linux-kernel - Re: [PATCH v2 1/4] gpio-f7188x: Add GPIO support for Nuvoton NCT6116

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Date:   Thu, 11 Aug 2022 15:52:39 +0200
From:   Henning Schild <henning.schild@...mens.com>
To:     simon.guinot@...uanux.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Pavel Machek <pavel@....cz>,
        Hans de Goede <hdegoede@...hat.com>,
        Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Lee Jones <lee@...nel.org>, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        Sheng-Yuan Huang <syhuang3@...oton.com>,
        Tasanakorn Phaipool <tasanakorn@...il.com>
Subject: Re: [PATCH v2 1/4] gpio-f7188x: Add GPIO support for Nuvoton
 NCT6116

Am Thu, 11 Aug 2022 15:31:39 +0200
schrieb simon.guinot@...uanux.org:

> On Tue, Aug 09, 2022 at 05:04:39PM +0200, Henning Schild wrote:
> > Add GPIO support for Nuvoton NCT6116 chip. Nuvoton SuperIO chips are
> > very similar to the ones from Fintek. In other subsystems they also
> > share drivers and are called a family of drivers.
> > 
> > For the GPIO subsystem the only difference is that the direction
> > bit is reversed and that there is only one data bit per pin. On the
> > SuperIO level the logical device is another one.
> > 
> > Signed-off-by: Henning Schild <henning.schild@...mens.com>  
> 
> Hi Henning,
> 
> This patch is looking good to me. I only have a couple of minor
> comments. Please see them below.
> 
> > ---
> >  drivers/gpio/gpio-f7188x.c | 70
> > +++++++++++++++++++++++++++----------- 1 file changed, 51
> > insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/gpio/gpio-f7188x.c b/drivers/gpio/gpio-f7188x.c
> > index 18a3147f5a42..4d8f38bc3b45 100644
> > --- a/drivers/gpio/gpio-f7188x.c
> > +++ b/drivers/gpio/gpio-f7188x.c
> > @@ -1,6 +1,7 @@
> >  // SPDX-License-Identifier: GPL-2.0-or-later
> >  /*
> >   * GPIO driver for Fintek Super-I/O F71869, F71869A, F71882,
> > F71889 and F81866
> > + * and Nuvoton Super-I/O NCT6116D
> >   *
> >   * Copyright (C) 2010-2013 LaCie
> >   *
> > @@ -22,13 +23,11 @@
> >  #define SIO_LDSEL		0x07	/* Logical device
> > select */ #define SIO_DEVID		0x20	/* Device ID
> > (2 bytes) */ #define SIO_DEVREV		0x22	/*
> > Device revision */ -#define SIO_MANID		0x23	/*
> > Fintek ID (2 bytes) */ 
> > -#define SIO_LD_GPIO		0x06	/* GPIO logical
> > device */ #define SIO_UNLOCK_KEY		0x87	/* Key
> > to enable Super-I/O */ #define SIO_LOCK_KEY
> > 0xAA	/* Key to disable Super-I/O */ 
> > -#define SIO_FINTEK_ID		0x1934	/* Manufacturer
> > ID */ +#define SIO_LD_GPIO_FINTEK	0x06	/* GPIO
> > logical device */ #define SIO_F71869_ID
> > 0x0814	/* F71869 chipset ID */ #define SIO_F71869A_ID
> > 	0x1007	/* F71869A chipset ID */ #define
> > SIO_F71882_ID		0x0541	/* F71882 chipset ID */
> > @@ -38,6 +37,8 @@ #define SIO_F81804_ID		0x1502  /*
> > F81804 chipset ID, same for f81966 */ #define SIO_F81865_ID
> > 	0x0704	/* F81865 chipset ID */ 
> > +#define SIO_LD_GPIO_NUVOTON	0x07	/* GPIO logical
> > device */ +#define SIO_NCT6116D_ID		0xD283  /*
> > NCT6116D chipset ID */  
> 
> Can we do better to make the definitions above more readable ? With
> the new additions I find it a little bit unclear.
> 
> Maybe we could add a comment on the top of the Fintek and Nuvoton
> specific sections ? Or maybe we could group the LD_GPIO_ definitions
> in a dedicated section ? Or something else :)

Not sure what you mean. But i think i will put the two logical device
definitions under each other and simply add the chipset id at the end
of the list. It is all a matter of taste, when i wrote it it felt like
putting all the Nuvoton block ... 

> >  
> >  enum chips {
> >  	f71869,
> > @@ -48,6 +49,7 @@ enum chips {
> >  	f81866,
> >  	f81804,
> >  	f81865,
> > +	nct6116d,
> >  };
> >  
> >  static const char * const f7188x_names[] = {
> > @@ -59,10 +61,12 @@ static const char * const f7188x_names[] = {
> >  	"f81866",
> >  	"f81804",
> >  	"f81865",
> > +	"nct6116d",
> >  };
> >  
> >  struct f7188x_sio {
> >  	int addr;
> > +	int device;
> >  	enum chips type;
> >  };
> >  
> > @@ -170,6 +174,9 @@ static int f7188x_gpio_set_config(struct
> > gpio_chip *chip, unsigned offset, /* Output mode register (0:open
> > drain 1:push-pull). */ #define gpio_out_mode(base) (base + 3)
> >  
> > +#define gpio_needs_invert(device)	((device) !=
> > SIO_LD_GPIO_FINTEK) +#define gpio_single_data(device)
> > ((device) != SIO_LD_GPIO_FINTEK)  
> 
> Since this macros are only used to get/set GPIO direction, then I
> think we should use the "gpio_dir_" prefix.

the first one yes, the second one is about data and not direction, but
i will go

gpio_dir_invert
gpio_data_single

> Also is there any reason to match the LD GPIO value rather than the
> chipset type ?
> 
> I think we should enable this specific path only for a Nuvoton NCT6116
> device for now (by matching the NCT6116 chipset type). So if more
> devices are added later then we are sure they still go on the original
> path.

Right the chipset is which says how exactly that variant works, not the
device number on that multi-function chip. Will fix.

Thanks!
Henning