Re: [PATCH v2 2/2] drm: bridge: Move HPD handling to PHY operations

Hi Neil,

Thank you for the patch.

On Thursday 02 Mar 2017 16:29:32 Neil Armstrong wrote:

The HDMI TX controller support HPD and RXSENSE signaling from the PHY via it's STAT0 PHY interface, but some vendor PHYs can manage these signals independently from the controller, thus these STAT0 handling should be moved to PHY specific operations and become optional.

The existing STAT0 HPD and RXSENSE handling code is refactored into a supplementaty set of default PHY operations that are used automatically when the platform glue doesn't provide its own operations.

Signed-off-by: Neil Armstrong narmstrong@baylibre.com

drivers/gpu/drm/bridge/dw-hdmi.c | 134 +++++++++++++++++++++++++----------- include/drm/bridge/dw_hdmi.h | 8 +++ 2 files changed, 104 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c index 653ecd7..58dcf7d 100644 --- a/drivers/gpu/drm/bridge/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/dw-hdmi.c @@ -1098,10 +1098,50 @@ static enum drm_connector_status dw_hdmi_phy_read_hpd(struct dw_hdmi *hdmi, connector_status_connected : connector_status_disconnected; }

+static void dw_hdmi_phy_update_hpd(struct dw_hdmi *hdmi, void *data,

• 		   bool force, bool disabled, bool rxsense)
  

+{

• if (force || disabled || !rxsense)

• hdmi->phy_mask |= HDMI_PHY_RX_SENSE;
  

• else

• hdmi->phy_mask &= ~HDMI_PHY_RX_SENSE;
  

+}

+static void dw_hdmi_phy_setup_hpd(struct dw_hdmi *hdmi, void *data) +{

• /* setup HPD and RXSENSE interrupt polarity */
• hdmi_writeb(hdmi, HDMI_PHY_HPD | HDMI_PHY_RX_SENSE, HDMI_PHY_POL0);

+}

+static void dw_hdmi_phy_configure_hpd(struct dw_hdmi *hdmi, void *data) +{

• /* enable cable hot plug irq */
• hdmi_writeb(hdmi, hdmi->phy_mask, HDMI_PHY_MASK0);

+}

+static void dw_hdmi_phy_clear_hpd(struct dw_hdmi *hdmi, void *data) +{

• /* Clear Hotplug interrupts */
• hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE,

•     HDMI_IH_PHY_STAT0);
  

+}

+static void dw_hdmi_phy_unmute_hpd(struct dw_hdmi *hdmi, void *data) +{

• /* Unmute Hotplug interrupts */
• hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD |

HDMI_IH_PHY_STAT0_RX_SENSE),

•     HDMI_IH_MUTE_PHY_STAT0);
  

+}

Do we really need all those new operations ? It looks to me like a bit of refactoring could help lowering the number of operations. We essentially need

- an init function called at probe time (or likely rather at runtime PM resume time when we'll implement runtime PM)

- an interrupt enable/disable function roughly equivalent to dw_hdmi_update_phy_mask()

- a read function to report the detection results called from dw_hdmi_connector_detect()

static const struct dw_hdmi_phy_ops dw_hdmi_synopsys_phy_ops = { .init = dw_hdmi_phy_init, .disable = dw_hdmi_phy_disable, .read_hpd = dw_hdmi_phy_read_hpd,

• .update_hpd = dw_hdmi_phy_update_hpd,
• .setup_hpd = dw_hdmi_phy_setup_hpd,
• .configure_hpd = dw_hdmi_phy_configure_hpd,
• .clear_hpd = dw_hdmi_phy_clear_hpd,
• .unmute_hpd = dw_hdmi_phy_unmute_hpd,

};

/* ------------------------------------------------------------------------ @@ -1507,11 +1547,12 @@ static int dw_hdmi_fb_registered(struct dw_hdmi *hdmi) HDMI_PHY_I2CM_CTLINT_ADDR);

/* enable cable hot plug irq */

• hdmi_writeb(hdmi, hdmi->phy_mask, HDMI_PHY_MASK0);

• if (hdmi->phy.ops->configure_hpd)

• hdmi->phy.ops->configure_hpd(hdmi, hdmi->phy.data);
  
  

  /* Clear Hotplug interrupts */

• hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE,

•     HDMI_IH_PHY_STAT0);
  

• if (hdmi->phy.ops->clear_hpd)

• hdmi->phy.ops->clear_hpd(hdmi, hdmi->phy.data);
  

The probe function contains the same code. Let's inline this function into probe, group all HPD-related initialization together and extract that into a function to keep probe easy to read. I think you can do that in a separate patch.

return 0; } @@ -1622,13 +1663,14 @@ static void dw_hdmi_update_phy_mask(struct dw_hdmi *hdmi) { u8 old_mask = hdmi->phy_mask;

• if (hdmi->force || hdmi->disabled || !hdmi->rxsense)

• hdmi->phy_mask |= HDMI_PHY_RX_SENSE;
  

• else

• hdmi->phy_mask &= ~HDMI_PHY_RX_SENSE;
  

• if (hdmi->phy.ops->update_hpd)

• hdmi->phy.ops->update_hpd(hdmi, hdmi->phy.data,
  

• 			  hdmi->force, hdmi->disabled,
  

• 			  hdmi->rxsense);
  
  

• if (old_mask != hdmi->phy_mask)

• hdmi_writeb(hdmi, hdmi->phy_mask, HDMI_PHY_MASK0);
  

• if (old_mask != hdmi->phy_mask &&

phy_mask isn't accessible to glue code, so this test will never be true with vendor PHYs.

•    hdmi->phy.ops->configure_hpd)
  

• hdmi->phy.ops->configure_hpd(hdmi, hdmi->phy.data);
  

}

static enum drm_connector_status @@ -1820,6 +1862,41 @@ static irqreturn_t dw_hdmi_hardirq(int irq, void *dev_id) return ret; }

+void __dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense) +{

• mutex_lock(&hdmi->mutex);
• if (!hdmi->disabled && !hdmi->force) {

• /*
  

•  * If the RX sense status indicates we're disconnected,
  

•  * clear the software rxsense status.
  

•  */
  

• if (!rx_sense)
  

• 	hdmi->rxsense = false;
  

• /*
  

•  * Only set the software rxsense status when both
  

•  * rxsense and hpd indicates we're connected.
  

•  * This avoids what seems to be bad behaviour in
  

•  * at least iMX6S versions of the phy.
  

•  */
  

• if (hpd)
  

• 	hdmi->rxsense = true;
  

This contradicts the above comment, hdmi->rxsense is set back to true solely based on the hpd parameter.

• dw_hdmi_update_power(hdmi);
  

• dw_hdmi_update_phy_mask(hdmi);
  

• }

I'd add a blank line here.

• mutex_unlock(&hdmi->mutex);

+}

+void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense) +{

• struct dw_hdmi *hdmi = dev_get_drvdata(dev);
• __dw_hdmi_setup_rx_sense(hdmi, hpd, rx_sense);

+} +EXPORT_SYMBOL_GPL(dw_hdmi_setup_rx_sense);

static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) { struct dw_hdmi *hdmi = dev_id; @@ -1852,30 +1929,10 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) * ask the source to re-read the EDID. */ if (intr_stat &

•    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
  

• mutex_lock(&hdmi->mutex);
  

• if (!hdmi->disabled && !hdmi->force) {
  

• 	/*
  

• 	 * If the RX sense status indicates we're 
  

disconnected,

• 	 * clear the software rxsense status.
  

• 	 */
  

• 	if (!(phy_stat & HDMI_PHY_RX_SENSE))
  

• 		hdmi->rxsense = false;
  

• 	/*
  

• 	 * Only set the software rxsense status when both
  

• 	 * rxsense and hpd indicates we're connected.
  

• 	 * This avoids what seems to be bad behaviour in
  

• 	 * at least iMX6S versions of the phy.
  

• 	 */
  

• 	if (phy_stat & HDMI_PHY_HPD)
  

• 		hdmi->rxsense = true;
  

• 	dw_hdmi_update_power(hdmi);
  

• 	dw_hdmi_update_phy_mask(hdmi);
  

• }
  

• mutex_unlock(&hdmi->mutex);
  

• }

•    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD))
  

Is this right ? If your SoC implements a custom HPD mechanism, does it still rely on the standard RX SENSE and HPD interrupts ? In particular, this function still writes the HDMI_IH_MUTE_PHY_STAT0 register directly, while you've extracted a write to the same register in the probe function into a PHY operation.

• __dw_hdmi_setup_rx_sense(hdmi,
  

• 			 phy_stat & HDMI_PHY_HPD,
  

• 			 phy_stat & HDMI_PHY_RX_SENSE);
  
  

  if (intr_stat & HDMI_IH_PHY_STAT0_HPD) { dev_dbg(hdmi->dev, "EVENT=%s\n",

@@ -2146,11 +2203,12 @@ static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi) * Configure registers related to HDMI interrupt * generation before registering IRQ. */

• hdmi_writeb(hdmi, HDMI_PHY_HPD | HDMI_PHY_RX_SENSE, HDMI_PHY_POL0);

• if (hdmi->phy.ops->setup_hpd)

• hdmi->phy.ops->setup_hpd(hdmi, hdmi->phy.data);
  
  

  /* Clear Hotplug interrupts */

• hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE,

•     HDMI_IH_PHY_STAT0);
  

• if (hdmi->phy.ops->clear_hpd)

• hdmi->phy.ops->clear_hpd(hdmi, hdmi->phy.data);
  
  

  hdmi->bridge.driver_private = hdmi; hdmi->bridge.funcs = &dw_hdmi_bridge_funcs;

@@ -2163,8 +2221,8 @@ static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi) goto err_iahb;

/* Unmute interrupts */

• hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD |

HDMI_IH_PHY_STAT0_RX_SENSE),

•     HDMI_IH_MUTE_PHY_STAT0);
  

• if (hdmi->phy.ops->unmute_hpd)

• hdmi->phy.ops->unmute_hpd(hdmi, hdmi->phy.data);
  
  

  memset(&pdevinfo, 0, sizeof(pdevinfo)); pdevinfo.parent = dev;

diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h index 8c0cc13..d72403f 100644 --- a/include/drm/bridge/dw_hdmi.h +++ b/include/drm/bridge/dw_hdmi.h @@ -64,6 +64,12 @@ struct dw_hdmi_phy_ops { struct drm_display_mode *mode); void (*disable)(struct dw_hdmi *hdmi, void *data); enum drm_connector_status (*read_hpd)(struct dw_hdmi *hdmi, void

*data);

• void (*update_hpd)(struct dw_hdmi *hdmi, void *data,

• 	   bool force, bool disabled, bool rxsense);
  

• void (*setup_hpd)(struct dw_hdmi *hdmi, void *data);
• void (*configure_hpd)(struct dw_hdmi *hdmi, void *data);
• void (*clear_hpd)(struct dw_hdmi *hdmi, void *data);
• void (*unmute_hpd)(struct dw_hdmi *hdmi, void *data);

That's quite a lot of new operations. I think we need documentation :-)

};

struct dw_hdmi_plat_data { @@ -93,6 +99,8 @@ int dw_hdmi_probe(struct platform_device *pdev, int dw_hdmi_bind(struct platform_device *pdev, struct drm_encoder *encoder, const struct dw_hdmi_plat_data *plat_data);

+void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense);

void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate); void dw_hdmi_audio_enable(struct dw_hdmi *hdmi); void dw_hdmi_audio_disable(struct dw_hdmi *hdmi);