[PATCH v2 3/7] iio: adc: adi-axi-adc: Add support for CRC

[Janani Sunil <janani.sunil@analog.com>]

Add support for enabling and disabling Cyclic Redundancy Check (CRC)
processing in the AXI ADC backend. CRC provides data integrity verification
for high-speed ADC data streams, ensuring reliable data transfer between
the ADC frontend and backend processing systems.

Signed-off-by: Janani Sunil <janani.sunil@analog.com>
---
 drivers/iio/adc/adi-axi-adc.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 26b9c75bd4d8..a9e25e09880e 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
@@ -47,6 +48,9 @@
 #define    ADI_AXI_ADC_CTRL_DDR_EDGESEL_MASK	BIT(1)
 
 #define ADI_AXI_ADC_REG_CNTRL_3			0x004c
+/* Bit 8 is common to all AXI ADC cores; bits 7-0 are per-HDL-project. */
+#define    ADI_AXI_ADC_CNTRL_3_CRC_EN_MASK	BIT(8)
+
 #define   AXI_AD485X_CNTRL_3_OS_EN_MSK		BIT(2)
 #define   AXI_AD485X_CNTRL_3_PACKET_FORMAT_MSK	GENMASK(1, 0)
 #define   AXI_AD485X_PACKET_FORMAT_20BIT	0x0
@@ -567,6 +571,22 @@ static int axi_adc_reg_access(struct iio_backend *back, unsigned int reg,
 	return regmap_write(st->regmap, reg, writeval);
 }
 
+static int axi_adc_crc_enable(struct iio_backend *back)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+
+	return regmap_set_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+			       ADI_AXI_ADC_CNTRL_3_CRC_EN_MASK);
+}
+
+static int axi_adc_crc_disable(struct iio_backend *back)
+{
+	struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+
+	return regmap_clear_bits(st->regmap, ADI_AXI_ADC_REG_CNTRL_3,
+				 ADI_AXI_ADC_CNTRL_3_CRC_EN_MASK);
+}
+
 static const struct regmap_config axi_adc_regmap_config = {
 	.val_bits = 32,
 	.reg_bits = 32,
@@ -615,6 +635,8 @@ static const struct iio_backend_ops adi_axi_adc_ops = {
 	.num_lanes_set = axi_adc_num_lanes_set,
 	.debugfs_reg_access = iio_backend_debugfs_ptr(axi_adc_reg_access),
 	.debugfs_print_chan_status = iio_backend_debugfs_ptr(axi_adc_debugfs_print_chan_status),
+	.crc_enable = axi_adc_crc_enable,
+	.crc_disable = axi_adc_crc_disable,
 };
 
 static const struct iio_backend_info adi_axi_adc_generic = {
@@ -684,6 +706,10 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
 	if (!st)
 		return -ENOMEM;
 
+	ret = devm_mutex_init(dev, &st->lock);
+	if (ret)
+		return ret;
+
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
 		return PTR_ERR(base);

-- 
2.43.0