Re: [PATCH v2 2/4] drm/bridge: imx: add bridge wrapper driver for i.MX8MP DWC HDMI

[Liu Ying <victor.liu@nxp.com>]

On Fri, 2022-12-16 at 22:07 +0100, Lucas Stach wrote:
> Add a simple wrapper driver for the DWC HDMI bridge driver that
> implements the few bits that are necessary to abstract the i.MX8MP
> SoC integration.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Tested-by: Marek Vasut <marex@denx.de>
> ---
>  drivers/gpu/drm/bridge/imx/Kconfig       |   9 ++
>  drivers/gpu/drm/bridge/imx/Makefile      |   2 +
>  drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c | 140
> +++++++++++++++++++++++
>  3 files changed, 151 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c
> 

Can you please provide a changelog since this is v2?

> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig
> b/drivers/gpu/drm/bridge/imx/Kconfig
> index 608f47f41bcd..d828d8bfd893 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -44,4 +44,13 @@ config DRM_IMX8QXP_PIXEL_LINK_TO_DPI
>  	  Choose this to enable pixel link to display pixel
> interface(PXL2DPI)
>  	  found in Freescale i.MX8qxp processor.
>  
> +config DRM_IMX8MP_DW_HDMI_BRIDGE

Sort the config names alphabetically please.

> +	tristate "i.MX8MP HDMI bridge support"

To show the prompts in this Kconfig file in a consistent fashion,
please add 'Freescale' before 'i.MX8MP'.

> +	depends on OF
> +	depends on COMMON_CLK
> +	select DRM_DW_HDMI
> +	help
> +	  Choose this to enable support for the internal HDMI encoder
> found
> +	  on the i.MX8MP SoC.
> +
>  endif # ARCH_MXC || COMPILE_TEST
> diff --git a/drivers/gpu/drm/bridge/imx/Makefile
> b/drivers/gpu/drm/bridge/imx/Makefile
> index aa90ec8d5433..03b0074ae538 100644
> --- a/drivers/gpu/drm/bridge/imx/Makefile
> +++ b/drivers/gpu/drm/bridge/imx/Makefile
> @@ -7,3 +7,5 @@ obj-$(CONFIG_DRM_IMX8QXP_LDB) += imx8qxp-ldb.o
>  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-combiner.o
>  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
>  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK_TO_DPI) += imx8qxp-pxl2dpi.o
> +
> +obj-$(CONFIG_DRM_IMX8MP_DW_HDMI_BRIDGE) += imx8mp-hdmi.o

Sort the config names alphabetically.

> diff --git a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c
> b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c
> new file mode 100644
> index 000000000000..06849b817aed
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c
> @@ -0,0 +1,140 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +/*
> + * Copyright (C) 2022 Pengutronix, Lucas Stach <
> kernel@pengutronix.de>
> + */
> +
> +#include <drm/bridge/dw_hdmi.h>
> +#include <drm/drm_modes.h>
> +#include <linux/clk.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>

Header files in linux/ come before those in drm/.

> +
> +struct imx8mp_hdmi {
> +	struct dw_hdmi_plat_data plat_data;
> +	struct dw_hdmi *dw_hdmi;
> +	struct clk *pixclk;
> +	struct clk *fdcc;
> +};
> +
> +static enum drm_mode_status
> +imx8mp_hdmi_mode_valid(struct dw_hdmi *dw_hdmi, void *data,
> +		       const struct drm_display_info *info,
> +		       const struct drm_display_mode *mode)
> +{
> +	struct imx8mp_hdmi *hdmi = (struct imx8mp_hdmi *)data;
> +
> +	if (mode->clock < 13500)
> +		return MODE_CLOCK_LOW;
> +
> +	if (mode->clock > 297000)
> +		return MODE_CLOCK_HIGH;
> +
> +	if (clk_round_rate(hdmi->pixclk, mode->clock * 1000) !=
> +	    mode->clock * 1000)
> +		return MODE_CLOCK_RANGE;
> +
> +	/* We don't support double-clocked and Interlaced modes */
> +	if ((mode->flags & DRM_MODE_FLAG_DBLCLK) ||
> +	    (mode->flags & DRM_MODE_FLAG_INTERLACE))
> +		return MODE_BAD;
> +
> +	return MODE_OK;
> +}
> +
> +static int imx8mp_hdmi_phy_init(struct dw_hdmi *dw_hdmi, void *data,
> +				const struct drm_display_info *display,
> +				const struct drm_display_mode *mode)
> +{
> +	return 0;
> +}
> +
> +static void imx8mp_hdmi_phy_disable(struct dw_hdmi *dw_hdmi, void
> *data)
> +{
> +}
> +
> +static void im8mp_hdmi_phy_setup_hpd(struct dw_hdmi *hdmi, void
> *data)
> +{
> +	/*
> +	 * Just release PHY core from reset, all other power management
> is done
> +	 * by the PHY driver.
> +	 */
> +	dw_hdmi_phy_gen1_reset(hdmi);
> +
> +	dw_hdmi_phy_setup_hpd(hdmi, data);
> +}
> +
> +static const struct dw_hdmi_phy_ops imx8mp_hdmi_phy_ops = {
> +	.init		= imx8mp_hdmi_phy_init,
> +	.disable	= imx8mp_hdmi_phy_disable,
> +	.setup_hpd	= im8mp_hdmi_phy_setup_hpd,
> +	.read_hpd	= dw_hdmi_phy_read_hpd,
> +	.update_hpd	= dw_hdmi_phy_update_hpd,
> +};
> +
> +static int imx8mp_dw_hdmi_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct dw_hdmi_plat_data *plat_data;
> +	struct imx8mp_hdmi *hdmi;
> +	int ret;

Please fix this build warning:

drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c: In function
‘imx8mp_dw_hdmi_probe’:
drivers/gpu/drm/bridge/imx/imx8mp-hdmi.c:80:13: warning: unused
variable ‘ret’ [-Wunused-variable]
   80 |         int ret;
      |             ^~~

> +
> +	hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
> +	if (!hdmi)
> +		return -ENOMEM;
> +
> +	plat_data = &hdmi->plat_data;
> +
> +	hdmi->pixclk = devm_clk_get(dev, "pix");
> +	if (IS_ERR(hdmi->pixclk))
> +		return dev_err_probe(dev, PTR_ERR(hdmi->pixclk),
> +				     "Unable to get pixel clock\n");
> +
> +	hdmi->fdcc = devm_clk_get_enabled(dev, "fdcc");
> +	if (IS_ERR(hdmi->fdcc))
> +		return dev_err_probe(dev, PTR_ERR(hdmi->fdcc),
> +				     "Unable to get FDCC clock\n");

Similar to Laurent's comment on v1 here, why does fdcc clock need to be
always enabled? 

> +
> +	plat_data->mode_valid = imx8mp_hdmi_mode_valid;
> +	plat_data->phy_ops = &imx8mp_hdmi_phy_ops;
> +	plat_data->phy_name = "SAMSUNG HDMI TX PHY";
> +	plat_data->priv_data = hdmi;

Need to set plat_data->phy_force_vendor to be true? Or, you rely on
reading the HDMI_CONFIG2_ID register to determine the phy type?

> +
> +	hdmi->dw_hdmi = dw_hdmi_probe(pdev, plat_data);
> +	if (IS_ERR(hdmi->dw_hdmi))
> +		return PTR_ERR(hdmi->dw_hdmi);
> +
> +	platform_set_drvdata(pdev, hdmi);
> +
> +	return 0;
> +}
> +
> +static int imx8mp_dw_hdmi_remove(struct platform_device *pdev)
> +{
> +	struct imx8mp_hdmi *hdmi = platform_get_drvdata(pdev);
> +
> +	dw_hdmi_remove(hdmi->dw_hdmi);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id imx8mp_dw_hdmi_of_table[] = {
> +	{ .compatible = "fsl,imx8mp-hdmi" },
> +	{ /* Sentinel */ },

Nitpick: ',' after the sentinel is not needed since it's the last one.

Regards,
Liu Ying

> +};
> +MODULE_DEVICE_TABLE(of, imx8mp_dw_hdmi_of_table);
> +
> +static struct platform_driver imx8mp_dw_hdmi_platform_driver = {
> +	.probe		= imx8mp_dw_hdmi_probe,
> +	.remove		= imx8mp_dw_hdmi_remove,
> +	.driver		= {
> +		.name	= "imx8mp-dw-hdmi",
> +		.of_match_table = imx8mp_dw_hdmi_of_table,
> +	},
> +};
> +
> +module_platform_driver(imx8mp_dw_hdmi_platform_driver);
> +
> +MODULE_DESCRIPTION("i.MX8MP HDMI encoder driver");
> +MODULE_LICENSE("GPL");