linux-kernel - Re: [PATCH v4] iio: mma8452: support either of the available interrupt pins

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Date:	Tue, 20 Oct 2015 13:03:10 +0200
From:	Martin Kepplinger <martink@...teo.de>
To:	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	jic23@...nel.org, knaack.h@....de, lars@...afoo.de,
	pmeerw@...erw.net, mfuzzey@...keon.com
CC:	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-iio@...r.kernel.org,
	Martin Kepplinger <martin.kepplinger@...obroma-systems.com>
Subject: Re: [PATCH v4] iio: mma8452: support either of the available interrupt
 pins

Am 2015-10-15 um 15:10 schrieb Martin Kepplinger:
> This change is important in order for everyone to be easily able to use the
> driver for one of the supported accelerometer chips!
> 
> Until now, the driver blindly assumed that the INT1 interrupt line is wired
> on a user's board. But these devices have 2 interrupt lines and can route
> their interrupt sources to one of them. Now, if "INT2" is found and matches
> i2c_client->irq, INT2 will be used.
> 
> The chip's default actually is INT2, which is why probably many boards will
> have it wired and can make use of this.
> 
> Of course, this also falls back to assuming INT1, so for existing users
> nothing will break. The new functionality is described in the bindings doc.
> 
> Signed-off-by: Martin Kepplinger <martin.kepplinger@...obroma-systems.com>
> ---
> changelog:
> v4: use irq that matches client->irq, backwards compatible
> v3: correctly assign irq if both pins are described in DT
> v2: don't warn but normally handle if both pins are described in dts
>     thanks Mark Rutland
> v1: initial post
> 
>  .../devicetree/bindings/iio/accel/mma8452.txt       |  6 ++++++
>  drivers/iio/accel/mma8452.c                         | 21 +++++++++++++++------
>  2 files changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/accel/mma8452.txt b/Documentation/devicetree/bindings/iio/accel/mma8452.txt
> index e3c3746..3c10e85 100644
> --- a/Documentation/devicetree/bindings/iio/accel/mma8452.txt
> +++ b/Documentation/devicetree/bindings/iio/accel/mma8452.txt
> @@ -7,13 +7,18 @@ Required properties:
>      * "fsl,mma8453"
>      * "fsl,mma8652"
>      * "fsl,mma8653"
> +
>    - reg: the I2C address of the chip
>  
>  Optional properties:
>  
>    - interrupt-parent: should be the phandle for the interrupt controller
> +
>    - interrupts: interrupt mapping for GPIO IRQ
>  
> +  - interrupt-names: should contain "INT1" and/or "INT2", the accelerometer's
> +		     interrupt line in use.
> +
>  Example:
>  
>  	mma8453fc@1d {
> @@ -21,4 +26,5 @@ Example:
>  		reg = <0x1d>;
>  		interrupt-parent = <&gpio1>;
>  		interrupts = <5 0>;
> +		interrupt-names = "INT2";
>  	};
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index 1eccc2d..116a6e4 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -29,6 +29,7 @@
>  #include <linux/iio/events.h>
>  #include <linux/delay.h>
>  #include <linux/of_device.h>
> +#include <linux/of_irq.h>
>  
>  #define MMA8452_STATUS				0x00
>  #define  MMA8452_STATUS_DRDY			(BIT(2) | BIT(1) | BIT(0))
> @@ -1130,13 +1131,21 @@ static int mma8452_probe(struct i2c_client *client,
>  					   MMA8452_INT_FF_MT;
>  		int enabled_interrupts = MMA8452_INT_TRANS |
>  					 MMA8452_INT_FF_MT;
> +		int irq2;
>  
> -		/* Assume wired to INT1 pin */
> -		ret = i2c_smbus_write_byte_data(client,
> -						MMA8452_CTRL_REG5,
> -						supported_interrupts);
> -		if (ret < 0)
> -			return ret;
> +		irq2 = of_irq_get_byname(client->dev.of_node, "INT2");
> +
> +		if (irq2 == client->irq) {
> +			dev_dbg(&client->dev, "using interrupt line INT2\n");
> +		} else {
> +			ret = i2c_smbus_write_byte_data(client,
> +							MMA8452_CTRL_REG5,
> +							supported_interrupts);
> +			if (ret < 0)
> +				return ret;
> +
> +			dev_dbg(&client->dev, "using interrupt line INT1\n");
> +		}
>  
>  		ret = i2c_smbus_write_byte_data(client,
>  						MMA8452_CTRL_REG4,
> 

This works fine and would be convenient to have. Any objections?

thanks
                         martin
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