linux-kernel - Re: [PATCH v2 0/3] hwmon: (pmbus) Add support for additional Flex BMR converters to the pmbus driver

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Date:   Mon, 10 May 2021 09:38:25 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Erik Rosen <erik.rosen@...ormote.com>
Cc:     Jean Delvare <jdelvare@...e.com>, Jonathan Corbet <corbet@....net>,
        linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/3] hwmon: (pmbus) Add support for additional Flex
 BMR converters to the pmbus driver

On Fri, May 07, 2021 at 09:40:20PM +0200, Erik Rosen wrote:
> Some Flex pmbus converters (BMR310, BMR458, BMR80, BMR490 and BMR491)
> end up in an undefined state when trying to read a register that does
> not exist in the chip. This causes the following chip access to also
> fail even if it is a valid register read or write. This will mess up the
> pmbus driver auto-detection process.
> 
> One way to reset the pmbus state machine to a known state is to read
> a register that is known to exist. This read will fail but will also
> reset the chip into a known state.
> 
> For such chips we suggest adding a new pmbus flag:
> PMBUS_READ_STATUS_AFTER_FAILED_CHECK
> By setting this flag the driver will try to read the STATUS register
> after each failed register check. This read may fail, but it will put
> the chip into a known state so that the auto-detection process can
> proceed correctly.
> 
> Add support for Flex BMR310, BMR456, BMR457, BMR458, BMR480, BMR490,
> BMR491 and BMR492 to the pmbus driver
> 
> This patch has been tested with Flex BMR310, BMR456, BMR457, BMR458,
> BMR480, BMR490, BMR491 and BMR492 converter modules
> 
> v2
> -Copy all flags to pmbus_platform_data struct instead of one by one
> -Fix code formatting in pmbus_core documentation
> -Add documentation for flag NO_CAPABILITY
> -Fix sorting of chip names and prefix in pmbus documentation
> 
Series applied, with minor whitespace fixes in documentation.

Guenter