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From:   Naresh Solanki <naresh.solanki@9elements.com>
Date:   Mon, 20 Nov 2023 15:40:21 +0530
Message-ID: <CABqG17hPnx465dRKdMdSd2s38_T6DQFn5hsx1SL0RtA+r4JFZQ@mail.gmail.com>
Subject: Re: [RESEND PATCH v3] leds: max5970: Add support for max5970
To:     Lee Jones <lee@kernel.org>
Cc:     Pavel Machek <pavel@ucw.cz>,
        Patrick Rudolph <patrick.rudolph@9elements.com>,
        linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org
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Hi

On Fri, 17 Nov 2023 at 17:45, Lee Jones <lee@kernel.org> wrote:
>
> On Thu, 09 Nov 2023, Naresh Solanki wrote:
>
> > Hey Lee,
> >
> > Is there anything specific you'd suggest changing in the current
> > patchset, or are we good to proceed?
>
> What do you mean by proceed?
>
> You are good to make changes and submit a subsequent version.
>
> Not entirely sure what you're asking.

As a follow up on previous discussion regarding use of DEFER on probe
if regmap isn't initialized, the implementation was based on other similar
drivers & hence it was retained although its not needed due to dependencies=
.

I'm not entirely sure to keep the regmap check or make another
patch revision with regmap check removed ?


Regards,
Naresh
>
> > On Mon, 30 Oct 2023 at 14:22, Naresh Solanki
> > <naresh.solanki@9elements.com> wrote:
> > >
> > > Hi,
> > >
> > > On Thu, 21 Sept 2023 at 16:02, Lee Jones <lee@kernel.org> wrote:
> > > >
> > > > On Thu, 21 Sep 2023, Naresh Solanki wrote:
> > > >
> > > > > Hi
> > > > >
> > > > >
> > > > > On Wed, 20 Sept 2023 at 18:35, Lee Jones <lee@kernel.org> wrote:
> > > > > >
> > > > > > On Thu, 14 Sep 2023, Naresh Solanki wrote:
> > > > > >
> > > > > > > From: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > > > > >
> > > > > > > The MAX5970 is hot swap controller and has 4 indication LED.
> > > > > > >
> > > > > > > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com=
>
> > > > > > > Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> > > > > > > ---
> > > > > > > Changes in V3:
> > > > > > > - Drop array for ddata variable.
> > > > > > > Changes in V2:
> > > > > > > - Add of_node_put before return.
> > > > > > > - Code cleanup
> > > > > > > - Refactor code & remove max5970_setup_led function.
> > > > > > > ---
> > > > > > >  drivers/leds/Kconfig        |  11 ++++
> > > > > > >  drivers/leds/Makefile       |   1 +
> > > > > > >  drivers/leds/leds-max5970.c | 110 ++++++++++++++++++++++++++=
++++++++++
> > > > > > >  3 files changed, 122 insertions(+)
> > > > > > >  create mode 100644 drivers/leds/leds-max5970.c
> > > > > >
> > > > > > Couple of nits and you're good to go.
> > > > > >
> > > > > > Once fixed please resubmit with my:
> > > > > >
> > > > > >   Reviewed-by: Lee Jones <lee@kernel.org>
> > > > > >
> > > > > > > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> > > > > > > index b92208eccdea..03ef527cc545 100644
> > > > > > > --- a/drivers/leds/Kconfig
> > > > > > > +++ b/drivers/leds/Kconfig
> > > > > > > @@ -637,6 +637,17 @@ config LEDS_ADP5520
> > > > > > >         To compile this driver as a module, choose M here: th=
e module will
> > > > > > >         be called leds-adp5520.
> > > > > > >
> > > > > > > +config LEDS_MAX5970
> > > > > > > +     tristate "LED Support for Maxim 5970"
> > > > > > > +     depends on LEDS_CLASS
> > > > > > > +     depends on MFD_MAX5970
> > > > > > > +     help
> > > > > > > +       This option enables support for the Maxim MAX5970 & M=
AX5978 smart
> > > > > > > +       switch indication LEDs via the I2C bus.
> > > > > > > +
> > > > > > > +       To compile this driver as a module, choose M here: th=
e module will
> > > > > > > +       be called leds-max5970.
> > > > > > > +
> > > > > > >  config LEDS_MC13783
> > > > > > >       tristate "LED Support for MC13XXX PMIC"
> > > > > > >       depends on LEDS_CLASS
> > > > > > > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> > > > > > > index d7348e8bc019..6eaee0a753c6 100644
> > > > > > > --- a/drivers/leds/Makefile
> > > > > > > +++ b/drivers/leds/Makefile
> > > > > > > @@ -56,6 +56,7 @@ obj-$(CONFIG_LEDS_LP8501)           +=3D le=
ds-lp8501.o
> > > > > > >  obj-$(CONFIG_LEDS_LP8788)            +=3D leds-lp8788.o
> > > > > > >  obj-$(CONFIG_LEDS_LP8860)            +=3D leds-lp8860.o
> > > > > > >  obj-$(CONFIG_LEDS_LT3593)            +=3D leds-lt3593.o
> > > > > > > +obj-$(CONFIG_LEDS_MAX5970)           +=3D leds-max5970.o
> > > > > > >  obj-$(CONFIG_LEDS_MAX77650)          +=3D leds-max77650.o
> > > > > > >  obj-$(CONFIG_LEDS_MAX8997)           +=3D leds-max8997.o
> > > > > > >  obj-$(CONFIG_LEDS_MC13783)           +=3D leds-mc13783.o
> > > > > > > diff --git a/drivers/leds/leds-max5970.c b/drivers/leds/leds-=
max5970.c
> > > > > > > new file mode 100644
> > > > > > > index 000000000000..c9685990e26e
> > > > > > > --- /dev/null
> > > > > > > +++ b/drivers/leds/leds-max5970.c
> > > > > > > @@ -0,0 +1,110 @@
> > > > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > > > +/*
> > > > > > > + * Device driver for leds in MAX5970 and MAX5978 IC
> > > > > > > + *
> > > > > > > + * Copyright (c) 2022 9elements GmbH
> > > > > > > + *
> > > > > > > + * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > > > > > + */
> > > > > > > +
> > > > > > > +#include <linux/leds.h>
> > > > > > > +#include <linux/mfd/max5970.h>
> > > > > > > +#include <linux/of.h>
> > > > > > > +#include <linux/platform_device.h>
> > > > > > > +#include <linux/regmap.h>
> > > > > > > +
> > > > > > > +#define ldev_to_maxled(c)       container_of(c, struct max59=
70_led, cdev)
> > > > > > > +
> > > > > > > +struct max5970_led {
> > > > > > > +     struct device *dev;
> > > > > > > +     struct regmap *regmap;
> > > > > > > +     struct led_classdev cdev;
> > > > > > > +     unsigned int index;
> > > > > > > +};
> > > > > > > +
> > > > > > > +static int max5970_led_set_brightness(struct led_classdev *c=
dev,
> > > > > > > +                                   enum led_brightness brigh=
tness)
> > > > > > > +{
> > > > > > > +     struct max5970_led *ddata =3D ldev_to_maxled(cdev);
> > > > > > > +     int ret, val;
> > > > > > > +
> > > > > > > +     /* Set/clear corresponding bit for given led index */
> > > > > > > +     val =3D !brightness ? BIT(ddata->index) : 0;
> > > > > > > +
> > > > > > > +     ret =3D regmap_update_bits(ddata->regmap, MAX5970_REG_L=
ED_FLASH, BIT(ddata->index), val);
> > > > > > > +     if (ret < 0)
> > > > > > > +             dev_err(cdev->dev, "failed to set brightness %d=
", ret);
> > > > > > > +
> > > > > > > +     return ret;
> > > > > > > +}
> > > > > > > +
> > > > > > > +static int max5970_led_probe(struct platform_device *pdev)
> > > > > > > +{
> > > > > > > +     struct device *dev =3D &pdev->dev;
> > > > > > > +     struct device_node *np =3D dev_of_node(dev->parent);
> > > > > > > +     struct regmap *regmap;
> > > > > > > +     struct device_node *led_node;
> > > > > > > +     struct device_node *child;
> > > > > >
> > > > > > Nit: You can place these on the same line.
> > > > > Ack
> > > > > >
> > > > > > > +     struct max5970_led *ddata;
> > > > > > > +     int ret =3D -ENODEV, num_leds =3D 0;
> > > > > > > +
> > > > > > > +     regmap =3D dev_get_regmap(pdev->dev.parent, NULL);
> > > > > > > +     if (!regmap)
> > > > > > > +             return -EPROBE_DEFER;
> > > > > >
> > > > > > Why are you deferring here?
> > > > > This is a Leaf driver. Making sure the parent driver has initiali=
zed regmap.
> > > >
> > > > How can this driver initialise before the parent driver?
> > > The parent driver in this case is simple_i2c_mfd.
> > > Based on reference from other similar implementations, the regmap
> > > check was adapted.
> > > As you mentioned, your right that leaf driver will not start before p=
arent
> > > driver is loaded successfully so probably the DEFER might not be need=
ed
> > > here.
> > >
> > > Thanks,
> > > Naresh
> > > >
> > > > --
> > > > Lee Jones [=E6=9D=8E=E7=90=BC=E6=96=AF]
>
> --
> Lee Jones [=E6=9D=8E=E7=90=BC=E6=96=AF]