Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756241AbbDOLqc (ORCPT ); Wed, 15 Apr 2015 07:46:32 -0400 Received: from mail-wg0-f51.google.com ([74.125.82.51]:33232 "EHLO mail-wg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896AbbDOLqX (ORCPT ); Wed, 15 Apr 2015 07:46:23 -0400 MIME-Version: 1.0 In-Reply-To: References: <1429095726-10055-1-git-send-email-daniel.baluta@intel.com> <1429095726-10055-2-git-send-email-daniel.baluta@intel.com> Date: Wed, 15 Apr 2015 14:46:22 +0300 X-Google-Sender-Auth: yG77e1EPZz2ck3mWV8fVBXWzxHk Message-ID: Subject: Re: [PATCH 1/3] iio: magnetometer: Add support for MEMSIC MMC35240 sensor From: Daniel Baluta To: Peter Meerwald Cc: Daniel Baluta , Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Linux Kernel Mailing List , "linux-iio@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 19084 Lines: 613 On Wed, Apr 15, 2015 at 2:28 PM, Peter Meerwald wrote: > Hello, > > looks good, some comments below... > >> Minimal implementation for MMC35240 3-axis magnetometer >> sensor. It provides processed readings and possiblity to change >> the sampling frequency. > > possibility Ok. > > link to datasheet missing > Unfortunately the datasheet isn't public. >> Signed-off-by: Daniel Baluta >> --- >> drivers/iio/magnetometer/Kconfig | 11 + >> drivers/iio/magnetometer/Makefile | 1 + >> drivers/iio/magnetometer/mmc35240.c | 476 ++++++++++++++++++++++++++++++++++++ >> 3 files changed, 488 insertions(+) >> create mode 100644 drivers/iio/magnetometer/mmc35240.c >> >> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig >> index a5d6de7..7aba685 100644 >> --- a/drivers/iio/magnetometer/Kconfig >> +++ b/drivers/iio/magnetometer/Kconfig >> @@ -47,6 +47,17 @@ config HID_SENSOR_MAGNETOMETER_3D >> Say yes here to build support for the HID SENSOR >> Magnetometer 3D. >> >> +config MMC35240 >> + tristate "MEMSIC MMC35240 3-axis magnetic sensor" >> + select REGMAP_I2C >> + depends on I2C >> + help >> + Say yes here to build support for the MEMSIC MMC35240 3-axis >> + magnetic sensor. >> + >> + To compile this driver as a module, choose M here: the module >> + will be called mmc35240. >> + >> config IIO_ST_MAGN_3AXIS >> tristate "STMicroelectronics magnetometers 3-Axis Driver" >> depends on (I2C || SPI_MASTER) && SYSFS >> diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile >> index 0f5d3c9..696a429 100644 >> --- a/drivers/iio/magnetometer/Makefile >> +++ b/drivers/iio/magnetometer/Makefile >> @@ -6,6 +6,7 @@ >> obj-$(CONFIG_AK8975) += ak8975.o >> obj-$(CONFIG_MAG3110) += mag3110.o >> obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o >> +obj-$(CONFIG_MMC35240) += mmc35240.o >> >> obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o >> st_magn-y := st_magn_core.o >> diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c >> new file mode 100644 >> index 0000000..c46c1f7 >> --- /dev/null >> +++ b/drivers/iio/magnetometer/mmc35240.c >> @@ -0,0 +1,476 @@ >> +/* >> + * MMC35240 - MEMSIC 3-axis Magnetic Sensor >> + * >> + * Copyright (c) 2015, Intel Corporation. >> + * >> + * This file is subject to the terms and conditions of version 2 of >> + * the GNU General Public License. See the file COPYING in the main >> + * directory of this archive for more details. >> + * >> + * IIO driver for MMC35240 (7-bit I2C slave address 0x30). >> + * >> + * TODO: offset, ACPI, continuous measurement mode, PM >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include >> +#include >> + >> +#define MMC35240_DRV_NAME "mmc35240" >> +#define MMC35240_REGMAP_NAME "mmc35240_regmap" >> + >> +#define MMC35240_REG_XOUT_L 0x00 >> +#define MMC35240_REG_XOUT_H 0x01 >> +#define MMC35240_REG_YOUT_L 0x02 >> +#define MMC35240_REG_YOUT_H 0x03 >> +#define MMC35240_REG_ZOUT_L 0x04 >> +#define MMC35240_REG_ZOUT_H 0x05 >> + >> +#define MMC35240_REG_STATUS 0x06 >> +#define MMC35240_REG_CTRL0 0x07 >> +#define MMC35240_REG_CTRL1 0x08 >> + >> +#define MMC35240_REG_ID 0x20 >> + >> +#define MMC35240_STATUS_MEAS_DONE_BIT BIT(0) >> + >> +#define MMC35240_CTRL0_REFILL_BIT BIT(7) >> +#define MMC35240_CTRL0_RESET_BIT BIT(6) >> +#define MMC35240_CTRL0_SET_BIT BIT(5) >> +#define MMC35240_CTRL0_CMM_BIT BIT(1) >> +#define MMC35240_CTRL0_TM_BIT BIT(0) >> + >> +/* output resolution bits */ >> +#define MMC35240_CTRL1_BW0_BIT BIT(0) >> +#define MMC35240_CTRL1_BW1_BIT BIT(1) >> + >> +#define MMC35240_CTRL1_BW_MASK (MMC35240_CTRL1_BW0_BIT | \ >> + MMC35240_CTRL1_BW1_BIT) >> +#define MMC35240_CTRL1_BW_SHIFT 0 >> + >> +#define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */ >> +#define MMC53240_WAIT_SET_RESET 1000 /* us */ >> + >> +enum mmc35240_resolution { >> + MMC35240_16_BITS_SLOW = 0, /* 100 Hz */ >> + MMC35240_16_BITS_FAST, /* 200 Hz */ >> + MMC35240_14_BITS, /* 333 Hz */ >> + MMC35240_12_BITS, /* 666 Hz */ >> + MMC35240_MAX_BITS /* this must be last */ > > _MAX_BITS is not used Will remove. Very likely, at the moment of coding this I thought of some sort of enumeration on all possible resolutions. > >> +}; >> + >> +enum mmc35240_axis { >> + AXIS_X = 0, >> + AXIS_Y, >> + AXIS_Z, >> +}; >> + >> +static const struct { >> + int sens[3]; /* sensitivity per X, Y, Z axis */ >> + int nfo; /* null field output */ >> +} mmc35240_props_table[] = { >> + /* 16 bits, 100Hz ODR */ >> + { >> + {1024, 1024, 770}, >> + 32768, >> + }, >> + /* 16 bits, 200Hz ODR */ >> + { >> + {1024, 1024, 770}, >> + 32768, >> + }, >> + /* 14 bits, 333Hz ODR */ >> + { >> + {256, 256, 193}, >> + 8192, >> + }, >> + /* 12 bits, 666Hz ODR */ >> + { >> + {64, 64, 48}, >> + 2048, >> + }, >> +}; >> + >> +struct mmc35240_data { >> + struct i2c_client *client; >> + struct mutex mutex; >> + struct regmap *regmap; >> + enum mmc35240_resolution res; >> +}; >> + >> +int mmc35240_samp_freq[] = {100, 200, 333, 666}; >> + >> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("100 200 333 666"); >> + >> +#define MMC35240_CHANNEL(_axis) { \ >> + .type = IIO_MAGN, \ >> + .modified = 1, \ >> + .channel2 = IIO_MOD_ ## _axis, \ >> + .address = AXIS_ ## _axis, \ >> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ >> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \ >> +} >> + >> +static const struct iio_chan_spec mmc35240_channels[] = { >> + MMC35240_CHANNEL(X), >> + MMC35240_CHANNEL(Y), >> + MMC35240_CHANNEL(Z), >> +}; >> + >> +static struct attribute *mmc35240_attributes[] = { >> + &iio_const_attr_sampling_frequency_available.dev_attr.attr, >> +}; >> + >> +static const struct attribute_group mmc35240_attribute_group = { >> + .attrs = mmc35240_attributes, >> +}; >> + >> +static int mmc35240_get_samp_freq_index(struct mmc35240_data *data, >> + int val, int val2) >> +{ >> + int i; >> + >> + for (i = 0; i < ARRAY_SIZE(mmc35240_samp_freq); i++) >> + if (mmc35240_samp_freq[i] == val) >> + return i; >> + return -EINVAL; >> +} >> + >> +static int mmc35240_hw_set(struct mmc35240_data *data, bool set) >> +{ >> + int ret; >> + u8 coil_bit; >> + >> + /* >> + * Recharge the capacitor at VCAP pin, requested to be issued >> + * before a SET/RESET command. >> + */ >> + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, >> + MMC35240_CTRL0_REFILL_BIT, >> + MMC35240_CTRL0_REFILL_BIT); >> + if (ret < 0) >> + return ret; >> + usleep_range(MMC35240_WAIT_CHARGE_PUMP, MMC35240_WAIT_CHARGE_PUMP + 1); >> + >> + if (set) >> + coil_bit = MMC35240_CTRL0_SET_BIT; >> + else >> + coil_bit = MMC35240_CTRL0_RESET_BIT; >> + >> + return regmap_update_bits(data->regmap, MMC35240_REG_CTRL0, >> + MMC35240_CTRL0_REFILL_BIT, >> + coil_bit); >> +} >> + >> +static int mmc35240_init(struct mmc35240_data *data) >> +{ >> + int ret; >> + unsigned int reg_id; >> + >> + ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); >> + if (ret < 0) { >> + dev_err(&data->client->dev, "Error reading product id\n"); >> + return ret; >> + } >> + >> + dev_info(&data->client->dev, "MMC35240 chip id %x\n", reg_id); > > better check the ID and avoid cluttering the log Hmm, ok. I've seen drivers with both versions. Perhaps dev_dbg instead of dev_info? Anyhow, will change in v2. > >> + >> + /* >> + * make sure we restore sensor characteristics, by doing >> + * a RESET/SET sequence >> + */ >> + ret = mmc35240_hw_set(data, false); >> + if (ret < 0) >> + return ret; >> + usleep_range(MMC53240_WAIT_SET_RESET, MMC53240_WAIT_SET_RESET + 1); >> + >> + ret = mmc35240_hw_set(data, true); >> + if (ret < 0) >> + return ret; >> + >> + /* set default sampling frequency */ >> + return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, >> + MMC35240_CTRL1_BW_MASK, >> + data->res << MMC35240_CTRL1_BW_SHIFT); >> +} >> + >> +static int mmc35240_take_measurement(struct mmc35240_data *data) >> +{ >> + int ret, tries = 100; >> + unsigned int reg_status; > > reg_status is probably a u8? > >> + >> + ret = regmap_write(data->regmap, MMC35240_REG_CTRL0, >> + MMC35240_CTRL0_TM_BIT); >> + if (ret < 0) >> + return ret; >> + >> + while (tries-- > 0) { >> + ret = regmap_read(data->regmap, MMC35240_REG_STATUS, >> + ®_status); >> + if (ret < 0) >> + return ret; >> + if (reg_status & MMC35240_STATUS_MEAS_DONE_BIT) >> + break; >> + msleep(20); >> + } >> + >> + if (tries < 0) { >> + dev_err(&data->client->dev, "data not ready\n"); >> + return -EIO; >> + } >> + >> + return 0; >> +} >> + >> +static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3]) >> +{ >> + int ret; >> + >> + ret = mmc35240_take_measurement(data); >> + if (ret < 0) >> + return ret; >> + >> + return regmap_bulk_read(data->regmap, MMC35240_REG_XOUT_L, (u8 *)buf, >> + 3 * sizeof(__be16)); > > sizeof(__le16) Correct. > >> +} >> + >> +int mmc35240_raw_to_gauss(struct mmc35240_data *data, int index, __le16 buf[], >> + int *val, int *val2) >> +{ >> + int raw_x, raw_y, raw_z; >> + int sens_x, sens_y, sens_z; >> + int nfo; >> + >> + raw_x = le16_to_cpu(buf[AXIS_X]); >> + raw_y = le16_to_cpu(buf[AXIS_Y]); >> + raw_z = le16_to_cpu(buf[AXIS_Z]); >> + >> + sens_x = mmc35240_props_table[data->res].sens[AXIS_X]; >> + sens_y = mmc35240_props_table[data->res].sens[AXIS_Y]; >> + sens_z = mmc35240_props_table[data->res].sens[AXIS_Z]; >> + >> + nfo = mmc35240_props_table[data->res].nfo; >> + >> + switch (index) { >> + case AXIS_X: > > I'd rather expose a _RAW with _SCALE/_OFFSET This is was also my intention at a first glance. But if you look on computation of Y or Z axis processed value you'll see that this is not possible. Processed value for Y depends on raw_y, raw_z, sensitivity_y, sensitivity_z and offset. Any idea on how to expose this as _RAW with _SCALE/_OFFSET is welcomed. > >> + *val = (raw_x - nfo) / sens_x; >> + *val2 = ((raw_x - nfo) % sens_x) * 1000000; >> + break; >> + case AXIS_Y: >> + *val = (raw_y - nfo) / sens_y - (raw_z - nfo) / sens_z; >> + *val2 = (((raw_y - nfo) % sens_y - (raw_z - nfo) % sens_z)) >> + * 1000000; >> + break; >> + case AXIS_Z: >> + *val = (raw_y - nfo) / sens_y + (raw_z - nfo) / sens_z; >> + *val2 = (((raw_y - nfo) % sens_y + (raw_z - nfo) % sens_z)) >> + * 1000000; >> + break; >> + default: >> + return -EINVAL; >> + } >> + return 0; >> +} >> + >> +static int mmc35240_read_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, int *val, >> + int *val2, long mask) >> +{ >> + struct mmc35240_data *data = iio_priv(indio_dev); >> + int ret, i; >> + unsigned int reg; > > reg is u8 probably regmap_read needs the third parameter (reg in our case) to be unsigned int. > >> + __le16 buf[3]; >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_PROCESSED: >> + mutex_lock(&data->mutex); >> + ret = mmc35240_read_measurement(data, buf); >> + mutex_unlock(&data->mutex); >> + if (ret < 0) >> + return ret; >> + ret = mmc35240_raw_to_gauss(data, chan->address, >> + buf, val, val2); >> + if (ret < 0) >> + return ret; >> + return IIO_VAL_INT_PLUS_MICRO; >> + case IIO_CHAN_INFO_SAMP_FREQ: >> + mutex_lock(&data->mutex); >> + ret = regmap_read(data->regmap, MMC35240_REG_CTRL1, ®); >> + mutex_unlock(&data->mutex); >> + if (ret < 0) >> + return ret; >> + >> + i = (reg & MMC35240_CTRL1_BW_MASK) >> MMC35240_CTRL1_BW_SHIFT; >> + if (i < 0 || i > ARRAY_SIZE(mmc35240_samp_freq)) > >>= ARRAY_SIZE > >> + return -EINVAL; >> + >> + *val = mmc35240_samp_freq[i]; >> + *val2 = 0; >> + return IIO_VAL_INT_PLUS_MICRO; > > return IIO_VAL_INT Ok. > >> + default: >> + return -EINVAL; >> + } >> +} >> + >> +static int mmc35240_write_raw(struct iio_dev *indio_dev, >> + struct iio_chan_spec const *chan, int val, >> + int val2, long mask) >> +{ >> + struct mmc35240_data *data = iio_priv(indio_dev); >> + int i, ret; >> + >> + switch (mask) { >> + case IIO_CHAN_INFO_SAMP_FREQ: >> + i = mmc35240_get_samp_freq_index(data, val, val2); >> + if (i < 0) >> + return -EINVAL; >> + mutex_lock(&data->mutex); >> + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, >> + MMC35240_CTRL1_BW_MASK, >> + i << MMC35240_CTRL1_BW_SHIFT); >> + mutex_unlock(&data->mutex); >> + return ret; >> + default: >> + return -EINVAL; >> + } >> +} >> + >> +static const struct iio_info mmc35240_info = { >> + .driver_module = THIS_MODULE, >> + .read_raw = mmc35240_read_raw, >> + .write_raw = mmc35240_write_raw, >> + .attrs = &mmc35240_attribute_group, >> +}; >> + >> +static bool mmc35240_is_writeable_reg(struct device *dev, unsigned int reg) >> +{ >> + switch (reg) { >> + case MMC35240_REG_CTRL0: >> + case MMC35240_REG_CTRL1: >> + return true; >> + default: >> + return false; >> + } >> +} >> + >> +static bool mmc35240_is_readable_reg(struct device *dev, unsigned int reg) >> +{ >> + switch (reg) { >> + case MMC35240_REG_XOUT_L: >> + case MMC35240_REG_XOUT_H: >> + case MMC35240_REG_YOUT_L: >> + case MMC35240_REG_YOUT_H: >> + case MMC35240_REG_ZOUT_L: >> + case MMC35240_REG_ZOUT_H: >> + case MMC35240_REG_STATUS: >> + case MMC35240_REG_ID: >> + return true; >> + default: >> + return false; >> + } >> +} >> + >> +static bool mmc35240_is_volatile_reg(struct device *dev, unsigned int reg) >> +{ >> + switch (reg) { >> + case MMC35240_REG_CTRL0: >> + case MMC35240_REG_CTRL1: >> + return false; >> + default: >> + return true; >> + } >> +} >> + >> +static struct reg_default mmc35240_reg_defaults[] = { >> + { MMC35240_REG_CTRL0, 0x00 }, >> + { MMC35240_REG_CTRL1, 0x00 }, >> +}; >> + >> +static const struct regmap_config mmc35240_regmap_config = { >> + .name = MMC35240_REGMAP_NAME, >> + >> + .reg_bits = 8, >> + .val_bits = 8, >> + >> + .max_register = MMC35240_REG_ID, >> + .cache_type = REGCACHE_FLAT, >> + >> + .writeable_reg = mmc35240_is_writeable_reg, >> + .readable_reg = mmc35240_is_readable_reg, >> + .volatile_reg = mmc35240_is_volatile_reg, >> + >> + .reg_defaults = mmc35240_reg_defaults, >> + .num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults), >> +}; >> + >> +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; >> + int ret; >> + >> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); >> + if (!indio_dev) >> + return -ENOMEM; >> + >> + regmap = devm_regmap_init_i2c(client, &mmc35240_regmap_config); >> + if (IS_ERR(regmap)) { >> + dev_err(&client->dev, "regmap initialization failed\n"); >> + return PTR_ERR(regmap); >> + } >> + >> + data = iio_priv(indio_dev); >> + i2c_set_clientdata(client, indio_dev); >> + data->client = client; >> + data->regmap = regmap; >> + data->res = MMC35240_16_BITS_SLOW; >> + >> + mutex_init(&data->mutex); >> + >> + indio_dev->dev.parent = &client->dev; >> + indio_dev->info = &mmc35240_info; >> + indio_dev->name = MMC35240_DRV_NAME; >> + indio_dev->channels = mmc35240_channels; >> + indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels); >> + indio_dev->modes = INDIO_DIRECT_MODE; >> + >> + ret = mmc35240_init(data); >> + if (ret < 0) { >> + dev_err(&client->dev, "mmc35240 chip init failed\n"); >> + return ret; >> + } >> + return devm_iio_device_register(&client->dev, indio_dev); >> +} >> + >> +static int mmc35240_remove(struct i2c_client *client) >> +{ > > no need for this function (yet) So this means I can remove it from mmc35240_driver struct definition? Will do. > >> + return 0; >> +} >> + >> +static const struct i2c_device_id mmc35240_id[] = { >> + {"MMC35240", 0}, >> + {} >> +}; >> +MODULE_DEVICE_TABLE(i2c, mmc35240_id); >> + >> +static struct i2c_driver mmc35240_driver = { >> + .driver = { >> + .name = MMC35240_DRV_NAME, >> + }, >> + .probe = mmc35240_probe, >> + .remove = mmc35240_remove, >> + .id_table = mmc35240_id, >> +}; >> + >> +module_i2c_driver(mmc35240_driver); >> + >> +MODULE_AUTHOR("Daniel Baluta "); >> +MODULE_DESCRIPTION("MEMSIC MMC35240 magnetic sensor driver"); >> +MODULE_LICENSE("GPL v2"); >> > Thanks a lot Peter for your comments. I will leave this here for others to have a look and send v2 in few days. Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/