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iio: adc: tlc4541: add support for TI tlc4541 adc

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This adds TI's tlc4541 16-bit ADC driver. Which is a single channel
ADC. Supports raw and trigger buffer access.
Also supports the tlc3541 14-bit device, which has not been tested.
Implementation of the tlc3541 is fairly straight forward thou.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
tirimbino
Phil Reid 8 years ago committed by Jonathan Cameron
parent 0dbe71c274
commit ac2bec9d58
4 changed files with 287 additions and 14 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 12
      drivers/iio/adc/Kconfig
  2. 1
      drivers/iio/adc/Makefile
  3. 17
      drivers/iio/adc/max11100.c
  4. 271
      drivers/iio/adc/ti-tlc4541.c

12
drivers/iio/adc/Kconfig
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@ -612,6 +612,18 @@ config TI_AM335X_ADC
To compile this driver as a module, choose M here: the module will be
called ti_am335x_adc.
config TI_TLC4541
tristate "Texas Instruments TLC4541 ADC driver"
depends on SPI
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say yes here to build support for Texas Instruments TLC4541 / TLC3541
ADC chips.
This driver can also be built as a module. If so, the module will be
called ti-tlc4541.
config TWL4030_MADC
tristate "TWL4030 MADC (Monitoring A/D Converter)"
depends on TWL4030_CORE

1
drivers/iio/adc/Makefile
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@ -56,6 +56,7 @@ obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
obj-$(CONFIG_VF610_ADC) += vf610_adc.o

17
drivers/iio/adc/max11100.c
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@ -30,7 +30,6 @@
#define MAX11100_LSB_DIV (1 << 16)
struct max11100_state {
const struct max11100_chip_desc *desc;
struct regulator *vref_reg;
struct spi_device *spi;
@ -49,14 +48,6 @@ static struct iio_chan_spec max11100_channels[] = {
},
};
static struct max11100_chip_desc {
unsigned int num_chan;
const struct iio_chan_spec *channels;
} max11100_desc = {
.num_chan = ARRAY_SIZE(max11100_channels),
.channels = max11100_channels,
};
static int max11100_read_single(struct iio_dev *indio_dev, int *val)
{
int ret;
@ -127,15 +118,14 @@ static int max11100_probe(struct spi_device *spi)
state = iio_priv(indio_dev);
state->spi = spi;
state->desc = &max11100_desc;
indio_dev->dev.parent = &spi->dev;
indio_dev->dev.of_node = spi->dev.of_node;
indio_dev->name = "max11100";
indio_dev->info = &max11100_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = state->desc->channels;
indio_dev->num_channels = state->desc->num_chan;
indio_dev->channels = max11100_channels,
indio_dev->num_channels = ARRAY_SIZE(max11100_channels),
state->vref_reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(state->vref_reg))
@ -162,9 +152,8 @@ static int max11100_remove(struct spi_device *spi)
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct max11100_state *state = iio_priv(indio_dev);
regulator_disable(state->vref_reg);
iio_device_unregister(indio_dev);
regulator_disable(state->vref_reg);
return 0;
}

271
drivers/iio/adc/ti-tlc4541.c
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@ -0,0 +1,271 @@
/*
* TI tlc4541 ADC Driver
*
* Copyright (C) 2017 Phil Reid
*
* Datasheets can be found here:
* http://www.ti.com/lit/gpn/tlc3541
* http://www.ti.com/lit/gpn/tlc4541
*
* 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.
*
* The tlc4541 requires 24 clock cycles to start a transfer.
* Conversion then takes 2.94us to complete before data is ready
* Data is returned MSB first.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
struct tlc4541_state {
struct spi_device *spi;
struct regulator *reg;
struct spi_transfer scan_single_xfer[3];
struct spi_message scan_single_msg;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
* 2 bytes data + 6 bytes padding + 8 bytes timestamp when
* call iio_push_to_buffers_with_timestamp.
*/
__be16 rx_buf[8] ____cacheline_aligned;
};
struct tlc4541_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
};
enum tlc4541_id {
TLC3541,
TLC4541,
};
#define TLC4541_V_CHAN(bits, bitshift) { \
.type = IIO_VOLTAGE, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.scan_type = { \
.sign = 'u', \
.realbits = (bits), \
.storagebits = 16, \
.shift = (bitshift), \
.endianness = IIO_BE, \
}, \
}
#define DECLARE_TLC4541_CHANNELS(name, bits, bitshift) \
const struct iio_chan_spec name ## _channels[] = { \
TLC4541_V_CHAN(bits, bitshift), \
IIO_CHAN_SOFT_TIMESTAMP(1), \
}
static DECLARE_TLC4541_CHANNELS(tlc3541, 14, 2);
static DECLARE_TLC4541_CHANNELS(tlc4541, 16, 0);
static const struct tlc4541_chip_info tlc4541_chip_info[] = {
[TLC3541] = {
.channels = tlc3541_channels,
.num_channels = ARRAY_SIZE(tlc3541_channels),
},
[TLC4541] = {
.channels = tlc4541_channels,
.num_channels = ARRAY_SIZE(tlc4541_channels),
},
};
static irqreturn_t tlc4541_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct tlc4541_state *st = iio_priv(indio_dev);
int ret;
ret = spi_sync(st->spi, &st->scan_single_msg);
if (ret < 0)
goto done;
iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
iio_get_time_ns(indio_dev));
done:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int tlc4541_get_range(struct tlc4541_state *st)
{
int vref;
vref = regulator_get_voltage(st->reg);
if (vref < 0)
return vref;
vref /= 1000;
return vref;
}
static int tlc4541_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret = 0;
struct tlc4541_state *st = iio_priv(indio_dev);
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
ret = spi_sync(st->spi, &st->scan_single_msg);
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
*val = be16_to_cpu(st->rx_buf[0]);
*val = *val >> chan->scan_type.shift;
*val &= GENMASK(chan->scan_type.realbits - 1, 0);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = tlc4541_get_range(st);
if (ret < 0)
return ret;
*val = ret;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static const struct iio_info tlc4541_info = {
.read_raw = &tlc4541_read_raw,
.driver_module = THIS_MODULE,
};
static int tlc4541_probe(struct spi_device *spi)
{
struct tlc4541_state *st;
struct iio_dev *indio_dev;
const struct tlc4541_chip_info *info;
int ret;
int8_t device_init = 0;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (indio_dev == NULL)
return -ENOMEM;
st = iio_priv(indio_dev);
spi_set_drvdata(spi, indio_dev);
st->spi = spi;
info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data];
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->dev.parent = &spi->dev;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = info->channels;
indio_dev->num_channels = info->num_channels;
indio_dev->info = &tlc4541_info;
/* perform reset */
spi_write(spi, &device_init, 1);
/* Setup default message */
st->scan_single_xfer[0].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[0].len = 3;
st->scan_single_xfer[1].delay_usecs = 3;
st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
st->scan_single_xfer[2].len = 2;
spi_message_init_with_transfers(&st->scan_single_msg,
st->scan_single_xfer, 3);
st->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = iio_triggered_buffer_setup(indio_dev, NULL,
&tlc4541_trigger_handler, NULL);
if (ret)
goto error_disable_reg;
ret = iio_device_register(indio_dev);
if (ret)
goto error_cleanup_buffer;
return 0;
error_cleanup_buffer:
iio_triggered_buffer_cleanup(indio_dev);
error_disable_reg:
regulator_disable(st->reg);
return ret;
}
static int tlc4541_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct tlc4541_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
regulator_disable(st->reg);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id tlc4541_dt_ids[] = {
{ .compatible = "ti,tlc3541", },
{ .compatible = "ti,tlc4541", },
{}
};
MODULE_DEVICE_TABLE(of, tlc4541_dt_ids);
#endif
static const struct spi_device_id tlc4541_id[] = {
{"tlc3541", TLC3541},
{"tlc4541", TLC4541},
{}
};
MODULE_DEVICE_TABLE(spi, tlc4541_id);
static struct spi_driver tlc4541_driver = {
.driver = {
.name = "tlc4541",
.of_match_table = of_match_ptr(tlc4541_dt_ids),
},
.probe = tlc4541_probe,
.remove = tlc4541_remove,
.id_table = tlc4541_id,
};
module_spi_driver(tlc4541_driver);
MODULE_AUTHOR("Phil Reid <preid@electromag.com.au>");
MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC");
MODULE_LICENSE("GPL v2");
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