Re: [PATCH v2 1/5] drm: bridge: dw_hdmi: cec: Add cec suspend/resume function

On 08/04/2022 12:32, Sandor Yu wrote:

CEC interrupt status/mask and logical address registers will be reset when device enter suspend. It will cause cec fail to work after device resume. Add CEC suspend/resume functions, reinitialize logical address registers and restore interrupt status/mask registers after resume.

Signed-off-by: Sandor Yu Sandor.yu@nxp.com

drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c | 37 +++++++++++++++++++ 1 file changed, 37 insertions(+)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c index c8f44bcb298a..ab176401b727 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c @@ -62,6 +62,10 @@ struct dw_hdmi_cec { bool rx_done; struct cec_notifier *notify; int irq;

• u8 regs_polarity;

• u8 regs_mask;

• u8 regs_mute_stat0; };

  static void dw_hdmi_write(struct dw_hdmi_cec *cec, u8 val, int offset)

@@ -306,11 +310,44 @@ static int dw_hdmi_cec_remove(struct platform_device *pdev) return 0; }

+static int __maybe_unused dw_hdmi_cec_resume(struct device *dev) +{

• struct dw_hdmi_cec *cec = dev_get_drvdata(dev);
• /* Restore logical address */
• dw_hdmi_write(cec, cec->addresses & 255, HDMI_CEC_ADDR_L);
• dw_hdmi_write(cec, cec->addresses >> 8, HDMI_CEC_ADDR_H);
• /* Restore interrupt status/mask register */
• dw_hdmi_write(cec, cec->regs_polarity, HDMI_CEC_POLARITY);
• dw_hdmi_write(cec, cec->regs_mask, HDMI_CEC_MASK);
• dw_hdmi_write(cec, cec->regs_mute_stat0, HDMI_IH_MUTE_CEC_STAT0);
• return 0;

+}

+static int __maybe_unused dw_hdmi_cec_suspend(struct device *dev) +{

• struct dw_hdmi_cec *cec = dev_get_drvdata(dev);
• /* store interrupt status/mask register */

• cec->regs_polarity = dw_hdmi_read(cec, HDMI_CEC_POLARITY);
  

• cec->regs_mask = dw_hdmi_read(cec, HDMI_CEC_MASK);
  

• cec->regs_mute_stat0 = dw_hdmi_read(cec, HDMI_IH_MUTE_CEC_STAT0);
  

• return 0;

+}

+static const struct dev_pm_ops dw_hdmi_cec_pm = {

• SET_SYSTEM_SLEEP_PM_OPS(dw_hdmi_cec_suspend, dw_hdmi_cec_resume)

+};

• static struct platform_driver dw_hdmi_cec_driver = { .probe = dw_hdmi_cec_probe, .remove = dw_hdmi_cec_remove, .driver = { .name = "dw-hdmi-cec",

• .pm = &dw_hdmi_cec_pm,
  

  }, }; module_platform_driver(dw_hdmi_cec_driver);

As Hans said on v1, why don't you call dw_hdmi_cec_enable(cec->adap, false) in suspend and dw_hdmi_cec_enable(cec->adap, true) in resume ?

With this, CEC engine is not disabled on suspend.

Do you plan to use the engine from the suspend code ?

Neil