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Date:   Fri, 20 Jan 2023 17:56:39 +0100
From:   Alexandre Belloni <alexandre.belloni@bootlin.com>
To:     Hugo Villeneuve <hugo@hugovil.com>
Cc:     a.zummo@towertech.it, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, linux-rtc@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hugo Villeneuve <hvilleneuve@dimonoff.com>
Subject: Re: [PATCH v3 08/14] rtc: pcf2127: add support for PCF2131
 interrupts on output INT_A
Message-ID: <Y8rHx8U4peB+fnW8@mail.local>
References: <20221215150214.1109074-1-hugo@hugovil.com>
 <20221215150214.1109074-9-hugo@hugovil.com>
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On 15/12/2022 10:02:09-0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> 
> The PCF2127 and PCF2129 have one output interrupt pin. The PCF2131 has
> two, named INT_A and INT_B. The hardware support that any interrupt
> source can be routed to either one or both of them.
> 
> Force all interrupt sources to go to the INT A pin.
> 
> Support to route any interrupt source to INT A/B pins is not supported
> by this driver at the moment.
> 

The main issue with this is that this will created a breaking change
once someone needs support for INTB

> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> ---
>  drivers/rtc/rtc-pcf2127.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 4148e135f935..68af4d0438b8 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -191,6 +191,7 @@ struct pcf21xx_config {
>  	int max_register;
>  	unsigned int has_nvmem:1;
>  	unsigned int has_bit_wd_ctl_cd0:1;
> +	unsigned int has_int_a_b:1; /* PCF2131 supports two interrupt outputs. */
>  	u8 regs_td_base; /* Time/data base registers. */
>  	u8 regs_alarm_base; /* Alarm function base registers. */
>  	u8 reg_wd_ctl; /* Watchdog control register. */
> @@ -879,6 +880,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>  		.max_register = 0x1d,
>  		.has_nvmem = 1,
>  		.has_bit_wd_ctl_cd0 = 1,
> +		.has_int_a_b = 0,
>  		.regs_td_base = PCF2127_REG_TIME_DATE_BASE,
>  		.regs_alarm_base = PCF2127_REG_ALARM_BASE,
>  		.reg_wd_ctl = PCF2127_REG_WD_CTL,
> @@ -902,6 +904,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>  		.max_register = 0x19,
>  		.has_nvmem = 0,
>  		.has_bit_wd_ctl_cd0 = 0,
> +		.has_int_a_b = 0,
>  		.regs_td_base = PCF2127_REG_TIME_DATE_BASE,
>  		.regs_alarm_base = PCF2127_REG_ALARM_BASE,
>  		.reg_wd_ctl = PCF2127_REG_WD_CTL,
> @@ -925,6 +928,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>  		.max_register = 0x36,
>  		.has_nvmem = 0,
>  		.has_bit_wd_ctl_cd0 = 0,
> +		.has_int_a_b = 1,
>  		.regs_td_base = PCF2131_REG_TIME_DATE_BASE,
>  		.regs_alarm_base = PCF2131_REG_ALARM_BASE,
>  		.reg_wd_ctl = PCF2131_REG_WD_CTL,
> @@ -1017,6 +1021,28 @@ static int pcf2127_enable_ts(struct device *dev, int ts_id)
>  	return ret;
>  }
>  
> +/* Route all interrupt sources to INT A pin. */
> +static int pcf2127_configure_interrupt_pins(struct device *dev)
> +{
> +	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> +	int ret;
> +
> +	/* Mask bits need to be cleared to enable corresponding
> +	 * interrupt source.
> +	 */
> +	ret = regmap_write(pcf2127->regmap,
> +			   PCF2131_REG_INT_A_MASK1, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(pcf2127->regmap,
> +			   PCF2131_REG_INT_A_MASK2, 0);
> +	if (ret)
> +		return ret;
> +
> +	return ret;
> +}
> +
>  static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>  			 int alarm_irq, const char *name, const struct pcf21xx_config *config)
>  {
> @@ -1076,6 +1102,15 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>  		set_bit(RTC_FEATURE_ALARM, pcf2127->rtc->features);
>  	}
>  
> +	if (pcf2127->cfg->has_int_a_b) {
> +		/* Configure int A/B pins, independently of alarm_irq. */
> +		ret = pcf2127_configure_interrupt_pins(dev);
> +		if (ret) {
> +			dev_err(dev, "failed to configure interrupt pins\n");
> +			return ret;
> +		}
> +	}
> +
>  	if (pcf2127->cfg->has_nvmem) {
>  		struct nvmem_config nvmem_cfg = {
>  			.priv = pcf2127,
> -- 
> 2.30.2
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com