[PATCH] iio: adc: max9611: Make enum relations more future proof

[Geert Uytterhoeven <geert+renesas@xxxxxxxxx>]

The relations between enum values and array indices values are currently
not enforced by the code, which makes them fragile w.r.t. future
changes.

Fix this by:
  1. Using designated array initializers, to make sure array indices and
     enums values match,
  2. Linking max9611_csa_gain enum values to the corresponding
     max9611_conf_ids enum values, as the latter is cast to the former
     in max9611_read_csa_voltage().

No change in generated code.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
 drivers/iio/adc/max9611.c | 36 +++++++++++-------------------------
 1 file changed, 11 insertions(+), 25 deletions(-)

diff --git a/drivers/iio/adc/max9611.c b/drivers/iio/adc/max9611.c
index b0755f25356d700d..cb306ff1a5d6a0b2 100644
--- a/drivers/iio/adc/max9611.c
+++ b/drivers/iio/adc/max9611.c
@@ -114,22 +114,17 @@ enum max9611_conf_ids {
  *		      where data shall be read from
  */
 static const unsigned int max9611_mux_conf[][2] = {
-	/* CONF_SENSE_1x */
-	{ MAX9611_MUX_SENSE_1x, MAX9611_REG_CSA_DATA },
-	/* CONF_SENSE_4x */
-	{ MAX9611_MUX_SENSE_4x, MAX9611_REG_CSA_DATA },
-	/* CONF_SENSE_8x */
-	{ MAX9611_MUX_SENSE_8x, MAX9611_REG_CSA_DATA },
-	/* CONF_IN_VOLT */
-	{ MAX9611_INPUT_VOLT, MAX9611_REG_RS_DATA },
-	/* CONF_TEMP */
-	{ MAX9611_MUX_TEMP, MAX9611_REG_TEMP_DATA },
+	[CONF_SENSE_1x]	= { MAX9611_MUX_SENSE_1x, MAX9611_REG_CSA_DATA },
+	[CONF_SENSE_4x]	= { MAX9611_MUX_SENSE_4x, MAX9611_REG_CSA_DATA },
+	[CONF_SENSE_8x]	= { MAX9611_MUX_SENSE_8x, MAX9611_REG_CSA_DATA },
+	[CONF_IN_VOLT]	= { MAX9611_INPUT_VOLT, MAX9611_REG_RS_DATA },
+	[CONF_TEMP]	= { MAX9611_MUX_TEMP, MAX9611_REG_TEMP_DATA },
 };
 
 enum max9611_csa_gain {
-	CSA_GAIN_1x,
-	CSA_GAIN_4x,
-	CSA_GAIN_8x,
+	CSA_GAIN_1x = CONF_SENSE_1x,
+	CSA_GAIN_4x = CONF_SENSE_4x,
+	CSA_GAIN_8x = CONF_SENSE_8x,
 };
 
 enum max9611_csa_gain_params {
@@ -147,18 +142,9 @@ enum max9611_csa_gain_params {
  * value; use this structure to retrieve the correct LSB and offset values.
  */
 static const unsigned int max9611_gain_conf[][2] = {
-	{ /* [0] CSA_GAIN_1x */
-		MAX9611_CSA_1X_LSB_nV,
-		MAX9611_CSA_1X_OFFS_RAW,
-	},
-	{ /* [1] CSA_GAIN_4x */
-		MAX9611_CSA_4X_LSB_nV,
-		MAX9611_CSA_4X_OFFS_RAW,
-	},
-	{ /* [2] CSA_GAIN_8x */
-		MAX9611_CSA_8X_LSB_nV,
-		MAX9611_CSA_8X_OFFS_RAW,
-	},
+	[CSA_GAIN_1x] = { MAX9611_CSA_1X_LSB_nV, MAX9611_CSA_1X_OFFS_RAW, },
+	[CSA_GAIN_4x] = { MAX9611_CSA_4X_LSB_nV, MAX9611_CSA_4X_OFFS_RAW, },
+	[CSA_GAIN_8x] = { MAX9611_CSA_8X_LSB_nV, MAX9611_CSA_8X_OFFS_RAW, },
 };
 
 enum max9611_chan_addrs {
-- 
2.17.1