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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-05 14:50:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-05 14:50:51 -0700 |
commit | 41844e36206be90cd4d962ea49b0abc3612a99d0 (patch) | |
tree | ce0b3a3403bc6abdb28f52779d0d7b57a51a5c86 /drivers/iio/adc/ltc2485.c | |
parent | 5691f0e9a3e7855832d5fd094801bf600347c2d0 (diff) | |
parent | fc1e2c8ea85e109acf09e74789e9b852f6eed251 (diff) | |
download | op-kernel-dev-41844e36206be90cd4d962ea49b0abc3612a99d0.zip op-kernel-dev-41844e36206be90cd4d962ea49b0abc3612a99d0.tar.gz |
Merge tag 'staging-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging and IIO updates from Greg KH:
"Here is the big staging and IIO driver pull request for 4.9-rc1.
There are a lot of patches in here, the majority due to the
drivers/staging/greybus/ subsystem being merged in with full
development history that went back a few years, in order to preserve
the work that those developers did over time.
Lots and lots of tiny cleanups happened in the tree as well, due to
the Outreachy application process and lots of other developers showing
up for the first time to clean code up. Along with those changes, we
deleted a wireless driver, and added a raspberrypi driver (currently
marked broken), and lots of new iio drivers.
Overall the tree still shrunk with more lines removed than added,
about 10 thousand lines removed in total. Full details are in the very
long shortlog below.
All of this has been in the linux-next tree with no issues. There will
be some merge problems with other subsystem trees, but those are all
minor problems and shouldn't be hard to work out when they happen
(MAINTAINERS and some lustre build problems with the IB tree)"
And furter from me asking for clarification about greybus:
"Right now there is a phone from Motorola shipping with this code (a
slightly older version, but the same tree), so even though Ara is not
alive in the same form, the functionality is happening. We are working
with the developers of that phone to merge the newer stuff in with
their fork so they can use the upstream version in future versions of
their phone product line.
Toshiba has at least one chip shipping in their catalog that
needs/uses this protocol over a Unipro link, and rumor has it that
there might be more in the future.
There are also other users of the greybus protocols, there is a talk
next week at ELC that shows how it is being used across a network
connection to control a device, and previous ELC talks have showed the
protocol stack being used over USB to drive embedded Linux boards.
I've also talked to some people who are starting to work to add a host
controller driver to control arduinos as the greybus PHY protocols are
very useful to control a serial/i2c/spio/whatever device across a
random physical link, as it is a way to have a self-describing device
be attached to a host without needing manual configuration.
So yes, people are using it, and there is still the chance that it
will show up in a phone/laptop/tablet/whatever from Google in the
future as well, the tech isn't dead, even if the original large phone
project happens to be"
* tag 'staging-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (3703 commits)
Staging: fbtft: Fix bug in fbtft-core
staging: rtl8188eu: fix double unlock error in rtw_resume_process()
staging:r8188eu: remove GEN_MLME_EXT_HANDLER macro
staging:r8188eu: remove GEN_DRV_CMD_HANDLER macro
staging:r8188eu: remove GEN_EVT_CODE macro
staging:r8188eu: remove GEN_CMD_CODE macro
staging:r8188eu: remove pkt_newalloc member of the recv_buf structure
staging:r8188eu: remove rtw_handle_dualmac declaration
staging:r8188eu: remove (RGTRY|BSSID)_(OFT|SZ) macros
staging:r8188eu: change rtl8188e_process_phy_info function argument type
Staging: fsl-mc: Remove blank lines
Staging: fsl-mc: Fix unaligned * in block comments
Staging: comedi: Align the * in block comments
Staging : ks7010 : Fix block comments warninig
Staging: vt6655: Remove explicit NULL comparison using Coccinelle
staging: rtl8188eu: core: rtw_xmit: Use macros instead of constants
staging: rtl8188eu: core: rtw_xmit: Move constant of the right side
staging: dgnc: Fix lines longer than 80 characters
Staging: dgnc: constify attribute_group structures
Staging: most: hdm-dim2: constify attribute_group structures
...
Diffstat (limited to 'drivers/iio/adc/ltc2485.c')
-rw-r--r-- | drivers/iio/adc/ltc2485.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/iio/adc/ltc2485.c b/drivers/iio/adc/ltc2485.c new file mode 100644 index 0000000..eab91f12 --- /dev/null +++ b/drivers/iio/adc/ltc2485.c @@ -0,0 +1,148 @@ +/* + * ltc2485.c - Driver for Linear Technology LTC2485 ADC + * + * Copyright (C) 2016 Alison Schofield <amsfield22@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Datasheet: http://cds.linear.com/docs/en/datasheet/2485fd.pdf + */ + +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/module.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +/* Power-on configuration: rejects both 50/60Hz, operates at 1x speed */ +#define LTC2485_CONFIG_DEFAULT 0 + +struct ltc2485_data { + struct i2c_client *client; + ktime_t time_prev; /* last conversion */ +}; + +static void ltc2485_wait_conv(struct ltc2485_data *data) +{ + const unsigned int conv_time = 147; /* conversion time ms */ + unsigned int time_elapsed; + + /* delay if conversion time not passed since last read or write */ + time_elapsed = ktime_ms_delta(ktime_get(), data->time_prev); + + if (time_elapsed < conv_time) + msleep(conv_time - time_elapsed); +} + +static int ltc2485_read(struct ltc2485_data *data, int *val) +{ + struct i2c_client *client = data->client; + __be32 buf = 0; + int ret; + + ltc2485_wait_conv(data); + + ret = i2c_master_recv(client, (char *)&buf, 4); + if (ret < 0) { + dev_err(&client->dev, "i2c_master_recv failed\n"); + return ret; + } + data->time_prev = ktime_get(); + *val = sign_extend32(be32_to_cpu(buf) >> 6, 24); + + return ret; +} + +static int ltc2485_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ltc2485_data *data = iio_priv(indio_dev); + int ret; + + if (mask == IIO_CHAN_INFO_RAW) { + ret = ltc2485_read(data, val); + if (ret < 0) + return ret; + + return IIO_VAL_INT; + + } else if (mask == IIO_CHAN_INFO_SCALE) { + *val = 5000; /* on board vref millivolts */ + *val2 = 25; /* 25 (24 + sign) data bits */ + return IIO_VAL_FRACTIONAL_LOG2; + + } else { + return -EINVAL; + } +} + +static const struct iio_chan_spec ltc2485_channel[] = { + { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) + }, +}; + +static const struct iio_info ltc2485_info = { + .read_raw = ltc2485_read_raw, + .driver_module = THIS_MODULE, +}; + +static int ltc2485_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct iio_dev *indio_dev; + struct ltc2485_data *data; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | + I2C_FUNC_SMBUS_WRITE_BYTE)) + return -EOPNOTSUPP; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + + indio_dev->dev.parent = &client->dev; + indio_dev->name = id->name; + indio_dev->info = <c2485_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ltc2485_channel; + indio_dev->num_channels = ARRAY_SIZE(ltc2485_channel); + + ret = i2c_smbus_write_byte(data->client, LTC2485_CONFIG_DEFAULT); + if (ret < 0) + return ret; + + data->time_prev = ktime_get(); + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct i2c_device_id ltc2485_id[] = { + { "ltc2485", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ltc2485_id); + +static struct i2c_driver ltc2485_driver = { + .driver = { + .name = "ltc2485", + }, + .probe = ltc2485_probe, + .id_table = ltc2485_id, +}; +module_i2c_driver(ltc2485_driver); + +MODULE_AUTHOR("Alison Schofield <amsfield22@gmail.com>"); +MODULE_DESCRIPTION("Linear Technology LTC2485 ADC driver"); +MODULE_LICENSE("GPL v2"); |