[PATCH v14 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver

[Rex-BC Chen]

On Mon, 2022-07-25 at 17:23 +0800, CK Hu wrote:
> Hi, Bo-Chen:
> 
> On Tue, 2022-07-12 at 19:12 +0800, Bo-Chen Chen wrote:
> > From: Markus Schneider-Pargmann <msp at baylibre.com>
> > 
> > This patch adds a embedded displayport driver for the MediaTek
> > mt8195
> > SoC.
> > 
> > It supports the MT8195, the embedded DisplayPort units. It offers
> > DisplayPort 1.4 with up to 4 lanes.
> > 
> > The driver creates a child device for the phy. The child device
> > will
> > never exist without the parent being active. As they are sharing a
> > register range, the parent passes a regmap pointer to the child so
> > that
> > both can work with the same register range. The phy driver sets
> > device
> > data that is read by the parent to get the phy device that can be
> > used
> > to control the phy properties.
> > 
> > This driver is based on an initial version by
> > Jitao shi <jitao.shi at mediatek.com>
> > 
> > Signed-off-by: Markus Schneider-Pargmann <msp at baylibre.com>
> > Signed-off-by: Guillaume Ranquet <granquet at baylibre.com>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen at mediatek.com>
> > ---
> 
> [snip]
> 
> > +
> > +/*
> > + * We need to handle HPD signal in eDP even though eDP is a always
> > connected
> > + * device. Besides connected status, there is another feature for
> > HPD signal -
> > + * HPD pulse: it presents an IRQ from sink devices to source
> > devices
> > (Refer to
> > + * 5.1.4 of DP1.4 spec).
> > + */
> > +static irqreturn_t mtk_dp_hpd_isr_handler(struct mtk_dp *mtk_dp)
> > +{
> > +	bool hpd_change = false;
> > +	u32 irq_status = mtk_dp_swirq_get_clear(mtk_dp) |
> > +			 mtk_dp_hwirq_get_clear(mtk_dp);
> > +	struct mtk_dp_train_info *train_info = &mtk_dp->train_info;
> > +
> > +	if (!irq_status)
> > +		return IRQ_HANDLED;
> > +
> > +	if (irq_status & MTK_DP_HPD_INTERRUPT)
> > +		train_info->irq_sta.hpd_inerrupt = true;
> > +	if (irq_status & MTK_DP_HPD_CONNECT ||
> > +	    irq_status & MTK_DP_HPD_DISCONNECT)
> > +		hpd_change = true;
> > +
> > +	if (!(hpd_change))
> > +		return IRQ_WAKE_THREAD;
> > +
> > +	if (mtk_dp_plug_state(mtk_dp))
> 
> mtk_dp_plug_state() is called only here, and prevent function call in
> isr handler, so squash mtk_dp_plug_state() into this function.
> 

Hello CK,

Thanks for review.

I would like to keep this because we will use this function for
mtk_dp_plug_state_avoid_pulse() in dp patch.

> > +		train_info->cable_plugged_in = true;
> > +	else
> > +		train_info->cable_plugged_in = false;
> > +
> > +	train_info->cable_state_change = true;
> > +
> > +	return IRQ_WAKE_THREAD;
> > +}
> > +
> > +static irqreturn_t mtk_dp_hpd_event(int hpd, void *dev)
> > +{
> > +	struct mtk_dp *mtk_dp = dev;
> > +	u32 irq_status;
> > +
> > +	irq_status = mtk_dp_read(mtk_dp, MTK_DP_TOP_IRQ_STATUS);
> > +
> > +	if (!irq_status)
> > +		return IRQ_HANDLED;
> > +
> > +	if (irq_status & RGS_IRQ_STATUS_TRANSMITTER)
> > +		return mtk_dp_hpd_isr_handler(mtk_dp);
> 
> Prevent function call in isr handler, squash mtk_dp_hpd_isr_handler()
> into this function.
> 

Is this really necessary? We also modify this function in following
patches. I think it's not a good idea to expand this.

BRs,
Bo-Chen

> Regards,
> CK
> 
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> 
>