 */
> +	struct drm_display_mode mode;
> +	/**
> +	 * @bus_flags: the DRM bus flags for this panel e.g. inverted clock
> +	 */
> +	u32 bus_flags;

bus_flags is never assigned. Should it maybe be left out?
Or is this just preparation for extra panels?

	Sam