linux-kernel - Re: [PATCH v2 1/2] rtc: add pcf85053a

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Message-ID: <5451ac26-c498-4af5-b3fa-fe2265433ccc@roeck-us.net>
Date:   Fri, 3 Nov 2023 07:09:27 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Carlos Menin <menin@...losaurelio.net>, linux-rtc@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-hwmon@...r.kernel.org
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Sergio Prado <sergio.prado@...abworks.com>
Subject: Re: [PATCH v2 1/2] rtc: add pcf85053a

On 11/3/23 05:51, Carlos Menin wrote:
> Add support for NXP's PCF85053A RTC chip.
> 
> Signed-off-by: Carlos Menin <menin@...losaurelio.net>
> Reviewed-by: Sergio Prado <sergio.prado@...abworks.com>
> ---

[ ... ]

> +static int pcf85053a_bvl_to_mv(unsigned int bvl)
> +{
> +	long mv_table[] = {
> +		1700,
> +		1900,
> +		2100,
> +		2300,
> +		2500,
> +		2700,
> +		2900,
> +		3100,

How are those numbers determined ? The datasheet gives voltage ranges.
I'd have assumed that the center of those ranges is chosen, but for the
most part it is the maximum, except for 2900 which is a bit above center
and 3100 for "> 3.0V". Not that I care too much, but it seems to me that
using the center voltage for each range would be more consistent.

> +static int pcf85053a_hwmon_register(struct device *dev, const char *name)
> +{
> +	struct pcf85053a *pcf85053a = dev_get_drvdata(dev);
> +	struct device *hwmon_dev;
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, name, pcf85053a,
> +							 &pcf85053a_hwmon_chip_info,
> +							 0);

This won't compile if CONFIG_HWMON=n or if CONFIG_RTC_DRV_PCF85053A=y and
CONFIG_HWMON=m.

Guenter