Re: [PATCH] serial: 8250: add IRQ trigger support

[Marc Zyngier]

On Fri, 12 Jun 2009 12:32:51 -0500
Vikram Pandita <vikram.pandita@xxxxxx> wrote:

> There is currently no provision for passing IRQ trigger flags for
> serial IRQs with triggering requirements (such as GPIO IRQs.)
> 
> This patch adds UPF_IRQ_TRIG_* flags which map on to IRQF_TRIGGER_*
> flags.
> 
> Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
> Acked-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>

Note that this patch doesn't allow  the interrupt to trigger on both
edges (not that I have ever seen a 8250 with this behavior, but this
is a valid configuration from an interrupt point of view).

Aside from this remark:
Acked-by: Marc Zyngier <maz@xxxxxxxxxxxxxxx>

> ---
>  drivers/serial/8250.c       |   10 ++++++++++
>  include/linux/serial_core.h |    4 ++++
>  2 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
> index bab115e..8235ef5 100644
> --- a/drivers/serial/8250.c
> +++ b/drivers/serial/8250.c
> @@ -1641,6 +1641,16 @@ static int serial_link_irq_chain(struct
> uart_8250_port *up) struct irq_info *i;
>  	int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ?
> IRQF_SHARED : 0; 
> +	/* Get IRQ Trigger Flag */
> +	if (up->port.flags & UPF_IRQ_TRIG_RISING)
> +		irq_flags |= IRQF_TRIGGER_RISING;
> +	else if (up->port.flags & UPF_IRQ_TRIG_FALLING)
> +		irq_flags |= IRQF_TRIGGER_FALLING;
> +	else if (up->port.flags & UPF_IRQ_TRIG_HIGH)
> +		irq_flags |= IRQF_TRIGGER_HIGH;
> +	else if (up->port.flags & UPF_IRQ_TRIG_LOW)
> +		irq_flags |= IRQF_TRIGGER_LOW;
> +
>  	mutex_lock(&hash_mutex);
>  
>  	h = &irq_lists[up->port.irq % NR_IRQ_HASH];
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 57a97e5..07591d5 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -296,7 +296,11 @@ struct uart_port {
>  #define UPF_SPD_WARP		((__force upf_t) (0x1010))
>  #define UPF_SKIP_TEST		((__force upf_t) (1 << 6))
>  #define UPF_AUTO_IRQ		((__force upf_t) (1 << 7))
> +#define UPF_IRQ_TRIG_RISING	((__force upf_t) (1 << 8))
> +#define UPF_IRQ_TRIG_FALLING	((__force upf_t) (1 << 9))
> +#define UPF_IRQ_TRIG_HIGH	((__force upf_t) (1 << 10))
>  #define UPF_HARDPPS_CD		((__force upf_t) (1 << 11))
> +#define UPF_IRQ_TRIG_LOW	((__force upf_t) (1 << 12))
>  #define UPF_LOW_LATENCY		((__force upf_t) (1 << 13))
>  #define UPF_BUGGY_UART		((__force upf_t) (1 << 14))
>  #define UPF_NO_TXEN_TEST	((__force upf_t) (1 << 15))

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