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Date: Fri, 8 Apr 2022 15:41:36 +0200 From: Neil Armstrong <narmstrong@...libre.com> To: Sandor Yu <Sandor.yu@....com>, dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, andrzej.hajda@...el.com, robert.foss@...aro.org, Laurent.pinchart@...asonboard.com, jonas@...boo.se, jernej.skrabec@...il.com, hverkuil-cisco@...all.nl Cc: shengjiu.wang@....com, cai.huoqing@...ux.dev, maxime@...no.tech, harry.wentland@....com Subject: 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@....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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