iio: adc: ad7124: move chip ID & name on the chip_info table

This change does the following:
* removes the SPI device table in favor of the OF device table
* adds 'name' && 'chip_id' fields to chip_info
* implements chip ID & silicon revision checking; the device ID for
  AD7124-4 is 0x0, so just checking that value can be useless;
  but at least the silicon revision isn't 0, so a non-zero value can be
  used to check that "a" device is on the SPI bus; it's probably the best
  way to narrow it down to one of the 2 AD7124 chip IDs

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index bb53ab2..8dce06e 100644 (file)
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -12,6 +12,7 @@
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
 
@@ -47,6 +48,15 @@
 #define AD7124_ADC_CTRL_MODE_MSK       GENMASK(5, 2)
 #define AD7124_ADC_CTRL_MODE(x)        FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
 
+/* AD7124 ID */
+#define AD7124_DEVICE_ID_MSK           GENMASK(7, 4)
+#define AD7124_DEVICE_ID_GET(x)                FIELD_GET(AD7124_DEVICE_ID_MSK, x)
+#define AD7124_SILICON_REV_MSK         GENMASK(3, 0)
+#define AD7124_SILICON_REV_GET(x)      FIELD_GET(AD7124_SILICON_REV_MSK, x)
+
+#define CHIPID_AD7124_4                        0x0
+#define CHIPID_AD7124_8                        0x1
+
 /* AD7124_CHANNEL_X */
 #define AD7124_CHANNEL_EN_MSK          BIT(15)
 #define AD7124_CHANNEL_EN(x)           FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
@@ -120,6 +130,8 @@ static const char * const ad7124_ref_names[] = {
 };
 
 struct ad7124_chip_info {
+       const char *name;
+       unsigned int chip_id;
        unsigned int num_inputs;
 };
 
@@ -165,9 +177,13 @@ static const struct iio_chan_spec ad7124_channel_template = {
 
 static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
        [ID_AD7124_4] = {
+               .name = "ad7127-4",
+               .chip_id = CHIPID_AD7124_4,
                .num_inputs = 8,
        },
        [ID_AD7124_8] = {
+               .name = "ad7127-8",
+               .chip_id = CHIPID_AD7124_8,
                .num_inputs = 16,
        },
 };
@@ -503,6 +519,34 @@ static int ad7124_soft_reset(struct ad7124_state *st)
        return -EIO;
 }
 
+static int ad7124_check_chip_id(struct ad7124_state *st)
+{
+       unsigned int readval, chip_id, silicon_rev;
+       int ret;
+
+       ret = ad_sd_read_reg(&st->sd, AD7124_ID, 1, &readval);
+       if (ret < 0)
+               return ret;
+
+       chip_id = AD7124_DEVICE_ID_GET(readval);
+       silicon_rev = AD7124_SILICON_REV_GET(readval);
+
+       if (chip_id != st->chip_info->chip_id) {
+               dev_err(&st->sd.spi->dev,
+                       "Chip ID mismatch: expected %u, got %u\n",
+                       st->chip_info->chip_id, chip_id);
+               return -ENODEV;
+       }
+
+       if (silicon_rev == 0) {
+               dev_err(&st->sd.spi->dev,
+                       "Silicon revision empty. Chip may not be present\n");
+               return -ENODEV;
+       }
+
+       return 0;
+}
+
 static int ad7124_init_channel_vref(struct ad7124_state *st,
                                    unsigned int channel_number)
 {
@@ -665,25 +709,28 @@ static int ad7124_setup(struct ad7124_state *st)
 
 static int ad7124_probe(struct spi_device *spi)
 {
-       const struct spi_device_id *id;
+       const struct ad7124_chip_info *info;
        struct ad7124_state *st;
        struct iio_dev *indio_dev;
        int i, ret;
 
+       info = of_device_get_match_data(&spi->dev);
+       if (!info)
+               return -ENODEV;
+
        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
        if (!indio_dev)
                return -ENOMEM;
 
        st = iio_priv(indio_dev);
 
-       id = spi_get_device_id(spi);
-       st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
+       st->chip_info = info;
 
        ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
 
        spi_set_drvdata(spi, indio_dev);
 
-       indio_dev->name = spi_get_device_id(spi)->name;
+       indio_dev->name = st->chip_info->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &ad7124_info;
 
@@ -721,6 +768,10 @@ static int ad7124_probe(struct spi_device *spi)
        if (ret < 0)
                goto error_clk_disable_unprepare;
 
+       ret = ad7124_check_chip_id(st);
+       if (ret)
+               goto error_clk_disable_unprepare;
+
        ret = ad7124_setup(st);
        if (ret < 0)
                goto error_clk_disable_unprepare;
@@ -768,16 +819,11 @@ static int ad7124_remove(struct spi_device *spi)
        return 0;
 }
 
-static const struct spi_device_id ad7124_id_table[] = {
-       { "ad7124-4", ID_AD7124_4 },
-       { "ad7124-8", ID_AD7124_8 },
-       {}
-};
-MODULE_DEVICE_TABLE(spi, ad7124_id_table);
-
 static const struct of_device_id ad7124_of_match[] = {
-       { .compatible = "adi,ad7124-4" },
-       { .compatible = "adi,ad7124-8" },
+       { .compatible = "adi,ad7124-4",
+               .data = &ad7124_chip_info_tbl[ID_AD7124_4], },
+       { .compatible = "adi,ad7124-8",
+               .data = &ad7124_chip_info_tbl[ID_AD7124_8], },
        { },
 };
 MODULE_DEVICE_TABLE(of, ad7124_of_match);
@@ -789,7 +835,6 @@ static struct spi_driver ad71124_driver = {
        },
        .probe = ad7124_probe,
        .remove = ad7124_remove,
-       .id_table = ad7124_id_table,
 };
 module_spi_driver(ad71124_driver);