linux-kernel - Re: [PATCH v2 6/6] usb: typec: tcpci_rt1711h: Fix CC PHY noise filter of voltage level

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Date:   Thu, 21 Jul 2022 17:13:50 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Gene Chen <gene.chen.richtek@...il.com>,
        heikki.krogerus@...ux.intel.com, gregkh@...uxfoundation.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, gene_chen@...htek.com,
        cy_huang@...htek.com
Subject: Re: [PATCH v2 6/6] usb: typec: tcpci_rt1711h: Fix CC PHY noise filter
 of voltage level

On 7/20/22 23:11, Gene Chen wrote:
> From: Gene Chen <gene_chen@...htek.com>
> 
> Fix CC PHY noise filter of voltage level according to
> current cc voltage level
> 
> Signed-off-by: Gene Chen <gene_chen@...htek.com>
> ---
>   drivers/usb/typec/tcpm/tcpci_rt1711h.c | 83 +++++++++++++++++++++++++-
>   1 file changed, 81 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpci_rt1711h.c b/drivers/usb/typec/tcpm/tcpci_rt1711h.c
> index 3316dfaeee0d..f0c46bf7f00b 100644
> --- a/drivers/usb/typec/tcpm/tcpci_rt1711h.c
> +++ b/drivers/usb/typec/tcpm/tcpci_rt1711h.c
> @@ -22,8 +22,11 @@
>   #define RT1711H_PHYCTRL1	0x80
>   #define RT1711H_PHYCTRL2	0x81
>   
> -#define RT1711H_RTCTRL8		0x9B
> +#define RT1711H_RTCTRL4		0x93
> +/* rx threshold of rd/rp: 1b0 for level 0.4V/0.7V, 1b1 for 0.35V/0.75V */
> +#define RT1711H_BMCIO_RXDZSEL	BIT(0)
>   
> +#define RT1711H_RTCTRL8		0x9B
>   /* Autoidle timeout = (tout * 2 + 1) * 6.4ms */
>   #define RT1711H_RTCTRL8_SET(ck300, ship_off, auto_idle, tout) \
>   			    (((ck300) << 7) | ((ship_off) << 5) | \
> @@ -32,7 +35,6 @@
>   #define RT1711H_ENEXTMSG_MASK	BIT(4)
>   
>   #define RT1711H_RTCTRL11	0x9E
> -
>   /* I2C timeout = (tout + 1) * 12.5ms */
>   #define RT1711H_RTCTRL11_SET(en, tout) \
>   			     (((en) << 7) | ((tout) & 0x0F))
> @@ -42,6 +44,10 @@
>   #define RT1711H_RTCTRL15	0xA2
>   #define RT1711H_RTCTRL16	0xA3
>   
> +#define RT1711H_RTCTRL18	0xAF
> +/* 1b0 as fixed rx threshold of rd/rp 0.55V, 1b1 depends on RTCRTL4[0] */
> +#define BMCIO_RXDZEN_MASK	BIT(0)

I really dislike the use of _MASK for register bit values.

> +
>   struct rt1711h_chip {
>   	struct tcpci_data data;
>   	struct tcpci *tcpci;
> @@ -162,6 +168,77 @@ static int rt1711h_set_vconn(struct tcpci *tcpci, struct tcpci_data *tdata,
>   				  RT1711H_AUTOIDLEEN_MASK, enable ? 0 : 0xFF);
>   }
>   
> +#define tcpc_presenting_rd(reg, cc) \
> +	(!(TCPC_ROLE_CTRL_DRP & (reg)) && \
> +	 (((reg) & (TCPC_ROLE_CTRL_## cc ##_MASK << TCPC_ROLE_CTRL_## cc ##_SHIFT)) == \
> +	  (TCPC_ROLE_CTRL_CC_RD << TCPC_ROLE_CTRL_## cc ##_SHIFT)))
> +
> +static enum typec_cc_status tcpci_to_typec_cc(unsigned int cc, bool sink)
> +{
> +	switch (cc) {
> +	case 0x1:
> +		return sink ? TYPEC_CC_RP_DEF : TYPEC_CC_RA;
> +	case 0x2:
> +		return sink ? TYPEC_CC_RP_1_5 : TYPEC_CC_RD;
> +	case 0x3:
> +		if (sink)
> +			return TYPEC_CC_RP_3_0;
> +		fallthrough;
> +	case 0x0:
> +	default:
> +		return TYPEC_CC_OPEN;
> +	}
> +}
> +
The above is a straight copy from tcpci.c. Can it be moved to
include/linux/usb/tcpci.h ?

> +/*
> + * Selects the CC PHY noise filter voltage level according to the current
> + * CC voltage level.
> + *
> + * @param cc_level The CC voltage level for the port's current role

I seem to be missing that parameter.

> + * @return 0 if writes succeed; failure code otherwise
> + */
> +static inline int rt1711h_init_cc_params(struct rt1711h_chip *chip, u8 status)
> +{
> +	int ret, cc1, cc2;
> +	u8 role = 0;
> +	u32 rxdz_en = 0, rxdz_sel = 0;

Those variables are always set and thus do not need to be initialized.
> +
> +	ret = rt1711h_read8(chip, TCPC_ROLE_CTRL, &role);
> +	if (ret < 0)
> +		return ret;
> +
> +	cc1 = tcpci_to_typec_cc((status >> TCPC_CC_STATUS_CC1_SHIFT) &
> +				TCPC_CC_STATUS_CC1_MASK,
> +				status & TCPC_CC_STATUS_TERM ||
> +				tcpc_presenting_rd(role, CC1));
> +	cc2 = tcpci_to_typec_cc((status >> TCPC_CC_STATUS_CC2_SHIFT) &
> +				TCPC_CC_STATUS_CC2_MASK,
> +				status & TCPC_CC_STATUS_TERM ||
> +				tcpc_presenting_rd(role, CC2));
> +
> +	if ((cc1 >= TYPEC_CC_RP_1_5 && cc2 < TYPEC_CC_RP_DEF) ||
> +	    (cc2 >= TYPEC_CC_RP_1_5 && cc1 < TYPEC_CC_RP_DEF)) {
> +		if (chip->did == RT1715_DID) {
> +			rxdz_en = 1;

This should be
			rxdz_en = BMCIO_RXDZEN;

> +			rxdz_sel = 1;

This should be
			rxdz_sel = RT1711H_BMCIO_RXDZSEL;

> +		} else {
> +			rxdz_en = 1;
> +			rxdz_sel = 0;
> +		}

The assignment of rxdz_en can be moved outside the if/else block.

> +	} else {
> +		rxdz_en = 0;
> +		rxdz_sel = 1;
> +	}
> +
> +	ret = regmap_update_bits(chip->data.regmap, RT1711H_RTCTRL18,
> +				 BMCIO_RXDZEN_MASK, rxdz_en);
> +	if (ret < 0)
> +		return ret;
> +
> +	return regmap_update_bits(chip->data.regmap, RT1711H_RTCTRL4,
> +				  RT1711H_BMCIO_RXDZSEL, rxdz_sel);
> +}
> +
>   static int rt1711h_start_drp_toggling(struct tcpci *tcpci,
>   				      struct tcpci_data *tdata,
>   				      enum typec_cc_status cc)
> @@ -222,6 +299,8 @@ static irqreturn_t rt1711h_irq(int irq, void *dev_id)
>   		/* Clear cc change event triggered by starting toggling */
>   		if (status & TCPC_CC_STATUS_TOGGLING)
>   			rt1711h_write8(chip, TCPC_ALERT, TCPC_ALERT_CC_STATUS);
> +		else
> +			rt1711h_init_cc_params(chip, status);
>   	}
>   
>   out: