Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210413025948.901867-1-kubernat@cesnet.cz> <250c1c16-541a-984f-c720-1a8b6176e97e@roeck-us.net>
In-Reply-To: <250c1c16-541a-984f-c720-1a8b6176e97e@roeck-us.net>
From:   =?UTF-8?B?VsOhY2xhdiBLdWJlcm7DoXQ=?= <kubernat@cesnet.cz>
Date:   Fri, 23 Apr 2021 12:55:22 +0200
Message-ID: <CABKa3nquWmP4Hx+eY5CpQ08M2uo2ePpmtZP-6yi45pVOh-Mqzw@mail.gmail.com>
Subject: Re: [PATCH v2 1/5] hwmon: (max31790) Rework to use regmap
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Jean Delvare <jdelvare@suse.com>, Jonathan Corbet <corbet@lwn.net>,
        linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hello.

I agree that it makes sense to swap yes_ranges and no_ranges. I tested
that, but it seems like it doesn't have an effect, I could still see
fan*_input changing (that's where I don't want caching). Does caching
work automatically? As in, all registers are cached by default in
regmap, and only registers that are in the volatile yes_ranges aren't?

V=C3=A1clav

=C4=8Dt 22. 4. 2021 v 3:31 odes=C3=ADlatel Guenter Roeck <linux@roeck-us.ne=
t> napsal:
>
> On 4/12/21 7:59 PM, V=C3=A1clav Kubern=C3=A1t wrote:
> > Converting the driver to use regmap makes it more generic. It also make=
s
> > it a lot easier to debug through debugfs.
> >
> > Signed-off-by: V=C3=A1clav Kubern=C3=A1t <kubernat@cesnet.cz>
> > ---
> >  drivers/hwmon/Kconfig    |   1 +
> >  drivers/hwmon/max31790.c | 254 ++++++++++++++++++++-------------------
> >  2 files changed, 133 insertions(+), 122 deletions(-)
> >
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 1ecf697d8d99..9f11d036c316 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -1095,6 +1095,7 @@ config SENSORS_MAX6697
> >  config SENSORS_MAX31790
> >       tristate "Maxim MAX31790 sensor chip"
> >       depends on I2C
> > +     select REGMAP_I2C
> >       help
> >         If you say yes here you get support for 6-Channel PWM-Output
> >         Fan RPM Controller.
> > diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
> > index 2c6b333a28e9..e3765ce4444a 100644
> > --- a/drivers/hwmon/max31790.c
> > +++ b/drivers/hwmon/max31790.c
> > @@ -12,6 +12,7 @@
> >  #include <linux/init.h>
> >  #include <linux/jiffies.h>
> >  #include <linux/module.h>
> > +#include <linux/regmap.h>
> >  #include <linux/slab.h>
> >
> >  /* MAX31790 registers */
> > @@ -46,92 +47,53 @@
> >
> >  #define NR_CHANNEL                   6
> >
> > +#define MAX31790_REG_USER_BYTE_67    0x67
> > +
> > +#define BULK_TO_U16(msb, lsb)                (((msb) << 8) + (lsb))
> > +#define U16_MSB(num)                 (((num) & 0xFF00) >> 8)
> > +#define U16_LSB(num)                 ((num) & 0x00FF)
> > +
> > +static const struct regmap_range max31790_ro_range =3D {
> > +     .range_min =3D MAX31790_REG_TACH_COUNT(0),
> > +     .range_max =3D MAX31790_REG_PWMOUT(0) - 1,
> > +};
> > +
> > +static const struct regmap_access_table max31790_wr_table =3D {
> > +     .no_ranges =3D &max31790_ro_range,
> > +     .n_no_ranges =3D 1,
> > +};
> > +
> > +static const struct regmap_range max31790_volatile_ranges[] =3D {
> > +     regmap_reg_range(MAX31790_REG_TACH_COUNT(0), MAX31790_REG_TACH_CO=
UNT(12)),
> > +     regmap_reg_range(MAX31790_REG_FAN_FAULT_STATUS2, MAX31790_REG_FAN=
_FAULT_STATUS1),
> > +};
> > +
> > +static const struct regmap_access_table max31790_volatile_table =3D {
> > +     .no_ranges =3D max31790_volatile_ranges,
> > +     .n_no_ranges =3D 2,
> > +     .n_yes_ranges =3D 0
> > +};
>
> Looks like my reply to this got lost. Other regmap code suggests that
> volatile register ranges are identified with yes_ranges, not with no_rang=
es.
> "no" seems to mean "not volatile". Please verify and confirm if the
> above code does what you want it to do.
>
> Thanks,
> Guenter