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 
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 
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);
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 
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 
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 
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 
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->dev = &spi->dev;
115 	sdata->tf = &st_sensors_tf_spi;
116 	sdata->get_irq_data_ready = st_sensors_spi_get_irq;
117 }
118 EXPORT_SYMBOL(st_sensors_spi_configure);
119 
120 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
121 MODULE_DESCRIPTION("STMicroelectronics ST-sensors spi driver");
122 MODULE_LICENSE("GPL v2");
123