iio: adc: Constify struct iio_map

'struct iio_map' are not modified in these drivers.

Constifying this structure moves some data to a read-only section, so
increase overall security.

In order to do it, the prototype of iio_map_array_register() and
devm_iio_map_array_register(), and a few structures that hold a
"struct iio_map *" need to be adjusted.

On a x86_64, with allmodconfig, as an example:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  21086	    760	      0	  21846	   5556	drivers/iio/adc/axp20x_adc.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  21470	    360	      0	  21830	   5546	drivers/iio/adc/axp20x_adc.o
  33842	   1697	    384	  35923	   8c53	drivers/iio/addac/ad74413r.o

--
Compile tested only

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/5729dc3cc3892ecf0d8ea28c5f7307b34e27493e.1725729801.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/axp20x_adc.c

@@ -155,7 +155,7 @@ enum axp813_adc_channel_v {
 	AXP813_BATT_V,
 };
 
-static struct iio_map axp20x_maps[] = {
+static const struct iio_map axp20x_maps[] = {
 	{
 		.consumer_dev_name = "axp20x-usb-power-supply",
 		.consumer_channel = "vbus_v",
@@ -187,7 +187,7 @@ static struct iio_map axp20x_maps[] = {
 	}, { /* sentinel */ }
 };
 
-static struct iio_map axp22x_maps[] = {
+static const struct iio_map axp22x_maps[] = {
 	{
 		.consumer_dev_name = "axp20x-battery-power-supply",
 		.consumer_channel = "batt_v",
@@ -1044,7 +1044,7 @@ struct axp_data {
 	unsigned long			adc_en2_mask;
 	int				(*adc_rate)(struct axp20x_adc_iio *info,
 						    int rate);
-	struct iio_map			*maps;
+	const struct iio_map		*maps;
 };
 
 static const struct axp_data axp192_data = {

drivers/iio/adc/axp288_adc.c

@@ -103,7 +103,7 @@ static const struct iio_chan_spec axp288_adc_channels[] = {
 };
 
 /* for consumer drivers */
-static struct iio_map axp288_adc_default_maps[] = {
+static const struct iio_map axp288_adc_default_maps[] = {
 	IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
 	IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
 	IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),

drivers/iio/adc/da9150-gpadc.c

@@ -291,7 +291,7 @@ static const struct iio_chan_spec da9150_gpadc_channels[] = {
 };
 
 /* Default maps used by da9150-charger */
-static struct iio_map da9150_gpadc_default_maps[] = {
+static const struct iio_map da9150_gpadc_default_maps[] = {
 	{
 		.consumer_dev_name = "da9150-charger",
 		.consumer_channel = "CHAN_IBUS",

drivers/iio/adc/intel_mrfld_adc.c

@@ -164,7 +164,7 @@ static const struct iio_chan_spec mrfld_adc_channels[] = {
 	BCOVE_ADC_CHANNEL(IIO_TEMP,       8, "CH8", 0xC6),
 };
 
-static struct iio_map iio_maps[] = {
+static const struct iio_map iio_maps[] = {
 	IIO_MAP("CH0", "bcove-battery", "VBATRSLT"),
 	IIO_MAP("CH1", "bcove-battery", "BATTID"),
 	IIO_MAP("CH2", "bcove-battery", "IBATRSLT"),

drivers/iio/adc/lp8788_adc.c

@@ -26,7 +26,7 @@
 
 struct lp8788_adc {
 	struct lp8788 *lp;
-	struct iio_map *map;
+	const struct iio_map *map;
 	struct mutex lock;
 };
 
@@ -149,7 +149,7 @@ static const struct iio_chan_spec lp8788_adc_channels[] = {
 };
 
 /* default maps used by iio consumer (lp8788-charger driver) */
-static struct iio_map lp8788_default_iio_maps[] = {
+static const struct iio_map lp8788_default_iio_maps[] = {
 	{
 		.consumer_dev_name = "lp8788-charger",
 		.consumer_channel = "lp8788_vbatt_5p0",
@@ -168,7 +168,7 @@ static int lp8788_iio_map_register(struct device *dev,
 				struct lp8788_platform_data *pdata,
 				struct lp8788_adc *adc)
 {
-	struct iio_map *map;
+	const struct iio_map *map;
 	int ret;
 
 	map = (!pdata || !pdata->adc_pdata) ?

drivers/iio/adc/mp2629_adc.c

@@ -52,7 +52,7 @@ static struct iio_chan_spec mp2629_channels[] = {
 	MP2629_ADC_CHAN(INPUT_CURRENT, IIO_CURRENT)
 };
 
-static struct iio_map mp2629_adc_maps[] = {
+static const struct iio_map mp2629_adc_maps[] = {
 	MP2629_MAP(BATT_VOLT, "batt-volt"),
 	MP2629_MAP(SYSTEM_VOLT, "system-volt"),
 	MP2629_MAP(INPUT_VOLT, "input-volt"),

drivers/iio/adc/rn5t618-adc.c

@@ -185,7 +185,7 @@ static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
 	RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
 };
 
-static struct iio_map rn5t618_maps[] = {
+static const struct iio_map rn5t618_maps[] = {
 	IIO_MAP("VADP", "rn5t618-power", "vadp"),
 	IIO_MAP("VUSB", "rn5t618-power", "vusb"),
 	{ /* sentinel */ }

drivers/iio/adc/sun4i-gpadc-iio.c

@@ -114,7 +114,7 @@ struct sun4i_gpadc_iio {
 	.datasheet_name = _name,				\
 }
 
-static struct iio_map sun4i_gpadc_hwmon_maps[] = {
+static const struct iio_map sun4i_gpadc_hwmon_maps[] = {
 	{
 		.adc_channel_label = "temp_adc",
 		.consumer_dev_name = "iio_hwmon.0",

drivers/iio/inkern.c

@@ -20,7 +20,7 @@
 
 struct iio_map_internal {
 	struct iio_dev *indio_dev;
-	struct iio_map *map;
+	const struct iio_map *map;
 	struct list_head l;
 };
 
@@ -42,7 +42,7 @@ static int iio_map_array_unregister_locked(struct iio_dev *indio_dev)
 	return ret;
 }
 
-int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
+int iio_map_array_register(struct iio_dev *indio_dev, const struct iio_map *maps)
 {
 	struct iio_map_internal *mapi;
 	int i = 0;
@@ -86,7 +86,8 @@ static void iio_map_array_unregister_cb(void *indio_dev)
 	iio_map_array_unregister(indio_dev);
 }
 
-int devm_iio_map_array_register(struct device *dev, struct iio_dev *indio_dev, struct iio_map *maps)
+int devm_iio_map_array_register(struct device *dev, struct iio_dev *indio_dev,
+				const struct iio_map *maps)
 {
 	int ret;
 

include/linux/iio/driver.h

@@ -18,7 +18,7 @@ struct iio_map;
  * @map:	array of mappings specifying association of channel with client
  */
 int iio_map_array_register(struct iio_dev *indio_dev,
-			   struct iio_map *map);
+			   const struct iio_map *map);
 
 /**
  * iio_map_array_unregister() - tell the core to remove consumer mappings for
@@ -38,6 +38,7 @@ int iio_map_array_unregister(struct iio_dev *indio_dev);
  * handle de-registration of the IIO map object when the device's refcount goes to
  * zero.
  */
-int devm_iio_map_array_register(struct device *dev, struct iio_dev *indio_dev, struct iio_map *maps);
+int devm_iio_map_array_register(struct device *dev, struct iio_dev *indio_dev,
+				const struct iio_map *maps);
 
 #endif