Hi Neil,
On 05/02/24 4:41 pm, neil.armstrong@xxxxxxxxxx wrote:
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>
> 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@xxxxxxxxxxxxx>
>> Signed-off-by: Dharma Balasubiramani <dharma.b@xxxxxxxxxxxxx>
>> ---
>> 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@xxxxxxxxxxxxx>
>> + * Author: Dharma Balasubiramani <dharma.b@xxxxxxxxxxxxx>
>> + *
>> + */
>> +
>> +#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@xxxxxxxxxxxxx>");
>> +MODULE_AUTHOR("Dharma Balasubiramani <dharma.b@xxxxxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Low Voltage Differential Signaling Controller
>> Driver");
>> +MODULE_LICENSE("GPL");
>
> Thanks,
> Neil
--
With Best Regards,
Dharma B.
