Re: [PATCH v5 5/6] drm: sun4i: Add support for enabling DDC I2C bus to sun8i_dw_hdmi glue

Maxime Ripard
2019-05-21T11:46:11Z

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Hi,

On Tue, May 21, 2019 at 01:50:08AM +0200, megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org wrote:
> From: Ondrej Jirman <megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org>
>
> Orange Pi 3 board requires enabling a voltage shifting circuit via GPIO
> for the DDC bus to be usable.
>
> Add support for hdmi-connector node's optional ddc-en-gpios property to
> support this use case.
>
> Signed-off-by: Ondrej Jirman <megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org>
> ---
> drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c | 55 +++++++++++++++++++++++++--
> drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h | 3 ++
> 2 files changed, 55 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> index 39d8509d96a0..59b81ba02d96 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> @@ -98,6 +98,30 @@ static u32 sun8i_dw_hdmi_find_possible_crtcs(struct drm_device *drm,
> return crtcs;
> }
>
> +static int sun8i_dw_hdmi_find_connector_pdev(struct device *dev,
> + struct platform_device **pdev_out)
> +{
> + struct platform_device *pdev;
> + struct device_node *remote;
> +
> + remote = of_graph_get_remote_node(dev->of_node, 1, -1);
> + if (!remote)
> + return -ENODEV;
> +
> + if (!of_device_is_compatible(remote, "hdmi-connector")) {
> + of_node_put(remote);
> + return -ENODEV;
> + }
> +
> + pdev = of_find_device_by_node(remote);
> + of_node_put(remote);
> + if (!pdev)
> + return -ENODEV;
> +
> + *pdev_out = pdev;
> + return 0;
> +}
> +
> static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
> void *data)
> {
> @@ -151,16 +175,29 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
> return PTR_ERR(hdmi->regulator);
> }
>
> + ret = sun8i_dw_hdmi_find_connector_pdev(dev, &hdmi->connector_pdev);
> + if (!ret) {
> + hdmi->ddc_en = gpiod_get_optional(&hdmi->connector_pdev->dev,
> + "ddc-en", GPIOD_OUT_HIGH);
> + if (IS_ERR(hdmi->ddc_en)) {
> + platform_device_put(hdmi->connector_pdev);
> + dev_err(dev, "Couldn't get ddc-en gpio\n");
> + return PTR_ERR(hdmi->ddc_en);
> + }
> + }
> +
> ret = regulator_enable(hdmi->regulator);
> if (ret) {
> dev_err(dev, "Failed to enable regulator\n");
> - return ret;
> + goto err_unref_ddc_en;
> }
>
> + gpiod_set_value(hdmi->ddc_en, 1);
> +

Do you really need this to be done all the time? I'm guessing you
would only need this when running .get_modes, right?

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering