Re: [PATCH 1/2] hwmon: (pmbus/ltc2978) Add driver specific regulator ops

[Marten Lindahl <martenli@axis.com>]

On Sun, Apr 24, 2022 at 06:49:10PM +0200, Guenter Roeck wrote:
> On Wed, Apr 06, 2022 at 02:43:20PM +0200, Mårten Lindahl wrote:
> > Several of the manuals for devices supported by this driver describes
> > the need for a minimum wait time before the chip is ready to receive
> > next command.
> > 
> > This wait time is already implemented in the driver as a ltc_wait_ready
> > function with a driver defined wait time of 100 ms, and is considered
> > for specific devices before reading/writing data on the pmbus.
> > 
> > But this driver uses the default pmbus_regulator_ops for the enable/
> > disable/is_enabled functions. By using these functions it bypasses the
> > wait time recommendations for several of the devices managed by the
> > driver (ltc3880/ltc3882/ltc3883/ltc3884/ltc3886/ltc3887/ltc3889/ltm4664/
> > ltm4675/ltm4676/ltm4677/ltm4678/ltm4680/ltm4686/ltm4700/ltc7880).
> > 
> > Lets add driver specific regulator enable/disable/is_enabled ops which
> > takes the wait time into consideration for the specified devices, by
> > overriding pmbus_read_byte_data with internal ltc_read_byte_data.
> > 
> > Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>

Hi Guenter!
Thanks for your comments.
> 
> This patch solves the wrong problem. The real problem is that the
> regulator code in the PMBus core writes direcetly into the chip
> and doesn't use the driver functions to do it if needed, and that
> the PMBus core does not support a chip-specific write_byte_data function
> (because so far it wasn't needed). That needs to get fixed, and then
> we won't need chip specific regulator functions.

Good point. I will add support for driver callback functions in pmbus
core and remove the ltc2978 enable/disable/is_enabled functions.

Kind regards
Mårten
> 
> Thanks,
> Guenter