[linux][PATCH v2 0/4] LVDS Controller Support for SAM9X75 SoC

[linux][PATCH v2 0/4] LVDS Controller Support for SAM9X75 SoC

[Dharma Balasubiramani]

This patch series introduces LVDS controller support for the SAM9X75 SoC. The
LVDS controller is designed to work with Microchip's sam9x7 series
System-on-Chip (SoC) devices, providing Low Voltage Differential Signaling
capabilities.

Patch series Changelog:
- Include configs: at91: Enable LVDS serializer

The Individual Changelogs are available on the respective patches.

Dharma Balasubiramani (4):
  dt-bindings: display: bridge: add sam9x75-lvds compatible
  drm/bridge: add lvds controller support for sam9x7
  MAINTAINERS: add SAM9X7 SoC's LVDS controller
  ARM: configs: at91: Enable LVDS serializer support

 .../bridge/microchip,sam9x75-lvds.yaml        |  55 ++++
 MAINTAINERS                                   |   8 +
 arch/arm/configs/at91_dt_defconfig            |   1 +
 drivers/gpu/drm/bridge/Kconfig                |   7 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 drivers/gpu/drm/bridge/microchip-lvds.c       | 246 ++++++++++++++++++
 6 files changed, 318 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
 create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c


base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a
-- 
2.25.1

[linux][PATCH v2 1/4] dt-bindings: display: bridge: add sam9x75-lvds compatible

[Dharma Balasubiramani]

Add the 'sam9x75-lvds' compatible binding, which describes the Low Voltage
Differential Signaling (LVDS) Controller found on some Microchip's sam9x7
series System-on-Chip (SoC) devices. This binding will be used to define
the properties and configuration for the LVDS Controller in DT.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
---
Changelog
v1 -> v2
- Remove '|' in description, as there is no formatting to preserve.
- Remove 'gclk' from clock-names as there is only one clock(pclk).
- Remove the unused headers and include only used ones.
- Change the compatible name specific to SoC (sam9x75) instead of entire series.
- Change file name to match the compatible name.
---
 .../bridge/microchip,sam9x75-lvds.yaml        | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml b/Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
new file mode 100644
index 000000000000..862ef441ac9f
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/microchip,sam9x75-lvds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip SAM9X75 LVDS Controller
+
+maintainers:
+  - Dharma Balasubiramani <dharma.b@microchip.com>
+
+description:
+  The Low Voltage Differential Signaling Controller (LVDSC) manages data
+  format conversion from the LCD Controller internal DPI bus to OpenLDI
+  LVDS output signals. LVDSC functions include bit mapping, balanced mode
+  management, and serializer.
+
+properties:
+  compatible:
+    const: microchip,sam9x75-lvds
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Peripheral Bus Clock
+
+  clock-names:
+    items:
+      - const: pclk
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/clock/at91.h>
+    lvds-controller@f8060000 {
+      compatible = "microchip,sam9x75-lvds";
+      reg = <0xf8060000 0x100>;
+      interrupts = <56 IRQ_TYPE_LEVEL_HIGH 0>;
+      clocks = <&pmc PMC_TYPE_PERIPHERAL 56>;
+      clock-names = "pclk";
+    };
-- 
2.25.1

[linux][PATCH v2 2/4] drm/bridge: add lvds controller support for sam9x7

[Dharma Balasubiramani]

Add a new LVDS controller driver for sam9x7 which does the following:
- Prepares and enables the LVDS Peripheral clock
- Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
to the global bridge list.
- Identifies its output endpoint as panel and adds it to the encoder
display pipeline
- Enables the LVDS serializer

Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
---
Changelog
v1 -> v2
- Drop 'res' variable and combine two lines into one.
- Handle deferred probe properly, use dev_err_probe().
- Don't print anything on deferred probe. Dropped print.
- Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
- symbol 'mchp_lvds_driver' was not declared. It should be static.
---
 drivers/gpu/drm/bridge/Kconfig          |   7 +
 drivers/gpu/drm/bridge/Makefile         |   1 +
 drivers/gpu/drm/bridge/microchip-lvds.c | 246 ++++++++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 3e6a4e2044c0..200afb36e421 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -173,6 +173,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
 	  to DP++. This is used with the i.MX6 imx-ldb
 	  driver. You are likely to say N here.
 
+config DRM_MICROCHIP_LVDS_SERIALIZER
+	tristate "Microchip LVDS serailzer support"
+	depends on OF
+	depends on DRM_ATMEL_HLCDC
+	help
+	  Support for Microchip's LVDS serializer.
+
 config DRM_NWL_MIPI_DSI
 	tristate "Northwest Logic MIPI DSI Host controller"
 	depends on DRM
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 2b892b7ed59e..e3804e93d324 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
 obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
 obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
 obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
+obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
 obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
 obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
 obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
new file mode 100644
index 000000000000..508321ad0f66
--- /dev/null
+++ b/drivers/gpu/drm/bridge/microchip-lvds.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Manikandan Muralidharan <manikandan.m@microchip.com>
+ * Author: Dharma Balasubiramani <dharma.b@microchip.com>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_graph.h>
+#include <linux/pinctrl/devinfo.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#define LVDS_POLL_TIMEOUT_MS 1000
+
+/* LVDSC register offsets */
+#define LVDSC_CR	0x00
+#define LVDSC_CFGR	0x04
+#define LVDSC_SR	0x0C
+#define LVDSC_WPMR	0xE4
+
+/* Bitfields in LVDSC_CR (Control Register) */
+#define LVDSC_CR_SER_EN	BIT(0)
+
+/* Bitfields in LVDSC_CFGR (Configuration Register) */
+#define LVDSC_CFGR_PIXSIZE_24BITS	0
+#define LVDSC_CFGR_DEN_POL_HIGH		0
+#define LVDSC_CFGR_DC_UNBALANCED	0
+#define LVDSC_CFGR_MAPPING_JEIDA	BIT(6)
+
+/*Bitfields in LVDSC_SR */
+#define LVDSC_SR_CS	BIT(0)
+
+/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
+#define LVDSC_WPMR_WPKEY_MASK	GENMASK(31, 8)
+#define LVDSC_WPMR_WPKEY_PSSWD	0x4C5644
+
+struct mchp_lvds {
+	struct device *dev;
+	void __iomem *regs;
+	struct clk *pclk;
+	int format; /* vesa or jeida format */
+	struct drm_panel *panel;
+	struct drm_bridge bridge;
+	struct drm_bridge *panel_bridge;
+};
+
+static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct mchp_lvds, bridge);
+}
+
+static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
+{
+	return readl_relaxed(lvds->regs + offset);
+}
+
+static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
+{
+	writel_relaxed(val, lvds->regs + offset);
+}
+
+static void lvds_serialiser_on(struct mchp_lvds *lvds)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
+
+	/* The LVDSC registers can only be written if WPEN is cleared */
+	lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
+				LVDSC_WPMR_WPKEY_MASK));
+
+	/* Wait for the status of configuration registers to be changed */
+	while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
+		if (time_after(jiffies, timeout)) {
+			dev_err(lvds->dev, "%s: timeout error\n", __func__);
+			return;
+		}
+		usleep_range(1000, 2000);
+	}
+
+	/* Configure the LVDSC */
+	lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
+				LVDSC_CFGR_DC_UNBALANCED |
+				LVDSC_CFGR_DEN_POL_HIGH |
+				LVDSC_CFGR_PIXSIZE_24BITS));
+
+	/* Enable the LVDS serializer */
+	lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
+}
+
+static int mchp_lvds_attach(struct drm_bridge *bridge,
+			    enum drm_bridge_attach_flags flags)
+{
+	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+
+	bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
+
+	return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
+				 bridge, flags);
+}
+
+static void mchp_lvds_enable(struct drm_bridge *bridge)
+{
+	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+	int ret;
+
+	ret = clk_enable(lvds->pclk);
+	if (ret < 0) {
+		DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
+		return;
+	}
+
+	ret = pm_runtime_get_sync(lvds->dev);
+	if (ret < 0) {
+		DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
+		clk_disable(lvds->pclk);
+		return;
+	}
+
+	lvds_serialiser_on(lvds);
+}
+
+static void mchp_lvds_disable(struct drm_bridge *bridge)
+{
+	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
+
+	pm_runtime_put(lvds->dev);
+	clk_disable(lvds->pclk);
+}
+
+static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
+	.attach = mchp_lvds_attach,
+	.enable = mchp_lvds_enable,
+	.disable = mchp_lvds_disable,
+};
+
+static int mchp_lvds_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mchp_lvds *lvds;
+	struct device_node *port;
+	int ret;
+
+	if (!dev->of_node)
+		return -ENODEV;
+
+	lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
+	if (!lvds)
+		return -ENOMEM;
+
+	lvds->dev = dev;
+
+	lvds->regs = devm_ioremap_resource(lvds->dev,
+			platform_get_resource(pdev, IORESOURCE_MEM, 0));
+	if (IS_ERR(lvds->regs))
+		return PTR_ERR(lvds->regs);
+
+	lvds->pclk = devm_clk_get(lvds->dev, "pclk");
+	if (IS_ERR(lvds->pclk))
+		return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
+				"could not get pclk_lvds\n");
+
+	ret = clk_prepare(lvds->pclk);
+	if (ret < 0) {
+		DRM_DEV_ERROR(lvds->dev, "failed to prepare pclk_lvds\n");
+		return ret;
+	}
+
+	port = of_graph_get_remote_node(dev->of_node, 1, 0);
+	if (!port) {
+		DRM_DEV_ERROR(dev,
+			      "can't find port point, please init lvds panel port!\n");
+		return -EINVAL;
+	}
+
+	lvds->panel = of_drm_find_panel(port);
+	of_node_put(port);
+
+	if (IS_ERR(lvds->panel))
+		return -EPROBE_DEFER;
+
+	lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
+
+	if (IS_ERR(lvds->panel_bridge))
+		return PTR_ERR(lvds->panel_bridge);
+
+	lvds->bridge.of_node = dev->of_node;
+	lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
+	lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
+
+	dev_set_drvdata(dev, lvds);
+	pm_runtime_enable(dev);
+
+	drm_bridge_add(&lvds->bridge);
+
+	return 0;
+}
+
+static int mchp_lvds_remove(struct platform_device *pdev)
+{
+	struct mchp_lvds *lvds = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(&pdev->dev);
+	clk_unprepare(lvds->pclk);
+
+	return 0;
+}
+
+static const struct of_device_id mchp_lvds_dt_ids[] = {
+	{
+		.compatible = "microchip,sam9x75-lvds",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
+
+static struct platform_driver mchp_lvds_driver = {
+	.probe = mchp_lvds_probe,
+	.remove = mchp_lvds_remove,
+	.driver = {
+		   .name = "microchip-lvds",
+		   .of_match_table = mchp_lvds_dt_ids,
+	},
+};
+module_platform_driver(mchp_lvds_driver);
+
+MODULE_AUTHOR("Manikandan Muralidharan <manikandan.m@microchip.com>");
+MODULE_AUTHOR("Dharma Balasubiramani <dharma.b@microchip.com>");
+MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1

[linux][PATCH v2 3/4] MAINTAINERS: add SAM9X7 SoC's LVDS controller

[Dharma Balasubiramani]

Add the newly added LVDS controller for the SAM9X7 SoC to the existing
MAINTAINERS entry.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
---
Changelog
v1 -> v2
- No Changes.
---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index a7c4cf8201e0..24a266d20df6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14230,6 +14230,14 @@ S:	Supported
 F:	Documentation/devicetree/bindings/power/reset/atmel,sama5d2-shdwc.yaml
 F:	drivers/power/reset/at91-sama5d2_shdwc.c
 
+MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
+M:	Manikandan Muralidharan <manikandan.m@microchip.com>
+M:	Dharma Balasubiramani <dharma.b@microchip.com>
+L:	dri-devel@lists.freedesktop.org
+S:	Supported
+F:	Documentation/devicetree/bindings/display/bridge/microchip,sam9x7-lvds.yaml
+F:	drivers/gpu/drm/bridge/microchip-lvds.c
+
 MICROCHIP SOC DRIVERS
 M:	Conor Dooley <conor@kernel.org>
 S:	Supported
-- 
2.25.1

[linux][PATCH v2 4/4] ARM: configs: at91: Enable LVDS serializer support

[Dharma Balasubiramani]

Enable LVDS serializer support for display pipeline.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
Acked-by: Hari Prasath Gujulan Elango <hari.prasathge@microchip.com>
---
 arch/arm/configs/at91_dt_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
index 71b5acc78187..6a7714beb099 100644
--- a/arch/arm/configs/at91_dt_defconfig
+++ b/arch/arm/configs/at91_dt_defconfig
@@ -143,6 +143,7 @@ CONFIG_VIDEO_OV2640=m
 CONFIG_VIDEO_OV7740=m
 CONFIG_DRM=y
 CONFIG_DRM_ATMEL_HLCDC=y
+CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER=y
 CONFIG_DRM_PANEL_SIMPLE=y
 CONFIG_DRM_PANEL_EDP=y
 CONFIG_FB_ATMEL=y
-- 
2.25.1

Re: [linux][PATCH v2 2/4] drm/bridge: add lvds controller support for sam9x7

[neil.armstrong]

Hi,

On 05/02/2024 12:06, Dharma Balasubiramani wrote:
> Add a new LVDS controller driver for sam9x7 which does the following:
> - Prepares and enables the LVDS Peripheral clock
> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
> to the global bridge list.
> - Identifies its output endpoint as panel and adds it to the encoder
> display pipeline
> - Enables the LVDS serializer
> 
> Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
> ---
> Changelog
> v1 -> v2
> - Drop 'res' variable and combine two lines into one.
> - Handle deferred probe properly, use dev_err_probe().
> - Don't print anything on deferred probe. Dropped print.
> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
> - symbol 'mchp_lvds_driver' was not declared. It should be static.
> ---
>   drivers/gpu/drm/bridge/Kconfig          |   7 +
>   drivers/gpu/drm/bridge/Makefile         |   1 +
>   drivers/gpu/drm/bridge/microchip-lvds.c | 246 ++++++++++++++++++++++++
>   3 files changed, 254 insertions(+)
>   create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 3e6a4e2044c0..200afb36e421 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -173,6 +173,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
>   	  to DP++. This is used with the i.MX6 imx-ldb
>   	  driver. You are likely to say N here.
>   
> +config DRM_MICROCHIP_LVDS_SERIALIZER
> +	tristate "Microchip LVDS serailzer support"
---------------------------------/\

Should be serializer

> +	depends on OF
> +	depends on DRM_ATMEL_HLCDC
> +	help
> +	  Support for Microchip's LVDS serializer.
> +
>   config DRM_NWL_MIPI_DSI
>   	tristate "Northwest Logic MIPI DSI Host controller"
>   	depends on DRM
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 2b892b7ed59e..e3804e93d324 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
>   obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
>   obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
>   obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> +obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>   obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
> diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
> new file mode 100644
> index 000000000000..508321ad0f66
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/microchip-lvds.c
> @@ -0,0 +1,246 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
> + *
> + * Author: Manikandan Muralidharan <manikandan.m@microchip.com>
> + * Author: Dharma Balasubiramani <dharma.b@microchip.com>
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/delay.h>
> +#include <linux/jiffies.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_graph.h>
> +#include <linux/pinctrl/devinfo.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +#include <drm/drm_probe_helper.h>
> +#include <drm/drm_simple_kms_helper.h>
> +
> +#define LVDS_POLL_TIMEOUT_MS 1000
> +
> +/* LVDSC register offsets */
> +#define LVDSC_CR	0x00
> +#define LVDSC_CFGR	0x04
> +#define LVDSC_SR	0x0C
> +#define LVDSC_WPMR	0xE4
> +
> +/* Bitfields in LVDSC_CR (Control Register) */
> +#define LVDSC_CR_SER_EN	BIT(0)
> +
> +/* Bitfields in LVDSC_CFGR (Configuration Register) */
> +#define LVDSC_CFGR_PIXSIZE_24BITS	0
> +#define LVDSC_CFGR_DEN_POL_HIGH		0
> +#define LVDSC_CFGR_DC_UNBALANCED	0
> +#define LVDSC_CFGR_MAPPING_JEIDA	BIT(6)
> +
> +/*Bitfields in LVDSC_SR */
> +#define LVDSC_SR_CS	BIT(0)
> +
> +/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
> +#define LVDSC_WPMR_WPKEY_MASK	GENMASK(31, 8)
> +#define LVDSC_WPMR_WPKEY_PSSWD	0x4C5644
> +
> +struct mchp_lvds {
> +	struct device *dev;
> +	void __iomem *regs;
> +	struct clk *pclk;
> +	int format; /* vesa or jeida format */
> +	struct drm_panel *panel;
> +	struct drm_bridge bridge;
> +	struct drm_bridge *panel_bridge;
> +};
> +
> +static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct mchp_lvds, bridge);
> +}
> +
> +static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
> +{
> +	return readl_relaxed(lvds->regs + offset);
> +}
> +
> +static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, u32 val)
> +{
> +	writel_relaxed(val, lvds->regs + offset);
> +}
> +
> +static void lvds_serialiser_on(struct mchp_lvds *lvds)
> +{
> +	unsigned long timeout = jiffies + msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
> +
> +	/* The LVDSC registers can only be written if WPEN is cleared */
> +	lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
> +				LVDSC_WPMR_WPKEY_MASK));
> +
> +	/* Wait for the status of configuration registers to be changed */
> +	while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
> +		if (time_after(jiffies, timeout)) {
> +			dev_err(lvds->dev, "%s: timeout error\n", __func__);
> +			return;
> +		}
> +		usleep_range(1000, 2000);
> +	}
> +
> +	/* Configure the LVDSC */
> +	lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
> +				LVDSC_CFGR_DC_UNBALANCED |
> +				LVDSC_CFGR_DEN_POL_HIGH |
> +				LVDSC_CFGR_PIXSIZE_24BITS));
> +
> +	/* Enable the LVDS serializer */
> +	lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
> +}
> +
> +static int mchp_lvds_attach(struct drm_bridge *bridge,
> +			    enum drm_bridge_attach_flags flags)
> +{
> +	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +
> +	bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
> +
> +	return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
> +				 bridge, flags);
> +}
> +
> +static void mchp_lvds_enable(struct drm_bridge *bridge)
> +{
> +	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +	int ret;
> +
> +	ret = clk_enable(lvds->pclk);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk %d\n", ret);
> +		return;
> +	}
> +
> +	ret = pm_runtime_get_sync(lvds->dev);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: %d\n", ret);
> +		clk_disable(lvds->pclk);
> +		return;
> +	}
> +
> +	lvds_serialiser_on(lvds);
> +}
> +
> +static void mchp_lvds_disable(struct drm_bridge *bridge)
> +{
> +	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +
> +	pm_runtime_put(lvds->dev);
> +	clk_disable(lvds->pclk);
> +}
> +
> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
> +	.attach = mchp_lvds_attach,
> +	.enable = mchp_lvds_enable,
> +	.disable = mchp_lvds_disable,
> +};
> +
> +static int mchp_lvds_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mchp_lvds *lvds;
> +	struct device_node *port;
> +	int ret;
> +
> +	if (!dev->of_node)
> +		return -ENODEV;
> +
> +	lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
> +	if (!lvds)
> +		return -ENOMEM;
> +
> +	lvds->dev = dev;
> +
> +	lvds->regs = devm_ioremap_resource(lvds->dev,
> +			platform_get_resource(pdev, IORESOURCE_MEM, 0));
> +	if (IS_ERR(lvds->regs))
> +		return PTR_ERR(lvds->regs);
> +
> +	lvds->pclk = devm_clk_get(lvds->dev, "pclk");
> +	if (IS_ERR(lvds->pclk))
> +		return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
> +				"could not get pclk_lvds\n");
> +
> +	ret = clk_prepare(lvds->pclk);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(lvds->dev, "failed to prepare pclk_lvds\n");
> +		return ret;
> +	}

I think you can switch to devm_clk_get_prepared() here

> +
> +	port = of_graph_get_remote_node(dev->of_node, 1, 0);
> +	if (!port) {
> +		DRM_DEV_ERROR(dev,
> +			      "can't find port point, please init lvds panel port!\n");
> +		return -EINVAL;
> +	}
> +
> +	lvds->panel = of_drm_find_panel(port);
> +	of_node_put(port);
> +
> +	if (IS_ERR(lvds->panel))
> +		return -EPROBE_DEFER;
> +
> +	lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
> +
> +	if (IS_ERR(lvds->panel_bridge))
> +		return PTR_ERR(lvds->panel_bridge);
> +
> +	lvds->bridge.of_node = dev->of_node;
> +	lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
> +	lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
> +
> +	dev_set_drvdata(dev, lvds);
> +	pm_runtime_enable(dev);

If you also use devm_pm_runtime_enable() you can drop mchp_lvds_remove()

> +
> +	drm_bridge_add(&lvds->bridge);
> +
> +	return 0;
> +}
> +
> +static int mchp_lvds_remove(struct platform_device *pdev)
> +{
> +	struct mchp_lvds *lvds = platform_get_drvdata(pdev);
> +
> +	pm_runtime_disable(&pdev->dev);
> +	clk_unprepare(lvds->pclk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mchp_lvds_dt_ids[] = {
> +	{
> +		.compatible = "microchip,sam9x75-lvds",
> +	},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
> +
> +static struct platform_driver mchp_lvds_driver = {
> +	.probe = mchp_lvds_probe,
> +	.remove = mchp_lvds_remove,
> +	.driver = {
> +		   .name = "microchip-lvds",
> +		   .of_match_table = mchp_lvds_dt_ids,
> +	},
> +};
> +module_platform_driver(mchp_lvds_driver);
> +
> +MODULE_AUTHOR("Manikandan Muralidharan <manikandan.m@microchip.com>");
> +MODULE_AUTHOR("Dharma Balasubiramani <dharma.b@microchip.com>");
> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller Driver");
> +MODULE_LICENSE("GPL");

Thanks,
Neil

Re: [linux][PATCH v2 3/4] MAINTAINERS: add SAM9X7 SoC's LVDS controller

[neil.armstrong]

On 05/02/2024 12:06, Dharma Balasubiramani wrote:
> Add the newly added LVDS controller for the SAM9X7 SoC to the existing
> MAINTAINERS entry.
> 
> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
> ---
> Changelog
> v1 -> v2
> - No Changes.
> ---
>   MAINTAINERS | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a7c4cf8201e0..24a266d20df6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14230,6 +14230,14 @@ S:	Supported
>   F:	Documentation/devicetree/bindings/power/reset/atmel,sama5d2-shdwc.yaml
>   F:	drivers/power/reset/at91-sama5d2_shdwc.c
>   
> +MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
> +M:	Manikandan Muralidharan <manikandan.m@microchip.com>
> +M:	Dharma Balasubiramani <dharma.b@microchip.com>
> +L:	dri-devel@lists.freedesktop.org
> +S:	Supported
> +F:	Documentation/devicetree/bindings/display/bridge/microchip,sam9x7-lvds.yaml
> +F:	drivers/gpu/drm/bridge/microchip-lvds.c
> +
>   MICROCHIP SOC DRIVERS
>   M:	Conor Dooley <conor@kernel.org>
>   S:	Supported

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Re: [linux][PATCH v2 4/4] ARM: configs: at91: Enable LVDS serializer support

[Nicolas Ferre]

On 05/02/2024 at 12:06, Dharma B - I70843 wrote:
> Enable LVDS serializer support for display pipeline.
> 
> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
> Acked-by: Hari Prasath Gujulan Elango <hari.prasathge@microchip.com>

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

> ---
>   arch/arm/configs/at91_dt_defconfig | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
> index 71b5acc78187..6a7714beb099 100644
> --- a/arch/arm/configs/at91_dt_defconfig
> +++ b/arch/arm/configs/at91_dt_defconfig
> @@ -143,6 +143,7 @@ CONFIG_VIDEO_OV2640=m
>   CONFIG_VIDEO_OV7740=m
>   CONFIG_DRM=y
>   CONFIG_DRM_ATMEL_HLCDC=y
> +CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER=y
>   CONFIG_DRM_PANEL_SIMPLE=y
>   CONFIG_DRM_PANEL_EDP=y
>   CONFIG_FB_ATMEL=y

Re: [linux][PATCH v2 3/4] MAINTAINERS: add SAM9X7 SoC's LVDS controller

[Nicolas Ferre]

On 05/02/2024 at 12:06, Dharma B - I70843 wrote:
> Add the newly added LVDS controller for the SAM9X7 SoC to the existing
> MAINTAINERS entry.
> 
> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>

If new series is to be done, this entry should be placed before this one
"MICROCHIP SAMA5D2-COMPATIBLE ADC DRIVER"

Otherwise:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Regards,
   Nicolas


> ---
> Changelog
> v1 -> v2
> - No Changes.
> ---
>   MAINTAINERS | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a7c4cf8201e0..24a266d20df6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14230,6 +14230,14 @@ S:	Supported
>   F:	Documentation/devicetree/bindings/power/reset/atmel,sama5d2-shdwc.yaml
>   F:	drivers/power/reset/at91-sama5d2_shdwc.c
>   
> +MICROCHIP SAM9x7-COMPATIBLE LVDS CONTROLLER
> +M:	Manikandan Muralidharan <manikandan.m@microchip.com>
> +M:	Dharma Balasubiramani <dharma.b@microchip.com>
> +L:	dri-devel@lists.freedesktop.org
> +S:	Supported
> +F:	Documentation/devicetree/bindings/display/bridge/microchip,sam9x7-lvds.yaml
> +F:	drivers/gpu/drm/bridge/microchip-lvds.c
> +
>   MICROCHIP SOC DRIVERS
>   M:	Conor Dooley <conor@kernel.org>
>   S:	Supported

Re: [linux][PATCH v2 1/4] dt-bindings: display: bridge: add sam9x75-lvds compatible

[Rob Herring]

On Mon, 05 Feb 2024 16:36:06 +0530, Dharma Balasubiramani wrote:
> Add the 'sam9x75-lvds' compatible binding, which describes the Low Voltage
> Differential Signaling (LVDS) Controller found on some Microchip's sam9x7
> series System-on-Chip (SoC) devices. This binding will be used to define
> the properties and configuration for the LVDS Controller in DT.
> 
> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
> ---
> Changelog
> v1 -> v2
> - Remove '|' in description, as there is no formatting to preserve.
> - Remove 'gclk' from clock-names as there is only one clock(pclk).
> - Remove the unused headers and include only used ones.
> - Change the compatible name specific to SoC (sam9x75) instead of entire series.
> - Change file name to match the compatible name.
> ---
>  .../bridge/microchip,sam9x75-lvds.yaml        | 55 +++++++++++++++++++
>  1 file changed, 55 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/microchip,sam9x75-lvds.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [linux][PATCH v2 2/4] drm/bridge: add lvds controller support for sam9x7

[Dharma.B]

Hi Neil,

On 05/02/24 4:41 pm, neil.armstrong@linaro.org wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know 
> the content is safe
> 
> Hi,
> 
> On 05/02/2024 12:06, Dharma Balasubiramani wrote:
>> Add a new LVDS controller driver for sam9x7 which does the following:
>> - Prepares and enables the LVDS Peripheral clock
>> - Defines its connector type as DRM_MODE_CONNECTOR_LVDS and adds itself
>> to the global bridge list.
>> - Identifies its output endpoint as panel and adds it to the encoder
>> display pipeline
>> - Enables the LVDS serializer
>>
>> Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>
>> Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
>> ---
>> Changelog
>> v1 -> v2
>> - Drop 'res' variable and combine two lines into one.
>> - Handle deferred probe properly, use dev_err_probe().
>> - Don't print anything on deferred probe. Dropped print.
>> - Remove the MODULE_ALIAS and add MODULE_DEVICE_TABLE().
>> - symbol 'mchp_lvds_driver' was not declared. It should be static.
>> ---
>>   drivers/gpu/drm/bridge/Kconfig          |   7 +
>>   drivers/gpu/drm/bridge/Makefile         |   1 +
>>   drivers/gpu/drm/bridge/microchip-lvds.c | 246 ++++++++++++++++++++++++
>>   3 files changed, 254 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/microchip-lvds.c
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig 
>> b/drivers/gpu/drm/bridge/Kconfig
>> index 3e6a4e2044c0..200afb36e421 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -173,6 +173,13 @@ config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
>>         to DP++. This is used with the i.MX6 imx-ldb
>>         driver. You are likely to say N here.
>>
>> +config DRM_MICROCHIP_LVDS_SERIALIZER
>> +     tristate "Microchip LVDS serailzer support"
> ---------------------------------/\
> 
> Should be serializer
Noted, Thanks.
> 
>> +     depends on OF
>> +     depends on DRM_ATMEL_HLCDC
>> +     help
>> +       Support for Microchip's LVDS serializer.
>> +
>>   config DRM_NWL_MIPI_DSI
>>       tristate "Northwest Logic MIPI DSI Host controller"
>>       depends on DRM
>> diff --git a/drivers/gpu/drm/bridge/Makefile 
>> b/drivers/gpu/drm/bridge/Makefile
>> index 2b892b7ed59e..e3804e93d324 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -11,6 +11,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
>>   obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
>>   obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
>>   obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += 
>> megachips-stdpxxxx-ge-b850v3-fw.o
>> +obj-$(CONFIG_DRM_MICROCHIP_LVDS_SERIALIZER) += microchip-lvds.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>>   obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
>> diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c 
>> b/drivers/gpu/drm/bridge/microchip-lvds.c
>> new file mode 100644
>> index 000000000000..508321ad0f66
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/microchip-lvds.c
>> @@ -0,0 +1,246 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2023 Microchip Technology Inc. and its subsidiaries
>> + *
>> + * Author: Manikandan Muralidharan <manikandan.m@microchip.com>
>> + * Author: Dharma Balasubiramani <dharma.b@microchip.com>
>> + *
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/component.h>
>> +#include <linux/delay.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/pinctrl/devinfo.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/regmap.h>
>> +#include <linux/reset.h>
>> +
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_print.h>
>> +#include <drm/drm_probe_helper.h>
>> +#include <drm/drm_simple_kms_helper.h>
>> +
>> +#define LVDS_POLL_TIMEOUT_MS 1000
>> +
>> +/* LVDSC register offsets */
>> +#define LVDSC_CR     0x00
>> +#define LVDSC_CFGR   0x04
>> +#define LVDSC_SR     0x0C
>> +#define LVDSC_WPMR   0xE4
>> +
>> +/* Bitfields in LVDSC_CR (Control Register) */
>> +#define LVDSC_CR_SER_EN      BIT(0)
>> +
>> +/* Bitfields in LVDSC_CFGR (Configuration Register) */
>> +#define LVDSC_CFGR_PIXSIZE_24BITS    0
>> +#define LVDSC_CFGR_DEN_POL_HIGH              0
>> +#define LVDSC_CFGR_DC_UNBALANCED     0
>> +#define LVDSC_CFGR_MAPPING_JEIDA     BIT(6)
>> +
>> +/*Bitfields in LVDSC_SR */
>> +#define LVDSC_SR_CS  BIT(0)
>> +
>> +/* Bitfields in LVDSC_WPMR (Write Protection Mode Register) */
>> +#define LVDSC_WPMR_WPKEY_MASK        GENMASK(31, 8)
>> +#define LVDSC_WPMR_WPKEY_PSSWD       0x4C5644
>> +
>> +struct mchp_lvds {
>> +     struct device *dev;
>> +     void __iomem *regs;
>> +     struct clk *pclk;
>> +     int format; /* vesa or jeida format */
>> +     struct drm_panel *panel;
>> +     struct drm_bridge bridge;
>> +     struct drm_bridge *panel_bridge;
>> +};
>> +
>> +static inline struct mchp_lvds *bridge_to_lvds(struct drm_bridge 
>> *bridge)
>> +{
>> +     return container_of(bridge, struct mchp_lvds, bridge);
>> +}
>> +
>> +static inline u32 lvds_readl(struct mchp_lvds *lvds, u32 offset)
>> +{
>> +     return readl_relaxed(lvds->regs + offset);
>> +}
>> +
>> +static inline void lvds_writel(struct mchp_lvds *lvds, u32 offset, 
>> u32 val)
>> +{
>> +     writel_relaxed(val, lvds->regs + offset);
>> +}
>> +
>> +static void lvds_serialiser_on(struct mchp_lvds *lvds)
>> +{
>> +     unsigned long timeout = jiffies + 
>> msecs_to_jiffies(LVDS_POLL_TIMEOUT_MS);
>> +
>> +     /* The LVDSC registers can only be written if WPEN is cleared */
>> +     lvds_writel(lvds, LVDSC_WPMR, (LVDSC_WPMR_WPKEY_PSSWD &
>> +                             LVDSC_WPMR_WPKEY_MASK));
>> +
>> +     /* Wait for the status of configuration registers to be changed */
>> +     while (lvds_readl(lvds, LVDSC_SR) & LVDSC_SR_CS) {
>> +             if (time_after(jiffies, timeout)) {
>> +                     dev_err(lvds->dev, "%s: timeout error\n", 
>> __func__);
>> +                     return;
>> +             }
>> +             usleep_range(1000, 2000);
>> +     }
>> +
>> +     /* Configure the LVDSC */
>> +     lvds_writel(lvds, LVDSC_CFGR, (LVDSC_CFGR_MAPPING_JEIDA |
>> +                             LVDSC_CFGR_DC_UNBALANCED |
>> +                             LVDSC_CFGR_DEN_POL_HIGH |
>> +                             LVDSC_CFGR_PIXSIZE_24BITS));
>> +
>> +     /* Enable the LVDS serializer */
>> +     lvds_writel(lvds, LVDSC_CR, LVDSC_CR_SER_EN);
>> +}
>> +
>> +static int mchp_lvds_attach(struct drm_bridge *bridge,
>> +                         enum drm_bridge_attach_flags flags)
>> +{
>> +     struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> +
>> +     bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
>> +
>> +     return drm_bridge_attach(bridge->encoder, lvds->panel_bridge,
>> +                              bridge, flags);
>> +}
>> +
>> +static void mchp_lvds_enable(struct drm_bridge *bridge)
>> +{
>> +     struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> +     int ret;
>> +
>> +     ret = clk_enable(lvds->pclk);
>> +     if (ret < 0) {
>> +             DRM_DEV_ERROR(lvds->dev, "failed to enable lvds pclk 
>> %d\n", ret);
>> +             return;
>> +     }
>> +
>> +     ret = pm_runtime_get_sync(lvds->dev);
>> +     if (ret < 0) {
>> +             DRM_DEV_ERROR(lvds->dev, "failed to get pm runtime: 
>> %d\n", ret);
>> +             clk_disable(lvds->pclk);
>> +             return;
>> +     }
>> +
>> +     lvds_serialiser_on(lvds);
>> +}
>> +
>> +static void mchp_lvds_disable(struct drm_bridge *bridge)
>> +{
>> +     struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>> +
>> +     pm_runtime_put(lvds->dev);
>> +     clk_disable(lvds->pclk);
>> +}
>> +
>> +static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
>> +     .attach = mchp_lvds_attach,
>> +     .enable = mchp_lvds_enable,
>> +     .disable = mchp_lvds_disable,
>> +};
>> +
>> +static int mchp_lvds_probe(struct platform_device *pdev)
>> +{
>> +     struct device *dev = &pdev->dev;
>> +     struct mchp_lvds *lvds;
>> +     struct device_node *port;
>> +     int ret;
>> +
>> +     if (!dev->of_node)
>> +             return -ENODEV;
>> +
>> +     lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
>> +     if (!lvds)
>> +             return -ENOMEM;
>> +
>> +     lvds->dev = dev;
>> +
>> +     lvds->regs = devm_ioremap_resource(lvds->dev,
>> +                     platform_get_resource(pdev, IORESOURCE_MEM, 0));
>> +     if (IS_ERR(lvds->regs))
>> +             return PTR_ERR(lvds->regs);
>> +
>> +     lvds->pclk = devm_clk_get(lvds->dev, "pclk");
>> +     if (IS_ERR(lvds->pclk))
>> +             return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
>> +                             "could not get pclk_lvds\n");
>> +
>> +     ret = clk_prepare(lvds->pclk);
>> +     if (ret < 0) {
>> +             DRM_DEV_ERROR(lvds->dev, "failed to prepare pclk_lvds\n");
>> +             return ret;
>> +     }
> 
> I think you can switch to devm_clk_get_prepared() here

Sure, I'll consolidate get() and prepare() as below

+       lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk");
+       if (IS_ERR(lvds->pclk))
+               return dev_err_probe(lvds->dev, PTR_ERR(lvds->pclk),
+                               "could not get pclk_lvds prepared\n");

Additionally I'll remove the "ret" variable as it is not used anywhere 
else in probe().
> 
>> +
>> +     port = of_graph_get_remote_node(dev->of_node, 1, 0);
>> +     if (!port) {
>> +             DRM_DEV_ERROR(dev,
>> +                           "can't find port point, please init lvds 
>> panel port!\n");
>> +             return -EINVAL;
>> +     }
>> +
>> +     lvds->panel = of_drm_find_panel(port);
>> +     of_node_put(port);
>> +
>> +     if (IS_ERR(lvds->panel))
>> +             return -EPROBE_DEFER;
>> +
>> +     lvds->panel_bridge = devm_drm_panel_bridge_add(dev, lvds->panel);
>> +
>> +     if (IS_ERR(lvds->panel_bridge))
>> +             return PTR_ERR(lvds->panel_bridge);
>> +
>> +     lvds->bridge.of_node = dev->of_node;
>> +     lvds->bridge.type = DRM_MODE_CONNECTOR_LVDS;
>> +     lvds->bridge.funcs = &mchp_lvds_bridge_funcs;
>> +
>> +     dev_set_drvdata(dev, lvds);
>> +     pm_runtime_enable(dev);
> 
> If you also use devm_pm_runtime_enable() you can drop mchp_lvds_remove()

Sure, I will use devm_pm_runtime_enable() and drop the 
mchp_lvds_remove() from ops.
> 
>> +
>> +     drm_bridge_add(&lvds->bridge);
>> +
>> +     return 0;
>> +}
>> +
>> +static int mchp_lvds_remove(struct platform_device *pdev)
>> +{
>> +     struct mchp_lvds *lvds = platform_get_drvdata(pdev);
>> +
>> +     pm_runtime_disable(&pdev->dev);
>> +     clk_unprepare(lvds->pclk);
>> +
>> +     return 0;
>> +}
>> +
>> +static const struct of_device_id mchp_lvds_dt_ids[] = {
>> +     {
>> +             .compatible = "microchip,sam9x75-lvds",
>> +     },
>> +     {},
>> +};
>> +MODULE_DEVICE_TABLE(of, mchp_lvds_dt_ids);
>> +
>> +static struct platform_driver mchp_lvds_driver = {
>> +     .probe = mchp_lvds_probe,
>> +     .remove = mchp_lvds_remove,
>> +     .driver = {
>> +                .name = "microchip-lvds",
>> +                .of_match_table = mchp_lvds_dt_ids,
>> +     },
>> +};
>> +module_platform_driver(mchp_lvds_driver);
>> +
>> +MODULE_AUTHOR("Manikandan Muralidharan <manikandan.m@microchip.com>");
>> +MODULE_AUTHOR("Dharma Balasubiramani <dharma.b@microchip.com>");
>> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller 
>> Driver");
>> +MODULE_LICENSE("GPL");
> 
> Thanks,
> Neil

-- 
With Best Regards,
Dharma B.