On Fri, Nov 23, 2012 at 03:49:37PM +0530, Leela Krishna Amudala wrote:
Hello Steffen,
On Fri, Nov 23, 2012 at 2:34 PM, Steffen Trumtrar s.trumtrar@pengutronix.de wrote:
This adds support for reading display timings from DT into a struct display_timings. The of_display_timing implementation supports multiple subnodes. All children are read into an array, that can be queried.
If no native mode is specified, the first subnode will be used.
For cases, where the graphics drivers knows, there can be only one mode description or where the driver only supports one mode, a helper function of_get_videomode is added, that gets a struct videomode from DT. (As this function is implemented in an expensive fashion, it should only be used in the aforementioned case).
This also demonstrates how of_display_timings may be utilized.
Signed-off-by: Steffen Trumtrar s.trumtrar@pengutronix.de Signed-off-by: Philipp Zabel p.zabel@pengutronix.de Acked-by: Stephen Warren swarren@nvidia.com Reviewed-by: Thierry Reding thierry.reding@avionic-design.de Acked-by: Thierry Reding thierry.reding@avionic-design.de Tested-by: Thierry Reding thierry.reding@avionic-design.de Tested-by: Philipp Zabel p.zabel@pengutronix.de Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
.../devicetree/bindings/video/display-timings.txt | 107 ++++++++++ drivers/video/Kconfig | 15 ++ drivers/video/Makefile | 2 + drivers/video/of_display_timing.c | 223 ++++++++++++++++++++ drivers/video/of_videomode.c | 48 +++++ include/linux/of_display_timings.h | 20 ++ include/linux/of_videomode.h | 18 ++ 7 files changed, 433 insertions(+) create mode 100644 Documentation/devicetree/bindings/video/display-timings.txt create mode 100644 drivers/video/of_display_timing.c create mode 100644 drivers/video/of_videomode.c create mode 100644 include/linux/of_display_timings.h create mode 100644 include/linux/of_videomode.h
<<<snip>>>
diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_display_timing.c new file mode 100644 index 0000000..645f43d --- /dev/null +++ b/drivers/video/of_display_timing.c @@ -0,0 +1,223 @@ +/*
- 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/export.h> +#include <linux/of_display_timings.h>
+/**
- parse_property - parse timing_entry from device_node
- @np: device_node with the property
- @name: name of the property
- @result: will be set to the return value
- DESCRIPTION:
- Every display_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 parse_property(const struct device_node *np, const char *name,
struct timing_entry *result)+{
struct property *prop;int length, cells, 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(np, name, &result->typ);result->min = result->typ;result->max = result->typ;} 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;+}
+/**
- of_get_display_timing - parse display_timing entry from device_node
- @np: device_node with the properties
- **/
+static struct display_timing *of_get_display_timing(const struct device_node
*np)+{
struct display_timing *dt;int ret = 0;dt = kzalloc(sizeof(*dt), GFP_KERNEL);if (!dt) {pr_err("%s: could not allocate display_timing struct\n",__func__);return NULL;}ret |= parse_property(np, "hback-porch", &dt->hback_porch);ret |= parse_property(np, "hfront-porch", &dt->hfront_porch);ret |= parse_property(np, "hactive", &dt->hactive);ret |= parse_property(np, "hsync-len", &dt->hsync_len);ret |= parse_property(np, "vback-porch", &dt->vback_porch);ret |= parse_property(np, "vfront-porch", &dt->vfront_porch);ret |= parse_property(np, "vactive", &dt->vactive);ret |= parse_property(np, "vsync-len", &dt->vsync_len);ret |= parse_property(np, "clock-frequency", &dt->pixelclock);of_property_read_u32(np, "vsync-active", &dt->vsync_pol_active);of_property_read_u32(np, "hsync-active", &dt->hsync_pol_active);of_property_read_u32(np, "de-active", &dt->de_pol_active);of_property_read_u32(np, "pixelclk-inverted", &dt->pixelclk_pol);dt->interlaced = of_property_read_bool(np, "interlaced");dt->doublescan = of_property_read_bool(np, "doublescan");if (ret) {pr_err("%s: error reading timing properties\n", __func__);kfree(dt);return NULL;}return dt;+}
+/**
- of_get_display_timings - parse all display_timing entries from a device_node
- @np: device_node with the subnodes
- **/
+struct display_timings *of_get_display_timings(struct device_node *np) +{
struct device_node *timings_np;struct device_node *entry;struct device_node *native_mode;struct display_timings *disp;if (!np) {pr_err("%s: no devicenode given\n", __func__);return NULL;}timings_np = of_find_node_by_name(np, "display-timings");if (!timings_np) {pr_err("%s: could not find display-timings node\n", __func__);return NULL;}disp = kzalloc(sizeof(*disp), GFP_KERNEL);if (!disp) {pr_err("%s: could not allocate struct disp'\n", __func__);goto dispfail;}entry = of_parse_phandle(timings_np, "native-mode", 0);/* assume first child as native mode if none provided */if (!entry)entry = of_get_next_child(np, NULL);/* if there is no child, it is useless to go on */if (!entry) {pr_err("%s: no timing specifications given\n", __func__);goto entryfail;}pr_info("%s: using %s as default timing\n", __func__, entry->name);native_mode = entry;disp->num_timings = of_get_child_count(timings_np);if (disp->num_timings == 0) {/* should never happen, as entry was already found above */pr_err("%s: no timings specified\n", __func__);goto entryfail;}disp->timings = kzalloc(sizeof(struct display_timing *) * disp->num_timings,GFP_KERNEL);if (!disp->timings) {pr_err("%s: could not allocate timings array\n", __func__);goto entryfail;}disp->num_timings = 0;disp->native_mode = 0;for_each_child_of_node(timings_np, entry) {struct display_timing *dt;dt = of_get_display_timing(entry);if (!dt) {/** to not encourage wrong devicetrees, fail in case of* an error*/pr_err("%s: error in timing %d\n", __func__,disp->num_timings + 1);goto timingfail;}if (native_mode == entry)disp->native_mode = disp->num_timings;disp->timings[disp->num_timings] = dt;disp->num_timings++;}of_node_put(timings_np);/** native_mode points to the device_node returned by of_parse_phandle* therefore call of_node_put on it*/of_node_put(native_mode);if (disp->num_timings > 0)pr_info("%s: got %d timings. Using timing #%d as default\n",__func__, disp->num_timings, disp->native_mode + 1);else {pr_err("%s: no valid timings specified\n", __func__);display_timings_release(disp);return NULL;}return disp;+timingfail:
if (native_mode)of_node_put(native_mode);display_timings_release(disp);+entryfail:
if (disp)kfree(disp);+dispfail:
of_node_put(timings_np);return NULL;+} +EXPORT_SYMBOL_GPL(of_get_display_timings);
+/**
- of_display_timings_exists - check if a display-timings node is provided
- @np: device_node with the timing
- **/
+int of_display_timings_exists(const struct device_node *np) +{
struct device_node *timings_np;if (!np)return -EINVAL;timings_np = of_parse_phandle(np, "display-timings", 0);I'm seeing warning for the above call "passing argument 1 of 'of_parse_phandle' discards qualifiers from pointer target type expected 'struct device_node *' but argument is of type 'const struct device_node *' " Please take care of it.
I already sent a patch for of_parse_phandle that makes its device_node pointer const. That fixes this warning. As I got that patch also on my tree, I did miss removing the const for the time being.
Regards, Steffen