Re: [RFC PATCH v2 1/4] tty: serial_mctrl_gpio: Add irqs helpers for input lines

[Janusz Użycki <j.uzycki@xxxxxxxxxxxxxx>]

W dniu 2015-01-13 o 14:04, Richard Genoud pisze:
> 2015-01-10 15:32 GMT+01:00 Janusz Uzycki <j.uzycki@xxxxxxxxxxxxxx>:
> > A driver using mctrl_gpio called gpiod_get_direction() to check if
> > gpio is input line. However .get_direction callback is not available
> > for all platforms. The patch allows to avoid the function.
> > The patch introduces the following helpers:
> > - mctrl_gpio_request_irqs
> > - mctrl_gpio_free_irqs
> > - mctrl_gpio_enable_ms
> > - mctrl_gpio_disable_ms
> > They allow to:
> > - simplify drivers which use mctrl_gpio
> > - hide irq table in mctrl_gpio
> > - use default irq handler for gpios
> > - better separate code for gpio modem lines from uart's code
> > In addition mctrl_gpio_init() has been renamed to mctrl_gpio_init_dt()
> > to focus DT usage. Also mctrl_gpio_init_dt() initializes irq table for
> > gpios now and passes struct uart_port into struct mctrl_gpios.
> > This resulted in changed mctrl_gpio_init_dt() parameter.
> > It also requires port->dev is set before the function is called.
> >
> > There were also fixed:
> > - irq = 0 means invalid/unused (-EINVAL no more used)
> > - mctrl_gpio_request_irqs() doesn't use negative enum value
> >    if request_irq() failed. It just calls mctrl_gpio_free_irqs().
> >
> > The mctrl_gpio_is_gpio() inline function is under discussion
> > and likely it can replace exported mctrl_gpio_to_gpiod() function.
> >
> > IRQ_NOAUTOEN setting and request_irq() order was not commented
> > but it looks right according to other drivers.
> >
> > Signed-off-by: Janusz Uzycki <j.uzycki@xxxxxxxxxxxxxx>
> > ---
> >
> > The patch requires to update the drivers which use mctrl_gpio:
> > - atmel_serial
> > - mxs-auart
> > - clps711x
> >
> > Changes since RFC v1:
> >   - patch renamed from:
> >     ("serial: mctrl-gpio: Add irqs helpers for input lines")
> >     to:
> >     ("tty: serial_mctrl_gpio: Add irqs helpers for input lines")
> >   - mctrl_gpio_request_irqs: changed mctrl_gpio_free_irqs() and
> >     dev_err() order to make debug easier
> >   - added patches for atmel_serial and clps711x serial drivers
> >
> > The patch applies to next (3.19.0-rc2) and was tested with mxs-auart
> > using kernel 3.14 and 3.18. It wasn't tested on the next (only compiled).
> >
> > The patchset delivers patches for mxs-auart, atmel_serial and clps711x.
> > atmel_serial and clps711x were not tested - only compile tests were done.
> >
> > ---
> >   drivers/tty/serial/serial_mctrl_gpio.c | 109 ++++++++++++++++++++++++++++++++-
> >   drivers/tty/serial/serial_mctrl_gpio.h |  59 +++++++++++++++++-
> >   2 files changed, 163 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
> > index a38596c..215b15c 100644
> > --- a/drivers/tty/serial/serial_mctrl_gpio.c
> > +++ b/drivers/tty/serial/serial_mctrl_gpio.c
> > @@ -19,11 +19,15 @@
> >   #include <linux/device.h>
> >   #include <linux/gpio/consumer.h>
> >   #include <linux/termios.h>
> > +#include <linux/irq.h>
> >
> >   #include "serial_mctrl_gpio.h"
> >
> >   struct mctrl_gpios {
> > +       struct uart_port *port;
> >          struct gpio_desc *gpio[UART_GPIO_MAX];
> > +       int irq[UART_GPIO_MAX];
> > +       unsigned int mctrl_prev;
> >   };
> >
> >   static const struct {
> > @@ -72,6 +76,12 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> >   }
> >   EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
> >
> > +inline
> > +bool mctrl_gpio_is_gpio(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx)
> > +{
> > +       return !IS_ERR_OR_NULL(gpios->gpio[gidx]);
> > +}
> > +
> >   unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
> >   {
> >          enum mctrl_gpio_idx i;
> > @@ -96,8 +106,9 @@ unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
> >   }
> >   EXPORT_SYMBOL_GPL(mctrl_gpio_get);
> >
> > -struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> > +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx)
> >   {
> > +       struct device *dev = port->dev;
> >          struct mctrl_gpios *gpios;
> >          enum mctrl_gpio_idx i;
> >          int err;
> > @@ -106,6 +117,7 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> >          if (!gpios)
> >                  return ERR_PTR(-ENOMEM);
> >
> > +       gpios->port = port;
> >          for (i = 0; i < UART_GPIO_MAX; i++) {
> >                  gpios->gpio[i] = devm_gpiod_get_index(dev,
> >                                                        mctrl_gpios_desc[i].name,
> > @@ -128,11 +140,13 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> >                          devm_gpiod_put(dev, gpios->gpio[i]);
> >                          gpios->gpio[i] = NULL;
> >                  }
> > +               if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out)
> > +                       gpios->irq[i] = gpiod_to_irq(gpios->gpio[i]);
> >          }
> >
> >          return gpios;
> >   }
> > -EXPORT_SYMBOL_GPL(mctrl_gpio_init);
> > +EXPORT_SYMBOL_GPL(mctrl_gpio_init_dt);
> >
> >   void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
> >   {
> > @@ -147,3 +161,94 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
> >          devm_kfree(dev, gpios);
> >   }
> >   EXPORT_SYMBOL_GPL(mctrl_gpio_free);
> > +
> > +/*
> > + * Dealing with GPIO interrupt
> > + */
> > +#define MCTRL_ANY_DELTA        (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
> > +static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
> > +{
> > +       struct mctrl_gpios *gpios = context;
> > +       struct uart_port *port = gpios->port;
> > +       u32 mctrl = gpios->mctrl_prev;
> > +       u32 mctrl_diff;
> > +
> > +       mctrl_gpio_get(gpios, &mctrl);
> > +
> > +       mctrl_diff = mctrl ^ gpios->mctrl_prev;
> > +       gpios->mctrl_prev = mctrl;
> > +       if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
> > +               if (mctrl_diff & TIOCM_RI)
> > +                       port->icount.rng++;
> > +               if (mctrl_diff & TIOCM_DSR)
> > +                       port->icount.dsr++;
> > +               if (mctrl_diff & TIOCM_CD)
> > +                       uart_handle_dcd_change(port, mctrl & TIOCM_CD);
> > +               if (mctrl_diff & TIOCM_CTS)
> > +                       uart_handle_cts_change(port, mctrl & TIOCM_CTS);
> > +
> > +               wake_up_interruptible(&port->state->port.delta_msr_wait);
> > +       }
> > +
> > +       return IRQ_HANDLED;
> > +}
> > +
> > +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios)
> > +{
> > +       struct uart_port *port = gpios->port;
> > +       int *irq = gpios->irq;
> > +       enum mctrl_gpio_idx i;
> > +       int err = 0;
> > +
> > +       for (i = 0; i < UART_GPIO_MAX; i++) {
> > +               if (irq[i] <= 0)
> > +                       continue;
> > +
> > +               irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
> > +               err = request_irq(irq[i], mctrl_gpio_irq_handle,
> > +                                 IRQ_TYPE_EDGE_BOTH,
> > +                                 dev_name(port->dev), gpios);
> > +               if (err) {
> > +                       dev_err(port->dev, "%s: Can't get %d irq\n",
> > +                               __func__, irq[i]);
> > +                       mctrl_gpio_free_irqs(gpios);
> > +                       break;
> > +               }
> > +       }
> > +
> > +       return err;
> > +}
> > +EXPORT_SYMBOL_GPL(mctrl_gpio_request_irqs);
> > +
> > +void mctrl_gpio_free_irqs(struct mctrl_gpios *gpios)
> > +{
> > +       enum mctrl_gpio_idx i;
> > +
> > +       for (i = 0; i < UART_GPIO_MAX; i++)
> > +               if (gpios->irq[i] > 0)
> > +                       free_irq(gpios->irq[i], gpios);
> > +}
> > +EXPORT_SYMBOL_GPL(mctrl_gpio_free_irqs);
> > +
> > +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
> > +{
> > +       enum mctrl_gpio_idx i;
> > +
> > +       /* get initial status of modem lines GPIOs */
> > +       mctrl_gpio_get(gpios, &gpios->mctrl_prev);
> > +
> > +       for (i = 0; i < UART_GPIO_MAX; i++)
> > +               if (gpios->irq[i] > 0)
> > +                       enable_irq(gpios->irq[i]);
> > +}
> > +EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
> > +
> > +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
> > +{
> > +       enum mctrl_gpio_idx i;
> > +
> > +       for (i = 0; i < UART_GPIO_MAX; i++)
> > +               if (gpios->irq[i] > 0)
> > +                       disable_irq(gpios->irq[i]);
> > +}
> > +EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
> > diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
> > index 400ba04..13ba3f4 100644
> > --- a/drivers/tty/serial/serial_mctrl_gpio.h
> > +++ b/drivers/tty/serial/serial_mctrl_gpio.h
> > @@ -21,6 +21,7 @@
> >   #include <linux/err.h>
> >   #include <linux/device.h>
> >   #include <linux/gpio/consumer.h>
> > +#include <linux/serial_core.h>
> >
> >   enum mctrl_gpio_idx {
> >          UART_GPIO_CTS,
> > @@ -40,6 +41,13 @@ enum mctrl_gpio_idx {
> >    */
> >   struct mctrl_gpios;
> >
> > +/*
> > + * Return true if gidx is GPIO line, otherwise false.
> > + * It assumes that gpios is allocated and not NULL.
> > + */
> > +inline
> > +bool mctrl_gpio_is_gpio(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx);
> > +
> This leads to a compile error :
>    CC      drivers/tty/serial/atmel_serial.o
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/atmel_serial.c: In function 'atmel_disable_ms.part.22':
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:536:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:539:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:542:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:545:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/atmel_serial.c: In function 'atmel_enable_ms':
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:503:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:506:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:509:25: error: called from here
> In file included from drivers/tty/serial/atmel_serial.c:64:0:
> drivers/tty/serial/serial_mctrl_gpio.h:49:6: error: inlining failed in
> call to always_inline 'mctrl_gpio_is_gpio': function body not
> available
> drivers/tty/serial/atmel_serial.c:512:25: error: called from here
> make[3]: *** [drivers/tty/serial/atmel_serial.o] Error 1
> make[2]: *** [drivers/tty/serial] Error 2
> make[1]: *** [drivers/tty] Error 2
> make: *** [drivers] Error 2

Do you compile atmel_serial as module? I compiled built-in and it was 
fine for me.
So the function should be exported like mctrl_gpio_to_gpiod() I guess.
An other reason can be you have CONFIG_GPIOLIB=n ?
In fact, mctrl_gpio_is_gpio() should depend on CONFIG_GPIOLIB for empty 
body.

> >   #ifdef CONFIG_GPIOLIB
> >
> >   /*
> > @@ -60,12 +68,13 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> >                                        enum mctrl_gpio_idx gidx);
> >
> >   /*
> > - * Request and set direction of modem control lines GPIOs.
> > + * Request and set direction of modem control lines GPIOs. DT is used.
> > + * Initialize irq table for GPIOs.
> >    * devm_* functions are used, so there's no need to call mctrl_gpio_free().
> >    * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
> >    * allocation error.
> >    */
> > -struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
> > +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx);
> >
> >   /*
> >    * Free the mctrl_gpios structure.
> > @@ -74,6 +83,28 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
> >    */
> >   void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
> >
> > +/*
> > + * Request irqs for input lines GPIOs. The irqs are set disabled
> > + * and triggered on both edges.
> > + * Returns zero if OK, otherwise an error code.
> > + */
> > +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios);
> > +
> > +/*
> > + * Free irqs for input lines GPIOs.
> > + */
> > +void mctrl_gpio_free_irqs(struct mctrl_gpios *gpios);
> > +
> > +/*
> > + * Disable modem status interrupts assigned to GPIOs
> > + */
> > +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
> > +
> > +/*
> > + * Enable modem status interrupts assigned to GPIOs
> > + */
> > +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
> > +
> >   #else /* GPIOLIB */
> >
> >   static inline
> > @@ -95,7 +126,7 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> >   }
> >
> >   static inline
> > -struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> > +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx)
> >   {
> >          return ERR_PTR(-ENOSYS);
> >   }
> > @@ -105,6 +136,28 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
> >   {
> >   }
> >
> > +static inline
> > +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios)
> > +{
> > +       /*return -ENOTSUP;*/
> > +       return 0;
> > +}
> > +
> > +static inline
> > +void mctrl_gpio_free_irqs(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
> > --
> > 1.7.11.3
> I think you should also update the documentation on mctrl_ helpers :
> Documentation/serial/driver

Right!

> I'm going to do some tests on atmel_serial.c

Thanks,
Janusz

> regards,
> Richard.

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