* [patch] spitz: better voltage-to-percentage conversion
@ 2009-11-27 7:31 Pavel Machek
2009-11-27 8:07 ` Eric Dumazet
2009-11-27 8:54 ` Russell King - ARM Linux
0 siblings, 2 replies; 5+ messages in thread
From: Pavel Machek @ 2009-11-27 7:31 UTC (permalink / raw)
To: linux-arm-kernel
Old code has two huge tables... unfortunately those tables are simple
linear relationships and wrong: li-ions do not behave like that.
Convert physical values to mV,mA,mOhm, add computation that makes
sense for physical point of view, and provide tables based on
measurements.
To get even better results, we should provide better battery_current
estimate (taking backlight into account), and adjust adjust
battery_resistance according to its age and temperature.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
--- a/arch/arm/mach-pxa/corgi_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/corgi_pm.c 2009-11-23 06:45:45.000000000 +0100
@@ -215,7 +215,6 @@
.fatal_noacin_volt= SHARPSL_FATAL_NOACIN_VOLT,
.bat_levels = 40,
.bat_levels_noac = sharpsl_battery_levels_noac,
- .bat_levels_acin = sharpsl_battery_levels_acin,
.status_high_acin = 188,
.status_low_acin = 178,
.status_high_noac = 185,
--- a/arch/arm/mach-pxa/sharpsl_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/sharpsl_pm.c 2009-11-23 06:47:01.000000000 +0100
@@ -78,90 +78,25 @@
-struct battery_thresh sharpsl_battery_levels_acin[] = {
- { 213, 100},
- { 212, 98},
- { 211, 95},
- { 210, 93},
- { 209, 90},
- { 208, 88},
- { 207, 85},
- { 206, 83},
- { 205, 80},
- { 204, 78},
- { 203, 75},
- { 202, 73},
- { 201, 70},
- { 200, 68},
- { 199, 65},
- { 198, 63},
- { 197, 60},
- { 196, 58},
- { 195, 55},
- { 194, 53},
- { 193, 50},
- { 192, 48},
- { 192, 45},
- { 191, 43},
- { 191, 40},
- { 190, 38},
- { 190, 35},
- { 189, 33},
- { 188, 30},
- { 187, 28},
- { 186, 25},
- { 185, 23},
- { 184, 20},
- { 183, 18},
- { 182, 15},
- { 181, 13},
- { 180, 10},
- { 179, 8},
- { 178, 5},
- { 0, 0},
-};
-
struct battery_thresh sharpsl_battery_levels_noac[] = {
- { 213, 100},
- { 212, 98},
- { 211, 95},
- { 210, 93},
- { 209, 90},
- { 208, 88},
- { 207, 85},
- { 206, 83},
- { 205, 80},
- { 204, 78},
- { 203, 75},
- { 202, 73},
- { 201, 70},
- { 200, 68},
- { 199, 65},
- { 198, 63},
- { 197, 60},
- { 196, 58},
- { 195, 55},
- { 194, 53},
- { 193, 50},
- { 192, 48},
- { 191, 45},
- { 190, 43},
- { 189, 40},
- { 188, 38},
- { 187, 35},
- { 186, 33},
- { 185, 30},
- { 184, 28},
- { 183, 25},
- { 182, 23},
- { 181, 20},
- { 180, 18},
- { 179, 15},
- { 178, 13},
- { 177, 10},
- { 176, 8},
- { 175, 5},
- { 0, 0},
+ { 3980, 100 },
+ { 3900, 95 },
+ { 3860, 90 },
+ { 3800, 85 },
+ { 3760, 80 },
+ { 3720, 74 },
+ { 3680, 69 },
+ { 3620, 65 },
+ { 3570, 59 },
+ { 3560, 55 },
+ { 3550, 48 },
+ { 3530, 45 },
+ { 3510, 39 },
+ { 3490, 33 },
+ { 3470, 29 },
+ { 3450, 23 },
+ { 3410, 16 },
+ { 0, 0 },
};
/* MAX1111 Commands */
@@ -194,16 +129,64 @@
#endif
}
-static int get_percentage(int voltage)
+
+typedef int miliamp_t;
+typedef int miliohm_t;
+typedef int milivolt_t;
+
+miliamp_t basic_current = 125;
+miliohm_t battery_resistance = 100;
+
+/* 422 seems to be suitable for very old, 1Ah battery.
+ 2Ah battery probably has better resistance */
+
+/* Unfortunately, resistance depends on state of charge, current
+ * direction and temperature.
+ *
+ * Ouch, and dependency is actually _not_ too simple. It is lowest
+ * at 3.55V, very slowly rises at 4V (approximately linear dependency),
+ * and quickly rises towards 3.2V (in something exponential-looking).
+ *
+ * It is about same at 25Celsius and 40Celsius, and about 2.5x the value
+ * on 0Celsius, rising _very_ sharply.
+ *
+ * Li-ion should only be charged between 0 and 45 Celsius, and discharged
+ * between -20 and 60 celsius.
+ */
+
+extern int backlight_current;
+
+/* Positive values: current drawn from battery */
+miliamp_t battery_current(void)
+{
+ if (sharpsl_pm.charge_mode == CHRG_ON)
+ return 0;
+
+ return basic_current;
+}
+
+milivolt_t liion_internal_voltage(milivolt_t voltage, miliamp_t current_ma)
+{
+ return voltage + (battery_resistance * current_ma / 1000);
+}
+
+/* returns mV */
+milivolt_t liion_voltage(int adc)
+{
+ /* Thanks to Stanislav B. ADC has 3.3V as reference,
+ is connected to battery over 47kOhm,
+ and to ground over 100kOhm. */
+ return (adc * 147 * 33)/256;
+}
+
+static int get_percentage(int voltage_adc)
{
int i = sharpsl_pm.machinfo->bat_levels - 1;
int bl_status = sharpsl_pm.machinfo->backlight_get_status ? sharpsl_pm.machinfo->backlight_get_status() : 0;
struct battery_thresh *thresh;
+ milivolt_t voltage = liion_voltage(voltage_adc);
- if (sharpsl_pm.charge_mode == CHRG_ON)
- thresh = bl_status ? sharpsl_pm.machinfo->bat_levels_acin_bl : sharpsl_pm.machinfo->bat_levels_acin;
- else
- thresh = bl_status ? sharpsl_pm.machinfo->bat_levels_noac_bl : sharpsl_pm.machinfo->bat_levels_noac;
+ thresh = sharpsl_pm.machinfo->bat_levels_noac;
while (i > 0 && (voltage > thresh[i].voltage))
i--;
--- a/arch/arm/mach-pxa/spitz_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/spitz_pm.c 2009-11-23 06:45:25.000000000 +0100
@@ -209,7 +209,6 @@
.fatal_noacin_volt= SHARPSL_FATAL_NOACIN_VOLT,
.bat_levels = 40,
.bat_levels_noac = sharpsl_battery_levels_noac,
- .bat_levels_acin = sharpsl_battery_levels_acin,
.status_high_acin = 188,
.status_low_acin = 178,
.status_high_noac = 185,
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply [flat|nested] 5+ messages in thread* [patch] spitz: better voltage-to-percentage conversion
2009-11-27 7:31 [patch] spitz: better voltage-to-percentage conversion Pavel Machek
@ 2009-11-27 8:07 ` Eric Dumazet
2009-11-27 8:54 ` Russell King - ARM Linux
1 sibling, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2009-11-27 8:07 UTC (permalink / raw)
To: linux-arm-kernel
Pavel Machek a ?crit :
> Old code has two huge tables... unfortunately those tables are simple
> linear relationships and wrong: li-ions do not behave like that.
>
> Convert physical values to mV,mA,mOhm, add computation that makes
> sense for physical point of view, and provide tables based on
> measurements.
>
> To get even better results, we should provide better battery_current
> estimate (taking backlight into account), and adjust adjust
> battery_resistance according to its age and temperature.
>
> Signed-off-by: Pavel Machek <pavel@ucw.cz>
>
>
> --- a/arch/arm/mach-pxa/corgi_pm.c 2009-11-23 20:48:26.000000000 +0100
> +typedef int miliamp_t;
> +typedef int miliohm_t;
> +typedef int milivolt_t;
milliamp, milliohm, millivolt ?
^ permalink raw reply [flat|nested] 5+ messages in thread
* [patch] spitz: better voltage-to-percentage conversion
2009-11-27 7:31 [patch] spitz: better voltage-to-percentage conversion Pavel Machek
2009-11-27 8:07 ` Eric Dumazet
@ 2009-11-27 8:54 ` Russell King - ARM Linux
2009-11-29 9:16 ` Pavel Machek
1 sibling, 1 reply; 5+ messages in thread
From: Russell King - ARM Linux @ 2009-11-27 8:54 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Nov 27, 2009 at 08:31:19AM +0100, Pavel Machek wrote:
> +
> +typedef int miliamp_t;
> +typedef int miliohm_t;
> +typedef int milivolt_t;
'milliamp' 'milliohm' 'millivolt'
^ permalink raw reply [flat|nested] 5+ messages in thread
* [patch] spitz: better voltage-to-percentage conversion
@ 2009-11-29 9:13 Pavel Machek
0 siblings, 0 replies; 5+ messages in thread
From: Pavel Machek @ 2009-11-29 9:13 UTC (permalink / raw)
To: linux-arm-kernel
Old code has two huge tables... unfortunately those tables are simple
linear relationships and wrong: li-ions do not behave like that.
Convert physical values to mV,mA,mOhm, add computation that makes
sense for physical point of view, and provide tables based on
measurements.
To get even better results, we should provide better battery_current
estimate (taking backlight into account), and adjust adjust
battery_resistance according to its age and temperature.
(Now with fixed spelling).
Signed-off-by: Pavel Machek <pavel@ucw.cz>
--- a/arch/arm/mach-pxa/corgi_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/corgi_pm.c 2009-11-23 06:45:45.000000000 +0100
@@ -215,7 +215,6 @@
.fatal_noacin_volt= SHARPSL_FATAL_NOACIN_VOLT,
.bat_levels = 40,
.bat_levels_noac = sharpsl_battery_levels_noac,
- .bat_levels_acin = sharpsl_battery_levels_acin,
.status_high_acin = 188,
.status_low_acin = 178,
.status_high_noac = 185,
--- a/arch/arm/mach-pxa/sharpsl_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/sharpsl_pm.c 2009-11-23 06:47:01.000000000 +0100
@@ -78,90 +78,25 @@
-struct battery_thresh sharpsl_battery_levels_acin[] = {
- { 213, 100},
- { 212, 98},
- { 211, 95},
- { 210, 93},
- { 209, 90},
- { 208, 88},
- { 207, 85},
- { 206, 83},
- { 205, 80},
- { 204, 78},
- { 203, 75},
- { 202, 73},
- { 201, 70},
- { 200, 68},
- { 199, 65},
- { 198, 63},
- { 197, 60},
- { 196, 58},
- { 195, 55},
- { 194, 53},
- { 193, 50},
- { 192, 48},
- { 192, 45},
- { 191, 43},
- { 191, 40},
- { 190, 38},
- { 190, 35},
- { 189, 33},
- { 188, 30},
- { 187, 28},
- { 186, 25},
- { 185, 23},
- { 184, 20},
- { 183, 18},
- { 182, 15},
- { 181, 13},
- { 180, 10},
- { 179, 8},
- { 178, 5},
- { 0, 0},
-};
-
struct battery_thresh sharpsl_battery_levels_noac[] = {
- { 213, 100},
- { 212, 98},
- { 211, 95},
- { 210, 93},
- { 209, 90},
- { 208, 88},
- { 207, 85},
- { 206, 83},
- { 205, 80},
- { 204, 78},
- { 203, 75},
- { 202, 73},
- { 201, 70},
- { 200, 68},
- { 199, 65},
- { 198, 63},
- { 197, 60},
- { 196, 58},
- { 195, 55},
- { 194, 53},
- { 193, 50},
- { 192, 48},
- { 191, 45},
- { 190, 43},
- { 189, 40},
- { 188, 38},
- { 187, 35},
- { 186, 33},
- { 185, 30},
- { 184, 28},
- { 183, 25},
- { 182, 23},
- { 181, 20},
- { 180, 18},
- { 179, 15},
- { 178, 13},
- { 177, 10},
- { 176, 8},
- { 175, 5},
- { 0, 0},
+ { 3980, 100 },
+ { 3900, 95 },
+ { 3860, 90 },
+ { 3800, 85 },
+ { 3760, 80 },
+ { 3720, 74 },
+ { 3680, 69 },
+ { 3620, 65 },
+ { 3570, 59 },
+ { 3560, 55 },
+ { 3550, 48 },
+ { 3530, 45 },
+ { 3510, 39 },
+ { 3490, 33 },
+ { 3470, 29 },
+ { 3450, 23 },
+ { 3410, 16 },
+ { 0, 0 },
};
/* MAX1111 Commands */
@@ -194,16 +129,64 @@
#endif
}
-static int get_percentage(int voltage)
+
+typedef int milliamp_t;
+typedef int milliohm_t;
+typedef int millivolt_t;
+
+milliamp_t basic_current = 125;
+milliohm_t battery_resistance = 100;
+
+/* 422 seems to be suitable for very old, 1Ah battery.
+ 2Ah battery probably has better resistance */
+
+/* Unfortunately, resistance depends on state of charge, current
+ * direction and temperature.
+ *
+ * Ouch, and dependency is actually _not_ too simple. It is lowest
+ * at 3.55V, very slowly rises at 4V (approximately linear dependency),
+ * and quickly rises towards 3.2V (in something exponential-looking).
+ *
+ * It is about same at 25Celsius and 40Celsius, and about 2.5x the value
+ * on 0Celsius, rising _very_ sharply.
+ *
+ * Li-ion should only be charged between 0 and 45 Celsius, and discharged
+ * between -20 and 60 celsius.
+ */
+
+extern int backlight_current;
+
+/* Positive values: current drawn from battery */
+milliamp_t battery_current(void)
+{
+ if (sharpsl_pm.charge_mode == CHRG_ON)
+ return 0;
+
+ return basic_current;
+}
+
+millivolt_t liion_internal_voltage(millivolt_t voltage, milliamp_t current_ma)
+{
+ return voltage + (battery_resistance * current_ma / 1000);
+}
+
+/* returns mV */
+millivolt_t liion_voltage(int adc)
+{
+ /* Thanks to Stanislav B. ADC has 3.3V as reference,
+ is connected to battery over 47kOhm,
+ and to ground over 100kOhm. */
+ return (adc * 147 * 33)/256;
+}
+
+static int get_percentage(int voltage_adc)
{
int i = sharpsl_pm.machinfo->bat_levels - 1;
int bl_status = sharpsl_pm.machinfo->backlight_get_status ? sharpsl_pm.machinfo->backlight_get_status() : 0;
struct battery_thresh *thresh;
+ millivolt_t voltage = liion_voltage(voltage_adc);
- if (sharpsl_pm.charge_mode == CHRG_ON)
- thresh = bl_status ? sharpsl_pm.machinfo->bat_levels_acin_bl : sharpsl_pm.machinfo->bat_levels_acin;
- else
- thresh = bl_status ? sharpsl_pm.machinfo->bat_levels_noac_bl : sharpsl_pm.machinfo->bat_levels_noac;
+ thresh = sharpsl_pm.machinfo->bat_levels_noac;
while (i > 0 && (voltage > thresh[i].voltage))
i--;
--- a/arch/arm/mach-pxa/spitz_pm.c 2009-11-23 20:48:26.000000000 +0100
+++ b/arch/arm/mach-pxa/spitz_pm.c 2009-11-23 06:45:25.000000000 +0100
@@ -209,7 +209,6 @@
.fatal_noacin_volt= SHARPSL_FATAL_NOACIN_VOLT,
.bat_levels = 40,
.bat_levels_noac = sharpsl_battery_levels_noac,
- .bat_levels_acin = sharpsl_battery_levels_acin,
.status_high_acin = 188,
.status_low_acin = 178,
.status_high_noac = 185,
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply [flat|nested] 5+ messages in thread
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2009-11-27 7:31 [patch] spitz: better voltage-to-percentage conversion Pavel Machek
2009-11-27 8:07 ` Eric Dumazet
2009-11-27 8:54 ` Russell King - ARM Linux
2009-11-29 9:16 ` Pavel Machek
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2009-11-29 9:13 Pavel Machek
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