mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-22 10:31:08 +00:00
Code Issues Releases Wiki Activity
linux-stable/drivers/iio/adc/mcp320x.c
Uwe Kleine-König a0386bba70
spi: make remove callback a void function 
The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09 13:00:45 +00:00

530 lines
14 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
* Copyright (C) 2014 Rose Technology
* Allan Bendorff Jensen <abj@rosetechnology.dk>
* Soren Andersen <san@rosetechnology.dk>
*
* Driver for following ADC chips from Microchip Technology's:
* 10 Bit converter
* MCP3001
* MCP3002
* MCP3004
* MCP3008
* ------------
* 12 bit converter
* MCP3201
* MCP3202
* MCP3204
* MCP3208
* ------------
* 13 bit converter
* MCP3301
* ------------
* 22 bit converter
* MCP3550
* MCP3551
* MCP3553
*
* Datasheet can be found here:
* https://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
* https://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
* https://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
* http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
* http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
* http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
* https://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
* http://ww1.microchip.com/downloads/en/DeviceDoc/21950D.pdf mcp3550/1/3
*/
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>
enum {
mcp3001,
mcp3002,
mcp3004,
mcp3008,
mcp3201,
mcp3202,
mcp3204,
mcp3208,
mcp3301,
mcp3550_50,
mcp3550_60,
mcp3551,
mcp3553,
};
struct mcp320x_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
unsigned int resolution;
unsigned int conv_time; /* usec */
};
/**
* struct mcp320x - Microchip SPI ADC instance
* @spi: SPI slave (parent of the IIO device)
* @msg: SPI message to select a channel and receive a value from the ADC
* @transfer: SPI transfers used by @msg
* @start_conv_msg: SPI message to start a conversion by briefly asserting CS
* @start_conv_transfer: SPI transfer used by @start_conv_msg
* @reg: regulator generating Vref
* @lock: protects read sequences
* @chip_info: ADC properties
* @tx_buf: buffer for @transfer[0] (not used on single-channel converters)
* @rx_buf: buffer for @transfer[1]
*/
struct mcp320x {
struct spi_device *spi;
struct spi_message msg;
struct spi_transfer transfer[2];
struct spi_message start_conv_msg;
struct spi_transfer start_conv_transfer;
struct regulator *reg;
struct mutex lock;
const struct mcp320x_chip_info *chip_info;
u8 tx_buf ____cacheline_aligned;
u8 rx_buf[4];
};
static int mcp320x_channel_to_tx_data(int device_index,
const unsigned int channel, bool differential)
{
int start_bit = 1;
switch (device_index) {
case mcp3002:
case mcp3202:
return ((start_bit << 4) | (!differential << 3) |
(channel << 2));
case mcp3004:
case mcp3204:
case mcp3008:
case mcp3208:
return ((start_bit << 6) | (!differential << 5) |
(channel << 2));
default:
return -EINVAL;
}
}
static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
bool differential, int device_index, int *val)
{
int ret;
if (adc->chip_info->conv_time) {
ret = spi_sync(adc->spi, &adc->start_conv_msg);
if (ret < 0)
return ret;
usleep_range(adc->chip_info->conv_time,
adc->chip_info->conv_time + 100);
}
memset(&adc->rx_buf, 0, sizeof(adc->rx_buf));
if (adc->chip_info->num_channels > 1)
adc->tx_buf = mcp320x_channel_to_tx_data(device_index, channel,
differential);
ret = spi_sync(adc->spi, &adc->msg);
if (ret < 0)
return ret;
switch (device_index) {
case mcp3001:
*val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
return 0;
case mcp3002:
case mcp3004:
case mcp3008:
*val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
return 0;
case mcp3201:
*val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
return 0;
case mcp3202:
case mcp3204:
case mcp3208:
*val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
return 0;
case mcp3301:
*val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
| adc->rx_buf[1], 12);
return 0;
case mcp3550_50:
case mcp3550_60:
case mcp3551:
case mcp3553: {
u32 raw = be32_to_cpup((__be32 *)adc->rx_buf);
if (!(adc->spi->mode & SPI_CPOL))
raw <<= 1; /* strip Data Ready bit in SPI mode 0,0 */
/*
* If the input is within -vref and vref, bit 21 is the sign.
* Up to 12% overrange or underrange are allowed, in which case
* bit 23 is the sign and bit 0 to 21 is the value.
*/
raw >>= 8;
if (raw & BIT(22) && raw & BIT(23))
return -EIO; /* cannot have overrange AND underrange */
else if (raw & BIT(22))
raw &= ~BIT(22); /* overrange */
else if (raw & BIT(23) || raw & BIT(21))
raw |= GENMASK(31, 22); /* underrange or negative */
*val = (s32)raw;
return 0;
}
default:
return -EINVAL;
}
}
static int mcp320x_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct mcp320x *adc = iio_priv(indio_dev);
int ret = -EINVAL;
int device_index = 0;
mutex_lock(&adc->lock);
device_index = spi_get_device_id(adc->spi)->driver_data;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = mcp320x_adc_conversion(adc, channel->address,
channel->differential, device_index, val);
if (ret < 0)
goto out;
ret = IIO_VAL_INT;
break;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->reg);
if (ret < 0)
goto out;
/* convert regulator output voltage to mV */
*val = ret / 1000;
*val2 = adc->chip_info->resolution;
ret = IIO_VAL_FRACTIONAL_LOG2;
break;
}
out:
mutex_unlock(&adc->lock);
return ret;
}
#define MCP320X_VOLTAGE_CHANNEL(num) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (num), \
.address = (num), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
#define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (chan1), \
.channel2 = (chan2), \
.address = (chan1), \
.differential = 1, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
static const struct iio_chan_spec mcp3201_channels[] = {
MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
};
static const struct iio_chan_spec mcp3202_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
};
static const struct iio_chan_spec mcp3204_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL(2),
MCP320X_VOLTAGE_CHANNEL(3),
MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
};
static const struct iio_chan_spec mcp3208_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL(2),
MCP320X_VOLTAGE_CHANNEL(3),
MCP320X_VOLTAGE_CHANNEL(4),
MCP320X_VOLTAGE_CHANNEL(5),
MCP320X_VOLTAGE_CHANNEL(6),
MCP320X_VOLTAGE_CHANNEL(7),
MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
};
static const struct iio_info mcp320x_info = {
.read_raw = mcp320x_read_raw,
};
static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
[mcp3001] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 10
},
[mcp3002] = {
.channels = mcp3202_channels,
.num_channels = ARRAY_SIZE(mcp3202_channels),
.resolution = 10
},
[mcp3004] = {
.channels = mcp3204_channels,
.num_channels = ARRAY_SIZE(mcp3204_channels),
.resolution = 10
},
[mcp3008] = {
.channels = mcp3208_channels,
.num_channels = ARRAY_SIZE(mcp3208_channels),
.resolution = 10
},
[mcp3201] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 12
},
[mcp3202] = {
.channels = mcp3202_channels,
.num_channels = ARRAY_SIZE(mcp3202_channels),
.resolution = 12
},
[mcp3204] = {
.channels = mcp3204_channels,
.num_channels = ARRAY_SIZE(mcp3204_channels),
.resolution = 12
},
[mcp3208] = {
.channels = mcp3208_channels,
.num_channels = ARRAY_SIZE(mcp3208_channels),
.resolution = 12
},
[mcp3301] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 13
},
[mcp3550_50] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 21,
/* 2% max deviation + 144 clock periods to exit shutdown */
.conv_time = 80000 * 1.02 + 144000 / 102.4,
},
[mcp3550_60] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 21,
.conv_time = 66670 * 1.02 + 144000 / 122.88,
},
[mcp3551] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 21,
.conv_time = 73100 * 1.02 + 144000 / 112.64,
},
[mcp3553] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 21,
.conv_time = 16670 * 1.02 + 144000 / 122.88,
},
};
static int mcp320x_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct mcp320x *adc;
const struct mcp320x_chip_info *chip_info;
int ret, device_index;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
adc->spi = spi;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &mcp320x_info;
spi_set_drvdata(spi, indio_dev);
device_index = spi_get_device_id(spi)->driver_data;
chip_info = &mcp320x_chip_infos[device_index];
indio_dev->channels = chip_info->channels;
indio_dev->num_channels = chip_info->num_channels;
adc->chip_info = chip_info;
adc->transfer[0].tx_buf = &adc->tx_buf;
adc->transfer[0].len = sizeof(adc->tx_buf);
adc->transfer[1].rx_buf = adc->rx_buf;
adc->transfer[1].len = DIV_ROUND_UP(chip_info->resolution, 8);
if (chip_info->num_channels == 1)
/* single-channel converters are rx only (no MOSI pin) */
spi_message_init_with_transfers(&adc->msg,
&adc->transfer[1], 1);
else
spi_message_init_with_transfers(&adc->msg, adc->transfer,
ARRAY_SIZE(adc->transfer));
switch (device_index) {
case mcp3550_50:
case mcp3550_60:
case mcp3551:
case mcp3553:
/* rx len increases from 24 to 25 bit in SPI mode 0,0 */
if (!(spi->mode & SPI_CPOL))
adc->transfer[1].len++;
/* conversions are started by asserting CS pin for 8 usec */
adc->start_conv_transfer.delay.value = 8;
adc->start_conv_transfer.delay.unit = SPI_DELAY_UNIT_USECS;
spi_message_init_with_transfers(&adc->start_conv_msg,
&adc->start_conv_transfer, 1);
/*
* If CS was previously kept low (continuous conversion mode)
* and then changed to high, the chip is in shutdown.
* Sometimes it fails to wake from shutdown and clocks out
* only 0xffffff. The magic sequence of performing two
* conversions without delay between them resets the chip
* and ensures all subsequent conversions succeed.
*/
mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
}
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
return PTR_ERR(adc->reg);
ret = regulator_enable(adc->reg);
if (ret < 0)
return ret;
mutex_init(&adc->lock);
ret = iio_device_register(indio_dev);
if (ret < 0)
goto reg_disable;
return 0;
reg_disable:
regulator_disable(adc->reg);
return ret;
}
static void mcp320x_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct mcp320x *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(adc->reg);
}
static const struct of_device_id mcp320x_dt_ids[] = {
/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
{ .compatible = "mcp3001" },
{ .compatible = "mcp3002" },
{ .compatible = "mcp3004" },
{ .compatible = "mcp3008" },
{ .compatible = "mcp3201" },
{ .compatible = "mcp3202" },
{ .compatible = "mcp3204" },
{ .compatible = "mcp3208" },
{ .compatible = "mcp3301" },
{ .compatible = "microchip,mcp3001" },
{ .compatible = "microchip,mcp3002" },
{ .compatible = "microchip,mcp3004" },
{ .compatible = "microchip,mcp3008" },
{ .compatible = "microchip,mcp3201" },
{ .compatible = "microchip,mcp3202" },
{ .compatible = "microchip,mcp3204" },
{ .compatible = "microchip,mcp3208" },
{ .compatible = "microchip,mcp3301" },
{ .compatible = "microchip,mcp3550-50" },
{ .compatible = "microchip,mcp3550-60" },
{ .compatible = "microchip,mcp3551" },
{ .compatible = "microchip,mcp3553" },
{ }
};
MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
static const struct spi_device_id mcp320x_id[] = {
{ "mcp3001", mcp3001 },
{ "mcp3002", mcp3002 },
{ "mcp3004", mcp3004 },
{ "mcp3008", mcp3008 },
{ "mcp3201", mcp3201 },
{ "mcp3202", mcp3202 },
{ "mcp3204", mcp3204 },
{ "mcp3208", mcp3208 },
{ "mcp3301", mcp3301 },
{ "mcp3550-50", mcp3550_50 },
{ "mcp3550-60", mcp3550_60 },
{ "mcp3551", mcp3551 },
{ "mcp3553", mcp3553 },
{ }
};
MODULE_DEVICE_TABLE(spi, mcp320x_id);
static struct spi_driver mcp320x_driver = {
.driver = {
.name = "mcp320x",
.of_match_table = mcp320x_dt_ids,
},
.probe = mcp320x_probe,
.remove = mcp320x_remove,
.id_table = mcp320x_id,
};
module_spi_driver(mcp320x_driver);
MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3");
MODULE_LICENSE("GPL v2");
Reference in a new issue View git blame Copy permalink