linux-kernel - Re: [PATCH] Revert "Input: bma150 - avoid binding to bma180 if IIO bma180 driver present" and "Input: bma150

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Date:   Sat, 1 Apr 2017 16:59:26 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     "H. Nikolaus Schaller" <hns@...delico.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Aniroop Mathur <a.mathur@...sung.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        letux-kernel@...nphoenux.org
Subject: Re: [PATCH] Revert "Input: bma150 - avoid binding to bma180 if IIO
 bma180 driver present" and "Input: bma150 - extend chip detection for bma180"

Hi,

On 01-04-17 16:44, H. Nikolaus Schaller wrote:
> This reverts commit baf28d91e7b1 ("Input: bma150 - avoid binding to bma180 if IIO bma180 driver present")
> and commit ef3714fdbc8d ("Input: bma150 - extend chip detection for bma180")
>
> Rationale: initially (2012) the GTA04 device using a bma180 chip simply refereced
> the bma150 platform driver in its board file [1] which happened to work in all
> scenarios that were tested.
>
> When conversion to DT started (2014), we needed to make the driver be still
> recognised. Hence we introduced the compatibility to the bma180 chip in
> Linux 3.15-rc5 [2] without further checks if it is really 100% compatible. This
> worked flawlessly for years with the GTA04 device.
>
> Recently (2016), Hans de Goede pointed out that the chips are not as similar
> as they appeared and the driver works with the bma180 for the GTA04 only
> by good luck. He proposed to remove the bma180 support completely [3], but
> we still did need it until we have a replacement. Thus, a condifional compile
> was added.
>
> We have now developed a generic iio-input-bridge which works with any 2 or
> 3 axis iio based accelerometer. It has been tested on GTA04 and Pyra and
> works as expected. Therefore we can remove the bma180 support from this
> driver completely. User-space API compatibility can be restored by using the
> iio-input-bridge.
>
> Maybe it is time to convert the bma150 driver to iio as well and retire the
> accelerometer input drivers completely but this is a different story and task.
>
> [1]: https://github.com/neilbrown/linux/blob/gta04/3.2.y/arch/arm/mach-omap2/board-omap3gta04.c#L976
> [2]: https://patchwork.kernel.org/patch/3961171/
> [3]: https://patchwork.kernel.org/patch/9325481/
>
> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>

Looks good to me:

Reviewed-by: Hans de Goede <hdegoede@...hat.com>

Regards,

Hans


> ---
>  drivers/input/misc/bma150.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
>
> diff --git a/drivers/input/misc/bma150.c b/drivers/input/misc/bma150.c
> index 1fa8537..1efcfdf 100644
> --- a/drivers/input/misc/bma150.c
> +++ b/drivers/input/misc/bma150.c
> @@ -70,7 +70,6 @@
>  #define BMA150_CFG_5_REG	0x11
>
>  #define BMA150_CHIP_ID		2
> -#define BMA180_CHIP_ID		3
>  #define BMA150_CHIP_ID_REG	BMA150_DATA_0_REG
>
>  #define BMA150_ACC_X_LSB_REG	BMA150_DATA_2_REG
> @@ -538,13 +537,8 @@ static int bma150_probe(struct i2c_client *client,
>  		return -EIO;
>  	}
>
> -	/*
> -	 * Note if the IIO CONFIG_BMA180 driver is enabled we want to fail
> -	 * the probe for the bma180 as the iio driver is preferred.
> -	 */
>  	chip_id = i2c_smbus_read_byte_data(client, BMA150_CHIP_ID_REG);
> -	if (chip_id != BMA150_CHIP_ID &&
> -	    (IS_ENABLED(CONFIG_BMA180) || chip_id != BMA180_CHIP_ID)) {
> +	if (chip_id != BMA150_CHIP_ID) {
>  		dev_err(&client->dev, "BMA150 chip id error: %d\n", chip_id);
>  		return -EINVAL;
>  	}
> @@ -648,9 +642,6 @@ static UNIVERSAL_DEV_PM_OPS(bma150_pm, bma150_suspend, bma150_resume, NULL);
>
>  static const struct i2c_device_id bma150_id[] = {
>  	{ "bma150", 0 },
> -#if !IS_ENABLED(CONFIG_BMA180)
> -	{ "bma180", 0 },
> -#endif
>  	{ "smb380", 0 },
>  	{ "bma023", 0 },
>  	{ }
>