[v2,1/2] iio: adc: ad9467: use DMA safe buffer for spi

Commit Message

Nuno Sa via B4 Relay May 22, 2024, 12:54 p.m. UTC

From: Nuno Sa <[e-mail]>

Make sure we use a DMA safe buffer (IIO_DMA_MINALIGN) for all the spi
transfers. Only relevant for writes since for reads
spi_write_then_read() is used which does not require DMA safe buffers.

Also note that for consistency, ad9467_spi_read() is also taking struct
ad9467_state as a parameter (even if not really needed).

Fixes: ad6797120238 ("iio: adc: ad9467: add support AD9467 ADC")
Signed-off-by: Nuno Sa <[e-mail]>
---
 drivers/iio/adc/ad9467.c | 65 +++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 34 deletions(-)

Patch

diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
index e85b763b9ffcb..3571cfe0f9cc2 100644
--- a/drivers/iio/adc/ad9467.c
+++ b/drivers/iio/adc/ad9467.c
@@ -141,9 +141,10 @@  struct ad9467_state {
 	struct gpio_desc		*pwrdown_gpio;
 	/* ensure consistent state obtained on multiple related accesses */
 	struct mutex			lock;
+	u8				buf[3] __aligned(IIO_DMA_MINALIGN);
 };
 
-static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
+static int ad9467_spi_read(struct ad9467_state *st, unsigned int reg)
 {
 	unsigned char tbuf[2], rbuf[1];
 	int ret;
@@ -151,7 +152,7 @@  static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
 	tbuf[0] = 0x80 | (reg >> 8);
 	tbuf[1] = reg & 0xFF;
 
-	ret = spi_write_then_read(spi,
+	ret = spi_write_then_read(st->spi,
 				  tbuf, ARRAY_SIZE(tbuf),
 				  rbuf, ARRAY_SIZE(rbuf));
 
@@ -161,35 +162,32 @@  static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
 	return rbuf[0];
 }
 
-static int ad9467_spi_write(struct spi_device *spi, unsigned int reg,
+static int ad9467_spi_write(struct ad9467_state *st, unsigned int reg,
 			    unsigned int val)
 {
-	unsigned char buf[3];
+	st->buf[0] = reg >> 8;
+	st->buf[1] = reg & 0xFF;
+	st->buf[2] = val;
 
-	buf[0] = reg >> 8;
-	buf[1] = reg & 0xFF;
-	buf[2] = val;
-
-	return spi_write(spi, buf, ARRAY_SIZE(buf));
+	return spi_write(st->spi, st->buf, ARRAY_SIZE(st->buf));
 }
 
 static int ad9467_reg_access(struct iio_dev *indio_dev, unsigned int reg,
 			     unsigned int writeval, unsigned int *readval)
 {
 	struct ad9467_state *st = iio_priv(indio_dev);
-	struct spi_device *spi = st->spi;
 	int ret;
 
 	if (!readval) {
 		guard(mutex)(&st->lock);
-		ret = ad9467_spi_write(spi, reg, writeval);
+		ret = ad9467_spi_write(st, reg, writeval);
 		if (ret)
 			return ret;
-		return ad9467_spi_write(spi, AN877_ADC_REG_TRANSFER,
+		return ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 					AN877_ADC_TRANSFER_SYNC);
 	}
 
-	ret = ad9467_spi_read(spi, reg);
+	ret = ad9467_spi_read(st, reg);
 	if (ret < 0)
 		return ret;
 	*readval = ret;
@@ -295,7 +293,7 @@  static int ad9467_get_scale(struct ad9467_state *st, int *val, int *val2)
 	unsigned int i, vref_val;
 	int ret;
 
-	ret = ad9467_spi_read(st->spi, AN877_ADC_REG_VREF);
+	ret = ad9467_spi_read(st, AN877_ADC_REG_VREF);
 	if (ret < 0)
 		return ret;
 
@@ -330,31 +328,31 @@  static int ad9467_set_scale(struct ad9467_state *st, int val, int val2)
 			continue;
 
 		guard(mutex)(&st->lock);
-		ret = ad9467_spi_write(st->spi, AN877_ADC_REG_VREF,
+		ret = ad9467_spi_write(st, AN877_ADC_REG_VREF,
 				       info->scale_table[i][1]);
 		if (ret < 0)
 			return ret;
 
-		return ad9467_spi_write(st->spi, AN877_ADC_REG_TRANSFER,
+		return ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 					AN877_ADC_TRANSFER_SYNC);
 	}
 
 	return -EINVAL;
 }
 
-static int ad9467_outputmode_set(struct spi_device *spi, unsigned int mode)
+static int ad9467_outputmode_set(struct ad9467_state *st, unsigned int mode)
 {
 	int ret;
 
-	ret = ad9467_spi_write(spi, AN877_ADC_REG_OUTPUT_MODE, mode);
+	ret = ad9467_spi_write(st, AN877_ADC_REG_OUTPUT_MODE, mode);
 	if (ret < 0)
 		return ret;
 
-	return ad9467_spi_write(spi, AN877_ADC_REG_TRANSFER,
+	return ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 				AN877_ADC_TRANSFER_SYNC);
 }
 
-static int ad9647_calibrate_prepare(const struct ad9467_state *st)
+static int ad9647_calibrate_prepare(struct ad9467_state *st)
 {
 	struct iio_backend_data_fmt data = {
 		.enable = false,
@@ -362,17 +360,17 @@  static int ad9647_calibrate_prepare(const struct ad9467_state *st)
 	unsigned int c;
 	int ret;
 
-	ret = ad9467_spi_write(st->spi, AN877_ADC_REG_TEST_IO,
+	ret = ad9467_spi_write(st, AN877_ADC_REG_TEST_IO,
 			       AN877_ADC_TESTMODE_PN9_SEQ);
 	if (ret)
 		return ret;
 
-	ret = ad9467_spi_write(st->spi, AN877_ADC_REG_TRANSFER,
+	ret = ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 			       AN877_ADC_TRANSFER_SYNC);
 	if (ret)
 		return ret;
 
-	ret = ad9467_outputmode_set(st->spi, st->info->default_output_mode);
+	ret = ad9467_outputmode_set(st, st->info->default_output_mode);
 	if (ret)
 		return ret;
 
@@ -390,7 +388,7 @@  static int ad9647_calibrate_prepare(const struct ad9467_state *st)
 	return iio_backend_chan_enable(st->back, 0);
 }
 
-static int ad9647_calibrate_polarity_set(const struct ad9467_state *st,
+static int ad9647_calibrate_polarity_set(struct ad9467_state *st,
 					 bool invert)
 {
 	enum iio_backend_sample_trigger trigger;
@@ -401,7 +399,7 @@  static int ad9647_calibrate_polarity_set(const struct ad9467_state *st,
 		if (invert)
 			phase |= AN877_ADC_INVERT_DCO_CLK;
 
-		return ad9467_spi_write(st->spi, AN877_ADC_REG_OUTPUT_PHASE,
+		return ad9467_spi_write(st, AN877_ADC_REG_OUTPUT_PHASE,
 					phase);
 	}
 
@@ -437,19 +435,18 @@  static unsigned int ad9467_find_optimal_point(const unsigned long *calib_map,
 	return cnt;
 }
 
-static int ad9467_calibrate_apply(const struct ad9467_state *st,
-				  unsigned int val)
+static int ad9467_calibrate_apply(struct ad9467_state *st, unsigned int val)
 {
 	unsigned int lane;
 	int ret;
 
 	if (st->info->has_dco) {
-		ret = ad9467_spi_write(st->spi, AN877_ADC_REG_OUTPUT_DELAY,
+		ret = ad9467_spi_write(st, AN877_ADC_REG_OUTPUT_DELAY,
 				       val);
 		if (ret)
 			return ret;
 
-		return ad9467_spi_write(st->spi, AN877_ADC_REG_TRANSFER,
+		return ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 					AN877_ADC_TRANSFER_SYNC);
 	}
 
@@ -462,7 +459,7 @@  static int ad9467_calibrate_apply(const struct ad9467_state *st,
 	return 0;
 }
 
-static int ad9647_calibrate_stop(const struct ad9467_state *st)
+static int ad9647_calibrate_stop(struct ad9467_state *st)
 {
 	struct iio_backend_data_fmt data = {
 		.sign_extend = true,
@@ -487,16 +484,16 @@  static int ad9647_calibrate_stop(const struct ad9467_state *st)
 	}
 
 	mode = st->info->default_output_mode | AN877_ADC_OUTPUT_MODE_TWOS_COMPLEMENT;
-	ret = ad9467_outputmode_set(st->spi, mode);
+	ret = ad9467_outputmode_set(st, mode);
 	if (ret)
 		return ret;
 
-	ret = ad9467_spi_write(st->spi, AN877_ADC_REG_TEST_IO,
+	ret = ad9467_spi_write(st, AN877_ADC_REG_TEST_IO,
 			       AN877_ADC_TESTMODE_OFF);
 	if (ret)
 		return ret;
 
-	return ad9467_spi_write(st->spi, AN877_ADC_REG_TRANSFER,
+	return ad9467_spi_write(st, AN877_ADC_REG_TRANSFER,
 			       AN877_ADC_TRANSFER_SYNC);
 }
 
@@ -846,7 +843,7 @@  static int ad9467_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
-	id = ad9467_spi_read(spi, AN877_ADC_REG_CHIP_ID);
+	id = ad9467_spi_read(st, AN877_ADC_REG_CHIP_ID);
 	if (id != st->info->id) {
 		dev_err(&spi->dev, "Mismatch CHIP_ID, got 0x%X, expected 0x%X\n",
 			id, st->info->id);