Re: [PATCH] drm/sun4i: hdmi: add support for ddc-i2c-bus property

Maxime Ripard
2019-03-11T15:47:07Z

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Hi!

On Mon, Mar 11, 2019 at 01:47:13PM +0000, Mans Rullgard wrote:
> Sometimes it is desirabled to use a separate i2c controller for ddc
> access. This adds support for the ddc-i2c-bus property of the
> hdmi-connector node, using the specified controller if provided.
>
> Signed-off-by: Mans Rullgard <mans@mansr.com>
> ---
> drivers/gpu/drm/sun4i/sun4i_hdmi.h | 1 +
> drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 37 +++++++++++++++++++++++---
> 2 files changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> index b685ee11623d..b08c4453d47c 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
> @@ -269,6 +269,7 @@ struct sun4i_hdmi {
> struct clk *tmds_clk;
>
> struct i2c_adapter *i2c;
> + struct i2c_adapter *ddc_i2c;
>
> /* Regmap fields for I2C adapter */
> struct regmap_field *field_ddc_en;
> diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> index 061d2e0d9011..5b2fac79f5d6 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
> @@ -212,7 +212,7 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
> struct edid *edid;
> int ret;
>
> - edid = drm_get_edid(connector, hdmi->i2c);
> + edid = drm_get_edid(connector, hdmi->ddc_i2c ?: hdmi->i2c);

You can't test whether ddc_i2c is NULL or not...

> if (!edid)
> return 0;
>
> @@ -228,6 +228,28 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
> return ret;
> }
>
> +static struct i2c_adapter *sun4i_hdmi_get_ddc(struct device *dev)
> +{
> + struct device_node *phandle, *remote;
> + struct i2c_adapter *ddc;
> +
> + remote = of_graph_get_remote_node(dev->of_node, 1, -1);
> + if (!remote)
> + return ERR_PTR(-EINVAL);
> +
> + phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0);
> + of_node_put(remote);
> + if (!phandle)
> + return NULL;
> +
> + ddc = of_get_i2c_adapter_by_node(phandle);
> + of_node_put(phandle);
> + if (!ddc)
> + return ERR_PTR(-EPROBE_DEFER);
> +
> + return ddc;

... Since even in (most) error cases you're returning a !NULL pointer.

> +}
> +
> static const struct drm_connector_helper_funcs sun4i_hdmi_connector_helper_funcs = {
> .get_modes = sun4i_hdmi_get_modes,
> };
> @@ -575,6 +597,12 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> goto err_disable_mod_clk;
> }
>
> + hdmi->ddc_i2c = sun4i_hdmi_get_ddc(dev);
> + if (IS_ERR(hdmi->ddc_i2c)) {
> + ret = PTR_ERR(hdmi->ddc_i2c);
> + goto err_del_i2c_adapter;
> + }
> +
> drm_encoder_helper_add(&hdmi->encoder,
> &sun4i_hdmi_helper_funcs);
> ret = drm_encoder_init(drm,
> @@ -584,14 +612,14 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> NULL);
> if (ret) {
> dev_err(dev, "Couldn't initialise the HDMI encoder\n");
> - goto err_del_i2c_adapter;
> + goto err_put_ddc_i2c;
> }
>
> hdmi->encoder.possible_crtcs = drm_of_find_possible_crtcs(drm,
> dev->of_node);
> if (!hdmi->encoder.possible_crtcs) {
> ret = -EPROBE_DEFER;
> - goto err_del_i2c_adapter;
> + goto err_put_ddc_i2c;
> }
>
> #ifdef CONFIG_DRM_SUN4I_HDMI_CEC
> @@ -630,6 +658,8 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
> err_cleanup_connector:
> cec_delete_adapter(hdmi->cec_adap);
> drm_encoder_cleanup(&hdmi->encoder);
> +err_put_ddc_i2c:
> + i2c_put_adapter(hdmi->ddc_i2c);
> err_del_i2c_adapter:
> i2c_del_adapter(hdmi->i2c);
> err_disable_mod_clk:
> @@ -650,6 +680,7 @@ static void sun4i_hdmi_unbind(struct device *dev, struct device *master,
> drm_connector_cleanup(&hdmi->connector);
> drm_encoder_cleanup(&hdmi->encoder);
> i2c_del_adapter(hdmi->i2c);
> + i2c_put_adapter(hdmi->ddc_i2c);
> clk_disable_unprepare(hdmi->mod_clk);
> clk_disable_unprepare(hdmi->bus_clk);
> }
> --
> 2.21.0
>

It looks good otherwise, thanks!