iio:imu:adis: Add support for 32bit registers

Some of the newer generation devices from the ADIS16XXX family have 32bit wide
register which spans two 16bit wide registers. This patch adds support for
reading and writing a 32bit wide register.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/imu/adis.c

@@ -27,36 +27,10 @@
 #define ADIS_MSC_CTRL_DATA_RDY_DIO2	BIT(0)
 #define ADIS_GLOB_CMD_SW_RESET		BIT(7)
 
-/**
- * adis_write_reg_8() - Write single byte to a register
- * @adis: The adis device
- * @reg: The address of the register to be written
- * @val: The value to write
- */
-int adis_write_reg_8(struct adis *adis, unsigned int reg, uint8_t val)
-{
-	int ret;
-
-	mutex_lock(&adis->txrx_lock);
-	adis->tx[0] = ADIS_WRITE_REG(reg);
-	adis->tx[1] = val;
-
-	ret = spi_write(adis->spi, adis->tx, 2);
-	mutex_unlock(&adis->txrx_lock);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(adis_write_reg_8);
-
-/**
- * adis_write_reg_16() - Write 2 bytes to a pair of registers
- * @adis: The adis device
- * @reg: The address of the lower of the two registers
- * @val: Value to be written
- */
-int adis_write_reg_16(struct adis *adis, unsigned int reg, uint16_t value)
+int adis_write_reg(struct adis *adis, unsigned int reg,
+	unsigned int value, unsigned int size)
 {
-	int ret;
+	int ret, i;
 	struct spi_message msg;
 	struct spi_transfer xfers[] = {
 		{
@@ -69,33 +43,69 @@ int adis_write_reg_16(struct adis *adis, unsigned int reg, uint16_t value)
 			.tx_buf = adis->tx + 2,
 			.bits_per_word = 8,
 			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = adis->data->write_delay,
+		}, {
+			.tx_buf = adis->tx + 4,
+			.bits_per_word = 8,
+			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = adis->data->write_delay,
+		}, {
+			.tx_buf = adis->tx + 6,
+			.bits_per_word = 8,
+			.len = 2,
 			.delay_usecs = adis->data->write_delay,
 		},
 	};
 
 	mutex_lock(&adis->txrx_lock);
-	adis->tx[0] = ADIS_WRITE_REG(reg);
-	adis->tx[1] = value & 0xff;
-	adis->tx[2] = ADIS_WRITE_REG(reg + 1);
-	adis->tx[3] = (value >> 8) & 0xff;
 
 	spi_message_init(&msg);
-	spi_message_add_tail(&xfers[0], &msg);
-	spi_message_add_tail(&xfers[1], &msg);
+	switch (size) {
+	case 4:
+		adis->tx[6] = ADIS_WRITE_REG(reg + 3);
+		adis->tx[7] = (value >> 24) & 0xff;
+		adis->tx[4] = ADIS_WRITE_REG(reg + 2);
+		adis->tx[5] = (value >> 16) & 0xff;
+	case 2:
+		adis->tx[2] = ADIS_WRITE_REG(reg + 1);
+		adis->tx[3] = (value >> 8) & 0xff;
+	case 1:
+		adis->tx[0] = ADIS_WRITE_REG(reg);
+		adis->tx[1] = value & 0xff;
+		break;
+	default:
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	xfers[size - 1].cs_change = 0;
+
+	for (i = 0; i < size; i++)
+		spi_message_add_tail(&xfers[i], &msg);
+
 	ret = spi_sync(adis->spi, &msg);
+	if (ret) {
+		dev_err(&adis->spi->dev, "Failed to write register 0x%02X: %d\n",
+				reg, ret);
+	}
+
+out_unlock:
 	mutex_unlock(&adis->txrx_lock);
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(adis_write_reg_16);
+EXPORT_SYMBOL_GPL(adis_write_reg);
 
 /**
- * adis_read_reg_16() - read 2 bytes from a 16-bit register
+ * adis_read_reg() - read 2 bytes from a 16-bit register
  * @adis: The adis device
  * @reg: The address of the lower of the two registers
  * @val: The value read back from the device
  */
-int adis_read_reg_16(struct adis *adis, unsigned int reg, uint16_t *val)
+int adis_read_reg(struct adis *adis, unsigned int reg,
+	unsigned int *val, unsigned int size)
 {
 	struct spi_message msg;
 	int ret;
@@ -107,33 +117,61 @@ int adis_read_reg_16(struct adis *adis, unsigned int reg, uint16_t *val)
 			.cs_change = 1,
 			.delay_usecs = adis->data->read_delay,
 		}, {
+			.tx_buf = adis->tx + 2,
 			.rx_buf = adis->rx,
 			.bits_per_word = 8,
 			.len = 2,
+			.cs_change = 1,
+			.delay_usecs = adis->data->read_delay,
+		}, {
+			.rx_buf = adis->rx + 2,
+			.bits_per_word = 8,
+			.len = 2,
 			.delay_usecs = adis->data->read_delay,
 		},
 	};
 
 	mutex_lock(&adis->txrx_lock);
-	adis->tx[0] = ADIS_READ_REG(reg);
-	adis->tx[1] = 0;
-
 	spi_message_init(&msg);
-	spi_message_add_tail(&xfers[0], &msg);
-	spi_message_add_tail(&xfers[1], &msg);
+
+	switch (size) {
+	case 4:
+		adis->tx[0] = ADIS_READ_REG(reg + 2);
+		adis->tx[1] = 0;
+		spi_message_add_tail(&xfers[0], &msg);
+	case 2:
+		adis->tx[2] = ADIS_READ_REG(reg);
+		adis->tx[3] = 0;
+		spi_message_add_tail(&xfers[1], &msg);
+		spi_message_add_tail(&xfers[2], &msg);
+		break;
+	default:
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
 	ret = spi_sync(adis->spi, &msg);
 	if (ret) {
-		dev_err(&adis->spi->dev, "Failed to read 16 bit register 0x%02X: %d\n",
+		dev_err(&adis->spi->dev, "Failed to read register 0x%02X: %d\n",
 				reg, ret);
-		goto error_ret;
+		goto out_unlock;
 	}
-	*val = get_unaligned_be16(adis->rx);
 
-error_ret:
+	switch (size) {
+	case 4:
+		*val = get_unaligned_be32(adis->rx);
+		break;
+	case 2:
+		*val = get_unaligned_be16(adis->rx + 2);
+		break;
+	}
+
+out_unlock:
 	mutex_unlock(&adis->txrx_lock);
+
 	return ret;
 }
-EXPORT_SYMBOL_GPL(adis_read_reg_16);
+EXPORT_SYMBOL_GPL(adis_read_reg);
 
 #ifdef CONFIG_DEBUG_FS
 
@@ -304,25 +342,26 @@ int adis_single_conversion(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan, unsigned int error_mask, int *val)
 {
 	struct adis *adis = iio_device_get_drvdata(indio_dev);
-	uint16_t val16;
+	unsigned int uval;
 	int ret;
 
 	mutex_lock(&indio_dev->mlock);
 
-	ret = adis_read_reg_16(adis, chan->address, &val16);
+	ret = adis_read_reg(adis, chan->address, &uval,
+			chan->scan_type.storagebits / 8);
 	if (ret)
 		goto err_unlock;
 
-	if (val16 & error_mask) {
+	if (uval & error_mask) {
 		ret = adis_check_status(adis);
 		if (ret)
 			goto err_unlock;
 	}
 
 	if (chan->scan_type.sign == 's')
-		*val = sign_extend32(val16, chan->scan_type.realbits - 1);
+		*val = sign_extend32(uval, chan->scan_type.realbits - 1);
 	else
-		*val = val16 & ((1 << chan->scan_type.realbits) - 1);
+		*val = uval & ((1 << chan->scan_type.realbits) - 1);
 
 	ret = IIO_VAL_INT;
 err_unlock:

drivers/iio/imu/adis_buffer.c

@@ -64,6 +64,8 @@ int adis_update_scan_mode(struct iio_dev *indio_dev,
 	for (i = 0; i < indio_dev->num_channels; i++, chan++) {
 		if (!test_bit(chan->scan_index, scan_mask))
 			continue;
+		if (chan->scan_type.storagebits == 32)
+			*tx++ = cpu_to_be16((chan->address + 2) << 8);
 		*tx++ = cpu_to_be16(chan->address << 8);
 	}
 

include/linux/iio/imu/adis.h

@@ -53,7 +53,7 @@ struct adis {
 	struct spi_transfer	*xfer;
 	void			*buffer;
 
-	uint8_t			tx[8] ____cacheline_aligned;
+	uint8_t			tx[10] ____cacheline_aligned;
 	uint8_t			rx[4];
 };
 
@@ -61,9 +61,82 @@ int adis_init(struct adis *adis, struct iio_dev *indio_dev,
 	struct spi_device *spi, const struct adis_data *data);
 int adis_reset(struct adis *adis);
 
-int adis_write_reg_8(struct adis *adis, unsigned int reg, uint8_t val);
-int adis_write_reg_16(struct adis *adis, unsigned int reg, uint16_t val);
-int adis_read_reg_16(struct adis *adis, unsigned int reg, uint16_t *val);
+int adis_write_reg(struct adis *adis, unsigned int reg,
+	unsigned int val, unsigned int size);
+int adis_read_reg(struct adis *adis, unsigned int reg,
+	unsigned int *val, unsigned int size);
+
+/**
+ * adis_write_reg_8() - Write single byte to a register
+ * @adis: The adis device
+ * @reg: The address of the register to be written
+ * @value: The value to write
+ */
+static inline int adis_write_reg_8(struct adis *adis, unsigned int reg,
+	uint8_t val)
+{
+	return adis_write_reg(adis, reg, val, 1);
+}
+
+/**
+ * adis_write_reg_16() - Write 2 bytes to a pair of registers
+ * @adis: The adis device
+ * @reg: The address of the lower of the two registers
+ * @value: Value to be written
+ */
+static inline int adis_write_reg_16(struct adis *adis, unsigned int reg,
+	uint16_t val)
+{
+	return adis_write_reg(adis, reg, val, 2);
+}
+
+/**
+ * adis_write_reg_32() - write 4 bytes to four registers
+ * @adis: The adis device
+ * @reg: The address of the lower of the four register
+ * @value: Value to be written
+ */
+static inline int adis_write_reg_32(struct adis *adis, unsigned int reg,
+	uint32_t val)
+{
+	return adis_write_reg(adis, reg, val, 4);
+}
+
+/**
+ * adis_read_reg_16() - read 2 bytes from a 16-bit register
+ * @adis: The adis device
+ * @reg: The address of the lower of the two registers
+ * @val: The value read back from the device
+ */
+static inline int adis_read_reg_16(struct adis *adis, unsigned int reg,
+	uint16_t *val)
+{
+	unsigned int tmp;
+	int ret;
+
+	ret = adis_read_reg(adis, reg, &tmp, 2);
+	*val = tmp;
+
+	return ret;
+}
+
+/**
+ * adis_read_reg_32() - read 4 bytes from a 32-bit register
+ * @adis: The adis device
+ * @reg: The address of the lower of the two registers
+ * @val: The value read back from the device
+ */
+static inline int adis_read_reg_32(struct adis *adis, unsigned int reg,
+	uint32_t *val)
+{
+	unsigned int tmp;
+	int ret;
+
+	ret = adis_read_reg(adis, reg, &tmp, 4);
+	*val = tmp;
+
+	return ret;
+}
 
 int adis_enable_irq(struct adis *adis, bool enable);
 int adis_check_status(struct adis *adis);