On Fri, 3 Aug 2018 16:02:16 +0300 Stefan Popa <stefan.popa@xxxxxxxxxx> wrote: > This patch adds basic support for Analog Devices ADXL372 SPI-Bus > Three-Axis Digital Accelerometer. > > The device is probed and configured the with some initial default > values. With this basic driver, it is possible to read raw acceleration > data. > > Datasheet: > http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL372.pdf > > Signed-off-by: Stefan Popa <stefan.popa@xxxxxxxxxx> One really minor suggestion inline. I'd only bother if you are respinning for some other reason. I'll hold this one to wait for the rest of the series (some of which needs other peoples acks). Jonathan > --- > MAINTAINERS | 6 + > drivers/iio/accel/Kconfig | 11 + > drivers/iio/accel/Makefile | 1 + > drivers/iio/accel/adxl372.c | 530 ++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 548 insertions(+) > create mode 100644 drivers/iio/accel/adxl372.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 60b1028..2ba47bb 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -543,6 +543,12 @@ W: http://ez.analog.com/community/linux-device-drivers > S: Supported > F: drivers/input/misc/adxl34x.c > > +ADXL372 THREE-AXIS DIGITAL ACCELEROMETER DRIVER > +M: Stefan Popa <stefan.popa@xxxxxxxxxx> > +W: http://ez.analog.com/community/linux-device-drivers > +S: Supported > +F: drivers/iio/accel/adxl372.c > + > AF9013 MEDIA DRIVER > M: Antti Palosaari <crope@xxxxxx> > L: linux-media@xxxxxxxxxxxxxxx > diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig > index 62ae7e5..1b496ef 100644 > --- a/drivers/iio/accel/Kconfig > +++ b/drivers/iio/accel/Kconfig > @@ -60,6 +60,17 @@ config ADXL345_SPI > will be called adxl345_spi and you will also get adxl345_core > for the core module. > > +config ADXL372 > + tristate "Analog Devices ADXL372 3-Axis Accelerometer Driver" > + depends on SPI > + select IIO_BUFFER > + select IIO_TRIGGERED_BUFFER > + help > + Say yes here to add support for the Analog Devices ADXL372 triaxial > + acceleration sensor. > + To compile this driver as a module, choose M here: the > + module will be called adxl372. > + > config BMA180 > tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver" > depends on I2C > diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile > index 636d4d1..5758ffc 100644 > --- a/drivers/iio/accel/Makefile > +++ b/drivers/iio/accel/Makefile > @@ -9,6 +9,7 @@ obj-$(CONFIG_ADIS16209) += adis16209.o > obj-$(CONFIG_ADXL345) += adxl345_core.o > obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o > obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o > +obj-$(CONFIG_ADXL372) += adxl372.o > obj-$(CONFIG_BMA180) += bma180.o > obj-$(CONFIG_BMA220) += bma220_spi.o > obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o > diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c > new file mode 100644 > index 0000000..7d5092d > --- /dev/null > +++ b/drivers/iio/accel/adxl372.c > @@ -0,0 +1,530 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * ADXL372 3-Axis Digital Accelerometer SPI driver > + * > + * Copyright 2018 Analog Devices Inc. > + */ > + > +#include <linux/bitops.h> > +#include <linux/module.h> > +#include <linux/regmap.h> > +#include <linux/spi/spi.h> > + > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > + > +/* ADXL372 registers definition */ > +#define ADXL372_DEVID 0x00 > +#define ADXL372_DEVID_MST 0x01 > +#define ADXL372_PARTID 0x02 > +#define ADXL372_REVID 0x03 > +#define ADXL372_STATUS_1 0x04 > +#define ADXL372_STATUS_2 0x05 > +#define ADXL372_FIFO_ENTRIES_2 0x06 > +#define ADXL372_FIFO_ENTRIES_1 0x07 > +#define ADXL372_X_DATA_H 0x08 > +#define ADXL372_X_DATA_L 0x09 > +#define ADXL372_Y_DATA_H 0x0A > +#define ADXL372_Y_DATA_L 0x0B > +#define ADXL372_Z_DATA_H 0x0C > +#define ADXL372_Z_DATA_L 0x0D > +#define ADXL372_X_MAXPEAK_H 0x15 > +#define ADXL372_X_MAXPEAK_L 0x16 > +#define ADXL372_Y_MAXPEAK_H 0x17 > +#define ADXL372_Y_MAXPEAK_L 0x18 > +#define ADXL372_Z_MAXPEAK_H 0x19 > +#define ADXL372_Z_MAXPEAK_L 0x1A > +#define ADXL372_OFFSET_X 0x20 > +#define ADXL372_OFFSET_Y 0x21 > +#define ADXL372_OFFSET_Z 0x22 > +#define ADXL372_X_THRESH_ACT_H 0x23 > +#define ADXL372_X_THRESH_ACT_L 0x24 > +#define ADXL372_Y_THRESH_ACT_H 0x25 > +#define ADXL372_Y_THRESH_ACT_L 0x26 > +#define ADXL372_Z_THRESH_ACT_H 0x27 > +#define ADXL372_Z_THRESH_ACT_L 0x28 > +#define ADXL372_TIME_ACT 0x29 > +#define ADXL372_X_THRESH_INACT_H 0x2A > +#define ADXL372_X_THRESH_INACT_L 0x2B > +#define ADXL372_Y_THRESH_INACT_H 0x2C > +#define ADXL372_Y_THRESH_INACT_L 0x2D > +#define ADXL372_Z_THRESH_INACT_H 0x2E > +#define ADXL372_Z_THRESH_INACT_L 0x2F > +#define ADXL372_TIME_INACT_H 0x30 > +#define ADXL372_TIME_INACT_L 0x31 > +#define ADXL372_X_THRESH_ACT2_H 0x32 > +#define ADXL372_X_THRESH_ACT2_L 0x33 > +#define ADXL372_Y_THRESH_ACT2_H 0x34 > +#define ADXL372_Y_THRESH_ACT2_L 0x35 > +#define ADXL372_Z_THRESH_ACT2_H 0x36 > +#define ADXL372_Z_THRESH_ACT2_L 0x37 > +#define ADXL372_HPF 0x38 > +#define ADXL372_FIFO_SAMPLES 0x39 > +#define ADXL372_FIFO_CTL 0x3A > +#define ADXL372_INT1_MAP 0x3B > +#define ADXL372_INT2_MAP 0x3C > +#define ADXL372_TIMING 0x3D > +#define ADXL372_MEASURE 0x3E > +#define ADXL372_POWER_CTL 0x3F > +#define ADXL372_SELF_TEST 0x40 > +#define ADXL372_RESET 0x41 > +#define ADXL372_FIFO_DATA 0x42 > + > +#define ADXL372_DEVID_VAL 0xAD > +#define ADXL372_PARTID_VAL 0xFA > +#define ADXL372_RESET_CODE 0x52 > + > +/* ADXL372_POWER_CTL */ > +#define ADXL372_POWER_CTL_MODE_MSK GENMASK_ULL(1, 0) > +#define ADXL372_POWER_CTL_MODE(x) (((x) & 0x3) << 0) > + > +/* ADXL372_MEASURE */ > +#define ADXL372_MEASURE_LINKLOOP_MSK GENMASK_ULL(5, 4) > +#define ADXL372_MEASURE_LINKLOOP_MODE(x) (((x) & 0x3) << 4) > +#define ADXL372_MEASURE_BANDWIDTH_MSK GENMASK_ULL(2, 0) > +#define ADXL372_MEASURE_BANDWIDTH_MODE(x) (((x) & 0x7) << 0) > + > +/* ADXL372_TIMING */ > +#define ADXL372_TIMING_ODR_MSK GENMASK_ULL(7, 5) > +#define ADXL372_TIMING_ODR_MODE(x) (((x) & 0x7) << 5) > + > +/* ADXL372_FIFO_CTL */ > +#define ADXL372_FIFO_CTL_FORMAT_MSK GENMASK(5, 3) > +#define ADXL372_FIFO_CTL_FORMAT_MODE(x) (((x) & 0x7) << 3) > +#define ADXL372_FIFO_CTL_MODE_MSK GENMASK(2, 1) > +#define ADXL372_FIFO_CTL_MODE_MODE(x) (((x) & 0x3) << 1) > +#define ADXL372_FIFO_CTL_SAMPLES_MSK BIT(1) > +#define ADXL372_FIFO_CTL_SAMPLES_MODE(x) (((x) > 0xFF) ? 1 : 0) > + > +/* ADXL372_STATUS_1 */ > +#define ADXL372_STATUS_1_DATA_RDY(x) (((x) >> 0) & 0x1) > +#define ADXL372_STATUS_1_FIFO_RDY(x) (((x) >> 1) & 0x1) > +#define ADXL372_STATUS_1_FIFO_FULL(x) (((x) >> 2) & 0x1) > +#define ADXL372_STATUS_1_FIFO_OVR(x) (((x) >> 3) & 0x1) > +#define ADXL372_STATUS_1_USR_NVM_BUSY(x) (((x) >> 5) & 0x1) > +#define ADXL372_STATUS_1_AWAKE(x) (((x) >> 6) & 0x1) > +#define ADXL372_STATUS_1_ERR_USR_REGS(x) (((x) >> 7) & 0x1) > + > +/* ADXL372_INT1_MAP */ > +#define ADXL372_INT1_MAP_DATA_RDY_MSK BIT(0) > +#define ADXL372_INT1_MAP_DATA_RDY_MODE(x) (((x) & 0x1) << 0) > +#define ADXL372_INT1_MAP_FIFO_RDY_MSK BIT(1) > +#define ADXL372_INT1_MAP_FIFO_RDY_MODE(x) (((x) & 0x1) << 1) > +#define ADXL372_INT1_MAP_FIFO_FULL_MSK BIT(2) > +#define ADXL372_INT1_MAP_FIFO_FULL_MODE(x) (((x) & 0x1) << 2) > +#define ADXL372_INT1_MAP_FIFO_OVR_MSK BIT(3) > +#define ADXL372_INT1_MAP_FIFO_OVR_MODE(x) (((x) & 0x1) << 3) > +#define ADXL372_INT1_MAP_INACT_MSK BIT(4) > +#define ADXL372_INT1_MAP_INACT_MODE(x) (((x) & 0x1) << 4) > +#define ADXL372_INT1_MAP_ACT_MSK BIT(5) > +#define ADXL372_INT1_MAP_ACT_MODE(x) (((x) & 0x1) << 5) > +#define ADXL372_INT1_MAP_AWAKE_MSK BIT(6) > +#define ADXL372_INT1_MAP_AWAKE_MODE(x) (((x) & 0x1) << 6) > +#define ADXL372_INT1_MAP_LOW_MSK BIT(7) > +#define ADXL372_INT1_MAP_LOW_MODE(x) (((x) & 0x1) << 7) > + > +/* > + * At +/- 200g with 12-bit resolution, scale is computed as: > + * (200 + 200) * 9.81 / (2^12 - 1) = 0.958241 > + */ > +#define ADXL372_USCALE 958241 > + > +enum adxl372_op_mode { > + ADXL372_STANDBY, > + ADXL372_WAKE_UP, > + ADXL372_INSTANT_ON, > + ADXL372_FULL_BW_MEASUREMENT, > +}; > + > +enum adxl372_act_proc_mode { > + ADXL372_DEFAULT, > + ADXL372_LINKED, > + ADXL372_LOOPED, > +}; > + > +enum adxl372_th_activity { > + ADXL372_ACTIVITY, > + ADXL372_ACTIVITY2, > + ADXL372_INACTIVITY, > +}; > + > +enum adxl372_odr { > + ADXL372_ODR_400HZ, > + ADXL372_ODR_800HZ, > + ADXL372_ODR_1600HZ, > + ADXL372_ODR_3200HZ, > + ADXL372_ODR_6400HZ, > +}; > + > +enum adxl372_bandwidth { > + ADXL372_BW_200HZ, > + ADXL372_BW_400HZ, > + ADXL372_BW_800HZ, > + ADXL372_BW_1600HZ, > + ADXL372_BW_3200HZ, > +}; > + > +#define ADXL372_ACCEL_CHANNEL(index, reg, axis) { \ > + .type = IIO_ACCEL, \ > + .address = reg, \ > + .modified = 1, \ > + .channel2 = IIO_MOD_##axis, \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > +} > + > +static const struct iio_chan_spec adxl372_channels[] = { > + ADXL372_ACCEL_CHANNEL(0, ADXL372_X_DATA_H, X), > + ADXL372_ACCEL_CHANNEL(1, ADXL372_Y_DATA_H, Y), > + ADXL372_ACCEL_CHANNEL(2, ADXL372_Z_DATA_H, Z), > +}; > + > +struct adxl372_state { > + struct spi_device *spi; > + struct regmap *regmap; > + enum adxl372_op_mode op_mode; > + enum adxl372_act_proc_mode act_proc_mode; > + enum adxl372_odr odr; > + enum adxl372_bandwidth bw; > + u32 act_time_ms; > + u32 inact_time_ms; > +}; > + > +static int adxl372_read_axis(struct adxl372_state *st, u8 addr) > +{ > + __be16 regval; > + int ret; > + > + ret = regmap_bulk_read(st->regmap, addr, ®val, sizeof(regval)); > + if (ret < 0) > + return ret; > + > + return be16_to_cpu(regval); > +} > + > +static int adxl372_set_op_mode(struct adxl372_state *st, > + enum adxl372_op_mode op_mode) > +{ > + int ret; > + > + ret = regmap_update_bits(st->regmap, ADXL372_POWER_CTL, > + ADXL372_POWER_CTL_MODE_MSK, > + ADXL372_POWER_CTL_MODE(op_mode)); > + if (ret < 0) > + return ret; > + > + st->op_mode = op_mode; > + > + return ret; > +} > + > +static int adxl372_set_odr(struct adxl372_state *st, > + enum adxl372_odr odr) > +{ > + int ret; > + > + ret = regmap_update_bits(st->regmap, ADXL372_TIMING, > + ADXL372_TIMING_ODR_MSK, > + ADXL372_TIMING_ODR_MODE(odr)); > + if (ret < 0) > + return ret; > + > + st->odr = odr; > + > + return ret; > +} > + > +static int adxl372_set_bandwidth(struct adxl372_state *st, > + enum adxl372_bandwidth bw) > +{ > + int ret; > + > + ret = regmap_update_bits(st->regmap, ADXL372_MEASURE, > + ADXL372_MEASURE_BANDWIDTH_MSK, > + ADXL372_MEASURE_BANDWIDTH_MODE(bw)); > + if (ret < 0) > + return ret; > + > + st->bw = bw; > + > + return ret; > +} > + > +static int adxl372_set_act_proc_mode(struct adxl372_state *st, > + enum adxl372_act_proc_mode mode) > +{ > + int ret; > + > + ret = regmap_update_bits(st->regmap, > + ADXL372_MEASURE, > + ADXL372_MEASURE_LINKLOOP_MSK, > + ADXL372_MEASURE_LINKLOOP_MODE(mode)); > + if (ret < 0) > + return ret; > + > + st->act_proc_mode = mode; > + > + return ret; > +} > + > +static int adxl372_set_activity_threshold(struct adxl372_state *st, > + enum adxl372_th_activity act, > + bool ref_en, bool enable, > + unsigned int threshold) > +{ > + unsigned char buf[6]; > + unsigned char th_reg_high_val, th_reg_low_val, th_reg_high_addr; > + > + /* scale factor is 100 mg/code */ > + th_reg_high_val = (threshold / 100) >> 3; > + th_reg_low_val = ((threshold / 100) << 5) | (ref_en << 1) | enable; > + > + switch (act) { > + case ADXL372_ACTIVITY: > + th_reg_high_addr = ADXL372_X_THRESH_ACT_H; > + break; > + case ADXL372_ACTIVITY2: > + th_reg_high_addr = ADXL372_X_THRESH_ACT2_H; > + break; > + case ADXL372_INACTIVITY: > + th_reg_high_addr = ADXL372_X_THRESH_INACT_H; Really minor but perhaps a constant lookup table would be more elegant? > + break; > + } > + > + buf[0] = th_reg_high_val; > + buf[1] = th_reg_low_val; > + buf[2] = th_reg_high_val; > + buf[3] = th_reg_low_val; > + buf[4] = th_reg_high_val; > + buf[5] = th_reg_low_val; > + > + return regmap_bulk_write(st->regmap, th_reg_high_addr, > + buf, ARRAY_SIZE(buf)); > +} > + > +static int adxl372_set_activity_time_ms(struct adxl372_state *st, > + unsigned int act_time_ms) > +{ > + unsigned int reg_val, scale_factor; > + int ret; > + > + /* > + * 3.3 ms per code is the scale factor of the TIME_ACT register for > + * ODR = 6400 Hz. It is 6.6 ms per code for ODR = 3200 Hz and below. > + */ > + if (st->odr == ADXL372_ODR_6400HZ) > + scale_factor = 3300; > + else > + scale_factor = 6600; > + > + reg_val = DIV_ROUND_CLOSEST(act_time_ms * 1000, scale_factor); > + > + /* TIME_ACT register is 8 bits wide */ > + if (reg_val > 0xFF) > + reg_val = 0xFF; > + > + ret = regmap_write(st->regmap, ADXL372_TIME_ACT, reg_val); > + if (ret < 0) > + return ret; > + > + st->act_time_ms = act_time_ms; > + > + return ret; > +} > + > +static int adxl372_set_inactivity_time_ms(struct adxl372_state *st, > + unsigned int inact_time_ms) > +{ > + unsigned int reg_val_h, reg_val_l, res, scale_factor; > + int ret; > + > + /* > + * 13 ms per code is the scale factor of the TIME_INACT register for > + * ODR = 6400 Hz. It is 26 ms per code for ODR = 3200 Hz and below. > + */ > + if (st->odr == ADXL372_ODR_6400HZ) > + scale_factor = 13; > + else > + scale_factor = 26; > + > + res = DIV_ROUND_CLOSEST(inact_time_ms, scale_factor); > + reg_val_h = (res >> 8) & 0xFF; > + reg_val_l = res & 0xFF; > + > + ret = regmap_write(st->regmap, ADXL372_TIME_INACT_H, reg_val_h); > + if (ret < 0) > + return ret; > + > + ret = regmap_write(st->regmap, ADXL372_TIME_INACT_L, reg_val_l); > + if (ret < 0) > + return ret; > + > + st->inact_time_ms = inact_time_ms; > + > + return ret; > +} > + > +static int adxl372_setup(struct adxl372_state *st) > +{ > + unsigned int regval; > + int ret; > + > + ret = regmap_read(st->regmap, ADXL372_DEVID, ®val); > + if (ret < 0) > + return ret; > + > + if (regval != ADXL372_DEVID_VAL) { > + dev_err(&st->spi->dev, "Invalid chip id %x\n", regval); > + return -ENODEV; > + } > + > + ret = adxl372_set_op_mode(st, ADXL372_STANDBY); > + if (ret < 0) > + return ret; > + > + /* Set threshold for activity detection to 1g */ > + ret = adxl372_set_activity_threshold(st, ADXL372_ACTIVITY, > + true, true, 1000); > + if (ret < 0) > + return ret; > + > + /* Set threshold for inactivity detection to 100mg */ > + ret = adxl372_set_activity_threshold(st, ADXL372_INACTIVITY, > + true, true, 100); > + if (ret < 0) > + return ret; > + > + /* Set activity processing in Looped mode */ > + ret = adxl372_set_act_proc_mode(st, ADXL372_LOOPED); > + if (ret < 0) > + return ret; > + > + ret = adxl372_set_odr(st, ADXL372_ODR_6400HZ); > + if (ret < 0) > + return ret; > + > + ret = adxl372_set_bandwidth(st, ADXL372_BW_3200HZ); > + if (ret < 0) > + return ret; > + > + /* Set activity timer to 1ms */ > + ret = adxl372_set_activity_time_ms(st, 1); > + if (ret < 0) > + return ret; > + > + /* Set inactivity timer to 10s */ > + ret = adxl372_set_inactivity_time_ms(st, 10000); > + if (ret < 0) > + return ret; > + > + /* Set the mode of operation to full bandwidth measurement mode */ > + return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT); > +} > + > +static int adxl372_reg_access(struct iio_dev *indio_dev, > + unsigned int reg, > + unsigned int writeval, > + unsigned int *readval) > +{ > + struct adxl372_state *st = iio_priv(indio_dev); > + > + if (readval) > + return regmap_read(st->regmap, reg, readval); > + else > + return regmap_write(st->regmap, reg, writeval); > +} > + > +static int adxl372_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long info) > +{ > + struct adxl372_state *st = iio_priv(indio_dev); > + int ret; > + > + switch (info) { > + case IIO_CHAN_INFO_RAW: > + ret = adxl372_read_axis(st, chan->address); > + if (ret < 0) > + return ret; > + > + *val = sign_extend32(ret >> chan->scan_type.shift, > + chan->scan_type.realbits - 1); > + return IIO_VAL_INT; > + case IIO_CHAN_INFO_SCALE: > + *val = 0; > + *val2 = ADXL372_USCALE; > + return IIO_VAL_INT_PLUS_MICRO; > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_info adxl372_info = { > + .read_raw = adxl372_read_raw, > + .debugfs_reg_access = &adxl372_reg_access, > +}; > + > +static const struct regmap_config adxl372_spi_regmap_config = { > + .reg_bits = 7, > + .pad_bits = 1, > + .val_bits = 8, > + .read_flag_mask = BIT(0), > +}; > + > +static int adxl372_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct adxl372_state *st; > + struct regmap *regmap; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); > + if (!indio_dev) > + return -ENOMEM; > + > + st = iio_priv(indio_dev); > + spi_set_drvdata(spi, indio_dev); > + > + st->spi = spi; > + > + regmap = devm_regmap_init_spi(spi, &adxl372_spi_regmap_config); > + if (IS_ERR(regmap)) > + return PTR_ERR(regmap); > + > + st->regmap = regmap; > + > + indio_dev->channels = adxl372_channels; > + indio_dev->num_channels = ARRAY_SIZE(adxl372_channels); > + indio_dev->dev.parent = &spi->dev; > + indio_dev->name = spi_get_device_id(spi)->name; > + indio_dev->info = &adxl372_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + > + ret = adxl372_setup(st); > + if (ret < 0) { > + dev_err(&st->spi->dev, "ADXL372 setup failed\n"); > + return ret; > + } > + > + return devm_iio_device_register(&st->spi->dev, indio_dev); > +} > + > +static const struct spi_device_id adxl372_id[] = { > + { "adxl372", 0 }, > + {} > +}; > +MODULE_DEVICE_TABLE(spi, adxl372_id); > + > +static struct spi_driver adxl372_driver = { > + .driver = { > + .name = KBUILD_MODNAME, > + }, > + .probe = adxl372_probe, > + .id_table = adxl372_id, > +}; > + > +module_spi_driver(adxl372_driver); > + > +MODULE_AUTHOR("Stefan Popa <stefan.popa@xxxxxxxxxx>"); > +MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer driver"); > +MODULE_LICENSE("GPL v2"); -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
