linux-kernel - Re: [PATCH v4 7/7] hwmon: (pmbus/tps25990): add initial support

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Message-ID: <1jpln62jtj.fsf@starbuckisacylon.baylibre.com>
Date: Fri, 08 Nov 2024 09:47:36 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Jean Delvare <jdelvare@...e.com>,  Jonathan Corbet <corbet@....net>,
  Patrick Rudolph <patrick.rudolph@...ements.com>,  Naresh Solanki
 <naresh.solanki@...ements.com>,  Rob Herring <robh@...nel.org>,  Krzysztof
 Kozlowski <krzk+dt@...nel.org>,  Conor Dooley <conor+dt@...nel.org>,
  Delphine CC Chiu <Delphine_CC_Chiu@...ynn.com>,
  linux-hwmon@...r.kernel.org,  linux-kernel@...r.kernel.org,
  linux-doc@...r.kernel.org,  devicetree@...r.kernel.org,
  linux-i2c@...r.kernel.org,  Vaishnav Achath <vaishnav.a@...com>
Subject: Re: [PATCH v4 7/7] hwmon: (pmbus/tps25990): add initial support

On Wed 06 Nov 2024 at 10:59, Guenter Roeck <linux@...ck-us.net> wrote:

>> +
>> +static int tps25990_mfr_write_protect_set(struct i2c_client *client,
>> +					  u8 protect)
>> +{
>> +	/*
>> +	 * The chip has a single protection mode, set it regardless of
>> +	 * the specific protection requested
>> +	 */
>> +	return pmbus_write_byte_data(client, -1, TPS25990_MFR_WRITE_PROTECT,
>> +				     protect ? 0x0 : 0xa2);
>
> After some thought, I think it would be better to reject all protect values
> other than 0 (no write protection) and PB_WP_ALL because that is what the chip
> supports. Something like

Since operation would not be allowed, it's maps the closest indeed.

>
> 	if (protect & ~PB_WP_ALL)
> 		return -ENXIO;		// or -EINVAL ? Not really sure.

The command is supported but the argument would not be, so -EINVAL seems
appropriate to me.

>
> Thanks,
> Guenter

-- 
Jerome