Re: [PATCH] iio: mma8452: add support for MMA8451Q

From: Peter Meerwald-Stadler
Date: Thu Jan 14 2016 - 06:45:31 EST


> 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@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Christoph Muellner <christoph.muellner@xxxxxxxxxxxxxxxxxxxxx>
> ---
>
> 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

>
> 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

> #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

> */
> + .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?)

> .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:
>

--

Peter Meerwald-Stadler
+43-664-2444418 (mobile)