iio: amplifiers: ad8366: prepare for device-tree support

Drop switch case on the enum ID in favor of extended chip info table,
containing:
- gain_step, indicating with sign the start of the code range;
- num_channels, to indicate the number IIO channels;
- pack_code() function to describe how SPI buffer is populated;

Which allowed for a simplified read_raw() and write_raw() callbacks. The
probe() function was adjusted accordingly. The linux/array_size.h include
is removed as number of channels is provided by chip info table.

Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 44 insertions, 90 deletions

diff --git a/drivers/iio/amplifiers/ad8366.c b/drivers/iio/amplifiers/ad8366.c
index 8b3d6825423e..22eb6c9bb0f6 100644
--- a/drivers/iio/amplifiers/ad8366.c
+++ b/drivers/iio/amplifiers/ad8366.c
@@ -11,7 +11,6 @@
  * Copyright 2012-2019 Analog Devices Inc.
  */
 
-#include <linux/array_size.h>
 #include <linux/bitrev.h>
 #include <linux/bits.h>
 #include <linux/dev_printk.h>
@@ -26,6 +25,7 @@
 #include <linux/reset.h>
 #include <linux/spi/spi.h>
 #include <linux/types.h>
+#include <linux/unaligned.h>
 
 #include <linux/iio/iio.h>
 
@@ -40,13 +40,16 @@ enum ad8366_type {
 struct ad8366_info {
 	int gain_min;
 	int gain_max;
+	int gain_step;
+	size_t num_channels;
+	size_t (*pack_code)(const unsigned char *code, size_t num_channels,
+			    unsigned char *data);
 };
 
 struct ad8366_state {
 	struct spi_device	*spi;
 	struct mutex            lock; /* protect sensor state */
 	unsigned char		ch[2];
-	enum ad8366_type	type;
 	const struct ad8366_info *info;
 	/*
 	 * DMA (thus cache coherency maintenance) may require the
@@ -55,60 +58,61 @@ struct ad8366_state {
 	unsigned char		data[2] __aligned(IIO_DMA_MINALIGN);
 };
 
+static size_t ad8366_pack_code(const unsigned char *code, size_t num_channels,
+			       unsigned char *data)
+{
+	u8 ch_a = bitrev8(code[0]) >> 2;
+	u8 ch_b = bitrev8(code[1]) >> 2;
+
+	put_unaligned_be16((ch_b << 6) | ch_a, &data[0]);
+	return sizeof(__be16);
+}
+
 static const struct ad8366_info ad8366_infos[] = {
 	[ID_AD8366] = {
 		.gain_min = 4500,
 		.gain_max = 20500,
+		.gain_step = 253,
+		.num_channels = 2,
+		.pack_code = ad8366_pack_code,
 	},
 	[ID_ADA4961] = {
 		.gain_min = -6000,
 		.gain_max = 15000,
+		.gain_step = -1000,
+		.num_channels = 1,
 	},
 	[ID_ADL5240] = {
 		.gain_min = -11500,
 		.gain_max = 20000,
+		.gain_step = 500,
+		.num_channels = 1,
 	},
 	[ID_HMC792] = {
 		.gain_min = -15750,
 		.gain_max = 0,
+		.gain_step = 250,
+		.num_channels = 1,
 	},
 	[ID_HMC1119] = {
 		.gain_min = -31750,
 		.gain_max = 0,
+		.gain_step = -250,
+		.num_channels = 1,
 	},
 };
 
-static int ad8366_write(struct iio_dev *indio_dev,
-			unsigned char ch_a, unsigned char ch_b)
+static int ad8366_write_code(struct ad8366_state *st)
 {
-	struct ad8366_state *st = iio_priv(indio_dev);
-	int ret;
-
-	switch (st->type) {
-	case ID_AD8366:
-		ch_a = bitrev8(ch_a & 0x3F);
-		ch_b = bitrev8(ch_b & 0x3F);
-
-		st->data[0] = ch_b >> 4;
-		st->data[1] = (ch_b << 4) | (ch_a >> 2);
-		break;
-	case ID_ADA4961:
-		st->data[0] = ch_a & 0x1F;
-		break;
-	case ID_ADL5240:
-		st->data[0] = (ch_a & 0x3F);
-		break;
-	case ID_HMC792:
-	case ID_HMC1119:
-		st->data[0] = ch_a;
-		break;
-	}
+	const struct ad8366_info *inf = st->info;
+	size_t len = 1;
 
-	ret = spi_write(st->spi, st->data, indio_dev->num_channels);
-	if (ret < 0)
-		dev_err(&indio_dev->dev, "write failed (%d)", ret);
+	if (inf->pack_code)
+		len = inf->pack_code(st->ch, inf->num_channels, st->data);
+	else
+		st->data[0] = st->ch[0];
 
-	return ret;
+	return spi_write(st->spi, st->data, len);
 }
 
 static int ad8366_read_raw(struct iio_dev *indio_dev,
@@ -118,6 +122,7 @@ static int ad8366_read_raw(struct iio_dev *indio_dev,
 			   long m)
 {
 	struct ad8366_state *st = iio_priv(indio_dev);
+	const struct ad8366_info *inf = st->info;
 	int ret;
 	int code, gain = 0;
 
@@ -125,25 +130,8 @@ static int ad8366_read_raw(struct iio_dev *indio_dev,
 	switch (m) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		code = st->ch[chan->channel];
-
-		switch (st->type) {
-		case ID_AD8366:
-			gain = code * 253 + 4500;
-			break;
-		case ID_ADA4961:
-			gain = 15000 - code * 1000;
-			break;
-		case ID_ADL5240:
-			gain = 20000 - 31500 + code * 500;
-			break;
-		case ID_HMC792:
-			gain = -1 * code * 500;
-			break;
-		case ID_HMC1119:
-			gain = -1 * code * 250;
-			break;
-		}
-
+		gain = inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
+		gain += inf->gain_step * code;
 		/* Values in dB */
 		*val = gain / 1000;
 		*val2 = (gain % 1000) * 1000;
@@ -178,29 +166,14 @@ static int ad8366_write_raw(struct iio_dev *indio_dev,
 	if (gain > inf->gain_max || gain < inf->gain_min)
 		return -EINVAL;
 
-	switch (st->type) {
-	case ID_AD8366:
-		code = (gain - 4500) / 253;
-		break;
-	case ID_ADA4961:
-		code = (15000 - gain) / 1000;
-		break;
-	case ID_ADL5240:
-		code = ((gain - 500 - 20000) / 500) & 0x3F;
-		break;
-	case ID_HMC792:
-		code = (abs(gain) / 500) & 0x3F;
-		break;
-	case ID_HMC1119:
-		code = (abs(gain) / 250) & 0x7F;
-		break;
-	}
+	gain -= inf->gain_step > 0 ? inf->gain_min : inf->gain_max;
+	code = DIV_ROUND_CLOSEST(gain, inf->gain_step);
 
 	mutex_lock(&st->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		st->ch[chan->channel] = code;
-		ret = ad8366_write(indio_dev, st->ch[0], st->ch[1]);
+		ret = ad8366_write_code(st);
 		break;
 	default:
 		ret = -EINVAL;
@@ -241,10 +214,6 @@ static const struct iio_chan_spec ad8366_channels[] = {
 	AD8366_CHAN(1),
 };
 
-static const struct iio_chan_spec ada4961_channels[] = {
-	AD8366_CHAN(0),
-};
-
 static int ad8366_probe(struct spi_device *spi)
 {
 	struct device *dev = &spi->dev;
@@ -268,35 +237,20 @@ static int ad8366_probe(struct spi_device *spi)
 		return dev_err_probe(dev, ret, "Failed to get regulator\n");
 
 	st->spi = spi;
-	st->type = spi_get_device_id(spi)->driver_data;
-
-	switch (st->type) {
-	case ID_AD8366:
-		indio_dev->channels = ad8366_channels;
-		indio_dev->num_channels = ARRAY_SIZE(ad8366_channels);
-		break;
-	case ID_ADA4961:
-	case ID_ADL5240:
-	case ID_HMC792:
-	case ID_HMC1119:
-		indio_dev->channels = ada4961_channels;
-		indio_dev->num_channels = ARRAY_SIZE(ada4961_channels);
-		break;
-	default:
-		return dev_err_probe(dev, -EINVAL, "Invalid device ID\n");
-	}
+	st->info = &ad8366_infos[spi_get_device_id(spi)->driver_data];
 
 	rstc = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
 	if (IS_ERR(rstc))
 		return dev_err_probe(dev, PTR_ERR(rstc),
 				     "Failed to get reset controller\n");
 
-	st->info = &ad8366_infos[st->type];
 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->info = &ad8366_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ad8366_channels;
+	indio_dev->num_channels = st->info->num_channels;
 
-	ret = ad8366_write(indio_dev, 0, 0);
+	ret = ad8366_write_code(st);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "failed to write initial gain\n");