iio: magnetometer: ak8974: debug AMI306 calibration data

Use AMI306 calibration data for randomness and debugging.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index 866f20b818b182d83123dd7830d1ca1853dab42f..0bff76e96950e685ed08e26988ba8057d2eec5cb 100644 (file)
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -445,6 +445,20 @@ static int ak8974_selftest(struct ak8974 *ak8974)
        return 0;
 }
 
+static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
+                                  __le16 *tab, size_t tab_size)
+{
+       int ret = regmap_bulk_read(ak8974->map, reg, tab, tab_size);
+       if (ret) {
+               memset(tab, 0xFF, tab_size);
+               dev_warn(&ak8974->i2c->dev,
+                        "can't read calibration data (regs %u..%zu): %d\n",
+                        reg, reg + tab_size - 1, ret);
+       } else {
+               add_device_randomness(tab, tab_size);
+       }
+}
+
 static int ak8974_detect(struct ak8974 *ak8974)
 {
        unsigned int whoami;
@@ -489,6 +503,33 @@ static int ak8974_detect(struct ak8974 *ak8974)
        ak8974->name = name;
        ak8974->variant = whoami;
 
+       if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
+               __le16 fab_data1[9], fab_data2[3];
+               int i;
+
+               ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
+                                      fab_data1, sizeof(fab_data1));
+               ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
+                                      fab_data2, sizeof(fab_data2));
+
+               for (i = 0; i < 3; ++i) {
+                       static const char axis[3] = "XYZ";
+                       static const char pgaxis[6] = "ZYZXYX";
+                       unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
+                       unsigned fine = le16_to_cpu(fab_data1[i]);
+                       unsigned sens = le16_to_cpu(fab_data1[i + 3]);
+                       unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
+                       unsigned pgain2 = pgain1 >> 8;
+
+                       pgain1 &= 0xFF;
+
+                       dev_info(&ak8974->i2c->dev,
+                                "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
+                                axis[i], offz, sens, fine, pgaxis[i * 2],
+                                pgain1, pgaxis[i * 2 + 1], pgain2);
+               }
+       }
+
        return 0;
 }