On Thu, Sep 28, 2017 at 06:02:27PM +0200, Noralf Trønnes wrote:
>
> Den 28.09.2017 16.08, skrev Daniel Vetter:
> >On Thu, Sep 28, 2017 at 02:44:34PM +0530, Meghana Madhyastha wrote:
> >>Rename tinydrm_of_find_backlight to drm_of_find_backlight
> >>and move it into drm_of.c from tinydrm-helpers.c. This is
> >>because other drivers in the drm subsystem might need to call
> >>this function. In that case and otherwise, it is better from
> >>an organizational point of view to move it into drm_of.c along
> >>with the other _of.c functions.
> >>
> >>Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>
> >>---
> >>Changes in v3:
> >>-Change it back to a single patch from two patches in v2
> >>
> >> drivers/gpu/drm/drm_of.c | 44 ++++++++++++++++++++++++++
> >> drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 40 -----------------------
> >> drivers/gpu/drm/tinydrm/mi0283qt.c | 3 +-
> >> include/drm/drm_of.h | 1 +
> >> include/drm/tinydrm/tinydrm-helpers.h | 1 -
> >> 5 files changed, 47 insertions(+), 42 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
> >>index 8dafbdf..d878d3a 100644
> >>--- a/drivers/gpu/drm/drm_of.c
> >>+++ b/drivers/gpu/drm/drm_of.c
> >>@@ -1,6 +1,7 @@
> >> #include <linux/component.h>
> >> #include <linux/export.h>
> >> #include <linux/list.h>
> >>+#include <linux/backlight.h>
> >> #include <linux/of_graph.h>
> >> #include <drm/drmP.h>
> >> #include <drm/drm_bridge.h>
> >>@@ -260,3 +261,46 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
> >> return ret;
> >> }
> >> EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
> >>+
> >>+/**
> >>+ * drm_of_find_backlight - Find backlight device in device-tree
> >>+ * @dev: Device
> >>+ *
> >>+ * This function looks for a DT node pointed to by a property named 'backlight'
> >>+ * and uses of_find_backlight_by_node() to get the backlight device.
> >>+ * Additionally if the brightness property is zero, it is set to
> >>+ * max_brightness.
> >>+ *
> >>+ * Note: It is the responsibility of the caller to call put_device() when
> >>+ * releasing the resource.
> >>+ *
> >>+ * Returns:
> >>+ * NULL if there's no backlight property.
> >>+ * Error pointer -EPROBE_DEFER if the DT node is found, but no backlight device
> >>+ * is found.
> >>+ * If the backlight device is found, a pointer to the structure is returned.
> >>+ */
> >>+struct backlight_device *drm_of_find_backlight(struct device *dev)
> >>+{
> >>+ struct backlight_device *backlight;
> >>+ struct device_node *np;
> >>+
> >>+ np = of_parse_phandle(dev->of_node, "backlight", 0);
> >>+ if (!np)
> >>+ return NULL;
> >>+
> >>+ backlight = of_find_backlight_by_node(np);
> >>+ of_node_put(np);
> >>+
> >>+ if (!backlight)
> >>+ return ERR_PTR(-EPROBE_DEFER);
> >>+
> >>+ if (!backlight->props.brightness) {
> >>+ backlight->props.brightness = backlight->props.max_brightness;
> >>+ DRM_DEBUG_KMS("Backlight brightness set to %d\n",
> >>+ backlight->props.brightness);
> >>+ }
> >>+
> >>+ return backlight;
> >>+}
> >>+EXPORT_SYMBOL(drm_of_find_backlight);
> >>diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
> >>index bd6cce0..cd4c6a5 100644
> >>--- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
> >>+++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
> >>@@ -237,46 +237,6 @@ void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
> >> EXPORT_SYMBOL(tinydrm_xrgb8888_to_gray8);
> >> /**
> >>- * tinydrm_of_find_backlight - Find backlight device in device-tree
> >>- * @dev: Device
> >>- *
> >>- * This function looks for a DT node pointed to by a property named 'backlight'
> >>- * and uses of_find_backlight_by_node() to get the backlight device.
> >>- * Additionally if the brightness property is zero, it is set to
> >>- * max_brightness.
> >>- *
> >>- * Returns:
> >>- * NULL if there's no backlight property.
> >>- * Error pointer -EPROBE_DEFER if the DT node is found, but no backlight device
> >>- * is found.
> >>- * If the backlight device is found, a pointer to the structure is returned.
> >>- */
> >>-struct backlight_device *tinydrm_of_find_backlight(struct device *dev)
> >>-{
> >>- struct backlight_device *backlight;
> >>- struct device_node *np;
> >>-
> >>- np = of_parse_phandle(dev->of_node, "backlight", 0);
> >>- if (!np)
> >>- return NULL;
> >>-
> >>- backlight = of_find_backlight_by_node(np);
> >>- of_node_put(np);
> >>-
> >>- if (!backlight)
> >>- return ERR_PTR(-EPROBE_DEFER);
> >>-
> >>- if (!backlight->props.brightness) {
> >>- backlight->props.brightness = backlight->props.max_brightness;
> >>- DRM_DEBUG_KMS("Backlight brightness set to %d\n",
> >>- backlight->props.brightness);
> >>- }
> >>-
> >>- return backlight;
> >>-}
> >>-EXPORT_SYMBOL(tinydrm_of_find_backlight);
> >>-
> >>-/**
> >> * tinydrm_enable_backlight - Enable backlight helper
> >> * @backlight: Backlight device
> >> *
> >>diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
> >>index 7e5bb7d..5e3d635 100644
> >>--- a/drivers/gpu/drm/tinydrm/mi0283qt.c
> >>+++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
> >>@@ -12,6 +12,7 @@
> >> #include <drm/tinydrm/ili9341.h>
> >> #include <drm/tinydrm/mipi-dbi.h>
> >> #include <drm/tinydrm/tinydrm-helpers.h>
> >>+#include <drm/drm_of.h>
> >> #include <linux/delay.h>
> >> #include <linux/gpio/consumer.h>
> >> #include <linux/module.h>
> >>@@ -189,7 +190,7 @@ static int mi0283qt_probe(struct spi_device *spi)
> >> if (IS_ERR(mipi->regulator))
> >> return PTR_ERR(mipi->regulator);
> >>- mipi->backlight = tinydrm_of_find_backlight(dev);
> >>+ mipi->backlight = drm_of_find_backlight(dev);
> >> if (IS_ERR(mipi->backlight))
> >> return PTR_ERR(mipi->backlight);
> >>diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h
> >>index 104dd51..e8fba5b 100644
> >>--- a/include/drm/drm_of.h
> >>+++ b/include/drm/drm_of.h
> >>@@ -29,6 +29,7 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
> >> int port, int endpoint,
> >> struct drm_panel **panel,
> >> struct drm_bridge **bridge);
> >>+struct backlight_device *drm_of_find_backlight(struct device *dev);
> >> #else
> >> static inline uint32_t drm_of_find_possible_crtcs(struct drm_device *dev,
> >> struct device_node *port)
> >Minor detail I missed: The dummy version for the #else here is missing.
> >Not a problem for tinydrm, but might be an issue for a driver where
> >CONFIG_OF is optional.
>
> Yeah, we need a dummy version. tinydrm can in theory be used on non-DT
> platforms. The only resource that isn't available there is backlight
> since there is no platform or ACPI way of describing that dependency.
>
> Another problem I discovered when trying to compile this, is that if
> DRM is builtin and LCD_CLASS_DEVICE is a module:
>
> drivers/gpu/drm/drm_of.c:292: undefined reference to
> `of_find_backlight_by_node'
>
> I see that I solved this in tinydrm by just selecting
> BACKLIGHT_LCD_SUPPORT and LCD_CLASS_DEVICE. I'm not aware of a way to
> force LCD_CLASS_DEVICE to be builtin if DRM is builtin.
>
> Arnd fixed a similar type of dependecy in the repaper driver by forcing
> repaper to be a module if necessary. To be honest, I don't know why his
> fix works:
> https://github.com/torvalds/linux/commit/8312a3fe84b96e30a010fa20f933606d976ac002
I didn't quite understand how we could use this fix for the current
case. Isn't this specific to the repaper driver dependency ?
> Another way of solving this is to put the function in
> drivers/gpu/drm/drm_backlight.c and add a DRM_BACKLIGHT konfig option
> that does the selection.
>
> Noralf.
>
> >Otherwise I think this patch looks good.
> >-Daniel
> >
> >>diff --git a/include/drm/tinydrm/tinydrm-helpers.h b/include/drm/tinydrm/tinydrm-helpers.h
> >>index d554ded..e40ef2d 100644
> >>--- a/include/drm/tinydrm/tinydrm-helpers.h
> >>+++ b/include/drm/tinydrm/tinydrm-helpers.h
> >>@@ -46,7 +46,6 @@ void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
> >> void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
> >> struct drm_clip_rect *clip);
> >>-struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
> >> int tinydrm_enable_backlight(struct backlight_device *backlight);
> >> int tinydrm_disable_backlight(struct backlight_device *backlight);
> >>--
> >>2.7.4
> >>
>
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