iio: accel: adxl345: use regmap cache for INT mapping

Use regmap cache to replace the maintenance of the interrupt mapping
state by a member variable intio. The interrupt mapping is initialized
when the driver is probed, and it is perfectly cacheable.

The patch will still leave the function set_interrupts(). A follow up
patch takes care of it, when cleaning up the INT enable register
variable.

Signed-off-by: Lothar Rubusch <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/accel/adxl345.h

···
  */
 #define ADXL375_USCALE	480000
 
+struct regmap;
+
+bool adxl345_is_volatile_reg(struct device *dev, unsigned int reg);
+
 struct adxl345_chip_info {
 	const char *name;
 	int uscale;

drivers/iio/accel/adxl345_core.c

···
 	struct regmap *regmap;
 	bool fifo_delay; /* delay: delay is needed for SPI */
 	int irq;
-	u8 intio;
 	u8 int_map;
 	u8 watermark;
 	u8 fifo_mode;
···
 	0
 };
 
+bool adxl345_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case ADXL345_REG_DATA_AXIS(0):
+	case ADXL345_REG_DATA_AXIS(1):
+	case ADXL345_REG_DATA_AXIS(2):
+	case ADXL345_REG_DATA_AXIS(3):
+	case ADXL345_REG_DATA_AXIS(4):
+	case ADXL345_REG_DATA_AXIS(5):
+	case ADXL345_REG_ACT_TAP_STATUS:
+	case ADXL345_REG_FIFO_STATUS:
+	case ADXL345_REG_INT_SOURCE:
+		return true;
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_NS_GPL(adxl345_is_volatile_reg, "IIO_ADXL345");
+
 /**
  * adxl345_set_measure_en() - Enable and disable measuring.
  *
···
 
 static int adxl345_set_interrupts(struct adxl345_state *st)
 {
-	int ret;
-	unsigned int int_enable = st->int_map;
-	unsigned int int_map;
-
-	/*
-	 * Any bits set to 0 in the INT map register send their respective
-	 * interrupts to the INT1 pin, whereas bits set to 1 send their respective
-	 * interrupts to the INT2 pin. The intio shall convert this accordingly.
-	 */
-	int_map = st->intio ? st->int_map : ~st->int_map;
-
-	ret = regmap_write(st->regmap, ADXL345_REG_INT_MAP, int_map);
-	if (ret)
-		return ret;
-
-	return regmap_write(st->regmap, ADXL345_REG_INT_ENABLE, int_enable);
+	return regmap_write(st->regmap, ADXL345_REG_INT_ENABLE, st->int_map);
 }
 
 static int adxl345_read_raw(struct iio_dev *indio_dev,
···
 
 static int adxl345_set_fifo(struct adxl345_state *st)
 {
+	unsigned int intio;
 	int ret;
 
 	/* FIFO should only be configured while in standby mode */
···
 	if (ret < 0)
 		return ret;
 
+	ret = regmap_read(st->regmap, ADXL345_REG_INT_MAP, &intio);
+	if (ret)
+		return ret;
+
 	ret = regmap_write(st->regmap, ADXL345_REG_FIFO_CTL,
 			   FIELD_PREP(ADXL345_FIFO_CTL_SAMPLES_MSK,
 				      st->watermark) |
-			   FIELD_PREP(ADXL345_FIFO_CTL_TRIGGER_MSK,
-				      st->intio) |
+			   FIELD_PREP(ADXL345_FIFO_CTL_TRIGGER_MSK, intio) |
 			   FIELD_PREP(ADXL345_FIFO_CTL_MODE_MSK,
 				      st->fifo_mode));
 	if (ret < 0)
···
 	struct adxl345_state *st;
 	struct iio_dev *indio_dev;
 	u32 regval;
+	u8 intio = ADXL345_INT1;
 	unsigned int data_format_mask = (ADXL345_DATA_FORMAT_RANGE |
 					 ADXL345_DATA_FORMAT_JUSTIFY |
 					 ADXL345_DATA_FORMAT_FULL_RES |
···
 	if (ret < 0)
 		return ret;
 
-	st->intio = ADXL345_INT1;
 	st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT1");
 	if (st->irq < 0) {
-		st->intio = ADXL345_INT2;
+		intio = ADXL345_INT2;
 		st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "INT2");
 		if (st->irq < 0)
-			st->intio = ADXL345_INT_NONE;
+			intio = ADXL345_INT_NONE;
 	}
 
-	if (st->intio != ADXL345_INT_NONE) {
+	if (intio != ADXL345_INT_NONE) {
+		/*
+		 * Any bits set to 0 in the INT map register send their respective
+		 * interrupts to the INT1 pin, whereas bits set to 1 send their respective
+		 * interrupts to the INT2 pin. The intio shall convert this accordingly.
+		 */
+		regval = intio ? 0xff : 0;
+
+		ret = regmap_write(st->regmap, ADXL345_REG_INT_MAP, regval);
+		if (ret)
+			return ret;
+
 		/* FIFO_STREAM mode is going to be activated later */
 		ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, &adxl345_buffer_ops);
 		if (ret)

drivers/iio/accel/adxl345_i2c.c

···
 static const struct regmap_config adxl345_i2c_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
+	.volatile_reg = adxl345_is_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
 };
 
 static int adxl345_i2c_probe(struct i2c_client *client)

drivers/iio/accel/adxl345_spi.c

···
 	.val_bits = 8,
 	 /* Setting bits 7 and 6 enables multiple-byte read */
 	.read_flag_mask = BIT(7) | BIT(6),
+	.volatile_reg = adxl345_is_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
 };
 
 static int adxl345_spi_setup(struct device *dev, struct regmap *regmap)