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// SPDX-License-Identifier: GPL-2.0-only
/*
* STMicroelectronics sensors spi library driver
*
* Copyright 2012-2013 STMicroelectronics Inc.
*
* Denis Ciocca <denis.ciocca@st.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/iio/iio.h>
#include <linux/iio/common/st_sensors_spi.h>
#define ST_SENSORS_SPI_MULTIREAD 0xc0
#define ST_SENSORS_SPI_READ 0x80
static unsigned int st_sensors_spi_get_irq(struct iio_dev *indio_dev)
{
struct st_sensor_data *sdata = iio_priv(indio_dev);
return to_spi_device(sdata->dev)->irq;
}
static int st_sensors_spi_read(struct st_sensor_transfer_buffer *tb,
struct device *dev, u8 reg_addr, int len, u8 *data, bool multiread_bit)
{
int err;
struct spi_transfer xfers[] = {
{
.tx_buf = tb->tx_buf,
.bits_per_word = 8,
.len = 1,
},
{
.rx_buf = tb->rx_buf,
.bits_per_word = 8,
.len = len,
}
};
mutex_lock(&tb->buf_lock);
if ((multiread_bit) && (len > 1))
tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
else
tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
err = spi_sync_transfer(to_spi_device(dev), xfers, ARRAY_SIZE(xfers));
if (err)
goto acc_spi_read_error;
memcpy(data, tb->rx_buf, len);
mutex_unlock(&tb->buf_lock);
return len;
acc_spi_read_error:
mutex_unlock(&tb->buf_lock);
return err;
}
static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
struct device *dev, u8 reg_addr, u8 *res_byte)
{
return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
}
static int st_sensors_spi_read_multiple_byte(
struct st_sensor_transfer_buffer *tb, struct device *dev,
u8 reg_addr, int len, u8 *data, bool multiread_bit)
{
return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
}
static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
struct device *dev, u8 reg_addr, u8 data)
{
int err;
struct spi_transfer xfers = {
.tx_buf = tb->tx_buf,
.bits_per_word = 8,
.len = 2,
};
mutex_lock(&tb->buf_lock);
tb->tx_buf[0] = reg_addr;
tb->tx_buf[1] = data;
err = spi_sync_transfer(to_spi_device(dev), &xfers, 1);
mutex_unlock(&tb->buf_lock);
return err;
}
static const struct st_sensor_transfer_function st_sensors_tf_spi = {
.read_byte = st_sensors_spi_read_byte,
.write_byte = st_sensors_spi_write_byte,
.read_multiple_byte = st_sensors_spi_read_multiple_byte,
};
/*
* st_sensors_is_spi_3_wire() - check if SPI 3-wire mode has been selected
* @spi: spi device reference.
*
* Return: true if SPI 3-wire mode is selected, false otherwise.
*/
static bool st_sensors_is_spi_3_wire(struct spi_device *spi)
{
struct device_node *np = spi->dev.of_node;
struct st_sensors_platform_data *pdata;
pdata = (struct st_sensors_platform_data *)spi->dev.platform_data;
if ((np && of_property_read_bool(np, "spi-3wire")) ||
(pdata && pdata->spi_3wire)) {
return true;
}
return false;
}
/*
* st_sensors_configure_spi_3_wire() - configure SPI 3-wire if needed
* @spi: spi device reference.
* @settings: sensor specific settings reference.
*
* Return: 0 on success, else a negative error code.
*/
static int st_sensors_configure_spi_3_wire(struct spi_device *spi,
struct st_sensor_settings *settings)
{
if (settings->sim.addr) {
u8 buffer[] = {
settings->sim.addr,
settings->sim.value
};
return spi_write(spi, buffer, 2);
}
return 0;
}
/*
* st_sensors_spi_configure() - configure SPI interface
* @indio_dev: IIO device reference.
* @spi: spi device reference.
*
* Return: 0 on success, else a negative error code.
*/
int st_sensors_spi_configure(struct iio_dev *indio_dev,
struct spi_device *spi)
{
struct st_sensor_data *sdata = iio_priv(indio_dev);
int err;
if (st_sensors_is_spi_3_wire(spi)) {
err = st_sensors_configure_spi_3_wire(spi,
sdata->sensor_settings);
if (err < 0)
return err;
}
spi_set_drvdata(spi, indio_dev);
indio_dev->dev.parent = &spi->dev;
indio_dev->name = spi->modalias;
sdata->dev = &spi->dev;
sdata->tf = &st_sensors_tf_spi;
sdata->get_irq_data_ready = st_sensors_spi_get_irq;
return 0;
}
EXPORT_SYMBOL(st_sensors_spi_configure);
MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
MODULE_LICENSE("GPL v2");
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