iio: adc: rzg2l_adc: Use adc-helpers

The new devm_iio_adc_device_alloc_chaninfo_se() -helper is intended to
help drivers avoid open-coding the for_each_node -loop for getting the
channel IDs. The helper provides standard way to detect the ADC channel
nodes (by the node name), and a standard way to convert the "reg"
-properties to channel identification numbers, used in the struct
iio_chan_spec. Furthermore, the helper can optionally check the found
channel IDs are smaller than given maximum. This is useful for callers
which later use the IDs for example for indexing a channel data array.

The original driver treated all found child nodes as channel nodes. The
new helper requires channel nodes to be named channel[@N]. This should
help avoid problems with devices which may contain also other but ADC
child nodes. Quick grep from arch/* with the rzg2l_adc's compatible
string didn't reveal any in-tree .dts with channel nodes named
otherwise. Also, same grep shows all the .dts seem to have channel IDs
between 0..num of channels.

Use the new helper.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/e84ccff01070eaee3dd1ae2d7e109f963168f586.1742560649.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index b210d6371a02e6bf18e62cb34f6a6236a5bc25c1..57ea8cd464ca33e615e4a4bc2cc624f960a94da4 100644 (file)
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1266,6 +1266,7 @@ config RICHTEK_RTQ6056
 config RZG2L_ADC
        tristate "Renesas RZ/G2L ADC driver"
        depends on ARCH_RZG2L || COMPILE_TEST
+       select IIO_ADC_HELPER
        help
          Say yes here to build support for the ADC found in Renesas
          RZ/G2L family.

diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
index 883c167c0670e2745d68bbca4ad1201737dc2a33..8097e59da5160ce9c130cbc613c1fb43f922dda6 100644 (file)
--- a/drivers/iio/adc/rzg2l_adc.c
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -11,6 +11,7 @@
 #include <linux/cleanup.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
+#include <linux/iio/adc-helpers.h>
 #include <linux/iio/iio.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -324,48 +325,39 @@ static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+static const struct iio_chan_spec rzg2l_adc_chan_template = {
+       .indexed = 1,
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+};
+
 static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l_adc *adc)
 {
        const struct rzg2l_adc_hw_params *hw_params = adc->hw_params;
        struct iio_chan_spec *chan_array;
        struct rzg2l_adc_data *data;
-       unsigned int channel;
        int num_channels;
-       int ret;
        u8 i;
 
        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;
 
-       num_channels = device_get_child_node_count(&pdev->dev);
-       if (!num_channels)
-               return dev_err_probe(&pdev->dev, -ENODEV, "no channel children\n");
+       num_channels = devm_iio_adc_device_alloc_chaninfo_se(&pdev->dev,
+                                               &rzg2l_adc_chan_template,
+                                               hw_params->num_channels - 1,
+                                               &chan_array);
+       if (num_channels < 0)
+               return num_channels;
 
        if (num_channels > hw_params->num_channels)
                return dev_err_probe(&pdev->dev, -EINVAL,
                                     "num of channel children out of range\n");
 
-       chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
-                                 GFP_KERNEL);
-       if (!chan_array)
-               return -ENOMEM;
+       for (i = 0; i < num_channels; i++) {
+               int channel = chan_array[i].channel;
 
-       i = 0;
-       device_for_each_child_node_scoped(&pdev->dev, fwnode) {
-               ret = fwnode_property_read_u32(fwnode, "reg", &channel);
-               if (ret)
-                       return ret;
-
-               if (channel >= hw_params->num_channels)
-                       return -EINVAL;
-
-               chan_array[i].type = rzg2l_adc_channels[channel].type;
-               chan_array[i].indexed = 1;
-               chan_array[i].channel = channel;
-               chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
                chan_array[i].datasheet_name = rzg2l_adc_channels[channel].name;
-               i++;
+               chan_array[i].type = rzg2l_adc_channels[channel].type;
        }
 
        data->num_channels = num_channels;
@@ -626,3 +618,4 @@ module_platform_driver(rzg2l_adc_driver);
 MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>");
 MODULE_DESCRIPTION("Renesas RZ/G2L ADC driver");
 MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS("IIO_DRIVER");