On 21/11/14 18:45, Gwendal Grignou wrote: > Add 2 new definition entries to support ak0991x compass. > Add a more advanced function to check we are dealing with the > expected device. > Remove standalone driver for ak09911. > > Tested-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> > Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx> Applied the equivalent changes with hartmut's alignment stuff as well for patch 2. > --- > drivers/iio/magnetometer/Kconfig | 15 +- > drivers/iio/magnetometer/Makefile | 1 - > drivers/iio/magnetometer/ak09911.c | 326 ------------------------------------- > drivers/iio/magnetometer/ak8975.c | 195 ++++++++++++++++++++-- > 4 files changed, 184 insertions(+), 353 deletions(-) > delete mode 100644 drivers/iio/magnetometer/ak09911.c > > diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig > index b2dba9e..4c7a4c5 100644 > --- a/drivers/iio/magnetometer/Kconfig > +++ b/drivers/iio/magnetometer/Kconfig > @@ -6,26 +6,21 @@ > menu "Magnetometer sensors" > > config AK8975 > - tristate "Asahi Kasei AK8975 3-Axis Magnetometer" > + tristate "Asahi Kasei AK 3-Axis Magnetometer" > depends on I2C > depends on GPIOLIB > help > - Say yes here to build support for Asahi Kasei AK8975 3-Axis > - Magnetometer. This driver can also support AK8963, if i2c > - device name is identified as ak8963. > + Say yes here to build support for Asahi Kasei AK8975, AK8963, > + AK09911 or AK09912 3-Axis Magnetometer. > > To compile this driver as a module, choose M here: the module > will be called ak8975. > > config AK09911 > tristate "Asahi Kasei AK09911 3-axis Compass" > - depends on I2C > + select AK8975 > help > - Say yes here to build support for Asahi Kasei AK09911 3-Axis > - Magnetometer. > - > - To compile this driver as a module, choose M here: the module > - will be called ak09911. > + Deprecated: AK09911 is now supported by AK8975 driver. > > config MAG3110 > tristate "Freescale MAG3110 3-Axis Magnetometer" > diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile > index b91315e..0f5d3c9 100644 > --- a/drivers/iio/magnetometer/Makefile > +++ b/drivers/iio/magnetometer/Makefile > @@ -3,7 +3,6 @@ > # > > # When adding new entries keep the list in alphabetical order > -obj-$(CONFIG_AK09911) += ak09911.o > obj-$(CONFIG_AK8975) += ak8975.o > obj-$(CONFIG_MAG3110) += mag3110.o > obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o > diff --git a/drivers/iio/magnetometer/ak09911.c b/drivers/iio/magnetometer/ak09911.c > deleted file mode 100644 > index b2bc942..0000000 > --- a/drivers/iio/magnetometer/ak09911.c > +++ /dev/null > @@ -1,326 +0,0 @@ > -/* > - * AK09911 3-axis compass driver > - * Copyright (c) 2014, Intel Corporation. > - * > - * This program is free software; you can redistribute it and/or modify it > - * under the terms and conditions of the GNU General Public License, > - * version 2, as published by the Free Software Foundation. > - * > - * This program is distributed in the hope it will be useful, but WITHOUT > - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > - * more details. > - */ > - > -#include <linux/kernel.h> > -#include <linux/module.h> > -#include <linux/init.h> > -#include <linux/types.h> > -#include <linux/slab.h> > -#include <linux/delay.h> > -#include <linux/i2c.h> > -#include <linux/acpi.h> > -#include <linux/iio/iio.h> > - > -#define AK09911_REG_WIA1 0x00 > -#define AK09911_REG_WIA2 0x01 > -#define AK09911_WIA1_VALUE 0x48 > -#define AK09911_WIA2_VALUE 0x05 > - > -#define AK09911_REG_ST1 0x10 > -#define AK09911_REG_HXL 0x11 > -#define AK09911_REG_HXH 0x12 > -#define AK09911_REG_HYL 0x13 > -#define AK09911_REG_HYH 0x14 > -#define AK09911_REG_HZL 0x15 > -#define AK09911_REG_HZH 0x16 > - > -#define AK09911_REG_ASAX 0x60 > -#define AK09911_REG_ASAY 0x61 > -#define AK09911_REG_ASAZ 0x62 > - > -#define AK09911_REG_CNTL1 0x30 > -#define AK09911_REG_CNTL2 0x31 > -#define AK09911_REG_CNTL3 0x32 > - > -#define AK09911_MODE_SNG_MEASURE 0x01 > -#define AK09911_MODE_SELF_TEST 0x10 > -#define AK09911_MODE_FUSE_ACCESS 0x1F > -#define AK09911_MODE_POWERDOWN 0x00 > -#define AK09911_RESET_DATA 0x01 > - > -#define AK09911_REG_CNTL1 0x30 > -#define AK09911_REG_CNTL2 0x31 > -#define AK09911_REG_CNTL3 0x32 > - > -#define AK09911_RAW_TO_GAUSS(asa) ((((asa) + 128) * 6000) / 256) > - > -#define AK09911_MAX_CONVERSION_TIMEOUT_MS 500 > -#define AK09911_CONVERSION_DONE_POLL_TIME_MS 10 > - > -struct ak09911_data { > - struct i2c_client *client; > - struct mutex lock; > - u8 asa[3]; > - long raw_to_gauss[3]; > -}; > - > -static const int ak09911_index_to_reg[] = { > - AK09911_REG_HXL, AK09911_REG_HYL, AK09911_REG_HZL, > -}; > - > -static int ak09911_set_mode(struct i2c_client *client, u8 mode) > -{ > - int ret; > - > - switch (mode) { > - case AK09911_MODE_SNG_MEASURE: > - case AK09911_MODE_SELF_TEST: > - case AK09911_MODE_FUSE_ACCESS: > - case AK09911_MODE_POWERDOWN: > - ret = i2c_smbus_write_byte_data(client, > - AK09911_REG_CNTL2, mode); > - if (ret < 0) { > - dev_err(&client->dev, "set_mode error\n"); > - return ret; > - } > - /* After mode change wait atleast 100us */ > - usleep_range(100, 500); > - break; > - default: > - dev_err(&client->dev, > - "%s: Unknown mode(%d).", __func__, mode); > - return -EINVAL; > - } > - > - return ret; > -} > - > -/* Get Sensitivity Adjustment value */ > -static int ak09911_get_asa(struct i2c_client *client) > -{ > - struct iio_dev *indio_dev = i2c_get_clientdata(client); > - struct ak09911_data *data = iio_priv(indio_dev); > - int ret; > - > - ret = ak09911_set_mode(client, AK09911_MODE_FUSE_ACCESS); > - if (ret < 0) > - return ret; > - > - /* Get asa data and store in the device data. */ > - ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_ASAX, > - 3, data->asa); > - if (ret < 0) { > - dev_err(&client->dev, "Not able to read asa data\n"); > - return ret; > - } > - > - ret = ak09911_set_mode(client, AK09911_MODE_POWERDOWN); > - if (ret < 0) > - return ret; > - > - data->raw_to_gauss[0] = AK09911_RAW_TO_GAUSS(data->asa[0]); > - data->raw_to_gauss[1] = AK09911_RAW_TO_GAUSS(data->asa[1]); > - data->raw_to_gauss[2] = AK09911_RAW_TO_GAUSS(data->asa[2]); > - > - return 0; > -} > - > -static int ak09911_verify_chip_id(struct i2c_client *client) > -{ > - u8 wia_val[2]; > - int ret; > - > - ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_WIA1, > - 2, wia_val); > - if (ret < 0) { > - dev_err(&client->dev, "Error reading WIA\n"); > - return ret; > - } > - > - dev_dbg(&client->dev, "WIA %02x %02x\n", wia_val[0], wia_val[1]); > - > - if (wia_val[0] != AK09911_WIA1_VALUE || > - wia_val[1] != AK09911_WIA2_VALUE) { > - dev_err(&client->dev, "Device ak09911 not found\n"); > - return -ENODEV; > - } > - > - return 0; > -} > - > -static int wait_conversion_complete_polled(struct ak09911_data *data) > -{ > - struct i2c_client *client = data->client; > - u8 read_status; > - u32 timeout_ms = AK09911_MAX_CONVERSION_TIMEOUT_MS; > - int ret; > - > - /* Wait for the conversion to complete. */ > - while (timeout_ms) { > - msleep_interruptible(AK09911_CONVERSION_DONE_POLL_TIME_MS); > - ret = i2c_smbus_read_byte_data(client, AK09911_REG_ST1); > - if (ret < 0) { > - dev_err(&client->dev, "Error in reading ST1\n"); > - return ret; > - } > - read_status = ret & 0x01; > - if (read_status) > - break; > - timeout_ms -= AK09911_CONVERSION_DONE_POLL_TIME_MS; > - } > - if (!timeout_ms) { > - dev_err(&client->dev, "Conversion timeout happened\n"); > - return -EIO; > - } > - > - return read_status; > -} > - > -static int ak09911_read_axis(struct iio_dev *indio_dev, int index, int *val) > -{ > - struct ak09911_data *data = iio_priv(indio_dev); > - struct i2c_client *client = data->client; > - int ret; > - > - mutex_lock(&data->lock); > - > - ret = ak09911_set_mode(client, AK09911_MODE_SNG_MEASURE); > - if (ret < 0) > - goto fn_exit; > - > - ret = wait_conversion_complete_polled(data); > - if (ret < 0) > - goto fn_exit; > - > - /* Read data */ > - ret = i2c_smbus_read_word_data(client, ak09911_index_to_reg[index]); > - if (ret < 0) { > - dev_err(&client->dev, "Read axis data fails\n"); > - goto fn_exit; > - } > - > - mutex_unlock(&data->lock); > - > - /* Clamp to valid range. */ > - *val = sign_extend32(clamp_t(s16, ret, -8192, 8191), 13); > - > - return IIO_VAL_INT; > - > -fn_exit: > - mutex_unlock(&data->lock); > - > - return ret; > -} > - > -static int ak09911_read_raw(struct iio_dev *indio_dev, > - struct iio_chan_spec const *chan, > - int *val, int *val2, > - long mask) > -{ > - struct ak09911_data *data = iio_priv(indio_dev); > - > - switch (mask) { > - case IIO_CHAN_INFO_RAW: > - return ak09911_read_axis(indio_dev, chan->address, val); > - case IIO_CHAN_INFO_SCALE: > - *val = 0; > - *val2 = data->raw_to_gauss[chan->address]; > - return IIO_VAL_INT_PLUS_MICRO; > - } > - > - return -EINVAL; > -} > - > -#define AK09911_CHANNEL(axis, index) \ > - { \ > - .type = IIO_MAGN, \ > - .modified = 1, \ > - .channel2 = IIO_MOD_##axis, \ > - .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ > - BIT(IIO_CHAN_INFO_SCALE), \ > - .address = index, \ > - } > - > -static const struct iio_chan_spec ak09911_channels[] = { > - AK09911_CHANNEL(X, 0), AK09911_CHANNEL(Y, 1), AK09911_CHANNEL(Z, 2), > -}; > - > -static const struct iio_info ak09911_info = { > - .read_raw = &ak09911_read_raw, > - .driver_module = THIS_MODULE, > -}; > - > -static const struct acpi_device_id ak_acpi_match[] = { > - {"AK009911", 0}, > - { }, > -}; > -MODULE_DEVICE_TABLE(acpi, ak_acpi_match); > - > -static int ak09911_probe(struct i2c_client *client, > - const struct i2c_device_id *id) > -{ > - struct iio_dev *indio_dev; > - struct ak09911_data *data; > - const char *name; > - int ret; > - > - ret = ak09911_verify_chip_id(client); > - if (ret) { > - dev_err(&client->dev, "AK00911 not detected\n"); > - return -ENODEV; > - } > - > - indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > - if (indio_dev == NULL) > - return -ENOMEM; > - > - data = iio_priv(indio_dev); > - i2c_set_clientdata(client, indio_dev); > - > - data->client = client; > - mutex_init(&data->lock); > - > - ret = ak09911_get_asa(client); > - if (ret) > - return ret; > - > - if (id) > - name = id->name; > - else if (ACPI_HANDLE(&client->dev)) > - name = dev_name(&client->dev); > - else > - return -ENODEV; > - > - dev_dbg(&client->dev, "Asahi compass chip %s\n", name); > - > - indio_dev->dev.parent = &client->dev; > - indio_dev->channels = ak09911_channels; > - indio_dev->num_channels = ARRAY_SIZE(ak09911_channels); > - indio_dev->info = &ak09911_info; > - indio_dev->modes = INDIO_DIRECT_MODE; > - indio_dev->name = name; > - > - return devm_iio_device_register(&client->dev, indio_dev); > -} > - > -static const struct i2c_device_id ak09911_id[] = { > - {"ak09911", 0}, > - {} > -}; > - > -MODULE_DEVICE_TABLE(i2c, ak09911_id); > - > -static struct i2c_driver ak09911_driver = { > - .driver = { > - .name = "ak09911", > - .acpi_match_table = ACPI_PTR(ak_acpi_match), > - }, > - .probe = ak09911_probe, > - .id_table = ak09911_id, > -}; > -module_i2c_driver(ak09911_driver); > - > -MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>"); > -MODULE_LICENSE("GPL v2"); > -MODULE_DESCRIPTION("AK09911 Compass driver"); > diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c > index 58c9a78..55d4732 100644 > --- a/drivers/iio/magnetometer/ak8975.c > +++ b/drivers/iio/magnetometer/ak8975.c > @@ -81,6 +81,58 @@ > #define AK8975_MAX_REGS AK8975_REG_ASAZ > > /* > + * AK09912 Register definitions > + */ > +#define AK09912_REG_WIA1 0x00 > +#define AK09912_REG_WIA2 0x01 > +#define AK09912_DEVICE_ID 0x04 > +#define AK09911_DEVICE_ID 0x05 > + > +#define AK09911_REG_INFO1 0x02 > +#define AK09911_REG_INFO2 0x03 > + > +#define AK09912_REG_ST1 0x10 > + > +#define AK09912_REG_ST1_DRDY_SHIFT 0 > +#define AK09912_REG_ST1_DRDY_MASK (1 << AK09912_REG_ST1_DRDY_SHIFT) > + > +#define AK09912_REG_HXL 0x11 > +#define AK09912_REG_HXH 0x12 > +#define AK09912_REG_HYL 0x13 > +#define AK09912_REG_HYH 0x14 > +#define AK09912_REG_HZL 0x15 > +#define AK09912_REG_HZH 0x16 > +#define AK09912_REG_TMPS 0x17 > + > +#define AK09912_REG_ST2 0x18 > +#define AK09912_REG_ST2_HOFL_SHIFT 3 > +#define AK09912_REG_ST2_HOFL_MASK (1 << AK09912_REG_ST2_HOFL_SHIFT) > + > +#define AK09912_REG_CNTL1 0x30 > + > +#define AK09912_REG_CNTL2 0x31 > +#define AK09912_REG_CNTL_MODE_POWER_DOWN 0x00 > +#define AK09912_REG_CNTL_MODE_ONCE 0x01 > +#define AK09912_REG_CNTL_MODE_SELF_TEST 0x10 > +#define AK09912_REG_CNTL_MODE_FUSE_ROM 0x1F > +#define AK09912_REG_CNTL2_MODE_SHIFT 0 > +#define AK09912_REG_CNTL2_MODE_MASK (0x1F << AK09912_REG_CNTL2_MODE_SHIFT) > + > +#define AK09912_REG_CNTL3 0x32 > + > +#define AK09912_REG_TS1 0x33 > +#define AK09912_REG_TS2 0x34 > +#define AK09912_REG_TS3 0x35 > +#define AK09912_REG_I2CDIS 0x36 > +#define AK09912_REG_TS4 0x37 > + > +#define AK09912_REG_ASAX 0x60 > +#define AK09912_REG_ASAY 0x61 > +#define AK09912_REG_ASAZ 0x62 > + > +#define AK09912_MAX_REGS AK09912_REG_ASAZ > + > +/* > * Miscellaneous values. > */ > #define AK8975_MAX_CONVERSION_TIMEOUT 500 > @@ -130,22 +182,37 @@ long ak8975_raw_to_gauss(u16 data) > } > > /* > - * For AK8963, same calculation, but the device is less sensitive: > + * For AK8963 and AK09911, same calculation, but the device is less sensitive: > * > * H is in the range of +-8190. The magnetometer has a range of > * +-4912uT. To go from the raw value to uT is: > * > * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10. > */ > -long ak8963_raw_to_gauss(u16 data) > +long ak8963_09911_raw_to_gauss(u16 data) > { > return (((long)data + 128) * 6000) / 256; > } > > +/* > + * For AK09912, same calculation, except the device is more sensitive: > + * > + * H is in the range of -32752 to 32752. The magnetometer has a range of > + * +-4912uT. To go from the raw value to uT is: > + * > + * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10. > + */ > +long ak09912_raw_to_gauss(u16 data) > +{ > + return (((long)data + 128) * 1500) / 256; > +} > + > /* Compatible Asahi Kasei Compass parts */ > enum asahi_compass_chipset { > AK8975, > AK8963, > + AK09911, > + AK09912, > AK_MAX_TYPE > }; > > @@ -210,7 +277,7 @@ struct ak_def { > }, > { > .type = AK8963, > - .raw_to_gauss = ak8963_raw_to_gauss, > + .raw_to_gauss = ak8963_09911_raw_to_gauss, > .range = 8190, > .ctrl_regs = { > AK8975_REG_ST1, > @@ -233,6 +300,56 @@ struct ak_def { > AK8975_REG_HYL, > AK8975_REG_HZL}, > }, > + { > + .type = AK09911, > + .raw_to_gauss = ak8963_09911_raw_to_gauss, > + .range = 8192, > + .ctrl_regs = { > + AK09912_REG_ST1, > + AK09912_REG_ST2, > + AK09912_REG_CNTL2, > + AK09912_REG_ASAX, > + AK09912_MAX_REGS}, > + .ctrl_masks = { > + AK09912_REG_ST1_DRDY_MASK, > + AK09912_REG_ST2_HOFL_MASK, > + 0, > + AK09912_REG_CNTL2_MODE_MASK}, > + .ctrl_modes = { > + AK09912_REG_CNTL_MODE_POWER_DOWN, > + AK09912_REG_CNTL_MODE_ONCE, > + AK09912_REG_CNTL_MODE_SELF_TEST, > + AK09912_REG_CNTL_MODE_FUSE_ROM}, > + .data_regs = { > + AK09912_REG_HXL, > + AK09912_REG_HYL, > + AK09912_REG_HZL}, > + }, > + { > + .type = AK09912, > + .raw_to_gauss = ak09912_raw_to_gauss, > + .range = 32752, > + .ctrl_regs = { > + AK09912_REG_ST1, > + AK09912_REG_ST2, > + AK09912_REG_CNTL2, > + AK09912_REG_ASAX, > + AK09912_MAX_REGS}, > + .ctrl_masks = { > + AK09912_REG_ST1_DRDY_MASK, > + AK09912_REG_ST2_HOFL_MASK, > + 0, > + AK09912_REG_CNTL2_MODE_MASK}, > + .ctrl_modes = { > + AK09912_REG_CNTL_MODE_POWER_DOWN, > + AK09912_REG_CNTL_MODE_ONCE, > + AK09912_REG_CNTL_MODE_SELF_TEST, > + AK09912_REG_CNTL_MODE_FUSE_ROM}, > + .data_regs = { > + AK09912_REG_HXL, > + AK09912_REG_HYL, > + AK09912_REG_HZL}, > + } > }; > > /* > @@ -253,6 +370,52 @@ struct ak8975_data { > }; > > /* > + * Return 0 if the i2c device is the one we expect. > + * return a negative error number otherwise > + */ > +static int ak8975_who_i_am(struct i2c_client *client, > + enum asahi_compass_chipset type) > +{ > + u8 wia_val[2]; > + int ret; > + > + /* > + * Signature for each device: > + * Device | WIA1 | WIA2 > + * AK09912 | DEVICE_ID | AK09912_DEVICE_ID > + * AK09911 | DEVICE_ID | AK09911_DEVICE_ID > + * AK8975 | DEVICE_ID | NA > + * AK8963 | DEVICE_ID | NA > + */ > + ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1, > + 2, wia_val); > + if (ret < 0) { > + dev_err(&client->dev, "Error reading WIA\n"); > + return ret; > + } > + > + if (wia_val[0] != AK8975_DEVICE_ID) > + return -ENODEV; > + > + switch (type) { > + case AK8975: > + case AK8963: > + return 0; > + case AK09911: > + if (wia_val[1] == AK09911_DEVICE_ID) > + return 0; > + break; > + case AK09912: > + if (wia_val[1] == AK09912_DEVICE_ID) > + return 0; > + break; > + default: > + dev_err(&client->dev, "Type %d unknown\n", type); > + } > + return -ENODEV; > +} > + > +/* > * Helper function to write to CNTL register. > */ > static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode) > @@ -327,21 +490,8 @@ static int ak8975_setup(struct i2c_client *client) > { > struct iio_dev *indio_dev = i2c_get_clientdata(client); > struct ak8975_data *data = iio_priv(indio_dev); > - u8 device_id; > int ret; > > - /* Confirm that the device we're talking to is really an AK8975. */ > - ret = i2c_smbus_read_byte_data(client, AK8975_REG_WIA); > - if (ret < 0) { > - dev_err(&client->dev, "Error reading WIA\n"); > - return ret; > - } > - device_id = ret; > - if (device_id != AK8975_DEVICE_ID) { > - dev_err(&client->dev, "Device ak8975 not found\n"); > - return -ENODEV; > - } > - > /* Write the fused rom access mode. */ > ret = ak8975_set_mode(data, FUSE_ROM); > if (ret < 0) { > @@ -552,6 +702,8 @@ static const struct acpi_device_id ak_acpi_match[] = { > {"AK8975", AK8975}, > {"AK8963", AK8963}, > {"INVN6500", AK8963}, > + {"AK09911", AK09911}, > + {"AK09912", AK09912}, > { }, > }; > MODULE_DEVICE_TABLE(acpi, ak_acpi_match); > @@ -631,6 +783,11 @@ static int ak8975_probe(struct i2c_client *client, > } > > data->def = &ak_def_array[chipset]; > + err = ak8975_who_i_am(client, data->def->type); > + if (err < 0) { > + dev_err(&client->dev, "Unexpected device\n"); > + return err; > + } > dev_dbg(&client->dev, "Asahi compass chip %s\n", name); > > /* Perform some basic start-of-day setup of the device. */ > @@ -653,6 +810,8 @@ static int ak8975_probe(struct i2c_client *client, > static const struct i2c_device_id ak8975_id[] = { > {"ak8975", AK8975}, > {"ak8963", AK8963}, > + {"ak09911", AK09911}, > + {"ak09912", AK09912}, > {} > }; > > @@ -663,6 +822,10 @@ static const struct of_device_id ak8975_of_match[] = { > { .compatible = "ak8975", }, > { .compatible = "asahi-kasei,ak8963", }, > { .compatible = "ak8963", }, > + { .compatible = "asahi-kasei,ak09911", }, > + { .compatible = "ak09911", }, > + { .compatible = "asahi-kasei,ak09912", }, > + { .compatible = "ak09912", }, > {} > }; > MODULE_DEVICE_TABLE(of, ak8975_of_match); > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html