iio: adc: ad7091r: Add chip_info callback to get conversion result channel

AD7091R-5 and AD7091R-2/-4/-8 have slightly different register field
layout and due to that require different masks for getting the index of
the channel associated with each read.
Add a callback function so the base driver can get correct channel ID
for each chip variant.

Signed-off-by: Marcelo Schmitt <[e-mail]>
Link: https://lore.kernel.org/r/1f7a40b4[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ad7091r-base.c

···
 
 #include "ad7091r-base.h"
 
-/* AD7091R_REG_RESULT */
-#define AD7091R_REG_RESULT_CH_ID(x)	    (((x) >> 13) & 0x3)
-#define AD7091R_REG_RESULT_CONV_RESULT(x)   ((x) & 0xfff)
-
 const struct iio_event_spec ad7091r_events[] = {
 	{
 		.type = IIO_EV_TYPE_THRESH,
···
 	if (ret)
 		return ret;
 
-	if (AD7091R_REG_RESULT_CH_ID(val) != channel)
+	if (st->chip_info->reg_result_chan_id(val) != channel)
 		return -EIO;
 
 	*read_val = AD7091R_REG_RESULT_CONV_RESULT(val);

drivers/iio/adc/ad7091r-base.h

···
 #define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5)
 #define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
 
+/* AD7091R_REG_RESULT */
+#define AD7091R5_REG_RESULT_CH_ID(x)	    (((x) >> 13) & 0x3)
+#define AD7091R8_REG_RESULT_CH_ID(x)	    (((x) >> 13) & 0x7)
+#define AD7091R_REG_RESULT_CONV_RESULT(x)   ((x) & 0xfff)
+
 /* AD7091R_REG_CONF */
 #define AD7091R_REG_CONF_INT_VREF	BIT(0)
 #define AD7091R_REG_CONF_ALERT_EN	BIT(4)
···
 	unsigned int num_channels;
 	const struct iio_chan_spec *channels;
 	unsigned int vref_mV;
+	unsigned int (*reg_result_chan_id)(unsigned int val);
 	int (*set_mode)(struct ad7091r_state *st, enum ad7091r_mode mode);
 };
 

drivers/iio/adc/ad7091r5.c

···
 	return 0;
 }
 
+static unsigned int ad7091r5_reg_result_chan_id(unsigned int val)
+{
+	return AD7091R5_REG_RESULT_CH_ID(val);
+}
+
 static const struct ad7091r_chip_info ad7091r5_chip_info_irq = {
 	.name = "ad7091r-5",
 	.channels = ad7091r5_channels_irq,
 	.num_channels = ARRAY_SIZE(ad7091r5_channels_irq),
 	.vref_mV = 2500,
+	.reg_result_chan_id = &ad7091r5_reg_result_chan_id,
 	.set_mode = &ad7091r5_set_mode,
 };
 
···
 	.channels = ad7091r5_channels_noirq,
 	.num_channels = ARRAY_SIZE(ad7091r5_channels_noirq),
 	.vref_mV = 2500,
+	.reg_result_chan_id = &ad7091r5_reg_result_chan_id,
 	.set_mode = &ad7091r5_set_mode,
 };