power: supply: ab8500: Use library interpolation

The kernel already has a static inline for linear interpolation
so use that instead of rolling our own.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/ab8500_btemp.c b/drivers/power/supply/ab8500_btemp.c
index dbdcff3..24958b9 100644 (file)
--- a/drivers/power/supply/ab8500_btemp.c
+++ b/drivers/power/supply/ab8500_btemp.c
@@ -27,6 +27,7 @@
 #include <linux/mfd/abx500.h>
 #include <linux/mfd/abx500/ab8500.h>
 #include <linux/iio/consumer.h>
+#include <linux/fixp-arith.h>
 
 #include "ab8500-bm.h"
 
@@ -437,8 +438,9 @@ static int ab8500_btemp_res_to_temp(struct ab8500_btemp *di,
                        i++;
        }
 
-       return tbl[i].temp + ((tbl[i + 1].temp - tbl[i].temp) *
-               (res - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
+       return fixp_linear_interpolate(tbl[i].resist, tbl[i].temp,
+                                      tbl[i + 1].resist, tbl[i + 1].temp,
+                                      res);
 }
 
 /**

diff --git a/drivers/power/supply/ab8500_fg.c b/drivers/power/supply/ab8500_fg.c
index 3d45ed0..bdbf3f1 100644 (file)
--- a/drivers/power/supply/ab8500_fg.c
+++ b/drivers/power/supply/ab8500_fg.c
@@ -34,6 +34,7 @@
 #include <linux/mfd/abx500/ab8500.h>
 #include <linux/iio/consumer.h>
 #include <linux/kernel.h>
+#include <linux/fixp-arith.h>
 
 #include "ab8500-bm.h"
 
@@ -56,9 +57,6 @@
 /* FG constants */
 #define BATT_OVV                       0x01
 
-#define interpolate(x, x1, y1, x2, y2) \
-       ((y1) + ((((y2) - (y1)) * ((x) - (x1))) / ((x2) - (x1))));
-
 /**
  * struct ab8500_fg_interrupts - ab8500 fg interrupts
  * @name:      name of the interrupt
@@ -868,11 +866,12 @@ static int ab8500_fg_volt_to_capacity(struct ab8500_fg *di, int voltage)
        }
 
        if ((i > 0) && (i < tbl_size)) {
-               cap = interpolate(voltage,
+               cap = fixp_linear_interpolate(
                        tbl[i].voltage,
                        tbl[i].capacity * 10,
                        tbl[i-1].voltage,
-                       tbl[i-1].capacity * 10);
+                       tbl[i-1].capacity * 10,
+                       voltage);
        } else if (i == 0) {
                cap = 1000;
        } else {
@@ -920,11 +919,12 @@ static int ab8500_fg_battery_resistance(struct ab8500_fg *di)
        }
 
        if ((i > 0) && (i < tbl_size)) {
-               resist = interpolate(di->bat_temp / 10,
+               resist = fixp_linear_interpolate(
                        tbl[i].temp,
                        tbl[i].resist,
                        tbl[i-1].temp,
-                       tbl[i-1].resist);
+                       tbl[i-1].resist,
+                       di->bat_temp / 10);
        } else if (i == 0) {
                resist = tbl[0].resist;
        } else {