iio: adc: ltc2497: split protocol independent part in a separate module

This allows to share most of this driver for the ltc2496 driver added in
the next commit that is an SPI variant of the ltc2497. Initially I named
the generic part ltc249x, but wild card names are frowned upon, so the
generic part is called ltc2497-core even though it's not obvious that
this is then to be reused for the ltc2496 driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Uwe Kleine-König 2019-12-09 21:32:47 +01:00 committed by Jonathan Cameron
parent 59c3662b8f
commit 69548b7c2c
4 changed files with 288 additions and 209 deletions

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@ -51,7 +51,7 @@ obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
obj-$(CONFIG_LTC2471) += ltc2471.o
obj-$(CONFIG_LTC2485) += ltc2485.o
obj-$(CONFIG_LTC2497) += ltc2497.o
obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.o
obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX11100) += max11100.o
obj-$(CONFIG_MAX1118) += max1118.o

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@ -0,0 +1,243 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* ltc2497-core.c - Common code for Analog Devices/Linear Technology
* LTC2496 and LTC2497 ADCs
*
* Copyright (C) 2017 Analog Devices Inc.
*/
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include "ltc2497.h"
#define LTC2497_SGL BIT(4)
#define LTC2497_DIFF 0
#define LTC2497_SIGN BIT(3)
static int ltc2497core_wait_conv(struct ltc2497core_driverdata *ddata)
{
s64 time_elapsed;
time_elapsed = ktime_ms_delta(ktime_get(), ddata->time_prev);
if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
/* delay if conversion time not passed
* since last read or write
*/
if (msleep_interruptible(
LTC2497_CONVERSION_TIME_MS - time_elapsed))
return -ERESTARTSYS;
return 0;
}
if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
/* We're in automatic mode -
* so the last reading is still not outdated
*/
return 0;
}
return 1;
}
static int ltc2497core_read(struct ltc2497core_driverdata *ddata, u8 address, int *val)
{
int ret;
ret = ltc2497core_wait_conv(ddata);
if (ret < 0)
return ret;
if (ret || ddata->addr_prev != address) {
ret = ddata->result_and_measure(ddata, address, NULL);
if (ret < 0)
return ret;
ddata->addr_prev = address;
if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
return -ERESTARTSYS;
}
ret = ddata->result_and_measure(ddata, address, val);
if (ret < 0)
return ret;
ddata->time_prev = ktime_get();
return ret;
}
static int ltc2497core_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
ret = ltc2497core_read(ddata, chan->address, val);
mutex_unlock(&indio_dev->mlock);
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(ddata->ref);
if (ret < 0)
return ret;
*val = ret / 1000;
*val2 = 17;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
#define LTC2497_CHAN(_chan, _addr, _ds_name) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan), \
.address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.datasheet_name = (_ds_name), \
}
#define LTC2497_CHAN_DIFF(_chan, _addr) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
.channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
.address = (_addr | _chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.differential = 1, \
}
static const struct iio_chan_spec ltc2497core_channel[] = {
LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
};
static const struct iio_info ltc2497core_info = {
.read_raw = ltc2497core_read_raw,
};
int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev)
{
struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
int ret;
indio_dev->dev.parent = dev;
indio_dev->name = dev_name(dev);
indio_dev->info = &ltc2497core_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ltc2497core_channel;
indio_dev->num_channels = ARRAY_SIZE(ltc2497core_channel);
ret = ddata->result_and_measure(ddata, LTC2497_CONFIG_DEFAULT, NULL);
if (ret < 0)
return ret;
ddata->ref = devm_regulator_get(dev, "vref");
if (IS_ERR(ddata->ref)) {
if (PTR_ERR(ddata->ref) != -EPROBE_DEFER)
dev_err(dev, "Failed to get vref regulator: %pe\n",
ddata->ref);
return PTR_ERR(ddata->ref);
}
ret = regulator_enable(ddata->ref);
if (ret < 0) {
dev_err(dev, "Failed to enable vref regulator: %pe\n",
ERR_PTR(ret));
return ret;
}
if (dev->platform_data) {
struct iio_map *plat_data;
plat_data = (struct iio_map *)dev->platform_data;
ret = iio_map_array_register(indio_dev, plat_data);
if (ret) {
dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
goto err_regulator_disable;
}
}
ddata->addr_prev = LTC2497_CONFIG_DEFAULT;
ddata->time_prev = ktime_get();
ret = iio_device_register(indio_dev);
if (ret < 0)
goto err_array_unregister;
return 0;
err_array_unregister:
iio_map_array_unregister(indio_dev);
err_regulator_disable:
regulator_disable(ddata->ref);
return ret;
}
EXPORT_SYMBOL_NS(ltc2497core_probe, LTC2497);
void ltc2497core_remove(struct iio_dev *indio_dev)
{
struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_map_array_unregister(indio_dev);
regulator_disable(ddata->ref);
}
EXPORT_SYMBOL_NS(ltc2497core_remove, LTC2497);
MODULE_DESCRIPTION("common code for LTC2496/LTC2497 drivers");
MODULE_LICENSE("GPL v2");

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@ -7,27 +7,18 @@
* Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/sysfs.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#define LTC2497_ENABLE 0xA0
#define LTC2497_SGL BIT(4)
#define LTC2497_DIFF 0
#define LTC2497_SIGN BIT(3)
#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
#define LTC2497_CONVERSION_TIME_MS 150ULL
#include "ltc2497.h"
struct ltc2497_st {
struct ltc2497_driverdata {
/* this must be the first member */
struct ltc2497core_driverdata common_ddata;
struct i2c_client *client;
struct regulator *ref;
ktime_t time_prev;
u8 addr_prev;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
@ -35,232 +26,59 @@ struct ltc2497_st {
__be32 buf ____cacheline_aligned;
};
static int ltc2497_wait_conv(struct ltc2497_st *st)
static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,
u8 address, int *val)
{
s64 time_elapsed;
time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev);
if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
/* delay if conversion time not passed
* since last read or write
*/
if (msleep_interruptible(
LTC2497_CONVERSION_TIME_MS - time_elapsed))
return -ERESTARTSYS;
return 0;
}
if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
/* We're in automatic mode -
* so the last reading is stil not outdated
*/
return 0;
}
return 1;
}
static int ltc2497_read(struct ltc2497_st *st, u8 address, int *val)
{
struct i2c_client *client = st->client;
struct ltc2497_driverdata *st =
container_of(ddata, struct ltc2497_driverdata, common_ddata);
int ret;
ret = ltc2497_wait_conv(st);
if (ret < 0)
return ret;
if (ret || st->addr_prev != address) {
ret = i2c_smbus_write_byte(st->client,
LTC2497_ENABLE | address);
if (ret < 0)
if (val) {
ret = i2c_master_recv(st->client, (char *)&st->buf, 3);
if (ret < 0) {
dev_err(&st->client->dev, "i2c_master_recv failed\n");
return ret;
st->addr_prev = address;
if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
return -ERESTARTSYS;
}
ret = i2c_master_recv(client, (char *)&st->buf, 3);
if (ret < 0) {
dev_err(&client->dev, "i2c_master_recv failed\n");
return ret;
}
st->time_prev = ktime_get();
}
/* convert and shift the result,
* and finally convert from offset binary to signed integer
*/
*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
}
ret = i2c_smbus_write_byte(st->client,
LTC2497_ENABLE | address);
if (ret)
dev_err(&st->client->dev, "i2c transfer failed: %pe\n",
ERR_PTR(ret));
return ret;
}
static int ltc2497_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ltc2497_st *st = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
ret = ltc2497_read(st, chan->address, val);
mutex_unlock(&indio_dev->mlock);
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(st->ref);
if (ret < 0)
return ret;
*val = ret / 1000;
*val2 = 17;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
#define LTC2497_CHAN(_chan, _addr, _ds_name) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan), \
.address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.datasheet_name = (_ds_name), \
}
#define LTC2497_CHAN_DIFF(_chan, _addr) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
.channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
.address = (_addr | _chan), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.differential = 1, \
}
static const struct iio_chan_spec ltc2497_channel[] = {
LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
};
static const struct iio_info ltc2497_info = {
.read_raw = ltc2497_read_raw,
};
static int ltc2497_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct iio_dev *indio_dev;
struct ltc2497_st *st;
struct iio_map *plat_data;
int ret;
struct ltc2497_driverdata *st;
struct device *dev = &client->dev;
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(*st));
indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
st->client = client;
st->common_ddata.result_and_measure = ltc2497_result_and_measure;
indio_dev->dev.parent = &client->dev;
indio_dev->name = id->name;
indio_dev->info = &ltc2497_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = ltc2497_channel;
indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel);
st->ref = devm_regulator_get(&client->dev, "vref");
if (IS_ERR(st->ref))
return PTR_ERR(st->ref);
ret = regulator_enable(st->ref);
if (ret < 0)
return ret;
if (client->dev.platform_data) {
plat_data = ((struct iio_map *)client->dev.platform_data);
ret = iio_map_array_register(indio_dev, plat_data);
if (ret) {
dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
goto err_regulator_disable;
}
}
ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT);
if (ret < 0)
goto err_array_unregister;
st->addr_prev = LTC2497_CONFIG_DEFAULT;
st->time_prev = ktime_get();
ret = iio_device_register(indio_dev);
if (ret < 0)
goto err_array_unregister;
return 0;
err_array_unregister:
iio_map_array_unregister(indio_dev);
err_regulator_disable:
regulator_disable(st->ref);
return ret;
return ltc2497core_probe(dev, indio_dev);
}
static int ltc2497_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ltc2497_st *st = iio_priv(indio_dev);
iio_map_array_unregister(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(st->ref);
ltc2497core_remove(indio_dev);
return 0;
}

18
drivers/iio/adc/ltc2497.h Normal file
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@ -0,0 +1,18 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#define LTC2497_ENABLE 0xA0
#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
#define LTC2497_CONVERSION_TIME_MS 150ULL
struct ltc2497core_driverdata {
struct regulator *ref;
ktime_t time_prev;
u8 addr_prev;
int (*result_and_measure)(struct ltc2497core_driverdata *ddata,
u8 address, int *val);
};
int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev);
void ltc2497core_remove(struct iio_dev *indio_dev);
MODULE_IMPORT_NS(LTC2497);