Re: [PATCH v3 2/2] iio: magnetometer: add mmc34160 magnetometer driver
From: Jonathan Cameron
Date: Sat Aug 15 2015 - 16:48:01 EST
On 02/08/15 17:43, Jonathan Cameron wrote:
> On 02/08/15 17:40, Jonathan Cameron wrote:
>> On 31/07/15 15:27, Teodora Baluta wrote:
>>> This patch adds support for the MMC34160 3-axis magnetometer driver. The
>>> MMC31460 magnetometer driver uses the same register map as MMC35240 with
>>> different specifications for sensitivity.
>>>
>>> According to Memsic specification, for the MMC31460 sensor, there is no
>>> need to apply compensation to the read values. Also, the MMC34160 sensor
>>> does not use the same formula as MMC35240 for transforming raw data into
>>> mgauss, and the current formula is based on the input driver (mmc3416x)
>>> provided by Memsic.
>>>
>>> Signed-off-by: Teodora Baluta <teodora.baluta@xxxxxxxxx>
>> Couple of comments inline.
>>
>> Applied to the togreg branch of iio.git - initially pushed out as testing
>> for the autobuilders to play with it.
>>
> oops, didn't check it had actually applied cleanly. Right now it doesn't.
> Perhaps connected to various fixes working there way through. I'll hold
> this patch back for now on the basis it'll probably work itself out
> as they hit the togreg branch (hopefully later this week).
>
> Jonathan
Applied to the togreg branch of iio.git (with some fuzz).
Thanks,
Jonathan
>> Thanks,
>>
>> Jonathan
>>> ---
>>> drivers/iio/magnetometer/Kconfig | 5 +-
>>> drivers/iio/magnetometer/mmc35240.c | 203 ++++++++++++++++++++++++++++--------
>>> 2 files changed, 161 insertions(+), 47 deletions(-)
>>>
>>> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
>>> index dcadfc4..baf59d9 100644
>>> --- a/drivers/iio/magnetometer/Kconfig
>>> +++ b/drivers/iio/magnetometer/Kconfig
>>> @@ -52,8 +52,9 @@ config MMC35240
>>> select REGMAP_I2C
>>> depends on I2C
>>> help
>>> - Say yes here to build support for the MEMSIC MMC35240 3-axis
>>> - magnetic sensor.
>>> + Say yes here to build support for the MEMSIC MMC35240 3-axis magnetic
>>> + sensor. This driver also adds support for the MEMSIC MMC34160 3-axis magnetic
>>> + sensor.
>> Sometimes I wonder if we should have a standard form for multi device supporting
>> driver Kconfig help text. This one seems rather unwieldy! Anyhow we don't
>> so until we do it can be like this.
>>>
>>> To compile this driver as a module, choose M here: the module
>>> will be called mmc35240.
>>> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
>>> index a4259bf..7a5921b 100644
>>> --- a/drivers/iio/magnetometer/mmc35240.c
>>> +++ b/drivers/iio/magnetometer/mmc35240.c
>>> @@ -83,6 +83,20 @@
>>>
>>> #define MMC35240_OTP_START_ADDR 0x1B
>>>
>>> +#define MMC35240_CHIP_ID 0x08
>>> +#define MMC34160_CHIP_ID 0x06
>>> +
>>> +enum mmc35240_chipset {
>>> + MMC35240,
>>> + MMC34160,
>>> + MMC_MAX_CHIPS
>>> +};
>>> +
>>> +static u8 chip_ids[MMC_MAX_CHIPS] = {
>>> + MMC35240_CHIP_ID,
>>> + MMC34160_CHIP_ID,
>>> +};
>>> +
>>> enum mmc35240_resolution {
>>> MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
>>> MMC35240_16_BITS_FAST, /* 4.08 ms */
>>> @@ -99,27 +113,53 @@ enum mmc35240_axis {
>>> static const struct {
>>> int sens[3]; /* sensitivity per X, Y, Z axis */
>>> int nfo; /* null field output */
>>> -} mmc35240_props_table[] = {
>>> - /* 16 bits, 125Hz ODR */
>>> - {
>>> - {1024, 1024, 1024},
>>> - 32768,
>>> - },
>>> - /* 16 bits, 250Hz ODR */
>>> - {
>>> - {1024, 1024, 770},
>>> - 32768,
>>> - },
>>> - /* 14 bits, 450Hz ODR */
>>> +} mmc35240_props_table[MMC_MAX_CHIPS][4] = {
>>> + /* MMC35240 */
>>> {
>>> - {256, 256, 193},
>>> - 8192,
>>> + /* 16 bits, 125Hz ODR */
>>> + {
>>> + {1024, 1024, 1024},
>>> + 32768,
>>> + },
>>> + /* 16 bits, 250Hz ODR */
>>> + {
>>> + {1024, 1024, 770},
>>> + 32768,
>>> + },
>>> + /* 14 bits, 450Hz ODR */
>>> + {
>>> + {256, 256, 193},
>>> + 8192,
>>> + },
>>> + /* 12 bits, 800Hz ODR */
>>> + {
>>> + {64, 64, 48},
>>> + 2048,
>>> + },
>>> },
>>> - /* 12 bits, 800Hz ODR */
>>> + /* MMC34160 */
>>> {
>>> - {64, 64, 48},
>>> - 2048,
>>> - },
>>> + /* 16 bits, 125Hz ODR */
>>> + {
>>> + {2048, 2048, 2048},
>>> + 32768,
>>> + },
>>> + /* 16 bits, 250Hz ODR */
>>> + {
>>> + {2048, 2048, 2048},
>>> + 32768,
>>> + },
>>> + /* 14 bits, 450Hz ODR */
>>> + {
>>> + {512, 512, 512},
>>> + 8192,
>>> + },
>>> + /* 12 bits, 800Hz ODR */
>>> + {
>>> + {128, 128, 128},
>>> + 2048,
>>> + },
>>> + }
>>> };
>>>
>>> struct mmc35240_data {
>>> @@ -131,6 +171,7 @@ struct mmc35240_data {
>>> /* OTP compensation */
>>> int axis_coef[3];
>>> int axis_scale[3];
>>> + enum mmc35240_chipset chipset;
>>> };
>>>
>>> static const struct {
>>> @@ -206,6 +247,16 @@ static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
>>> coil_bit);
>>> }
>>>
>>> +static inline bool mmc35240_needs_compensation(enum mmc35240_chipset chipset)
>>> +{
>>> + switch (chipset) {
>>> + case MMC35240:
>>> + return true;
>>> + default:
>>> + return false;
>>> + }
>>> +}
>>> +
>>> static int mmc35240_init(struct mmc35240_data *data)
>>> {
>>> int ret, y_convert, z_convert;
>>> @@ -220,6 +271,10 @@ static int mmc35240_init(struct mmc35240_data *data)
>>>
>>> dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
>>>
>>> + if (reg_id != chip_ids[data->chipset]) {
>>> + dev_err(&data->client->dev, "Invalid chip %x\n", ret);
>>> + return -ENODEV;
>>> + }
>>> /*
>>> * make sure we restore sensor characteristics, by doing
>>> * a RESET/SET sequence
>>> @@ -240,6 +295,9 @@ static int mmc35240_init(struct mmc35240_data *data)
>>> if (ret < 0)
>>> return ret;
>>>
>>> + if (!mmc35240_needs_compensation(data->chipset))
>>> + return 0;
>>> +
>>> ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
>>> (u8 *)otp_data, sizeof(otp_data));
>>> if (ret < 0)
>>> @@ -301,9 +359,38 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
>>> 3 * sizeof(__le16));
>>> }
>>>
>>> +static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
>>> + int index, int *val)
>>> +{
>>> + *val = (raw[index] - nfo) * 1000 / sens[index];
>>> + return 0;
>>> +}
>>> +
>>> +static int mmc35240_raw_to_mgauss(int raw[3], int sens[3], int nfo,
>>> + int index, int *val)
>>> +{
>>> + switch (index) {
>>> + case AXIS_X:
>>> + *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
>>> + break;
>>> + case AXIS_Y:
>>> + *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
>>> + (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>>> + break;
>>> + case AXIS_Z:
>>> + *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
>>> + (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>>> + break;
>>> + default:
>>> + return -EINVAL;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> /**
>>> - * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
>>> - compensation for output value.
>>> + * memsic_raw_to_mgauss - convert raw readings to milli gauss. Also apply
>>> + compensation for output value.
>>> *
>>> * @data: device private data
>>> * @index: axis index for which we want the conversion
>>> @@ -312,8 +399,8 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
>>> *
>>> * Returns: 0 in case of success, -EINVAL when @index is not valid
>>> */
>>> -static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
>>> - __le16 buf[], int *val)
>>> +static int memsic_raw_to_mgauss(struct mmc35240_data *data, int index,
>> Awkward. Normally I'd argue in favour of keeping the original prefix
>> (in keeping with the driver name) but here you have reused that name
>> as was obviously appropriate. Ah well I guess memsic_ will have
>> to do as a prefix!
>>> + __le16 buf[], int *val)
>>> {
>>> int raw[3];
>>> int sens[3];
>>> @@ -323,29 +410,29 @@ static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
>>> raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
>>> raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
>>>
>>> - sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
>>> - sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
>>> - sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
>>> + sens[AXIS_X] = mmc35240_props_table[id][data->res].sens[AXIS_X];
>>> + sens[AXIS_Y] = mmc35240_props_table[id][data->res].sens[AXIS_Y];
>>> + sens[AXIS_Z] = mmc35240_props_table[id][data->res].sens[AXIS_Z];
>>>
>>> - nfo = mmc35240_props_table[data->res].nfo;
>>>
>>> - switch (index) {
>>> - case AXIS_X:
>>> - *val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
>>> - break;
>>> - case AXIS_Y:
>>> - *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
>>> - (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>>> - break;
>>> - case AXIS_Z:
>>> - *val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
>>> - (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>>> - break;
>>> + nfo = mmc35240_props_table[id][data->res].nfo;
>>> +
>>> + switch (id) {
>>> + case MMC35240:
>>> + ret = mmc35240_raw_to_mgauss(raw, sens, nfo, index, val);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + /* apply OTP compensation */
>>> + *val = (*val) * data->axis_coef[index] /
>>> + data->axis_scale[index];
>>> +
>>> + return 0;
>>> + case MMC34160:
>>> + return mmc34160_raw_to_mgauss(raw, sens, nfo, index, val);
>>> default:
>>> return -EINVAL;
>>> }
>>> - /* apply OTP compensation */
>>> - *val = (*val) * data->axis_coef[index] / data->axis_scale[index];
>>>
>>> return 0;
>>> }
>>> @@ -366,7 +453,7 @@ static int mmc35240_read_raw(struct iio_dev *indio_dev,
>>> mutex_unlock(&data->mutex);
>>> if (ret < 0)
>>> return ret;
>>> - ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
>>> + ret = memsic_raw_to_mgauss(data, chan->address, buf, val);
>>> if (ret < 0)
>>> return ret;
>>> return IIO_VAL_INT;
>>> @@ -484,12 +571,27 @@ static const struct regmap_config mmc35240_regmap_config = {
>>> .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
>>> };
>>>
>>> +static const char *mmc35240_match_acpi_device(struct device *dev,
>>> + enum mmc35240_chipset *chipset)
>>> +{
>>> + const struct acpi_device_id *id;
>>> +
>>> + id = acpi_match_device(dev->driver->acpi_match_table, dev);
>>> + if (!id)
>>> + return NULL;
>>> +
>>> + *chipset = (enum mmc35240_chipset)id->driver_data;
>>> +
>>> + return dev_name(dev);
>>> +}
>>> +
>>> static int mmc35240_probe(struct i2c_client *client,
>>> const struct i2c_device_id *id)
>>> {
>>> struct mmc35240_data *data;
>>> struct iio_dev *indio_dev;
>>> struct regmap *regmap;
>>> + const char *name;
>>> int ret;
>>>
>>> indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>> @@ -507,11 +609,20 @@ static int mmc35240_probe(struct i2c_client *client,
>>> data->regmap = regmap;
>>> data->res = MMC35240_16_BITS_SLOW;
>>>
>>> + if (id) {
>>> + data->chipset = (enum mmc35240_chipset)(id->driver_data);
>>> + name = id->name;
>>> + } else if (ACPI_HANDLE(&client->dev)) {
>>> + name = mmc35240_match_acpi_device(&client->dev,
>>> + &data->chipset);
>>> + } else
>>> + return -ENODEV;
>>> +
>>> mutex_init(&data->mutex);
>>>
>>> indio_dev->dev.parent = &client->dev;
>>> indio_dev->info = &mmc35240_info;
>>> - indio_dev->name = MMC35240_DRV_NAME;
>>> + indio_dev->name = name;
>>> indio_dev->channels = mmc35240_channels;
>>> indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
>>> indio_dev->modes = INDIO_DIRECT_MODE;
>>> @@ -564,14 +675,16 @@ static const struct of_device_id mmc35240_of_match[] = {
>>> MODULE_DEVICE_TABLE(of, mmc35240_of_match);
>>>
>>> static const struct acpi_device_id mmc35240_acpi_match[] = {
>>> - {"MMC35240", 0},
>>> + {"MMC35240", MMC35240},
>>> + {"MMC34160", MMC34160},
>>> { },
>>> };
>>> MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
>>>
>>> static const struct i2c_device_id mmc35240_id[] = {
>>> - {"mmc35240", 0},
>>> - {}
>>> + {"mmc35240", MMC35240},
>>> + {"mmc34160", MMC34160},
>>> + { }
>>> };
>>> MODULE_DEVICE_TABLE(i2c, mmc35240_id);
>>>
>>>
>>
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