[PATCH v5 06/11] iio: adc: hx711: introduce hx711_chip_info structure

[Piyush Patle <piyushpatle228@gmail.com>]

Add a per-variant static configuration structure and populate the IIO
device fields from it at probe time.

This is a preparatory change for adding support for more HX711-compatible
hardware variants without duplicating the probe-time setup.

No functional change for existing HX711 users.

Signed-off-by: Piyush Patle <piyushpatle228@gmail.com>
---
Changes in v5:
- State explicitly that this is preparatory for adding another
  HX711-compatible variant.
- Move linux/array_size.h and linux/dev_printk.h here where they become
  needed.
- Use "missing driver data" for the NULL guard and preserve local
  declaration ordering.
Changes in v4:
- New patch split out from the earlier refactor during review.
- Keep hx711_chip_info fields in their final order from introduction.
- Add the NULL guard on device_get_match_data().
---
drivers/iio/adc/hx711.c | 43 +++++++++++++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
index 8485e18c949d..666f64284a0d 100644
--- a/drivers/iio/adc/hx711.c
+++ b/drivers/iio/adc/hx711.c
@@ -4,6 +4,8 @@
  *
  * Copyright (c) 2016 Andreas Klinger <ak@it-klinger.de>
  */
+#include <linux/array_size.h>
+#include <linux/dev_printk.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -74,6 +76,20 @@ static int hx711_get_scale_to_gain(const int *gain_scale, int scale)
 	return -EINVAL;
 }
 
+/**
+ * struct hx711_chip_info - per-variant static configuration
+ * @name: IIO device name
+ * @channels: channel specification array
+ * @iio_info: IIO info ops for this variant
+ * @num_channels: number of entries in @channels
+ */
+struct hx711_chip_info {
+	const char			*name;
+	const struct iio_chan_spec	*channels;
+	const struct iio_info		*iio_info;
+	unsigned int			num_channels;
+};
+
 struct hx711_data {
 	struct device		*dev;
 	struct gpio_desc	*gpiod_pd_sck;
@@ -81,6 +97,7 @@ struct hx711_data {
 	int			gain_set;	/* gain set on device */
 	int			gain_chan_a;	/* gain for channel A */
 	int			gain_scale[HX711_GAIN_MAX];
+	const struct hx711_chip_info	*chip_info;
 	struct mutex		lock;
 	/*
 	 * triggered buffer
@@ -456,11 +473,19 @@ static const struct iio_chan_spec hx711_chan_spec[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(2),
 };
 
+static const struct hx711_chip_info hx711_chip = {
+	.name		= "hx711",
+	.channels	= hx711_chan_spec,
+	.iio_info	= &hx711_iio_info,
+	.num_channels	= ARRAY_SIZE(hx711_chan_spec),
+};
+
 static int hx711_probe(struct platform_device *pdev)
 {
-	struct device *dev = &pdev->dev;
+	const struct hx711_chip_info *chip_info;
 	struct hx711_data *hx711_data;
 	struct iio_dev *indio_dev;
+	struct device *dev = &pdev->dev;
 	int ret;
 	int i;
 
@@ -473,6 +498,12 @@ static int hx711_probe(struct platform_device *pdev)
 
 	mutex_init(&hx711_data->lock);
 
+	chip_info = device_get_match_data(dev);
+	if (!chip_info)
+		return dev_err_probe(dev, -ENODEV, "missing driver data\n");
+
+	hx711_data->chip_info = chip_info;
+
 	/*
 	 * PD_SCK stands for power down and serial clock input of HX711
 	 * in the driver it is an output
@@ -534,11 +565,11 @@ static int hx711_probe(struct platform_device *pdev)
 	hx711_data->data_ready_delay_ns =
 				1000000000 / hx711_data->clock_frequency;
 
-	indio_dev->name = "hx711";
-	indio_dev->info = &hx711_iio_info;
+	indio_dev->name = chip_info->name;
+	indio_dev->info = chip_info->iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = hx711_chan_spec;
-	indio_dev->num_channels = ARRAY_SIZE(hx711_chan_spec);
+	indio_dev->channels = chip_info->channels;
+	indio_dev->num_channels = chip_info->num_channels;
 
 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 					      iio_pollfunc_store_time,
@@ -555,7 +586,7 @@ static int hx711_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id of_hx711_match[] = {
-	{ .compatible = "avia,hx711", },
+	{ .compatible = "avia,hx711", .data = &hx711_chip },
 	{ }
 };
 
-- 
2.43.0