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iio: adc: mcp3911: add support for buffers 

Add support for buffers to make the driver fit for more use cases.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220815061625.35568-6-marcus.folkesson@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Marcus Folkesson 2022-08-15 08:16:21 +02:00 committed by Jonathan Cameron
parent 0e0a07adaf
commit 5db9f38d39
2 changed files with 97 additions and 8 deletions
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2
drivers/iio/adc/Kconfig
View File

@ -732,6 +732,8 @@ config MCP3422
config MCP3911
tristate "Microchip Technology MCP3911 driver"
depends on SPI
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
Say yes here to build support for Microchip Technology's MCP3911
analog to digital converter.

103
drivers/iio/adc/mcp3911.c
View File

@ -5,16 +5,25 @@
* Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
* Copyright (C) 2018 Kent Gustavsson <kent@minoris.se>
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/trigger.h>
#include <asm/unaligned.h>
#define MCP3911_REG_CHANNEL0 0x00
#define MCP3911_REG_CHANNEL1 0x03
#define MCP3911_REG_MOD 0x06
@ -22,6 +31,7 @@
#define MCP3911_REG_GAIN 0x09
#define MCP3911_REG_STATUSCOM 0x0a
#define MCP3911_STATUSCOM_READ GENMASK(7, 6)
#define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4)
#define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3)
#define MCP3911_STATUSCOM_EN_OFFCAL BIT(2)
@ -54,6 +64,13 @@ struct mcp3911 {
struct regulator *vref;
struct clk *clki;
u32 dev_addr;
struct {
u32 channels[MCP3911_NUM_CHANNELS];
s64 ts __aligned(8);
} scan;
u8 tx_buf __aligned(IIO_DMA_MINALIGN);
u8 rx_buf[MCP3911_NUM_CHANNELS * 3];
};
static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len)
@ -196,16 +213,66 @@ out:
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = idx, \
.scan_index = idx, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
BIT(IIO_CHAN_INFO_OFFSET) | \
BIT(IIO_CHAN_INFO_SCALE), \
.scan_type = { \
.sign = 's', \
.realbits = 24, \
.storagebits = 32, \
.endianness = IIO_BE, \
}, \
}
static const struct iio_chan_spec mcp3911_channels[] = {
MCP3911_CHAN(0),
MCP3911_CHAN(1),
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct mcp3911 *adc = iio_priv(indio_dev);
struct spi_transfer xfer[] = {
{
.tx_buf = &adc->tx_buf,
.len = 1,
}, {
.rx_buf = adc->rx_buf,
.len = sizeof(adc->rx_buf),
},
};
int scan_index;
int i = 0;
int ret;
mutex_lock(&adc->lock);
adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr);
ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer));
if (ret < 0) {
dev_warn(&adc->spi->dev,
"failed to get conversion data\n");
goto out;
}
for_each_set_bit(scan_index, indio_dev->active_scan_mask, indio_dev->masklength) {
const struct iio_chan_spec *scan_chan = &indio_dev->channels[scan_index];
adc->scan.channels[i] = get_unaligned_be24(&adc->rx_buf[scan_chan->channel * 3]);
i++;
}
iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
iio_get_time_ns(indio_dev));
out:
mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_info mcp3911_info = {
.read_raw = mcp3911_read_raw,
.write_raw = mcp3911_write_raw,
@ -214,7 +281,7 @@ static const struct iio_info mcp3911_info = {
static int mcp3911_config(struct mcp3911 *adc)
{
struct device *dev = &adc->spi->dev;
u32 configreg;
u32 regval;
int ret;
ret = device_property_read_u32(dev, "microchip,device-addr", &adc->dev_addr);
@ -233,29 +300,43 @@ static int mcp3911_config(struct mcp3911 *adc)
}
dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);
ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2);
ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &regval, 2);
if (ret)
return ret;
regval &= ~MCP3911_CONFIG_VREFEXT;
if (adc->vref) {
dev_dbg(&adc->spi->dev, "use external voltage reference\n");
configreg |= MCP3911_CONFIG_VREFEXT;
regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1);
} else {
dev_dbg(&adc->spi->dev,
"use internal voltage reference (1.2V)\n");
configreg &= ~MCP3911_CONFIG_VREFEXT;
regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 0);
}
regval &= ~MCP3911_CONFIG_CLKEXT;
if (adc->clki) {
dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");
configreg |= MCP3911_CONFIG_CLKEXT;
regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 1);
} else {
dev_dbg(&adc->spi->dev,
"use crystal oscillator as clocksource\n");
configreg &= ~MCP3911_CONFIG_CLKEXT;
regval |= FIELD_PREP(MCP3911_CONFIG_CLKEXT, 0);
}
return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
ret = mcp3911_write(adc, MCP3911_REG_CONFIG, regval, 2);
if (ret)
return ret;
ret = mcp3911_read(adc, MCP3911_REG_STATUSCOM, &regval, 2);
if (ret)
return ret;
/* Address counter incremented, cycle through register types */
regval &= ~MCP3911_STATUSCOM_READ;
regval |= FIELD_PREP(MCP3911_STATUSCOM_READ, 0x02);
return mcp3911_write(adc, MCP3911_REG_STATUSCOM, regval, 2);
}
static void mcp3911_cleanup_regulator(void *vref)
@ -324,6 +405,12 @@ static int mcp3911_probe(struct spi_device *spi)
mutex_init(&adc->lock);
ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
NULL,
mcp3911_trigger_handler, NULL);
if (ret)
return ret;
return devm_iio_device_register(&adc->spi->dev, indio_dev);
}