Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <1cc12337-759e-c932-0303-b1b78e254c27@roeck-us.net>
Date:   Fri, 28 Jul 2023 03:00:27 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.13.0
Content-Language: en-US
To:     Naresh Solanki <naresh.solanki@9elements.com>,
        Jean Delvare <jdelvare@suse.com>,
        krzysztof.kozlowski+dt@linaro.org
Cc:     linux-hwmon@vger.kernel.org,
        Patrick Rudolph <patrick.rudolph@9elements.com>,
        linux-kernel@vger.kernel.org
References: <20230728082527.3531940-1-Naresh.Solanki@9elements.com>
From:   Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH] hwmon: (pmbus/mp2975) Fix PGOOD in READ_STATUS_WORD
In-Reply-To: <20230728082527.3531940-1-Naresh.Solanki@9elements.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 7/28/23 01:25, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> MPS returns PGOOD instead of PB_STATUS_POWER_GOOD_N.
> Fix that in the read_word_data hook.
> 
Datasheets are not public, so I can not verify, but the code below
only handles MP2973 and MP2971. What about MP2975 ?

Either case, this appears to affect most Monolithic chips, but
not all of them. Please limit the statement to known to be affected
chips.

> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---
>   drivers/hwmon/pmbus/mp2975.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/mp2975.c b/drivers/hwmon/pmbus/mp2975.c
> index 28f33f4618fa..410b6eae6d02 100644
> --- a/drivers/hwmon/pmbus/mp2975.c
> +++ b/drivers/hwmon/pmbus/mp2975.c
> @@ -297,6 +297,10 @@ static int mp2973_read_word_data(struct i2c_client *client, int page,
>   	int ret;
>   
>   	switch (reg) {
> +	case PMBUS_STATUS_WORD:
> +		ret = pmbus_read_word_data(client, page, phase, reg);

		if (ret < 0)
			return ret;

Please add a comment explaining what is going on.

> +		ret ^= PB_STATUS_POWER_GOOD_N;
> +		break;
>   	case PMBUS_OT_FAULT_LIMIT:
>   		ret = mp2975_read_word_helper(client, page, phase, reg,
>   					      GENMASK(7, 0));
> 
> base-commit: a4bb1ce5b9e3ca403c04e20ebeae77fd6447cb11