Parse a display-node with timings and hardware-specs from devictree.

Signed-off-by: Steffen Trumtrar s.trumtrar@pengutronix.de --- Documentation/devicetree/bindings/video/display | 208 +++++++++++++++++++++++ drivers/of/Kconfig | 5 + drivers/of/Makefile | 1 + drivers/of/of_display.c | 157 +++++++++++++++++ include/linux/display.h | 85 +++++++++ include/linux/of_display.h | 15 ++ 6 files changed, 471 insertions(+) create mode 100644 Documentation/devicetree/bindings/video/display create mode 100644 drivers/of/of_display.c create mode 100644 include/linux/display.h create mode 100644 include/linux/of_display.h

diff --git a/Documentation/devicetree/bindings/video/display b/Documentation/devicetree/bindings/video/display new file mode 100644 index 0000000..722766a --- /dev/null +++ b/Documentation/devicetree/bindings/video/display @@ -0,0 +1,208 @@ +display bindings +================== + +display-node +------------ + +required properties: + - none + +optional properties: + - default-timing: the default timing value + - width-mm, height-mm: Display dimensions in mm + - hsync-active-high (bool): Hsync pulse is active high + - vsync-active-high (bool): Vsync pulse is active high + - de-active-high (bool): Data-Enable pulse is active high + - pixelclk-inverted (bool): pixelclock is inverted + - pixel-per-clk + - link-width: number of channels (e.g. LVDS) + - bpp: bits-per-pixel + +timings-subnode +--------------- + +required properties: +subnodes that specify + - hactive, vactive: Display resolution + - hfront-porch, hback-porch, hsync-len: Horizontal Display timing parameters + in pixels + vfront-porch, vback-porch, vsync-len: Vertical display timing parameters in + lines + - clock: displayclock in Hz + +There are different ways of describing a display and its capabilities. The devicetree +representation corresponds to the one commonly found in datasheets for displays. +The description of the display and its timing is split in two parts: first the display +properties like size in mm and (optionally) multiple subnodes with the supported timings. +If a display supports multiple signal timings, the default-timing can be specified. + +Example: + + display@0 { + width-mm = <800>; + height-mm = <480>; + default-timing = <&timing0>; + timings { + timing0: timing@0 { + /* 1920x1080p24 */ + clock = <52000000>; + hactive = <1920>; + vactive = <1080>; + hfront-porch = <25>; + hback-porch = <25>; + hsync-len = <25>; + vback-porch = <2>; + vfront-porch = <2>; + vsync-len = <2>; + hsync-active-high; + }; + }; + }; + +Every property also supports the use of ranges, so the commonly used datasheet +description with <min typ max>-tuples can be used. + +Example: + + timing1: timing@1 { + /* 1920x1080p24 */ + clock = <148500000>; + hactive = <1920>; + vactive = <1080>; + hsync-len = <0 44 60>; + hfront-porch = <80 88 95>; + hback-porch = <100 148 160>; + vfront-porch = <0 4 6>; + vback-porch = <0 36 50>; + vsync-len = <0 5 6>; + }; + +The "display"-property in a connector-node (e.g. hdmi, ldb,...) is used to connect +the display to that driver. +of_display expects a phandle, that specifies the display-node, in that property. + +Example: + + hdmi@00120000 { + status = "okay"; + display = <&acme>; + }; + +Usage in backend +================ + +A backend driver may choose to use the display directly and convert the timing +ranges to a suitable mode. Or it may just use the conversion of the display timings +to the required mode via the generic videomode struct. + + dtb + | + | of_get_display + ↓ + struct display + | + | videomode_from_timings + ↓ + --- struct videomode --- + | | + videomode_to_displaymode | | videomode_to_fb_videomode + ↓ ↓ + drm_display_mode fb_videomode + + +Conversion to videomode +======================= + +As device drivers normally work with some kind of video mode, the timings can be +converted (may be just a simple copying of the typical value) to a generic videomode +structure which then can be converted to the according mode used by the backend. + +Supported modes +=============== + +The generic videomode read in by the driver can be converted to the following +modes with the following parameters + +struct fb_videomode +=================== + + +----------+---------------------------------------------+----------+-------+ + | | ↑ | | | + | | |upper_margin | | | + | | ↓ | | | + +----------###############################################----------+-------+ + | # ↑ # | | + | # | # | | + | # | # | | + | # | # | | + | left # | # right | hsync | + | margin # | xres # margin | len | + |<-------->#<---------------+--------------------------->#<-------->|<----->| + | # | # | | + | # | # | | + | # | # | | + | # |yres # | | + | # | # | | + | # | # | | + | # | # | | + | # | # | | + | # | # | | + | # | # | | + | # | # | | + | # | # | | + | # ↓ # | | + +----------###############################################----------+-------+ + | | ↑ | | | + | | |lower_margin | | | + | | ↓ | | | + +----------+---------------------------------------------+----------+-------+ + | | ↑ | | | + | | |vsync_len | | | + | | ↓ | | | + +----------+---------------------------------------------+----------+-------+ + +clock in nanoseconds + +struct drm_display_mode +======================= + + +----------+---------------------------------------------+----------+-------+ + | | | | | ↑ + | | | | | | + | | | | | | + +----------###############################################----------+-------+ | + | # ↑ ↑ ↑ # | | | + | # | | | # | | | + | # | | | # | | | + | # | | | # | | | + | # | | | # | | | + | # | | | hdisplay # | | | + | #<--+--------------------+-------------------># | | | + | # | | | # | | | + | # |vsync_start | # | | | + | # | | | # | | | + | # | |vsync_end | # | | | + | # | | |vdisplay # | | | + | # | | | # | | | + | # | | | # | | | + | # | | | # | | | vtotal + | # | | | # | | | + | # | | | hsync_start # | | | + | #<--+---------+----------+------------------------------>| | | + | # | | | # | | | + | # | | | hsync_end # | | | + | #<--+---------+----------+-------------------------------------->| | + | # | | ↓ # | | | + +----------####|#########|################################----------+-------+ | + | | | | | | | | + | | | | | | | | + | | ↓ | | | | | + +----------+-------------+-------------------------------+----------+-------+ | + | | | | | | | + | | | | | | | + | | ↓ | | | ↓ + +----------+---------------------------------------------+----------+-------+ + htotal + <-------------------------------------------------------------------------> + +clock in kilohertz diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index dfba3e6..a4e3074 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -83,4 +83,9 @@ config OF_MTD depends on MTD def_bool y

+config OF_DISPLAY + def_bool y + help + helper to parse displays from the devicetree + endmenu # OF diff --git a/drivers/of/Makefile b/drivers/of/Makefile index e027f44..0756bee 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_OF_MDIO) += of_mdio.o obj-$(CONFIG_OF_PCI) += of_pci.o obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o obj-$(CONFIG_OF_MTD) += of_mtd.o +obj-$(CONFIG_OF_DISPLAY) += of_display.o diff --git a/drivers/of/of_display.c b/drivers/of/of_display.c new file mode 100644 index 0000000..632a351 --- /dev/null +++ b/drivers/of/of_display.c @@ -0,0 +1,157 @@ +/* + * OF helpers for parsing display timings + * + * Copyright (c) 2012 Steffen Trumtrar s.trumtrar@pengutronix.de, Pengutronix + * + * based on of_videomode.c by Sascha Hauer s.hauer@pengutronix.de + * + * This file is released under the GPLv2 + */ +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/display.h> +#include <linux/of_display.h> +#include <linux/fb.h> + +/* every signal_timing can be specified with either + * just the typical value or a range consisting of + * min/typ/max. + * This function helps handling this + */ +static int of_display_parse_property(struct device_node *np, char *name, + struct timing_entry *result) +{ + struct property *prop; + int length; + int cells; + int ret; + + prop = of_find_property(np, name, &length); + if (!prop) { + pr_err("%s: could not find property %s\n", __func__, + name); + return -EINVAL; + } + + cells = length / sizeof(u32); + + if (cells == 1) + ret = of_property_read_u32_array(np, name, &result->typ, cells); + else if (cells == 3) + ret = of_property_read_u32_array(np, name, &result->min, cells); + else { + pr_err("%s: illegal timing specification in %s\n", __func__, + name); + return -EINVAL; + } + + return ret; +} + +struct display *of_get_display(struct device_node *np) +{ + struct device_node *display_np; + struct device_node *timing_np; + struct device_node *timings; + struct display *disp; + char *default_timing; + + if (!np) { + pr_err("%s: no devicenode given\n", __func__); + return NULL; + } + + display_np = of_parse_phandle(np, "display", 0); + + if (!display_np) { + pr_err("%s: could not find display node\n", __func__); + return NULL; + } + + disp = kmalloc(sizeof(struct display *), GFP_KERNEL); + + memset(disp, 0, sizeof(struct display *)); + + of_property_read_u32(display_np, "width-mm", &disp->width_mm); + of_property_read_u32(display_np, "height-mm", &disp->height_mm); + + timing_np = of_parse_phandle(display_np, "default-timing", 0); + + if (!timing_np) { + pr_info("%s: no default-timing specified\n", __func__); + timing_np = of_find_node_by_name(np, "timing"); + } + + if (!timing_np) { + pr_info("%s: no timing specifications given\n", __func__); + return disp; + } + + default_timing = (char *)timing_np->full_name; + + timings = of_find_node_by_name(np, "timings"); + + disp->num_timings = 0; + + disp->timings = kmalloc(sizeof(struct signal_timing *), GFP_KERNEL); + + for_each_child_of_node(timings, timing_np) { + struct signal_timing *st; + int ret; + + st = kmalloc(sizeof(struct signal_timing *), GFP_KERNEL); + disp->timings[disp->num_timings] = kmalloc(sizeof(struct signal_timing *), GFP_KERNEL); + + ret |= of_display_parse_property(timing_np, "hback-porch", &st->hback_porch); + ret |= of_display_parse_property(timing_np, "hfront-porch", &st->hfront_porch); + ret |= of_display_parse_property(timing_np, "hactive", &st->hactive); + ret |= of_display_parse_property(timing_np, "hsync-len", &st->hsync_len); + ret |= of_display_parse_property(timing_np, "vback-porch", &st->vback_porch); + ret |= of_display_parse_property(timing_np, "vfront-porch", &st->vfront_porch); + ret |= of_display_parse_property(timing_np, "vactive", &st->vactive); + ret |= of_display_parse_property(timing_np, "vsync-len", &st->vsync_len); + ret |= of_display_parse_property(timing_np, "clock", &st->pixelclock); + + if (strcmp(default_timing, timing_np->full_name) == 0) + disp->default_timing = disp->num_timings; + + disp->timings[disp->num_timings] = st; + disp->num_timings++; + } + + disp->vsync_pol_active_high = of_property_read_bool(display_np, "vsync-active-high"); + disp->hsync_pol_active_high = of_property_read_bool(display_np, "hsync-active-high"); + disp->de_pol_active_high = of_property_read_bool(display_np, "de-active-high"); + disp->pixelclk_pol_inverted = of_property_read_bool(display_np, "pixelclk-inverted"); + of_property_read_u32(display_np, "pixel-per-clk", &disp->if_pixel_per_clk); + of_property_read_u32(display_np, "link-width", &disp->if_link_width); + of_property_read_u32(display_np, "bpp", &disp->if_bpp); + + + pr_info("%s: got %d timings. Using #%d as default\n", __func__, disp->num_timings, disp->default_timing + 1); + + return disp; +} +EXPORT_SYMBOL(of_get_display); + +int of_display_exists(struct device_node *np) +{ + struct device_node *display_np; + struct device_node *timing_np; + + if (!np) + return -EINVAL; + + display_np = of_parse_phandle(np, "display", 0); + + if (!display_np) + return -EINVAL; + + timing_np = of_parse_phandle(np, "default-timing", 0); + + if (timing_np) + return 0; + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(of_display_exists); diff --git a/include/linux/display.h b/include/linux/display.h new file mode 100644 index 0000000..bb84ed9 --- /dev/null +++ b/include/linux/display.h @@ -0,0 +1,85 @@ +/* + * Copyright 2012 Steffen Trumtrar s.trumtrar@pengutronix.de + * + * Hardware-description of a display + * + * This file is released under the GPLv2 + */ + +#ifndef __LINUX_DISPLAY_H +#define __LINUX_DISPLAY_H + +#include <linux/list.h> + +#define OF_DEFAULT_TIMING -1 + +struct display { + u32 width_mm; + u32 height_mm; + unsigned int num_timings; + unsigned int default_timing; + + struct signal_timing **timings; + + bool vsync_pol_active_high; + bool hsync_pol_active_high; + bool de_pol_active_high; + bool pixelclk_pol_inverted; + + u32 if_bpp; + u32 if_link_width; + u32 if_pixel_per_clk; +}; + +struct timing_entry { + u32 min; + u32 typ; + u32 max; +}; + +struct signal_timing { + struct timing_entry pixelclock; + + struct timing_entry hactive; + struct timing_entry hfront_porch; + struct timing_entry hback_porch; + struct timing_entry hsync_len; + + struct timing_entry vactive; + struct timing_entry vfront_porch; + struct timing_entry vback_porch; + struct timing_entry vsync_len; +}; + +/* placeholder function until ranges are really needed */ +static inline u32 signal_timing_get_value(struct timing_entry *te, int index) +{ + return te->typ; +} + +static inline void timings_release(struct display *disp) +{ + int i; + for (i = 0; i < disp->num_timings; i++) + kfree(disp->timings[i]); +} + +static inline void display_release(struct display *disp) +{ + timings_release(disp); + kfree(disp->timings); +} + +static inline struct signal_timing *display_get_timing(struct display *disp, int index) +{ + if (disp->num_timings >= index) + return disp->timings[index]; + else + return NULL; +} + + +int of_display_exists(struct device_node *np); +struct display *of_get_display(struct device_node *np); + +#endif /* __LINUX_DISPLAY_H */ diff --git a/include/linux/of_display.h b/include/linux/of_display.h new file mode 100644 index 0000000..500ff94 --- /dev/null +++ b/include/linux/of_display.h @@ -0,0 +1,15 @@ +/* + * Copyright 2012 Steffen Trumtrar s.trumtrar@pengutronix.de + * + * This file is released under the GPLv2 + */ + +#ifndef __LINUX_OF_DISPLAY_H +#define __LINUX_OF_DISPALY_H + +#include <linux/fb.h> + +struct display *of_get_display(struct device_node *np); +int of_display_exists(struct device_node *np); + +#endif

Backend-independent videomode. At the moment this is not very different from fb_mode or drm_mode. It is supposed to be a generic description of videomodes and conversion step to the desired backend video mode representation. At the moment, only really makes sense when used with of_display

Signed-off-by: Steffen Trumtrar s.trumtrar@pengutronix.de --- drivers/video/Makefile | 1 + drivers/video/videomode.c | 146 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/videomode.h | 38 ++++++++++++ 3 files changed, 185 insertions(+) create mode 100644 drivers/video/videomode.c create mode 100644 include/linux/videomode.h

diff --git a/drivers/video/Makefile b/drivers/video/Makefile index ee8dafb..6a02fe0 100644 --- a/drivers/video/Makefile +++ b/drivers/video/Makefile @@ -170,3 +170,4 @@ obj-$(CONFIG_FB_VIRTUAL) += vfb.o

#video output switch sysfs driver obj-$(CONFIG_VIDEO_OUTPUT_CONTROL) += output.o +obj-y += videomode.o diff --git a/drivers/video/videomode.c b/drivers/video/videomode.c new file mode 100644 index 0000000..b118d00 --- /dev/null +++ b/drivers/video/videomode.c @@ -0,0 +1,146 @@ +/* + * generic videomode helper + * + * Copyright (c) 2012 Steffen Trumtrar s.trumtrar@pengutronix.de, Pengutronix + * + * This file is released under the GPLv2 + */ +#include <linux/of.h> +#include <linux/fb.h> +#include <linux/slab.h> +#include <drm/drm_mode.h> +#include <linux/display.h> +#include <linux/videomode.h> + +struct videomode *videomode_from_display(struct display *disp, int index) +{ + struct videomode *vm; + struct signal_timing *st; + + vm = kmalloc(sizeof(struct videomode *), GFP_KERNEL); + + if (!vm) + return NULL; + + st = display_get_timing(disp, index); + + vm->pixelclock = signal_timing_get_value(&st->pixelclock, 0); + vm->hactive = signal_timing_get_value(&st->hactive, 0); + vm->hfront_porch = signal_timing_get_value(&st->hfront_porch, 0); + vm->hback_porch = signal_timing_get_value(&st->hback_porch, 0); + vm->hsync_len = signal_timing_get_value(&st->hsync_len, 0); + + vm->vactive = signal_timing_get_value(&st->vactive, 0); + vm->vfront_porch = signal_timing_get_value(&st->vfront_porch, 0); + vm->vback_porch = signal_timing_get_value(&st->vback_porch, 0); + vm->vsync_len = signal_timing_get_value(&st->vsync_len, 0); + + vm->vah = disp->vsync_pol_active_high; + vm->hah = disp->hsync_pol_active_high; + + return vm; +} + +#if defined(CONFIG_DRM) +int videomode_to_display_mode(struct videomode *vm, struct drm_display_mode *dmode) +{ + memset(dmode, 0, sizeof(*dmode)); + + dmode->hdisplay = vm->hactive; + dmode->hsync_start = dmode->hdisplay + vm->hfront_porch; + dmode->hsync_end = dmode->hsync_start + vm->hsync_len; + dmode->htotal = dmode->hsync_end + vm->hback_porch; + + dmode->vdisplay = vm->vactive; + dmode->vsync_start = dmode->vdisplay + vm->vfront_porch; + dmode->vsync_end = dmode->vsync_start + vm->vsync_len; + dmode->vtotal = dmode->vtotal + vm->vback_porch; + + dmode->clock = vm->pixelclock / 1000; + + if (vm->hah) + dmode->flags |= DRM_MODE_FLAG_PHSYNC; + else + dmode->flags |= DRM_MODE_FLAG_NHSYNC; + if (vm->vah) + dmode->flags |= DRM_MODE_FLAG_PVSYNC; + else + dmode->flags |= DRM_MODE_FLAG_NVSYNC; + if (vm->interlaced) + dmode->flags |= DRM_MODE_FLAG_INTERLACE; + if (vm->doublescan) + dmode->flags |= DRM_MODE_FLAG_DBLSCAN; + drm_mode_set_name(dmode); + + return 0; +} +EXPORT_SYMBOL_GPL(videomode_to_display_mode); +#else +int videomode_to_displaymode(struct videomode *vm, struct drm_display_mode *dmode) +{ + return 0; +} +#endif + +int videomode_to_fb_videomode(struct videomode *vm, struct fb_videomode *fbmode) +{ + memset(fbmode, 0, sizeof(*fbmode)); + + fbmode->xres = vm->hactive; + fbmode->left_margin = vm->hback_porch; + fbmode->right_margin = vm->hfront_porch; + fbmode->hsync_len = vm->hsync_len; + + fbmode->yres = vm->vactive; + fbmode->upper_margin = vm->vback_porch; + fbmode->lower_margin = vm->vfront_porch; + fbmode->vsync_len = vm->vsync_len; + + fbmode->pixclock = KHZ2PICOS(vm->pixelclock) / 1000; + + if (vm->hah) + fbmode->sync |= FB_SYNC_HOR_HIGH_ACT; + if (vm->vah) + fbmode->sync |= FB_SYNC_VERT_HIGH_ACT; + if (vm->interlaced) + fbmode->vmode |= FB_VMODE_INTERLACED; + if (vm->doublescan) + fbmode->vmode |= FB_VMODE_DOUBLE; + + return 0; +} +EXPORT_SYMBOL_GPL(videomode_to_fb_videomode); + +int of_get_display_mode(struct device_node *np, struct drm_display_mode *dmode, int index) +{ + struct videomode *vm; + struct display *disp; + + disp = of_get_display(np); + + if (!disp) { + pr_err("%s: no display specified\n", __func__); + return -EINVAL; + } + + if (index == OF_DEFAULT_TIMING) + index = disp->default_timing; + + vm = videomode_from_display(disp, index); + + if (!vm) { + pr_err("%s: could not get videomode %d\n", __func__, index); + return -EINVAL; + } + + videomode_to_display_mode(vm, dmode); + + pr_info("%s: got %dx%d display mode from %s\n", __func__, vm->hactive, vm->vactive, np->name); + + display_release(disp); + kfree(vm); + + return 0; + +} +EXPORT_SYMBOL_GPL(of_get_display_mode); diff --git a/include/linux/videomode.h b/include/linux/videomode.h new file mode 100644 index 0000000..100c88b --- /dev/null +++ b/include/linux/videomode.h @@ -0,0 +1,38 @@ +/* + * Copyright 2012 Steffen Trumtrar s.trumtrar@pengutronix.de + * + * generic videomode description + * + * This file is released under the GPLv2 + */ + +#ifndef __LINUX_VIDEOMODE_H +#define __LINUX_VIDEOMODE_H + +#include <drm/drmP.h> + +struct videomode { + u32 pixelclock; + u32 refreshrate; + + u32 hactive; + u32 hfront_porch; + u32 hback_porch; + u32 hsync_len; + + u32 vactive; + u32 vfront_porch; + u32 vback_porch; + u32 vsync_len; + + bool hah; + bool vah; + bool interlaced; + bool doublescan; + +}; + +int videomode_to_display_mode(struct videomode *vm, struct drm_display_mode *dmode); +int videomode_to_fb_videomode(struct videomode *vm, struct fb_videomode *fbmode); +int of_get_display_mode(struct device_node *np, struct drm_display_mode *dmode, int index); +#endif /* __LINUX_VIDEOMODE_H */