Some panels support multiple LVDS data mapping formats, which can be
used e.g. run displays on jeida-18 format when only 3 LVDS lanes are
available.
Add parsing of an optional data-mapping devicetree property, which also
touches up the bits per color to match the bus format.
Signed-off-by: Johannes Zink <j.zink@pengutronix.de>
---
Changes:
v2 -> v3: - worked in Laurent's review findings (thanks for reviewing
my work):
- extract fixing up the bus format to separate
function
- only call function on LVDS panels
- fix typos found by Laurent
- simplified error handling
v1 -> v2: - fix missing unwind goto found by test robot
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202304160359.4LHmFOlU-lkp@intel.com/
---
drivers/gpu/drm/panel/panel-simple.c | 55 +++++++++++++++++++++++++++++++++++-
1 file changed, 54 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 4badda6570d5..0c25718dcb56 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -40,6 +40,7 @@
#include <drm/drm_edid.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_panel.h>
+#include <drm/drm_of.h>
/**
* struct panel_desc - Describes a simple panel.
@@ -549,6 +550,51 @@ static void panel_simple_parse_panel_timing_node(struct device *dev,
dev_err(dev, "Reject override mode: No display_timing found\n");
}
+static int panel_simple_override_nondefault_lvds_datamapping(struct device *dev,
+ struct panel_simple *panel)
+{
+ int ret, bpc;
+
+ ret = drm_of_lvds_get_data_mapping(dev->of_node);
+ if (ret < 0) {
+ if (ret == -EINVAL)
+ dev_warn(dev, "Ignore invalid data-mapping property\n");
+
+ /*
+ * Ignore non-existing or malformatted property, fallback to
+ * default data-mapping, and return 0.
+ */
+ return 0;
+ }
+
+ switch (ret) {
+ default:
+ WARN_ON(1);
+ fallthrough;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+ fallthrough;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+ bpc = 8;
+ break;
+ case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+ bpc = 6;
+ }
+
+ if (panel->desc->bpc != bpc || panel->desc->bus_format != ret) {
+ struct panel_desc *override_desc;
+
+ override_desc = devm_kmemdup(dev, panel->desc, sizeof(*panel->desc), GFP_KERNEL);
+ if (!override_desc)
+ return -ENOMEM;
+
+ override_desc->bus_format = ret;
+ override_desc->bpc = bpc;
+ panel->desc = override_desc;
+ }
+
+ return 0;
+}
+
static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
{
struct panel_simple *panel;
@@ -556,7 +602,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
struct device_node *ddc;
int connector_type;
u32 bus_flags;
- int err;
+ int err, ret;
panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
if (!panel)
@@ -601,6 +647,13 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
panel_simple_parse_panel_timing_node(dev, panel, &dt);
}
+ if (desc->connector_type == DRM_MODE_CONNECTOR_LVDS) {
+ /* Optional data-mapping property for overriding bus format */
+ ret = panel_simple_override_nondefault_lvds_datamapping(dev, panel);
+ if (ret)
+ goto free_ddc;
+ }
+
connector_type = desc->connector_type;
/* Catch common mistakes for panels. */
switch (connector_type) {
--
2.39.2On Fri, Jul 28, 2023 at 01:54:40PM +0200, Johannes Zink wrote:
> @@ -556,7 +602,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
> struct device_node *ddc;
> int connector_type;
> u32 bus_flags;
> - int err;
> + int err, ret;
I don't like this at all...
>
> panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
> if (!panel)
> @@ -601,6 +647,13 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
> panel_simple_parse_panel_timing_node(dev, panel, &dt);
> }
>
> + if (desc->connector_type == DRM_MODE_CONNECTOR_LVDS) {
> + /* Optional data-mapping property for overriding bus format */
> + ret = panel_simple_override_nondefault_lvds_datamapping(dev, panel);
> + if (ret)
> + goto free_ddc;
This *looks* like we are returning an error but we aren't. I think we
should be. If not then we need to have a discussion about that and
add some comments.
regards,
dan carpenter
> + }
> +
> connector_type = desc->connector_type;
> /* Catch common mistakes for panels. */
> switch (connector_type) {
>
> --
> 2.39.2
Hi Dan,
thanks for your feedback.
On 7/28/23 14:03, Dan Carpenter wrote:
> On Fri, Jul 28, 2023 at 01:54:40PM +0200, Johannes Zink wrote:
>> @@ -556,7 +602,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
>> struct device_node *ddc;
>> int connector_type;
>> u32 bus_flags;
>> - int err;
>> + int err, ret;
>
> I don't like this at all...
>
>>
>> panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
>> if (!panel)
>> @@ -601,6 +647,13 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
>> panel_simple_parse_panel_timing_node(dev, panel, &dt);
>> }
>>
>> + if (desc->connector_type == DRM_MODE_CONNECTOR_LVDS) {
>> + /* Optional data-mapping property for overriding bus format */
>> + ret = panel_simple_override_nondefault_lvds_datamapping(dev, panel);
>> + if (ret)
>> + goto free_ddc;
>
> This *looks* like we are returning an error but we aren't. I think we
> should be. If not then we need to have a discussion about that and
> add some comments.
>
Good catch. This should actually be err instead of ret. This way we'd make sure
to return -ENOMEM from panel_simple_probe() in case an error occured due
to devm_kmemdup failing in panel_simple_override_nondefault_lvds_datamapping().
I'll send a v4 with that fixed.
Thanks for having my back!
Johannes
> regards,
> dan carpenter
>
>> + }
>> +
>> connector_type = desc->connector_type;
>> /* Catch common mistakes for panels. */
>> switch (connector_type) {
>>
>> --
>> 2.39.2
>
>
--
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