Re: [PATCH 2/2] drm/vc4: hdmi: Convert to gpiod

From: Maxime Ripard
Date: Fri Jul 02 2021 - 09:16:54 EST


Hi Nathan,

On Thu, Jul 01, 2021 at 08:29:34PM -0700, Nathan Chancellor wrote:
> On Mon, May 24, 2021 at 03:18:52PM +0200, Maxime Ripard wrote:
> > The new gpiod interface takes care of parsing the GPIO flags and to
> > return the logical value when accessing an active-low GPIO, so switching
> > to it simplifies a lot the driver.
> >
> > Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/vc4/vc4_hdmi.c | 24 +++++++-----------------
> > drivers/gpu/drm/vc4/vc4_hdmi.h | 3 +--
> > 2 files changed, 8 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > index ccc6c8079dc6..34622c59f6a7 100644
> > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > @@ -159,10 +159,9 @@ vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
> > struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
> > bool connected = false;
> >
> > - if (vc4_hdmi->hpd_gpio) {
> > - if (gpio_get_value_cansleep(vc4_hdmi->hpd_gpio) ^
> > - vc4_hdmi->hpd_active_low)
> > - connected = true;
> > + if (vc4_hdmi->hpd_gpio &&
> > + gpiod_get_value_cansleep(vc4_hdmi->hpd_gpio)) {
> > + connected = true;
> > } else if (drm_probe_ddc(vc4_hdmi->ddc)) {
> > connected = true;
> > } else if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED) {
> > @@ -1993,7 +1992,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
> > struct vc4_hdmi *vc4_hdmi;
> > struct drm_encoder *encoder;
> > struct device_node *ddc_node;
> > - u32 value;
> > int ret;
> >
> > vc4_hdmi = devm_kzalloc(dev, sizeof(*vc4_hdmi), GFP_KERNEL);
> > @@ -2031,18 +2029,10 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
> > /* Only use the GPIO HPD pin if present in the DT, otherwise
> > * we'll use the HDMI core's register.
> > */
> > - if (of_find_property(dev->of_node, "hpd-gpios", &value)) {
> > - enum of_gpio_flags hpd_gpio_flags;
> > -
> > - vc4_hdmi->hpd_gpio = of_get_named_gpio_flags(dev->of_node,
> > - "hpd-gpios", 0,
> > - &hpd_gpio_flags);
> > - if (vc4_hdmi->hpd_gpio < 0) {
> > - ret = vc4_hdmi->hpd_gpio;
> > - goto err_put_ddc;
> > - }
> > -
> > - vc4_hdmi->hpd_active_low = hpd_gpio_flags & OF_GPIO_ACTIVE_LOW;
> > + vc4_hdmi->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN);
> > + if (IS_ERR(vc4_hdmi->hpd_gpio)) {
> > + ret = PTR_ERR(vc4_hdmi->hpd_gpio);
> > + goto err_put_ddc;
> > }
> >
> > vc4_hdmi->disable_wifi_frequencies =
> > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
> > index 060bcaefbeb5..2688a55461d6 100644
> > --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> > @@ -146,8 +146,7 @@ struct vc4_hdmi {
> > /* VC5 Only */
> > void __iomem *rm_regs;
> >
> > - int hpd_gpio;
> > - bool hpd_active_low;
> > + struct gpio_desc *hpd_gpio;
> >
> > /*
> > * On some systems (like the RPi4), some modes are in the same
> > --
> > 2.31.1
>
> This patch as commit 6800234ceee0 ("drm/vc4: hdmi: Convert to gpiod")
> causes my Raspberry Pi 3 to lock up shortly after boot in combination
> with commit 411efa18e4b0 ("drm/vc4: hdmi: Move the HSM clock enable to
> runtime_pm"). The serial console and ssh are completely unresponsive and
> I do not see any messages in dmesg with "debug ignore_loglevel". The
> device is running with a 32-bit kernel (multi_v7_defconfig) with 32-bit
> userspace. If there is any further information that I can provide,
> please let me know.

Thanks for reporting this. The same bug has been reported on wednesday
on the RPi repo here:
https://github.com/raspberrypi/linux/pull/4418

More specifically, this commit should fix it:
https://github.com/raspberrypi/linux/pull/4418/commits/6d404373c20a794da3d6a7b4f1373903183bb5d0

Even though it's based on the 5.10 kernel, it should apply without any
warning on a mainline tree. Let me know if it fixes your issue too

Maxime

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