linux-kernel - Re: [PATCH 1/2] Input: atmel_mxt_ts - Get IRQ edge/level flags on DT booting

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Date:	Thu, 07 Aug 2014 03:14:32 +0200
From:	Tomasz Figa <tomasz.figa@...il.com>
To:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	Nick Dyer <nick.dyer@...ev.co.uk>,
	Stephen Warren <swarren@...dia.com>,
	Yufeng Shen <miletus@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Doug Anderson <dianders@...omium.org>,
	Olof Johansson <olof@...om.net>, linux-input@...r.kernel.org,
	devicetree@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] Input: atmel_mxt_ts - Get IRQ edge/level flags on
 DT booting

Hi Javier,

On 07.08.2014 02:48, Javier Martinez Canillas wrote:
> The Atmel maXTouch driver assumed that the IRQ type flags will
> always be passed using platform data but this is not true when
> booting using Device Trees. In these setups the interrupt type
> was ignored by the driver when requesting an IRQ.
> 
> This means that it will fail if a machine specified other type
> than IRQ_TYPE_NONE. The right approach is to get the IRQ flags
> that was parsed by OF from the "interrupt" Device Tree propery.

Have you observed an actual failure due to this? I believe that
irq_of_parse_and_map() already sets up IRQ trigger type based on DT
data, by calling irq_create_of_mapping() which in turn calls
irq_set_irq_type().

> 
> Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 03b8571..0fb56c9 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -22,6 +22,7 @@
>  #include <linux/i2c.h>
>  #include <linux/i2c/atmel_mxt_ts.h>
>  #include <linux/input/mt.h>
> +#include <linux/irq.h>
>  #include <linux/interrupt.h>
>  #include <linux/of.h>
>  #include <linux/slab.h>
> @@ -2130,6 +2131,7 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	struct mxt_data *data;
>  	const struct mxt_platform_data *pdata;
>  	int error;
> +	unsigned long irqflags;
>  
>  	pdata = dev_get_platdata(&client->dev);
>  	if (!pdata) {
> @@ -2156,8 +2158,13 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	init_completion(&data->reset_completion);
>  	init_completion(&data->crc_completion);
>  
> +	if (client->dev.of_node)
> +		irqflags = irq_get_trigger_type(client->irq);

It might be a bit cleaner to just assign the flags to pdata->irqflags in
mxt_parse_dt() instead. That would also account for the fact that pdata,
if provided, should have priority over DT.

Best regards,
Tomasz
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