Messages in this thread |  | | Date | Fri, 29 Nov 2024 14:54:36 +0100 | | From | neil.armstrong@linaro ... | | Subject | Re: [PATCH 8/8] drm/msm/dp: Support external GPIO HPD with 3rd pinctrl chip |
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On 29/11/2024 08:57, Xiangxu Yin wrote: > Add support for handling HPD (Hot Plug Detect) signals via external > GPIOs connected through pinctrl chips (e.g., Semtech SX1509Q). This > involves reinitializing the relevant GPIO and binding an interrupt > handler to process hot plug events. Since external GPIOs only support > edge interrupts (rising or falling) rather than state interrupts, the > GPIO state must be read during the first DP bridge HPD enablement. This > ensures the current connection state is determined and a hot plug event > is reported accordingly. > > Signed-off-by: Xiangxu Yin <quic_xiangxuy@quicinc.com> > --- > drivers/gpu/drm/msm/dp/dp_display.c | 83 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 83 insertions(+) > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c > index eb6fb76c68e505fafbec563440e9784f51e1894b..22c288ca61b9b444a7b8d4a574c614bfef9d88be 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -13,6 +13,8 @@ > #include <linux/delay.h> > #include <drm/display/drm_dp_aux_bus.h> > #include <drm/drm_edid.h> > +#include <linux/gpio/consumer.h> > +#include <linux/of_gpio.h> > > #include "msm_drv.h" > #include "msm_kms.h" > @@ -78,6 +80,10 @@ struct msm_dp_display_private { > > unsigned int id; > > + bool ext_gpio; > + int gpio_num; > + struct work_struct gpio_work; > + > /* state variables */ > bool core_initialized; > bool phy_initialized; > @@ -1182,6 +1188,42 @@ static irqreturn_t msm_dp_display_irq_handler(int irq, void *dev_id) > return ret; > } > > + > +static void msm_dp_gpio_work_handler(struct work_struct *work) > +{ > + struct msm_dp_display_private *dp = container_of(work, > + struct msm_dp_display_private, gpio_work); > + struct gpio_desc *desc; > + bool hpd; > + > + if (dp->ext_gpio) { > + desc = gpio_to_desc(dp->gpio_num); > + if (!desc) { > + pr_err("Failed to get gpio_desc for GPIO %d\n", dp->gpio_num); > + return; > + } > + > + hpd = gpiod_get_value_cansleep(desc); > + if (hpd) > + msm_dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0); > + else > + msm_dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0); > + } > +} > + > +static irqreturn_t msm_dp_gpio_isr(int unused, void *data) > +{ > + struct msm_dp_display_private *dp = data; > + > + if (!dp) { > + DRM_ERROR("NULL data\n"); > + return IRQ_NONE; > + } > + > + schedule_work(&dp->gpio_work);
this msm_dp_gpio_isr is already threaded, would would you also schedule a work ?
> + return IRQ_HANDLED; > +} > + > static int msm_dp_display_request_irq(struct msm_dp_display_private *dp) > { > int rc = 0; > @@ -1193,6 +1235,21 @@ static int msm_dp_display_request_irq(struct msm_dp_display_private *dp) > return dp->irq; > } > > + if (dp->ext_gpio) { > + int edge, gpio_irq; > + > + gpio_irq = gpio_to_irq(dp->gpio_num);
But as Dmitry reported, the system should use a dp-connected as a next bridge instead which already supports all this much better: drivers/gpu/drm/bridge/display-connector.c Documentation/devicetree/bindings/display/connector/dp-connector.yaml
> + edge = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; > + > + rc = devm_request_threaded_irq(&pdev->dev, gpio_irq, NULL, > + msm_dp_gpio_isr, edge, "dp_gpio_isr", dp); > + if (rc < 0) { > + DRM_ERROR("failed to request ext-gpio IRQ%u: %d\n", > + gpio_irq, rc); > + return rc; > + } > + } > + > rc = devm_request_irq(&pdev->dev, dp->irq, msm_dp_display_irq_handler, > IRQF_TRIGGER_HIGH|IRQF_NO_AUTOEN, > "dp_display_isr", dp); > @@ -1308,10 +1365,32 @@ static int msm_dp_display_probe(struct platform_device *pdev) > return -EPROBE_DEFER; > } > > + if (of_find_property(pdev->dev.of_node, "dp-hpd-gpio", NULL)) { > + dp->ext_gpio = true; > + dp->gpio_num = of_get_named_gpio(pdev->dev.of_node, "dp-hpd-gpio", 0); > + if (dp->gpio_num < 0) { > + dev_err(&pdev->dev, "Failed to get gpio:%d\n", dp->gpio_num); > + return dp->gpio_num; > + } > + > + if (!gpio_is_valid(dp->gpio_num)) { > + DRM_ERROR("gpio(%d) invalid\n", dp->gpio_num); > + return -EINVAL; > + } > + > + rc = gpio_request(dp->gpio_num, "dp-hpd-gpio"); > + if (rc) { > + dev_err(&pdev->dev, "Failed to request gpio:%d\n", dp->gpio_num); > + return rc; > + } > + gpio_direction_input(dp->gpio_num); > + } > + > /* setup event q */ > mutex_init(&dp->event_mutex); > init_waitqueue_head(&dp->event_q); > spin_lock_init(&dp->event_lock); > + INIT_WORK(&dp->gpio_work, msm_dp_gpio_work_handler); > > /* Store DP audio handle inside DP display */ > dp->msm_dp_display.msm_dp_audio = dp->audio; > @@ -1678,6 +1757,10 @@ void msm_dp_bridge_hpd_enable(struct drm_bridge *bridge) > msm_dp_catalog_hpd_config_intr(dp->catalog, DP_DP_HPD_INT_MASK, true); > > msm_dp_display->internal_hpd = true; > + > + if (dp->ext_gpio) > + schedule_work(&dp->gpio_work); > + > mutex_unlock(&dp->event_mutex); > } > >
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