1/*
2 * STMicroelectronics sensors spi library driver
3 *
4 * Copyright 2012-2013 STMicroelectronics Inc.
5 *
6 * Denis Ciocca <denis.ciocca@st.com>
7 *
8 * Licensed under the GPL-2.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/iio/iio.h>
15
16#include <linux/iio/common/st_sensors_spi.h>
17
18
19#define ST_SENSORS_SPI_MULTIREAD	0xc0
20#define ST_SENSORS_SPI_READ		0x80
21
22static unsigned int st_sensors_spi_get_irq(struct iio_dev *indio_dev)
23{
24	struct st_sensor_data *sdata = iio_priv(indio_dev);
25
26	return to_spi_device(sdata->dev)->irq;
27}
28
29static int st_sensors_spi_read(struct st_sensor_transfer_buffer *tb,
30	struct device *dev, u8 reg_addr, int len, u8 *data, bool multiread_bit)
31{
32	int err;
33
34	struct spi_transfer xfers[] = {
35		{
36			.tx_buf = tb->tx_buf,
37			.bits_per_word = 8,
38			.len = 1,
39		},
40		{
41			.rx_buf = tb->rx_buf,
42			.bits_per_word = 8,
43			.len = len,
44		}
45	};
46
47	mutex_lock(&tb->buf_lock);
48	if ((multiread_bit) && (len > 1))
49		tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_MULTIREAD;
50	else
51		tb->tx_buf[0] = reg_addr | ST_SENSORS_SPI_READ;
52
53	err = spi_sync_transfer(to_spi_device(dev), xfers, ARRAY_SIZE(xfers));
54	if (err)
55		goto acc_spi_read_error;
56
57	memcpy(data, tb->rx_buf, len);
58	mutex_unlock(&tb->buf_lock);
59	return len;
60
61acc_spi_read_error:
62	mutex_unlock(&tb->buf_lock);
63	return err;
64}
65
66static int st_sensors_spi_read_byte(struct st_sensor_transfer_buffer *tb,
67				struct device *dev, u8 reg_addr, u8 *res_byte)
68{
69	return st_sensors_spi_read(tb, dev, reg_addr, 1, res_byte, false);
70}
71
72static int st_sensors_spi_read_multiple_byte(
73	struct st_sensor_transfer_buffer *tb, struct device *dev,
74			u8 reg_addr, int len, u8 *data, bool multiread_bit)
75{
76	return st_sensors_spi_read(tb, dev, reg_addr, len, data, multiread_bit);
77}
78
79static int st_sensors_spi_write_byte(struct st_sensor_transfer_buffer *tb,
80				struct device *dev, u8 reg_addr, u8 data)
81{
82	int err;
83
84	struct spi_transfer xfers = {
85		.tx_buf = tb->tx_buf,
86		.bits_per_word = 8,
87		.len = 2,
88	};
89
90	mutex_lock(&tb->buf_lock);
91	tb->tx_buf[0] = reg_addr;
92	tb->tx_buf[1] = data;
93
94	err = spi_sync_transfer(to_spi_device(dev), &xfers, 1);
95	mutex_unlock(&tb->buf_lock);
96
97	return err;
98}
99
100static const struct st_sensor_transfer_function st_sensors_tf_spi = {
101	.read_byte = st_sensors_spi_read_byte,
102	.write_byte = st_sensors_spi_write_byte,
103	.read_multiple_byte = st_sensors_spi_read_multiple_byte,
104};
105
106void st_sensors_spi_configure(struct iio_dev *indio_dev,
107			struct spi_device *spi, struct st_sensor_data *sdata)
108{
109	spi_set_drvdata(spi, indio_dev);
110
111	indio_dev->dev.parent = &spi->dev;
112	indio_dev->name = spi->modalias;
113
114	sdata->dev = &spi->dev;
115	sdata->tf = &st_sensors_tf_spi;
116	sdata->get_irq_data_ready = st_sensors_spi_get_irq;
117}
118EXPORT_SYMBOL(st_sensors_spi_configure);
119
120MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
121MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
122MODULE_LICENSE("GPL v2");
123