1 /* ST Microelectronics STMEMS hal i/f
2 *
3 * Copyright (c) 2021 STMicroelectronics
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * zephyrproject-rtos/modules/hal/st/sensor/stmemsc/
8 */
9
10 #include "stmemsc.h"
11
12 #define SPI_READ (1 << 7)
13
14 /*
15 * SPI read
16 */
stmemsc_spi_read(const struct spi_dt_spec * stmemsc,uint8_t reg_addr,uint8_t * value,uint8_t len)17 int stmemsc_spi_read(const struct spi_dt_spec *stmemsc,
18 uint8_t reg_addr, uint8_t *value, uint8_t len)
19 {
20 uint8_t buffer_tx[2] = { reg_addr | SPI_READ, 0 };
21
22 /* write 1 byte with reg addr (msb at 1) + 1 dummy byte */
23 const struct spi_buf tx_buf = { .buf = buffer_tx, .len = 2, };
24 const struct spi_buf_set tx = { .buffers = &tx_buf, .count = 1 };
25
26 /*
27 * transaction #1: dummy read to skip first byte
28 * transaction #2: read "len" byte of data
29 */
30 const struct spi_buf rx_buf[2] = {
31 { .buf = NULL, .len = 1, },
32 { .buf = value, .len = len, }
33 };
34 const struct spi_buf_set rx = { .buffers = rx_buf, .count = 2 };
35
36 return spi_transceive_dt(stmemsc, &tx, &rx);
37 }
38
39 /*
40 * SPI write
41 */
stmemsc_spi_write(const struct spi_dt_spec * stmemsc,uint8_t reg_addr,uint8_t * value,uint8_t len)42 int stmemsc_spi_write(const struct spi_dt_spec *stmemsc,
43 uint8_t reg_addr, uint8_t *value, uint8_t len)
44 {
45 uint8_t buffer_tx[1] = { reg_addr & ~SPI_READ };
46
47 /*
48 * transaction #1: write 1 byte with reg addr (msb at 0)
49 * transaction #2: write "len" byte of data
50 */
51 const struct spi_buf tx_buf[2] = {
52 { .buf = buffer_tx, .len = 1, },
53 { .buf = value, .len = len, }
54 };
55 const struct spi_buf_set tx = { .buffers = tx_buf, .count = 2 };
56
57 return spi_write_dt(stmemsc, &tx);
58 }
59
