Convert the driver to platform specific structures. This means:
- create a register layout struct that will hold offsets for registers
- create a platform struct that will hold platform information (number of
channels, indexes for different channels and pointer to layout struct)
- convert specific macros that are platform dependent into platform variables

This step is in fact a no-op, but allows the driver to be more flexible
and for future enhancement including adding new platforms that are partly
compatible with the current driver and differ slightly in register layout
or capabilities for example.

Signed-off-by: Eugen Hristev <redacted>
---
 drivers/iio/adc/at91-sama5d2_adc.c | 410 +++++++++++++++++------------
 1 file changed, 247 insertions(+), 163 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 9d71dcffcf93..8ede18b8d789 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c

@@ -27,8 +27,9 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/regulator/consumer.h>
 
+struct at91_adc_reg_layout {
 /* Control Register */
-#define AT91_SAMA5D2_CR		0x00
+	u16				CR;
 /* Software Reset */
 #define	AT91_SAMA5D2_CR_SWRST		BIT(0)
 /* Start Conversion */

@@ -39,7 +40,7 @@
 #define	AT91_SAMA5D2_CR_CMPRST		BIT(4)
 
 /* Mode Register */
-#define AT91_SAMA5D2_MR		0x04
+	u16				MR;
 /* Trigger Selection */
 #define	AT91_SAMA5D2_MR_TRGSEL(v)	((v) << 1)
 /* ADTRG */

@@ -82,19 +83,19 @@
 #define	AT91_SAMA5D2_MR_USEQ		BIT(31)
 
 /* Channel Sequence Register 1 */
-#define AT91_SAMA5D2_SEQR1	0x08
+	u16				SEQR1;
 /* Channel Sequence Register 2 */
-#define AT91_SAMA5D2_SEQR2	0x0c
+	u16				SEQR2;
 /* Channel Enable Register */
-#define AT91_SAMA5D2_CHER	0x10
+	u16				CHER;
 /* Channel Disable Register */
-#define AT91_SAMA5D2_CHDR	0x14
+	u16				CHDR;
 /* Channel Status Register */
-#define AT91_SAMA5D2_CHSR	0x18
+	u16				CHSR;
 /* Last Converted Data Register */
-#define AT91_SAMA5D2_LCDR	0x20
+	u16				LCDR;
 /* Interrupt Enable Register */
-#define AT91_SAMA5D2_IER	0x24
+	u16				IER;
 /* Interrupt Enable Register - TS X measurement ready */
 #define AT91_SAMA5D2_IER_XRDY   BIT(20)
 /* Interrupt Enable Register - TS Y measurement ready */

@@ -109,22 +110,23 @@
 #define AT91_SAMA5D2_IER_PEN    BIT(29)
 /* Interrupt Enable Register - No pen detect */
 #define AT91_SAMA5D2_IER_NOPEN  BIT(30)
+
 /* Interrupt Disable Register */
-#define AT91_SAMA5D2_IDR	0x28
+	u16				IDR;
 /* Interrupt Mask Register */
-#define AT91_SAMA5D2_IMR	0x2c
+	u16				IMR;
 /* Interrupt Status Register */
-#define AT91_SAMA5D2_ISR	0x30
+	u16				ISR;
 /* Interrupt Status Register - Pen touching sense status */
 #define AT91_SAMA5D2_ISR_PENS   BIT(31)
 /* Last Channel Trigger Mode Register */
-#define AT91_SAMA5D2_LCTMR	0x34
+	u16				LCTMR;
 /* Last Channel Compare Window Register */
-#define AT91_SAMA5D2_LCCWR	0x38
+	u16				LCCWR;
 /* Overrun Status Register */
-#define AT91_SAMA5D2_OVER	0x3c
+	u16				OVER;
 /* Extended Mode Register */
-#define AT91_SAMA5D2_EMR	0x40
+	u16				EMR;
 /* Extended Mode Register - Oversampling rate */
 #define AT91_SAMA5D2_EMR_OSR(V)			((V) << 16)
 #define AT91_SAMA5D2_EMR_OSR_MASK		GENMASK(17, 16)

@@ -134,22 +136,22 @@
 
 /* Extended Mode Register - Averaging on single trigger event */
 #define AT91_SAMA5D2_EMR_ASTE(V)		((V) << 20)
+
 /* Compare Window Register */
-#define AT91_SAMA5D2_CWR	0x44
+	u16				CWR;
 /* Channel Gain Register */
-#define AT91_SAMA5D2_CGR	0x48
-
+	u16				CGR;
 /* Channel Offset Register */
-#define AT91_SAMA5D2_COR	0x4c
+	u16				COR;
 #define AT91_SAMA5D2_COR_DIFF_OFFSET	16
 
 /* Analog Control Register */
-#define AT91_SAMA5D2_ACR	0x94
+	u16				ACR;
 /* Analog Control Register - Pen detect sensitivity mask */
 #define AT91_SAMA5D2_ACR_PENDETSENS_MASK        GENMASK(1, 0)
 
 /* Touchscreen Mode Register */
-#define AT91_SAMA5D2_TSMR	0xb0
+	u16				TSMR;
 /* Touchscreen Mode Register - No touch mode */
 #define AT91_SAMA5D2_TSMR_TSMODE_NONE           0
 /* Touchscreen Mode Register - 4 wire screen, no pressure measurement */

@@ -178,13 +180,13 @@
 #define AT91_SAMA5D2_TSMR_PENDET_ENA            BIT(24)
 
 /* Touchscreen X Position Register */
-#define AT91_SAMA5D2_XPOSR	0xb4
+	u16				XPOSR;
 /* Touchscreen Y Position Register */
-#define AT91_SAMA5D2_YPOSR	0xb8
+	u16				YPOSR;
 /* Touchscreen Pressure Register */
-#define AT91_SAMA5D2_PRESSR	0xbc
+	u16				PRESSR;
 /* Trigger Register */
-#define AT91_SAMA5D2_TRGR	0xc0
+	u16				TRGR;
 /* Mask for TRGMOD field of TRGR register */
 #define AT91_SAMA5D2_TRGR_TRGMOD_MASK GENMASK(2, 0)
 /* No trigger, only software trigger can start conversions */

@@ -203,30 +205,52 @@
 #define AT91_SAMA5D2_TRGR_TRGPER(x)             ((x) << 16)
 
 /* Correction Select Register */
-#define AT91_SAMA5D2_COSR	0xd0
+	u16				COSR;
 /* Correction Value Register */
-#define AT91_SAMA5D2_CVR	0xd4
+	u16				CVR;
 /* Channel Error Correction Register */
-#define AT91_SAMA5D2_CECR	0xd8
+	u16				CECR;
 /* Write Protection Mode Register */
-#define AT91_SAMA5D2_WPMR	0xe4
+	u16				WPMR;
 /* Write Protection Status Register */
-#define AT91_SAMA5D2_WPSR	0xe8
+	u16				WPSR;
 /* Version Register */
-#define AT91_SAMA5D2_VERSION	0xfc
-
-#define AT91_SAMA5D2_HW_TRIG_CNT 3
-#define AT91_SAMA5D2_SINGLE_CHAN_CNT 12
-#define AT91_SAMA5D2_DIFF_CHAN_CNT 6
-
-#define AT91_SAMA5D2_TIMESTAMP_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
-					 AT91_SAMA5D2_DIFF_CHAN_CNT + 1)
+	u16				VERSION;
+};
 
-#define AT91_SAMA5D2_TOUCH_X_CHAN_IDX (AT91_SAMA5D2_SINGLE_CHAN_CNT + \
-					 AT91_SAMA5D2_DIFF_CHAN_CNT * 2)
-#define AT91_SAMA5D2_TOUCH_Y_CHAN_IDX   (AT91_SAMA5D2_TOUCH_X_CHAN_IDX + 1)
-#define AT91_SAMA5D2_TOUCH_P_CHAN_IDX   (AT91_SAMA5D2_TOUCH_Y_CHAN_IDX + 1)
-#define AT91_SAMA5D2_MAX_CHAN_IDX	AT91_SAMA5D2_TOUCH_P_CHAN_IDX
+static const struct at91_adc_reg_layout sama5d2_layout = {
+	.CR =			0x00,
+	.MR =			0x04,
+	.SEQR1 =		0x08,
+	.SEQR2 =		0x0c,
+	.CHER =			0x10,
+	.CHDR =			0x14,
+	.CHSR =			0x18,
+	.LCDR =			0x20,
+	.IER =			0x24,
+	.IDR =			0x28,
+	.IMR =			0x2c,
+	.ISR =			0x30,
+	.LCTMR =		0x34,
+	.LCCWR =		0x38,
+	.OVER =			0x3c,
+	.EMR =			0x40,
+	.CWR =			0x44,
+	.CGR =			0x48,
+	.COR =			0x4c,
+	.ACR =			0x94,
+	.TSMR =			0xb0,
+	.XPOSR =		0xb4,
+	.YPOSR =		0xb8,
+	.PRESSR =		0xbc,
+	.TRGR =			0xc0,
+	.COSR =			0xd0,
+	.CVR =			0xd4,
+	.CECR =			0xd8,
+	.WPMR =			0xe4,
+	.WPSR =			0xe8,
+	.VERSION =		0xfc,
+};
 
 #define AT91_SAMA5D2_TOUCH_SAMPLE_PERIOD_US          2000    /* 2ms */
 #define AT91_SAMA5D2_TOUCH_PEN_DETECT_DEBOUNCE_US    200

@@ -235,18 +259,6 @@
 
 #define AT91_SAMA5D2_MAX_POS_BITS			12
 
-/*
- * Maximum number of bytes to hold conversion from all channels
- * without the timestamp.
- */
-#define AT91_BUFFER_MAX_CONVERSION_BYTES ((AT91_SAMA5D2_SINGLE_CHAN_CNT + \
-					 AT91_SAMA5D2_DIFF_CHAN_CNT) * 2)
-
-/* This total must also include the timestamp */
-#define AT91_BUFFER_MAX_BYTES (AT91_BUFFER_MAX_CONVERSION_BYTES + 8)
-
-#define AT91_BUFFER_MAX_HWORDS (AT91_BUFFER_MAX_BYTES / 2)
-
 #define AT91_HWFIFO_MAX_SIZE_STR	"128"
 #define AT91_HWFIFO_MAX_SIZE		128
 

@@ -255,12 +267,12 @@
 #define AT91_OSR_4SAMPLES		4
 #define AT91_OSR_16SAMPLES		16
 
-#define AT91_SAMA5D2_CHAN_SINGLE(num, addr)				\
+#define AT91_SAMA5D2_CHAN_SINGLE(index, num, addr)			\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.channel = num,						\
 		.address = addr,					\
-		.scan_index = num,					\
+		.scan_index = index,					\
 		.scan_type = {						\
 			.sign = 'u',					\
 			.realbits = 14,					\

@@ -274,14 +286,14 @@
 		.indexed = 1,						\
 	}
 
-#define AT91_SAMA5D2_CHAN_DIFF(num, num2, addr)				\
+#define AT91_SAMA5D2_CHAN_DIFF(index, num, num2, addr)			\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.differential = 1,					\
 		.channel = num,						\
 		.channel2 = num2,					\
 		.address = addr,					\
-		.scan_index = num + AT91_SAMA5D2_SINGLE_CHAN_CNT,	\
+		.scan_index = index,					\
 		.scan_type = {						\
 			.sign = 's',					\
 			.realbits = 14,					\

@@ -328,13 +340,48 @@
 		.datasheet_name = name,					\
 	}
 
-#define at91_adc_readl(st, reg)		readl_relaxed(st->base + reg)
-#define at91_adc_writel(st, reg, val)	writel_relaxed(val, st->base + reg)
+#define at91_adc_readl(st, reg)						\
+	readl_relaxed((st)->base + (st)->soc_info.platform->layout->reg)