[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Richard Genoud]

2014-09-02 13:40 GMT+02:00 Peter Hurley <peter at hurleysoftware.com>:
> On 09/01/2014 05:26 AM, Richard Genoud wrote:
>> 2014-08-10 21:33 GMT+02:00 Peter Hurley <peter at hurleysoftware.com>:
>>> Hi Richard,
>>
>> Hi !
>> Sorry for the delay !
>>
>>> On 05/13/2014 02:20 PM, Richard Genoud wrote:
>>>> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
>>>>
>>>> Signed-off-by: Richard Genoud <richard.genoud at gmail.com>
>>>> Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
>>>> Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
>>>> ---
>>>>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>>>>  1 file changed, 122 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>>>> index 43ca659..3fceae0 100644
>>>> --- a/drivers/tty/serial/atmel_serial.c
>>>> +++ b/drivers/tty/serial/atmel_serial.c
>>>> @@ -45,6 +45,7 @@
>>>>  #include <linux/gpio.h>
>>>>  #include <linux/gpio/consumer.h>
>>>>  #include <linux/err.h>
>>>> +#include <linux/irq.h>
>>>>
>>>>  #include <asm/io.h>
>>>>  #include <asm/ioctls.h>
>>>> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>>>>
>>>>       struct serial_rs485     rs485;          /* rs485 settings */
>>>>       struct mctrl_gpios      *gpios;
>>>> +     int                     gpio_irq[UART_GPIO_MAX];
>>>>       unsigned int            tx_done_mask;
>>>> +     bool                    ms_irq_enabled;
>>>>       bool                    is_usart;       /* usart or uart */
>>>>       struct timer_list       uart_timer;     /* uart timer */
>>>>       int (*prepare_rx)(struct uart_port *port);
>>>> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>>>>   */
>>>>  static void atmel_enable_ms(struct uart_port *port)
>>>>  {
>>>> -     UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
>>>> -                     | ATMEL_US_DCDIC | ATMEL_US_CTSIC);
>>>> +     struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>>>> +     uint32_t ier = 0;
>>>> +
>>>> +     /*
>>>> +      * Interrupt should not be enabled twice
>>>> +      */
>>>> +     if (atmel_port->ms_irq_enabled)
>>>> +             return;
>>>> +
>>>> +     atmel_port->ms_irq_enabled = true;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
>>>> +     else
>>>> +             ier |= ATMEL_US_CTSIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
>>>> +     else
>>>> +             ier |= ATMEL_US_DSRIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
>>>> +     else
>>>> +             ier |= ATMEL_US_RIIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
>>>> +     else
>>>> +             ier |= ATMEL_US_DCDIC;
>>>
>>> Where are these gpio irqs disabled if !UART_ENABLE_MS()?
>> They are disabled in atmel_shutdown()/atmel_free_gpio_irq().
>> Like the doc says in Documentation/serial/driver
>>   enable_ms(port)
>>     Enable the modem status interrupts.
>>
>>     This method may be called multiple times.  Modem status
>>     interrupts should be disabled when the shutdown method is
>>     called.
>
> Thanks for replying.
>
> The point of the UART_ENABLE_MS() macro is to allow the UART driver
> to determine if modem status interrupts need to be enabled when
> handling the .set_termios() method.
>
> When handling set_termios(), if UART_ENABLE_MS is false (ie., the
> serial core does not require modem status interrupts), the UART
> driver can and should turn modem status interrupts off.
>
> It is _also_ true that "modem status interrupts should be disabled
> when the shutdown method is called"; in fact, _all_ UART-sourced
> interrupts should be disabled when the shutdown method is called.

That's right. I totally missed that !
I'll come with a patch.

Thanks !!

Richard.