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

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