Re: [PATCH 15/21] drm: sun4i: add support for HVCC regulator for DWC HDMI glue

Maxime Ripard
2018-05-02T11:48:43Z

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On Mon, Apr 30, 2018 at 05:10:52PM +0530, Jagan Teki wrote:
> From: Icenowy Zheng <icenowy@aosc.io>
>
> Allwinner SoCs with DWC HDMI controller have a "HVCC" power pin for the
> HDMI part, and on some boards it's connected to a dedicated regulator
> rather than the main 3.3v.
>
> Add support for optional HVCC regulator. For boards that doesn't use a
> dedicated regulator to power it, the default dummy regulator is used.
>
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
> drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c | 14 ++++++++++++++
> drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h | 2 ++
> 2 files changed, 16 insertions(+)
>
> diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> index 9f40a44b456b..7c33faff7ad4 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.c
> @@ -73,6 +73,12 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
> if (encoder->possible_crtcs == 0)
> return -EPROBE_DEFER;
>
> + hdmi->vcc_hdmi = devm_regulator_get(dev, "hvcc");
> + if (IS_ERR(hdmi->vcc_hdmi)) {
> + dev_err(dev, "Could not get HDMI power supply\n");
> + return PTR_ERR(hdmi->vcc_hdmi);
> + }
> +

You're not making it optional here, unlike what your commit log
says. Not that I'm fine with both, but we need to be consistent :)

> hdmi->rst_ctrl = devm_reset_control_get(dev, "ctrl");
> if (IS_ERR(hdmi->rst_ctrl)) {
> dev_err(dev, "Could not get ctrl reset control\n");
> @@ -91,6 +97,12 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
> return ret;
> }
>
> + ret = regulator_enable(hdmi->vcc_hdmi);
> + if (ret) {
> + dev_err(dev, "Cannot enable HDMI power supply\n");
> + goto err_disable_vcc;
> + }
> +
> ret = clk_prepare_enable(hdmi->clk_tmds);
> if (ret) {
> dev_err(dev, "Could not enable tmds clock\n");
> @@ -143,6 +155,8 @@ static int sun8i_dw_hdmi_bind(struct device *dev, struct device *master,
> clk_disable_unprepare(hdmi->clk_tmds);
> err_assert_ctrl_reset:
> reset_control_assert(hdmi->rst_ctrl);
> +err_disable_vcc:
> + regulator_disable(hdmi->vcc_hdmi);

The err_disable_vcc label will disable the regulator, but if there's
an error in regulator_enable, it will disable it while it wasn't
enabled in the first place, which is not really something we want to
do.

Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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