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
st_sensors_spi_get_irq(struct iio_dev * indio_dev)22 static 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
st_sensors_spi_read(struct st_sensor_transfer_buffer * tb,struct device * dev,u8 reg_addr,int len,u8 * data,bool multiread_bit)29 static 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*sizeof(u8));
58 mutex_unlock(&tb->buf_lock);
59 return len;
60
61 acc_spi_read_error:
62 mutex_unlock(&tb->buf_lock);
63 return err;
64 }
65
st_sensors_spi_read_byte(struct st_sensor_transfer_buffer * tb,struct device * dev,u8 reg_addr,u8 * res_byte)66 static 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
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)72 static 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
st_sensors_spi_write_byte(struct st_sensor_transfer_buffer * tb,struct device * dev,u8 reg_addr,u8 data)79 static 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
100 static 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
st_sensors_spi_configure(struct iio_dev * indio_dev,struct spi_device * spi,struct st_sensor_data * sdata)106 void 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->tf = &st_sensors_tf_spi;
115 sdata->get_irq_data_ready = st_sensors_spi_get_irq;
116 }
117 EXPORT_SYMBOL(st_sensors_spi_configure);
118
119 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
120 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
121 MODULE_LICENSE("GPL v2");
122