driver/sensor: add LIS2DS12 sensor support

Add support to STM LIS2DS12 3-axis accelerometer driver.
The driver support I2C and SPI bus communication and both
polling and drdy trigger mode.
Currently it uses high resolution only as power mode.

Signed-off-by: Armando Visconti <armando.visconti@st.com>

drivers/sensor/lis2ds12/lis2ds12_spi.c

@@ -0,0 +1,182 @@
+/* ST Microelectronics LIS2DS12 3-axis accelerometer driver
+ *
+ * Copyright (c) 2019 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Datasheet:
+ * https://www.st.com/resource/en/datasheet/lis2ds12.pdf
+ */
+
+
+#include <string.h>
+#include <spi.h>
+#include "lis2ds12.h"
+#include <logging/log.h>
+
+#ifdef DT_ST_LIS2DS12_BUS_SPI
+
+#define LIS2DS12_SPI_READ		(1 << 7)
+
+#define LOG_LEVEL CONFIG_SENSOR_LOG_LEVEL
+LOG_MODULE_DECLARE(LIS2DS12);
+
+#if defined(CONFIG_LIS2DS12_SPI_GPIO_CS)
+static struct spi_cs_control lis2ds12_cs_ctrl;
+#endif
+
+static struct spi_config lis2ds12_spi_conf = {
+	.frequency = DT_ST_LIS2DS12_0_SPI_MAX_FREQUENCY,
+	.operation = (SPI_OP_MODE_MASTER | SPI_MODE_CPOL |
+		      SPI_MODE_CPHA | SPI_WORD_SET(8) | SPI_LINES_SINGLE),
+	.slave     = DT_ST_LIS2DS12_0_BASE_ADDRESS,
+	.cs        = NULL,
+};
+
+static int lis2ds12_raw_read(struct lis2ds12_data *data, u8_t reg_addr,
+			    u8_t *value, u8_t len)
+{
+	struct spi_config *spi_cfg = &lis2ds12_spi_conf;
+	u8_t buffer_tx[2] = { reg_addr | LIS2DS12_SPI_READ, 0 };
+	const struct spi_buf tx_buf = {
+			.buf = buffer_tx,
+			.len = 2,
+	};
+	const struct spi_buf_set tx = {
+		.buffers = &tx_buf,
+		.count = 1
+	};
+	const struct spi_buf rx_buf[2] = {
+		{
+			.buf = NULL,
+			.len = 1,
+		},
+		{
+			.buf = value,
+			.len = len,
+		}
+	};
+	const struct spi_buf_set rx = {
+		.buffers = rx_buf,
+		.count = 2
+	};
+
+
+	if (len > 64) {
+		return -EIO;
+	}
+
+	if (spi_transceive(data->comm_master, spi_cfg, &tx, &rx)) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int lis2ds12_raw_write(struct lis2ds12_data *data, u8_t reg_addr,
+			     u8_t *value, u8_t len)
+{
+	struct spi_config *spi_cfg = &lis2ds12_spi_conf;
+	u8_t buffer_tx[1] = { reg_addr & ~LIS2DS12_SPI_READ };
+	const struct spi_buf tx_buf[2] = {
+		{
+			.buf = buffer_tx,
+			.len = 1,
+		},
+		{
+			.buf = value,
+			.len = len,
+		}
+	};
+	const struct spi_buf_set tx = {
+		.buffers = tx_buf,
+		.count = 2
+	};
+
+
+	if (len > 64) {
+		return -EIO;
+	}
+
+	if (spi_write(data->comm_master, spi_cfg, &tx)) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int lis2ds12_spi_read_data(struct lis2ds12_data *data, u8_t reg_addr,
+				 u8_t *value, u8_t len)
+{
+	return lis2ds12_raw_read(data, reg_addr, value, len);
+}
+
+static int lis2ds12_spi_write_data(struct lis2ds12_data *data, u8_t reg_addr,
+				  u8_t *value, u8_t len)
+{
+	return lis2ds12_raw_write(data, reg_addr, value, len);
+}
+
+static int lis2ds12_spi_read_reg(struct lis2ds12_data *data, u8_t reg_addr,
+				u8_t *value)
+{
+	return lis2ds12_raw_read(data, reg_addr, value, 1);
+}
+
+static int lis2ds12_spi_write_reg(struct lis2ds12_data *data, u8_t reg_addr,
+				u8_t value)
+{
+	u8_t tmp_val = value;
+
+	return lis2ds12_raw_write(data, reg_addr, &tmp_val, 1);
+}
+
+static int lis2ds12_spi_update_reg(struct lis2ds12_data *data, u8_t reg_addr,
+				  u8_t mask, u8_t value)
+{
+	u8_t tmp_val;
+
+	lis2ds12_raw_read(data, reg_addr, &tmp_val, 1);
+	tmp_val = (tmp_val & ~mask) | (value & mask);
+
+	return lis2ds12_raw_write(data, reg_addr, &tmp_val, 1);
+}
+
+static const struct lis2ds12_transfer_function lis2ds12_spi_transfer_fn = {
+	.read_data = lis2ds12_spi_read_data,
+	.write_data = lis2ds12_spi_write_data,
+	.read_reg  = lis2ds12_spi_read_reg,
+	.write_reg  = lis2ds12_spi_write_reg,
+	.update_reg = lis2ds12_spi_update_reg,
+};
+
+int lis2ds12_spi_init(struct device *dev)
+{
+	struct lis2ds12_data *data = dev->driver_data;
+
+	data->hw_tf = &lis2ds12_spi_transfer_fn;
+
+#if defined(CONFIG_LIS2DS12_SPI_GPIO_CS)
+	/* handle SPI CS thru GPIO if it is the case */
+	if (IS_ENABLED(CONFIG_LIS2DS12_SPI_GPIO_CS)) {
+		lis2ds12_cs_ctrl.gpio_dev = device_get_binding(
+			CONFIG_LIS2DS12_SPI_GPIO_CS_DRV_NAME);
+		if (!lis2ds12_cs_ctrl.gpio_dev) {
+			LOG_ERR("Unable to get GPIO SPI CS device");
+			return -ENODEV;
+		}
+
+		lis2ds12_cs_ctrl.gpio_pin = CONFIG_LIS2DS12_SPI_GPIO_CS_PIN;
+		lis2ds12_cs_ctrl.delay = 0;
+
+		lis2ds12_spi_conf.cs = &lis2ds12_cs_ctrl;
+
+		LOG_DBG("SPI GPIO CS configured on %s:%u",
+			    CONFIG_LIS2DS12_SPI_GPIO_CS_DRV_NAME,
+			    CONFIG_LIS2DS12_SPI_GPIO_CS_PIN);
+	}
+#endif
+
+	return 0;
+}
+#endif /* DT_ST_LIS2DS12_BUS_SPI */