On Mon, Mar 6, 2017 at 11:02 AM, Uwe Kleine-K?nig
[off-list ref] wrote:

On Mon, Mar 06, 2017 at 10:53:27AM +0100, Geert Uytterhoeven wrote:

quoted

On Mon, Mar 6, 2017 at 10:30 AM, Uwe Kleine-K?nig

quoted

quoted

I wouldn't want to code this in each driver (something like:

        if (IS_ENABLED(GPIOLIB) || device_is_instantiated_by_dt(dev) || device_is_instantiated_by_acpi(dev))
                gpios = mctrl_gpio_init(...);
        else
                gpios = NULL;

). Putting this into GPIOLIB is the right approach, and so this is
another argument for HALFGPIOLIB. This would fix mctrl_gpio_init en
passant.

Do we have platforms where DT=y || ACPI=y, but GPIOLIB=n?
Ah, x86 ;-)

Yeah, and I think rm -r arch/x86 won't be acceptable :-) I assume you
can also configure some arm or powerpc systems without GPIOLIB.

quoted

Anyway, for sh-sci.c, platforms either have DT and GPIOLIB, or they do not
need mctrl-gpio.

So we're in agreement now that HALFGPIOLIB is the way to go?
Linus, what do you think?

OK modem lines over GPIO.

So the problem is that GPIOLIB is needed (obviously) for mctrl_gpio_init() to
work properly, and then there are some stubs in
drivers/tty/serial/serial_mctrl_gpio.h
for !GPIOLIB.

And this whole discussion is all about that !GPIOLIB case really,
whether DT, ACPI, SFI or board files machine data is used doesn't
really matter.

We're talking about:

git grep mctrl_gpio_init

drivers/tty/serial/atmel_serial.c:      atmel_port->gpios =
mctrl_gpio_init(&atmel_port->uart, 0);
drivers/tty/serial/clps711x.c:  s->gpios =
mctrl_gpio_init_noauto(&pdev->dev, 0);
drivers/tty/serial/etraxfs-uart.c:      up->gpios =
mctrl_gpio_init_noauto(&pdev->dev, 0);
drivers/tty/serial/imx.c:       sport->gpios = mctrl_gpio_init(&sport->port, 0);
drivers/tty/serial/mxs-auart.c: s->gpios = mctrl_gpio_init_noauto(dev, 0);
drivers/tty/serial/sh-sci.c:    sciport->gpios =
mctrl_gpio_init(&sciport->port, 0);

Atmel, ARM, ETRAX, ARM, ARM, Super-H, all have GPIOLIB.
Right now no x86, correct?

They actually all even do things like this in Kconfig:

config SERIAL_ATMEL
(...)
        select SERIAL_MCTRL_GPIO if GPIOLIB

What stops us from removing all the stubs in
drivers/tty/serial/serial_mctrl_gpio.h
and just make SERIAL_MCTRL_GPIO depends on GPIOLIB?

From 2ecc70acc510784d953add707f2a5acfebe484c2 Mon Sep 17 00:00:00 2001

From: Linus Walleij <redacted>
Date: Thu, 16 Mar 2017 16:18:21 +0100
Subject: [PATCH] stab at mctrl

Signed-off-by: Linus Walleij <redacted>
---
 drivers/tty/serial/Kconfig             |  1 +
 drivers/tty/serial/serial_mctrl_gpio.h | 55 ----------------------------------
 2 files changed, 1 insertion(+), 55 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 6117ac8da48f..39833d009c18 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig

@@ -1681,5 +1681,6 @@ endmenu

 config SERIAL_MCTRL_GPIO
     tristate
+    depends on GPIOLIB

 endif # TTY

diff --git a/drivers/tty/serial/serial_mctrl_gpio.h

b/drivers/tty/serial/serial_mctrl_gpio.h
index fa000bcff217..ba8f8e531d56 100644

--- a/drivers/tty/serial/serial_mctrl_gpio.h
+++ b/drivers/tty/serial/serial_mctrl_gpio.h

@@ -40,8 +40,6 @@ enum mctrl_gpio_idx {
  */
 struct mctrl_gpios;

-#ifdef CONFIG_GPIOLIB
-
 /*
  * Set state of the modem control output lines via GPIOs.
  */

@@ -101,57 +99,4 @@ void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
  */
 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);

-#else /* GPIOLIB */
-
-static inline
-void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
-{
-}
-
-static inline
-unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
-{
-    return *mctrl;
-}
-
-static inline unsigned int
-mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
-{
-    return *mctrl;
-}
-
-static inline
-struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
-                      enum mctrl_gpio_idx gidx)
-{
-    return ERR_PTR(-ENOSYS);
-}
-
-static inline
-struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
-{
-    return ERR_PTR(-ENOSYS);
-}
-
-static inline
-struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev,

unsigned int idx)
-{
-    return ERR_PTR(-ENOSYS);
-}
-
-static inline
-void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
-{
-}
-
-static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
-{
-}
-
-static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
-{
-}
-
-#endif /* GPIOLIB */
-
 #endif
-- 
2.9.3


Yours,
Linus Walleij