Staging: iio: adis16209: Remove and add some comments and group the definitions

Remove some unnecessay comments and group the control
register and register field macros together.
Some of the register names does not make it's puporse
very clear and hence, add some comments for more
information.
Also there are certain unit based comments which are not
providing sufficient information, so expand those comments.

Signed-off-by: Shreeya Patel <shreeya.patel23498@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/staging/iio/accel/adis16209.c b/drivers/staging/iio/accel/adis16209.c
index 151120fab58a12b2123973fa768add61cc9eece4..e0a5e350214bcadc1e7f91fdbe88439bdcc966e2 100644 (file)
--- a/drivers/staging/iio/accel/adis16209.c
+++ b/drivers/staging/iio/accel/adis16209.c
@@ -21,135 +21,70 @@
 #include <linux/iio/imu/adis.h>
 
 #define ADIS16209_STARTUP_DELAY_MS     220
-
-/* Flash memory write count */
 #define ADIS16209_FLASH_CNT_REG                0x00
 
-/* Output, power supply */
+/* Data Output Register Definitions */
 #define ADIS16209_SUPPLY_OUT_REG       0x02
-
-/* Output, x-axis accelerometer */
 #define ADIS16209_XACCL_OUT_REG                0x04
-
-/* Output, y-axis accelerometer */
 #define ADIS16209_YACCL_OUT_REG                0x06
-
 /* Output, auxiliary ADC input */
 #define ADIS16209_AUX_ADC_REG          0x08
-
 /* Output, temperature */
 #define ADIS16209_TEMP_OUT_REG         0x0A
-
-/* Output, x-axis inclination */
+/* Output, +/- 90 degrees X-axis inclination */
 #define ADIS16209_XINCL_OUT_REG                0x0C
-
-/* Output, y-axis inclination */
 #define ADIS16209_YINCL_OUT_REG                0x0E
-
 /* Output, +/-180 vertical rotational position */
 #define ADIS16209_ROT_OUT_REG          0x10
 
-/* Calibration, x-axis acceleration offset null */
+/*
+ * Calibration Register Definitions.
+ * Acceleration, inclination or rotation offset null.
+ */
 #define ADIS16209_XACCL_NULL_REG       0x12
-
-/* Calibration, y-axis acceleration offset null */
 #define ADIS16209_YACCL_NULL_REG       0x14
-
-/* Calibration, x-axis inclination offset null */
 #define ADIS16209_XINCL_NULL_REG       0x16
-
-/* Calibration, y-axis inclination offset null */
 #define ADIS16209_YINCL_NULL_REG       0x18
-
-/* Calibration, vertical rotation offset null */
 #define ADIS16209_ROT_NULL_REG         0x1A
 
-/* Alarm 1 amplitude threshold */
+/* Alarm Register Definitions */
 #define ADIS16209_ALM_MAG1_REG         0x20
-
-/* Alarm 2 amplitude threshold */
 #define ADIS16209_ALM_MAG2_REG         0x22
-
-/* Alarm 1, sample period */
 #define ADIS16209_ALM_SMPL1_REG                0x24
-
-/* Alarm 2, sample period */
 #define ADIS16209_ALM_SMPL2_REG                0x26
-
-/* Alarm control */
 #define ADIS16209_ALM_CTRL_REG         0x28
 
-/* Auxiliary DAC data */
 #define ADIS16209_AUX_DAC_REG          0x30
-
-/* General-purpose digital input/output control */
 #define ADIS16209_GPIO_CTRL_REG                0x32
-
-/* Miscellaneous control */
-#define ADIS16209_MSC_CTRL_REG         0x34
-
-/* Internal sample period (rate) control */
 #define ADIS16209_SMPL_PRD_REG         0x36
-
-/* Operation, filter configuration */
 #define ADIS16209_AVG_CNT_REG          0x38
-
-/* Operation, sleep mode control */
 #define ADIS16209_SLP_CNT_REG          0x3A
 
-/* Diagnostics, system status register */
-#define ADIS16209_DIAG_STAT_REG                0x3C
-
-/* Operation, system command register */
-#define ADIS16209_GLOB_CMD_REG         0x3E
-
-/* MSC_CTRL */
-
-/* Self-test at power-on: 1 = disabled, 0 = enabled */
-#define ADIS16209_MSC_CTRL_PWRUP_SELF_TEST     BIT(10)
-
-/* Self-test enable */
-#define ADIS16209_MSC_CTRL_SELF_TEST_EN                BIT(8)
-
-/* Data-ready enable: 1 = enabled, 0 = disabled */
-#define ADIS16209_MSC_CTRL_DATA_RDY_EN         BIT(2)
-
+#define ADIS16209_MSC_CTRL_REG                 0x34
+#define  ADIS16209_MSC_CTRL_PWRUP_SELF_TEST    BIT(10)
+#define  ADIS16209_MSC_CTRL_SELF_TEST_EN       BIT(8)
+#define  ADIS16209_MSC_CTRL_DATA_RDY_EN                BIT(2)
 /* Data-ready polarity: 1 = active high, 0 = active low */
-#define ADIS16209_MSC_CTRL_ACTIVE_HIGH         BIT(1)
+#define  ADIS16209_MSC_CTRL_ACTIVE_HIGH                BIT(1)
+#define  ADIS16209_MSC_CTRL_DATA_RDY_DIO2      BIT(0)
 
-/* Data-ready line selection: 1 = DIO2, 0 = DIO1 */
-#define ADIS16209_MSC_CTRL_DATA_RDY_DIO2       BIT(0)
-
-/* DIAG_STAT */
-
-/* Alarm 2 status: 1 = alarm active, 0 = alarm inactive */
-#define ADIS16209_DIAG_STAT_ALARM2        BIT(9)
-
-/* Alarm 1 status: 1 = alarm active, 0 = alarm inactive */
-#define ADIS16209_DIAG_STAT_ALARM1        BIT(8)
-
-/* Self-test diagnostic error flag: 1 = error condition, 0 = normal operation */
+#define ADIS16209_DIAG_STAT_REG                        0x3C
+#define  ADIS16209_DIAG_STAT_ALARM2            BIT(9)
+#define  ADIS16209_DIAG_STAT_ALARM1            BIT(8)
 #define ADIS16209_DIAG_STAT_SELFTEST_FAIL_BIT  5
-
-/* SPI communications failure */
 #define ADIS16209_DIAG_STAT_SPI_FAIL_BIT       3
-
-/* Flash update failure */
 #define ADIS16209_DIAG_STAT_FLASH_UPT_BIT      2
-
 /* Power supply above 3.625 V */
 #define ADIS16209_DIAG_STAT_POWER_HIGH_BIT     1
-
 /* Power supply below 3.15 V */
 #define ADIS16209_DIAG_STAT_POWER_LOW_BIT      0
 
-/* GLOB_CMD */
-
-#define ADIS16209_GLOB_CMD_SW_RESET    BIT(7)
-#define ADIS16209_GLOB_CMD_CLEAR_STAT  BIT(4)
-#define ADIS16209_GLOB_CMD_FACTORY_CAL BIT(1)
+#define ADIS16209_GLOB_CMD_REG                 0x3E
+#define  ADIS16209_GLOB_CMD_SW_RESET           BIT(7)
+#define  ADIS16209_GLOB_CMD_CLEAR_STAT         BIT(4)
+#define  ADIS16209_GLOB_CMD_FACTORY_CAL                BIT(1)
 
-#define ADIS16209_ERROR_ACTIVE          BIT(14)
+#define ADIS16209_ERROR_ACTIVE                 BIT(14)
 
 enum adis16209_scan {
        ADIS16209_SCAN_SUPPLY,
@@ -226,24 +161,38 @@ static int adis16209_read_raw(struct iio_dev *indio_dev,
                                *val2 = 610500; /* 0.6105 mV */
                        return IIO_VAL_INT_PLUS_MICRO;
                case IIO_TEMP:
-                       *val = -470; /* -0.47 C */
+                       *val = -470;
                        *val2 = 0;
                        return IIO_VAL_INT_PLUS_MICRO;
                case IIO_ACCEL:
+                       /*
+                        * IIO base unit for sensitivity of accelerometer
+                        * is milli g.
+                        * 1 LSB represents 0.244 mg.
+                        */
                        *val = 0;
-                       *val2 = IIO_G_TO_M_S_2(244140); /* 0.244140 mg */
+                       *val2 = IIO_G_TO_M_S_2(244140);
                        return IIO_VAL_INT_PLUS_NANO;
                case IIO_INCLI:
                case IIO_ROT:
+                       /*
+                        * IIO base units for rotation are degrees.
+                        * 1 LSB represents 0.025 milli degrees.
+                        */
                        *val = 0;
-                       *val2 = 25000; /* 0.025 degree */
+                       *val2 = 25000;
                        return IIO_VAL_INT_PLUS_MICRO;
                default:
                        return -EINVAL;
                }
                break;
        case IIO_CHAN_INFO_OFFSET:
-               *val = 25000 / -470 - 0x4FE; /* 25 C = 0x4FE */
+               /*
+                * The raw ADC value is 0x4FE when the temperature
+                * is 25 degrees and the scale factor per milli
+                * degree celcius is -470.
+                */
+               *val = 25000 / -470 - 0x4FE;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_CALIBBIAS:
                switch (chan->type) {
@@ -320,12 +269,10 @@ static int adis16209_probe(struct spi_device *spi)
        struct adis *st;
        struct iio_dev *indio_dev;
 
-       /* setup the industrialio driver allocated elements */
        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
        if (!indio_dev)
                return -ENOMEM;
        st = iio_priv(indio_dev);
-       /* this is only used for removal purposes */
        spi_set_drvdata(spi, indio_dev);
 
        indio_dev->name = spi->dev.driver->name;
@@ -342,7 +289,6 @@ static int adis16209_probe(struct spi_device *spi)
        if (ret)
                return ret;
 
-       /* Get the device into a sane initial state */
        ret = adis_initial_startup(st);
        if (ret)
                goto error_cleanup_buffer_trigger;