linux-kernel - Re: [PATCH 2/4] hwmon: (pmbus) mark registers READ_VIN and READ

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Message-ID: <20190416194032.GB8093@roeck-us.net>
Date:   Tue, 16 Apr 2019 12:40:33 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Ruslan Babayev <ruslan@...ayev.com>
Cc:     xe-linux-external@...co.com, Jean Delvare <jdelvare@...e.com>,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] hwmon: (pmbus) mark registers READ_VIN and READ_IIN
 as paged

On Tue, Apr 16, 2019 at 11:36:17AM -0700, Ruslan Babayev wrote:
> On some devices (like IR35215) READ_VIN and READ_IIN registers are
> paged.
> 
> For devices where these registers are not paged the extra check
> ensures we expose only the registers that are actually present.
> 
> Cc: xe-linux-external@...co.com
> Signed-off-by: Ruslan Babayev <ruslan@...ayev.com>
> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index f35b239961e3..fac966967816 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -1379,6 +1379,9 @@ static int pmbus_add_sensor_attrs(struct i2c_client *client,
>  		for (page = 0; page < pages; page++) {
>  			if (!(info->func[page] & attrs->func))
>  				continue;
> +			if (!pmbus_check_word_register(client, page,
> +						       attrs->reg))
> +				continue;

This won't work. Most other chips will just report the values from page 0
when trying to read VIN/IIN from other pages.

Guenter

>  			ret = pmbus_add_sensor_attrs_one(client, data, info,
>  							 name, index, page,
>  							 attrs);
> @@ -1498,6 +1501,7 @@ static const struct pmbus_sensor_attr voltage_attributes[] = {
>  		.reg = PMBUS_READ_VIN,
>  		.class = PSC_VOLTAGE_IN,
>  		.label = "vin",
> +		.paged = true,
>  		.func = PMBUS_HAVE_VIN,
>  		.sfunc = PMBUS_HAVE_STATUS_INPUT,
>  		.sbase = PB_STATUS_INPUT_BASE,
> @@ -1602,6 +1606,7 @@ static const struct pmbus_sensor_attr current_attributes[] = {
>  		.reg = PMBUS_READ_IIN,
>  		.class = PSC_CURRENT_IN,
>  		.label = "iin",
> +		.paged = true,
>  		.func = PMBUS_HAVE_IIN,
>  		.sfunc = PMBUS_HAVE_STATUS_INPUT,
>  		.sbase = PB_STATUS_INPUT_BASE,
> -- 
> 2.17.1
>