linux-kernel - Re: [PATCH] iio: mma8452: add support for MMA8451Q

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Date:	Sat, 16 Jan 2016 12:10:14 +0000
From:	Jonathan Cameron <jic23@...nel.org>
To:	Martin Kepplinger <martink@...teo.de>,
	Peter Meerwald-Stadler <pmeerw@...erw.net>
Cc:	knaack.h@....de, lars@...afoo.de,
	christoph.muellner@...obroma-systems.com, mfuzzey@...keon.com,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Martin Kepplinger <martin.kepplinger@...obroma-systems.com>
Subject: Re: [PATCH] iio: mma8452: add support for MMA8451Q

On 14/01/16 12:03, Martin Kepplinger wrote:
> Am 2016-01-14 um 12:45 schrieb Peter Meerwald-Stadler:
>>
>>> This adds support for this series' 14 bit accelerometer chip, MMA8451Q.
>>> It's datasheet is available at the vendor's website:
>>>
>>> https://cache.freescale.com/files/sensors/doc/data_sheet/MMA8451Q.pdf
>>
>> comments below
>>  
>>> Signed-off-by: Martin Kepplinger <martin.kepplinger@...obroma-systems.com>
>>> Signed-off-by: Christoph Muellner <christoph.muellner@...obroma-systems.com>
>>> ---
>>>
>>> This applies on top of
>>> [PATCH v5] iio: mma8452: add freefall detection for Freescale's accelerometers
>>> which should be in good shape (I think it already is) and accepted before this.
>>>
>>>
>>> this is sent early for review, just for you to know what to expect for v4.6.
>>>
>>> thanks
>>>                              martin
>>>
>>>
>>>  .../devicetree/bindings/iio/accel/mma8452.txt      |  4 +-
>>>  drivers/iio/accel/Kconfig                          |  2 +-
>>>  drivers/iio/accel/mma8452.c                        | 46 ++++++++++++++++++----
>>>  3 files changed, 42 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/iio/accel/mma8452.txt b/Documentation/devicetree/bindings/iio/accel/mma8452.txt
>>> index 3c10e85..165937e 100644
>>> --- a/Documentation/devicetree/bindings/iio/accel/mma8452.txt
>>> +++ b/Documentation/devicetree/bindings/iio/accel/mma8452.txt
>>> @@ -1,8 +1,10 @@
>>> -Freescale MMA8452Q, MMA8453Q, MMA8652FC or MMA8653FC triaxial accelerometer
>>> +Freescale MMA8451Q, MMA8452Q, MMA8453Q, MMA8652FC or MMA8653FC
>>> +triaxial accelerometer
>>>  
>>>  Required properties:
>>>  
>>>    - compatible: should contain one of
>>> +    * "fsl,mma8451"
>>>      * "fsl,mma8452"
>>>      * "fsl,mma8453"
>>>      * "fsl,mma8652"
>>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>>> index edc29b1..0e02c36 100644
>>> --- a/drivers/iio/accel/Kconfig
>>> +++ b/drivers/iio/accel/Kconfig
>>> @@ -143,7 +143,7 @@ config MMA8452
>>>  	select IIO_TRIGGERED_BUFFER
>>>  	help
>>>  	  Say yes here to build support for the following Freescale 3-axis
>>> -	  accelerometers: MMA8452Q, MMA8453Q, MMA8652FC, MMA8653FC.
>>> +	  accelerometers: MMA8341Q, MMA8452Q, MMA8453Q, MMA8652FC, MMA8653FC.
>>
>> should be MMA8451Q, not 8341
>>
> 
> thanks!
> 
>>>  
>>>  	  To compile this driver as a module, choose M here: the module
>>>  	  will be called mma8452.
>>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>>> index 820a8a3..b46694e 100644
>>> --- a/drivers/iio/accel/mma8452.c
>>> +++ b/drivers/iio/accel/mma8452.c
>>> @@ -1,6 +1,7 @@
>>>  /*
>>>   * mma8452.c - Support for following Freescale 3-axis accelerometers:
>>>   *
>>> + * MMA8451Q (14 bit)
>>>   * MMA8452Q (12 bit)
>>>   * MMA8453Q (10 bit)
>>>   * MMA8652FC (12 bit)
>>> @@ -85,8 +86,9 @@
>>>  #define  MMA8452_INT_FF_MT			BIT(2)
>>>  #define  MMA8452_INT_TRANS			BIT(5)
>>>  
>>> -#define  MMA8452_DEVICE_ID			0x2a
>>> -#define  MMA8453_DEVICE_ID			0x3a
>>> +#define MMA8451_DEVICE_ID			0x1a
>>> +#define MMA8452_DEVICE_ID			0x2a
>>> +#define MMA8453_DEVICE_ID			0x3a
>>
>> extra whitespace cleanup here
>>
> 
> Isn't it ok to stash it in here in this case?
Definitely preferable to do it as a precursor patch.
Always best to keep the trivial fixes separate as if nothing else reviewers can read those
whilst half asleep ;)
> 
>>>  #define MMA8652_DEVICE_ID			0x4a
>>>  #define MMA8653_DEVICE_ID			0x5a
>>>  
>>> @@ -937,6 +939,14 @@ static struct attribute_group mma8452_event_attribute_group = {
>>>  	.num_event_specs = ARRAY_SIZE(mma8452_motion_event), \
>>>  }
>>>  
>>> +static const struct iio_chan_spec mma8451_channels[] = {
>>> +	MMA8452_CHANNEL(X, idx_x, 14),
>>> +	MMA8452_CHANNEL(Y, idx_y, 14),
>>> +	MMA8452_CHANNEL(Z, idx_z, 14),
>>> +	IIO_CHAN_SOFT_TIMESTAMP(idx_ts),
>>> +	MMA8452_FREEFALL_CHANNEL(IIO_MOD_X_AND_Y_AND_Z),
>>> +};
>>> +
>>>  static const struct iio_chan_spec mma8452_channels[] = {
>>>  	MMA8452_CHANNEL(X, idx_x, 12),
>>>  	MMA8452_CHANNEL(Y, idx_y, 12),
>>> @@ -970,6 +980,7 @@ static const struct iio_chan_spec mma8653_channels[] = {
>>>  };
>>>  
>>>  enum {
>>> +	mma8451,
>>>  	mma8452,
>>>  	mma8453,
>>>  	mma8652,
>>> @@ -977,17 +988,34 @@ enum {
>>>  };
>>>  
>>>  static const struct mma_chip_info mma_chip_info_table[] = {
>>> -	[mma8452] = {
>>> -		.chip_id = MMA8452_DEVICE_ID,
>>> -		.channels = mma8452_channels,
>>> -		.num_channels = ARRAY_SIZE(mma8452_channels),
>>> +	[mma8451] = {
>>> +		.chip_id = MMA8451_DEVICE_ID,
>>> +		.channels = mma8451_channels,
>>> +		.num_channels = ARRAY_SIZE(mma8451_channels),
>>>  		/*
>>>  		 * Hardware has fullscale of -2G, -4G, -8G corresponding to
>>> -		 * raw value -2048 for 12 bit or -512 for 10 bit.
>>> +		 * raw value -8192 for 14 bit, -2048 for 12 bit or -512 for 10
>>> +		 * bit.
>>>  		 * The userspace interface uses m/s^2 and we declare micro units
>>>  		 * So scale factor for 12 bit here is given by:
>>> -		 *	g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
>>> +		 *      g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665
>>
>> this changes a tab to whitespace, probably not intended
>>
> 
> thanks!
> 
>>>  		 */
>>> +		.mma_scales = { {0, 2394}, {0, 4788}, {0, 9576} },
>>> +		.ev_cfg = MMA8452_TRANSIENT_CFG,
>>> +		.ev_cfg_ele = MMA8452_TRANSIENT_CFG_ELE,
>>> +		.ev_cfg_chan_shift = 1,
>>> +		.ev_src = MMA8452_TRANSIENT_SRC,
>>> +		.ev_src_xe = MMA8452_TRANSIENT_SRC_XTRANSE,
>>> +		.ev_src_ye = MMA8452_TRANSIENT_SRC_YTRANSE,
>>> +		.ev_src_ze = MMA8452_TRANSIENT_SRC_ZTRANSE,
>>> +		.ev_ths = MMA8452_TRANSIENT_THS,
>>> +		.ev_ths_mask = MMA8452_TRANSIENT_THS_MASK,
>>> +		.ev_count = MMA8452_TRANSIENT_COUNT,
>>> +	},
>>> +	[mma8452] = {
>>> +		.chip_id = MMA8452_DEVICE_ID,
>>> +		.channels = mma8452_channels,
>>> +		.num_channels = ARRAY_SIZE(mma8452_channels),
>>>  		.mma_scales = { {0, 9577}, {0, 19154}, {0, 38307} },
>>
>> the first scale is 9577 here, the last scale for 8451 is 9576 -- probably 
>> this should be the same value (rounding issue?)
>>
> 
> rounding issue, yes. I'll change it to 9577. The rest is ok.
> 
> Thanks Peter, for the good review!
> 
>>>  		.ev_cfg = MMA8452_TRANSIENT_CFG,
>>>  		.ev_cfg_ele = MMA8452_TRANSIENT_CFG_ELE,
>>> @@ -1168,6 +1196,7 @@ static int mma8452_reset(struct i2c_client *client)
>>>  }
>>>  
>>>  static const struct of_device_id mma8452_dt_ids[] = {
>>> +	{ .compatible = "fsl,mma8451", .data = &mma_chip_info_table[mma8451] },
>>>  	{ .compatible = "fsl,mma8452", .data = &mma_chip_info_table[mma8452] },
>>>  	{ .compatible = "fsl,mma8453", .data = &mma_chip_info_table[mma8453] },
>>>  	{ .compatible = "fsl,mma8652", .data = &mma_chip_info_table[mma8652] },
>>> @@ -1204,6 +1233,7 @@ static int mma8452_probe(struct i2c_client *client,
>>>  		return ret;
>>>  
>>>  	switch (ret) {
>>> +	case MMA8451_DEVICE_ID:
>>>  	case MMA8452_DEVICE_ID:
>>>  	case MMA8453_DEVICE_ID:
>>>  	case MMA8652_DEVICE_ID:
>>>
>>
>