dt-bindings: samsung,mipi-dsim: Add 'lane-polarities'

PATCH Applied Fabio Estevam 3 participants 6 messages May 14, 2023 – May 22, 2023

Subsystems (5)

Device tree bindings DRM drivers DRM misc DRM drivers for bridge chips +1 more subsystems

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Fabio Estevam

author

2023-05-14 11:46 UTC #0 lore raw

PATCH v4 1/2 dt-bindings: samsung,mipi-dsim: Add 'lane-polarities'

From: Fabio Estevam <[email protected]>

The Samsung DSIM IP block allows the inversion of the clock and data lanes.

Add an optional property called 'lane-polarities' that describes the polarities of the MIPI DSI clock and data lanes.

This property is useful for properly describing the hardware when the board designer decided to switch the polarities of the MIPI DSI clock and/or data lanes.

Signed-off-by Fabio Estevam <[email protected]>

---
Changes since v3:
- Dropped oneOf, no need for it. (Krzysztof)
- Dropped description as it is obvious. (Krzysztof)
- Dropped items, as it is already in video-interfaces. (Krzysztof)
- Dropped "See ../../media/video-interfaces.yaml". (Krzysztof)

 .../display/bridge/samsung,mipi-dsim.yaml     | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

Documentation/devicetree/bindings/display/bridge/samsung,mipi-dsim.yaml +23 -0

index e841659e20cd..9f61ebdfefa8 100644
@@ -105,6 +105,29 @@ properties:
           DSI output port node to the panel or the next bridge
           in the chain.
 
+        properties:
+          endpoint:
+            $ref: /schemas/media/video-interfaces.yaml#
+            unevaluatedProperties: false
+
+            properties:
+              data-lanes:
+                minItems: 1
+                maxItems: 4
+                uniqueItems: true
+                items:
+                  enum: [ 1, 2, 3, 4 ]
+
+              lane-polarities:
+                minItems: 1
+                maxItems: 5
+                description:
+                  The Samsung MIPI DSI IP requires that all the data lanes have
+                  the same polarity.
+
+            dependencies:
+              lane-polarities: [data-lanes]
+
 required:
   - clock-names
   - clocks

Signature · 1 line

2.34.1

Fabio Estevam

author

2023-05-14 11:46 UTC #1 lore raw

PATCH v4 2/2 drm: bridge: samsung-dsim: Implement support for clock/data polarity swap

From: Marek Vasut <[email protected]>

Implement support for DSI clock and data lane DN/DP polarity swap by means of decoding 'lane-polarities' DT property. The controller does support DN/DP swap of clock lane and all data lanes, the controller does not support polarity swap of individual data lane bundles, add a check which verifies all data lanes have the same polarity.

This has been validated on an imx8mm board that actually has the MIPI DSI clock lanes inverted.

Signed-off-by Marek Vasut <[email protected]>

Signed-off-by Fabio Estevam <[email protected]>

Reviewed-by Jagan Teki <[email protected]>

---
Changes since v3:
- None

 drivers/gpu/drm/bridge/samsung-dsim.c | 27 ++++++++++++++++++++++++++-
 include/drm/bridge/samsung-dsim.h     |  2 ++
 2 files changed, 28 insertions(+), 1 deletion(-)

drivers/gpu/drm/bridge/samsung-dsim.c +26 -1

index e0a402a85787..5791148e2da2 100644
@@ -183,6 +183,8 @@
 #define DSIM_AFC_CTL(x)			(((x) & 0x7) << 5)
 
 /* DSIM_PLLCTRL */
+#define DSIM_PLL_DPDNSWAP_CLK		(1 << 25)
+#define DSIM_PLL_DPDNSWAP_DAT		(1 << 24)
 #define DSIM_FREQ_BAND(x)		((x) << 24)
 #define DSIM_PLL_EN			BIT(23)
 #define DSIM_PLL_P(x, offset)		((x) << (offset))

@@ -622,6 +624,11 @@ static unsigned long samsung_dsim_set_pll(struct samsung_dsim *dsi,
 		reg |= DSIM_FREQ_BAND(band);
 	}
 
+	if (dsi->swap_dn_dp_clk)
+		reg |= DSIM_PLL_DPDNSWAP_CLK;
+	if (dsi->swap_dn_dp_data)
+		reg |= DSIM_PLL_DPDNSWAP_DAT;
+
 	samsung_dsim_write(dsi, DSIM_PLLCTRL_REG, reg);
 
 	timeout = 1000;

@@ -1696,7 +1703,9 @@ static int samsung_dsim_parse_dt(struct samsung_dsim *dsi)
 {
 	struct device *dev = dsi->dev;
 	struct device_node *node = dev->of_node;
-	int ret;
+	u32 lane_polarities[5] = { 0 };
+	struct device_node *endpoint;
+	int i, nr_lanes, ret;
 
 	ret = samsung_dsim_of_read_u32(node, "samsung,pll-clock-frequency",
 				       &dsi->pll_clk_rate);

@@ -1713,6 +1722,22 @@ static int samsung_dsim_parse_dt(struct samsung_dsim *dsi)
 	if (ret < 0)
 		return ret;
 
+	endpoint = of_graph_get_endpoint_by_regs(node, 1, -1);
+	nr_lanes = of_property_count_u32_elems(endpoint, "data-lanes");
+	if (nr_lanes > 0 && nr_lanes <= 4) {
+		/* Polarity 0 is clock lane, 1..4 are data lanes. */
+		of_property_read_u32_array(endpoint, "lane-polarities",
+					   lane_polarities, nr_lanes + 1);
+		for (i = 1; i <= nr_lanes; i++) {
+			if (lane_polarities[1] != lane_polarities[i])
+				DRM_DEV_ERROR(dsi->dev, "Data lanes polarities do not match");
+		}
+		if (lane_polarities[0])
+			dsi->swap_dn_dp_clk = true;
+		if (lane_polarities[1])
+			dsi->swap_dn_dp_data = true;
+	}
+
 	return 0;
 }

include/drm/bridge/samsung-dsim.h +2 -0

index ba5484de2b30..6a37d1e079bf 100644
@@ -95,6 +95,8 @@ struct samsung_dsim {
 	u32 mode_flags;
 	u32 format;
 
+	bool swap_dn_dp_clk;
+	bool swap_dn_dp_data;
 	int state;
 	struct drm_property *brightness;
 	struct completion completed;

Signature · 1 line

2.34.1

Krzysztof Kozlowski

Reviewed-by on v4 1/2

2023-05-14 12:29 UTC #2 lore raw

In reply to Fabio Estevam

Quoted 7 lines · Fabio Estevam

From: Fabio Estevam <[email protected]>
The Samsung DSIM IP block allows the inversion of the clock and data lanes.
Add an optional property called 'lane-polarities' that describes the polarities of the MIPI DSI clock and data lanes.

Reviewed-by Krzysztof Kozlowski <[email protected]>

Best regards,
Krzysztof

Fabio Estevam

author

2023-05-22 12:53 UTC #3 lore raw

Re: [PATCH v4 1/2] dt-bindings: samsung, mipi-dsim: Add 'lane-polarities'

Hi Neil,

Quoted 4 lines · Krzysztof Kozlowski

Quoted 2 lines · Fabio Estevam
From: Fabio Estevam <[email protected]>

Quoted 8 lines

Quoted 5 lines
The Samsung DSIM IP block allows the inversion of the clock and data lanes.
Add an optional property called 'lane-polarities' that describes the polarities of the MIPI DSI clock and data lanes.
Reviewed-by Krzysztof Kozlowski <[email protected]>

Could you please apply this series?

Thanks

[email protected]

maintainer

2023-05-22 13:45 UTC #4 lore raw

Quoted 11 lines · Fabio Estevam

Hi Neil,
Quoted 7 lines · Krzysztof Kozlowski
Quoted 5 lines · Fabio Estevam
From: Fabio Estevam <[email protected]>
The Samsung DSIM IP block allows the inversion of the clock and data lanes.

Quoted 7 lines

Quoted 5 lines
Quoted 2 lines
Add an optional property called 'lane-polarities' that describes the polarities of the MIPI DSI clock and data lanes.
Reviewed-by Krzysztof Kozlowski <[email protected]>
Could you please apply this series?

Done !

Thanks,
Neil

Quoted 2 lines

Thanks

Neil Armstrong

maintainer Applied

2023-05-22 13:44 UTC #5 lore raw

In reply to Fabio Estevam

Hi,

Quoted 11 lines · Fabio Estevam

The Samsung DSIM IP block allows the inversion of the clock and data lanes.
Add an optional property called 'lane-polarities' that describes the polarities of the MIPI DSI clock and data lanes.
This property is useful for properly describing the hardware when the board designer decided to switch the polarities of the MIPI DSI clock and/or data lanes.
[...]

Thanks, Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)

[1/2] dt-bindings: samsung,mipi-dsim: Add 'lane-polarities'

      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ec7743c9c48a14aa884d27f2feee1da30810ce0a
[2/2] drm: bridge: samsung-dsim: Implement support for clock/data polarity swap
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=74629c49e66cc6d36c46ac4e3f059780873ceedf

Signature · 1 line

Neil