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