hwmon: (max31827) Make code cleaner

Used enums and while loops to replace switch for selecting and getting
update interval from conversion rate bits.

Divided the write_alarm_val function into 2 functions. The new function
is more generic: it can be used not only for alarm writes, but for any
kind of writes which require the device to be in shutdown mode.

Signed-off-by: Daniel Matyas <daniel.matyas@analog.com>
Link: https://lore.kernel.org/r/20230919093456.10592-1-daniel.matyas@analog.com
[groeck: Reverted error return value change (EOPNOTSUPP -> EINVAL)]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/max31827.c b/drivers/hwmon/max31827.c
index 602f4e4f81ff926a9b3bf6f86739a5261f378db3..6e3e034aae32943a6b7a59c46f8977899b971f51 100644 (file)
--- a/drivers/hwmon/max31827.c
+++ b/drivers/hwmon/max31827.c
@@ -27,18 +27,30 @@
 
 #define MAX31827_12_BIT_CNV_TIME       141
 
-#define MAX31827_CNV_1_DIV_64_HZ       0x1
-#define MAX31827_CNV_1_DIV_32_HZ       0x2
-#define MAX31827_CNV_1_DIV_16_HZ       0x3
-#define MAX31827_CNV_1_DIV_4_HZ                0x4
-#define MAX31827_CNV_1_HZ              0x5
-#define MAX31827_CNV_4_HZ              0x6
-#define MAX31827_CNV_8_HZ              0x7
-
 #define MAX31827_16_BIT_TO_M_DGR(x)    (sign_extend32(x, 15) * 1000 / 16)
 #define MAX31827_M_DGR_TO_16_BIT(x)    (((x) << 4) / 1000)
 #define MAX31827_DEVICE_ENABLE(x)      ((x) ? 0xA : 0x0)
 
+enum max31827_cnv {
+       MAX31827_CNV_1_DIV_64_HZ = 1,
+       MAX31827_CNV_1_DIV_32_HZ,
+       MAX31827_CNV_1_DIV_16_HZ,
+       MAX31827_CNV_1_DIV_4_HZ,
+       MAX31827_CNV_1_HZ,
+       MAX31827_CNV_4_HZ,
+       MAX31827_CNV_8_HZ,
+};
+
+static const u16 max31827_conversions[] = {
+       [MAX31827_CNV_1_DIV_64_HZ] = 64000,
+       [MAX31827_CNV_1_DIV_32_HZ] = 32000,
+       [MAX31827_CNV_1_DIV_16_HZ] = 16000,
+       [MAX31827_CNV_1_DIV_4_HZ] = 4000,
+       [MAX31827_CNV_1_HZ] = 1000,
+       [MAX31827_CNV_4_HZ] = 250,
+       [MAX31827_CNV_8_HZ] = 125,
+};
+
 struct max31827_state {
        /*
         * Prevent simultaneous access to the i2c client.
@@ -54,15 +66,13 @@ static const struct regmap_config max31827_regmap = {
        .max_register = 0xA,
 };
 
-static int write_alarm_val(struct max31827_state *st, unsigned int reg,
-                          long val)
+static int shutdown_write(struct max31827_state *st, unsigned int reg,
+                         unsigned int val)
 {
        unsigned int cfg;
-       unsigned int tmp;
+       unsigned int cnv_rate;
        int ret;
 
-       val = MAX31827_M_DGR_TO_16_BIT(val);
-
        /*
         * Before the Temperature Threshold Alarm and Alarm Hysteresis Threshold
         * register values are changed over I2C, the part must be in shutdown
@@ -82,9 +92,10 @@ static int write_alarm_val(struct max31827_state *st, unsigned int reg,
        if (ret)
                goto unlock;
 
-       tmp = cfg & ~(MAX31827_CONFIGURATION_1SHOT_MASK |
+       cnv_rate = MAX31827_CONFIGURATION_CNV_RATE_MASK & cfg;
+       cfg = cfg & ~(MAX31827_CONFIGURATION_1SHOT_MASK |
                      MAX31827_CONFIGURATION_CNV_RATE_MASK);
-       ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, tmp);
+       ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, cfg);
        if (ret)
                goto unlock;
 
@@ -92,13 +103,23 @@ static int write_alarm_val(struct max31827_state *st, unsigned int reg,
        if (ret)
                goto unlock;
 
-       ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, cfg);
+       ret = regmap_update_bits(st->regmap, MAX31827_CONFIGURATION_REG,
+                                MAX31827_CONFIGURATION_CNV_RATE_MASK,
+                                cnv_rate);
 
 unlock:
        mutex_unlock(&st->lock);
        return ret;
 }
 
+static int write_alarm_val(struct max31827_state *st, unsigned int reg,
+                          long val)
+{
+       val = MAX31827_M_DGR_TO_16_BIT(val);
+
+       return shutdown_write(st, reg, val);
+}
+
 static umode_t max31827_is_visible(const void *state,
                                   enum hwmon_sensor_types type, u32 attr,
                                   int channel)
@@ -243,32 +264,7 @@ static int max31827_read(struct device *dev, enum hwmon_sensor_types type,
 
                        uval = FIELD_GET(MAX31827_CONFIGURATION_CNV_RATE_MASK,
                                         uval);
-                       switch (uval) {
-                       case MAX31827_CNV_1_DIV_64_HZ:
-                               *val = 64000;
-                               break;
-                       case MAX31827_CNV_1_DIV_32_HZ:
-                               *val = 32000;
-                               break;
-                       case MAX31827_CNV_1_DIV_16_HZ:
-                               *val = 16000;
-                               break;
-                       case MAX31827_CNV_1_DIV_4_HZ:
-                               *val = 4000;
-                               break;
-                       case MAX31827_CNV_1_HZ:
-                               *val = 1000;
-                               break;
-                       case MAX31827_CNV_4_HZ:
-                               *val = 250;
-                               break;
-                       case MAX31827_CNV_8_HZ:
-                               *val = 125;
-                               break;
-                       default:
-                               *val = 0;
-                               break;
-                       }
+                       *val = max31827_conversions[uval];
                }
                break;
 
@@ -284,6 +280,7 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type,
                          u32 attr, int channel, long val)
 {
        struct max31827_state *st = dev_get_drvdata(dev);
+       int res = 1;
        int ret;
 
        switch (type) {
@@ -333,39 +330,27 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type,
                        if (!st->enable)
                                return -EINVAL;
 
-                       switch (val) {
-                       case 125:
-                               val = MAX31827_CNV_8_HZ;
-                               break;
-                       case 250:
-                               val = MAX31827_CNV_4_HZ;
-                               break;
-                       case 1000:
-                               val = MAX31827_CNV_1_HZ;
-                               break;
-                       case 4000:
-                               val = MAX31827_CNV_1_DIV_4_HZ;
-                               break;
-                       case 16000:
-                               val = MAX31827_CNV_1_DIV_16_HZ;
-                               break;
-                       case 32000:
-                               val = MAX31827_CNV_1_DIV_32_HZ;
-                               break;
-                       case 64000:
-                               val = MAX31827_CNV_1_DIV_64_HZ;
-                               break;
-                       default:
+                       /*
+                        * Convert the desired conversion rate into register
+                        * bits. res is already initialized with 1.
+                        *
+                        * This was inspired by lm73 driver.
+                        */
+                       while (res < ARRAY_SIZE(max31827_conversions) &&
+                              val < max31827_conversions[res])
+                               res++;
+
+                       if (res == ARRAY_SIZE(max31827_conversions) ||
+                           val != max31827_conversions[res])
                                return -EINVAL;
-                       }
 
-                       val = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK,
-                                        val);
+                       res = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK,
+                                        res);
 
                        return regmap_update_bits(st->regmap,
                                                  MAX31827_CONFIGURATION_REG,
                                                  MAX31827_CONFIGURATION_CNV_RATE_MASK,
-                                                 val);
+                                                 res);
                }
                break;