imx233/fuze+: rework lradc/adc code, add external temperature sensing(battery)

Rework code to be more useful:
- move battery channel init to lradc
- always init lradc from system (previously from adc)
- don't reserve channels for vddio, nmos or pmos
- implement external temperature sensing using current source
- use this for battery sensing on the Fuze+ (calibration needed)

Change-Id: I5f9a24b9243db7d1e6bdb16b84bc891e61d0c318

7 files changed, 135 insertions, 51 deletions

diff --git a/firmware/target/arm/imx233/adc-imx233.c b/firmware/target/arm/imx233/adc-imx233.c
index 08adba442d..b24f7f6c43 100644
--- a/firmware/target/arm/imx233/adc-imx233.c
+++ b/firmware/target/arm/imx233/adc-imx233.c
@@ -25,46 +25,11 @@
 #include "system.h"
 #include "adc-imx233.h"
 
-/* dedicate two channels to temperature sensing
- * dedicate channel 7 to battery
- * and channel 6 to vddio */
-static int pmos_chan, nmos_chan;
-static int battery_chan, vddio_chan;
-static int battery_delay_chan;
-
 void adc_init(void)
 {
-    imx233_lradc_init();
-    /* reserve channels 6 for vddio and 7 for battery (special for conversion) */
-    battery_chan = 7;
-    vddio_chan = 6;
-    imx233_lradc_reserve_channel(battery_chan);
-    imx233_lradc_reserve_channel(vddio_chan);
-    /* reserve any channels for PMOS and NMOS */
-    pmos_chan = imx233_lradc_acquire_channel(TIMEOUT_NOBLOCK);
-    if(pmos_chan < 0) panicf("No LRADC channel for PMOS !");
-    nmos_chan = imx233_lradc_acquire_channel(TIMEOUT_NOBLOCK);
-    if(nmos_chan < 0) panicf("No LRADC channel for NMOS !");
-
-    /* setup them for the simplest use: no accumulation, no division*/
-    imx233_lradc_setup_channel(battery_chan, false, false, 0, HW_LRADC_CHANNEL_BATTERY);
-    imx233_lradc_setup_channel(vddio_chan, false, false, 0, HW_LRADC_CHANNEL_VDDIO);
-    imx233_lradc_setup_channel(nmos_chan, false, false, 0, HW_LRADC_CHANNEL_NMOS_THIN);
-    imx233_lradc_setup_channel(pmos_chan, false, false, 0, HW_LRADC_CHANNEL_PMOS_THIN);
-    /* setup delay channel for battery for automatic reading and scaling */
-    battery_delay_chan = 0;
-    imx233_lradc_reserve_delay(battery_delay_chan);
-    /* setup delay to trigger battery channel and retrigger itself.
-     * The counter runs at 2KHz so a delay of 200 will trigger 10
-     * conversions per seconds */
-    imx233_lradc_setup_delay(battery_delay_chan, 1 << battery_chan,
-        1 << battery_delay_chan, 0, 200);
-    imx233_lradc_kick_delay(battery_delay_chan);
-    /* enable automatic conversion, use Li-Ion type battery */
-    imx233_lradc_setup_battery_conversion(true, HW_LRADC_CONVERSION__SCALE_FACTOR__LI_ION);
 }
 
-int adc_read_physical_ex(int virt)
+static short adc_read_physical_ex(int virt)
 {
     imx233_lradc_clear_channel(virt);
     imx233_lradc_kick_channel(virt);
@@ -72,27 +37,51 @@ int adc_read_physical_ex(int virt)
     return imx233_lradc_read_channel(virt);
 }
 
-int adc_read_physical(int src)
+static short adc_read_physical(int src, bool div2)
 {
     int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
     // divide by two for wider ranger
-    imx233_lradc_setup_channel(virt, true, false, 0, src);
+    imx233_lradc_setup_channel(virt, div2, false, 0, src);
     int val = adc_read_physical_ex(virt);
     imx233_lradc_release_channel(virt);
     return val;
 }
 
-unsigned short adc_read_virtual(int c)
+static short adc_read_virtual(int c)
 {
     switch(c)
     {
         case IMX233_ADC_BATTERY:
-            return adc_read_physical_ex(battery_chan);
+            return imx233_lradc_read_battery_voltage();
         case IMX233_ADC_VDDIO:
-            return adc_read_physical_ex(vddio_chan);
+            /* VddIO pin has a builtin 2:1 divide */
+            return adc_read_physical(HW_LRADC_CHANNEL_VDDIO, false);
+        case IMX233_ADC_VDD5V:
+            /* Vdd5V pin has a builtin 4:1 divide */
+            return adc_read_physical(HW_LRADC_CHANNEL_5V, false) * 2;
         case IMX233_ADC_DIE_TEMP:
-            // do kelvin to celsius conversion
-            return imx233_lradc_sense_die_temperature(nmos_chan, pmos_chan) - 273;
+        {
+            // don't block on second channel otherwise we might deadlock !
+            int nmos_chan = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
+            int pmos_chan = imx233_lradc_acquire_channel(TIMEOUT_NOBLOCK);
+            int val = 0;
+            if(pmos_chan >= 0)
+            {
+                val = imx233_lradc_sense_die_temperature(nmos_chan, pmos_chan) - 273;
+                imx233_lradc_release_channel(pmos_chan);
+            }
+            imx233_lradc_release_channel(nmos_chan);
+            return val;
+        }
+#ifdef IMX233_ADC_BATT_TEMP_SENSOR
+        case IMX233_ADC_BATT_TEMP:
+        {
+            int virt = imx233_lradc_acquire_channel(TIMEOUT_BLOCK);
+            int val = imx233_lradc_sense_ext_temperature(virt, IMX233_ADC_BATT_TEMP_SENSOR);
+            imx233_lradc_release_channel(virt);
+            return val;
+        }
+#endif
         default:
             return 0;
     }
@@ -104,5 +93,5 @@ unsigned short adc_read(int channel)
     if(c < 0)
         return adc_read_virtual(c);
     else
-        return adc_read_physical(c);
+        return adc_read_physical(c, true);
 }
diff --git a/firmware/target/arm/imx233/adc-imx233.h b/firmware/target/arm/imx233/adc-imx233.h
index 6025fdcdf8..c54e79dc8d 100644
--- a/firmware/target/arm/imx233/adc-imx233.h
+++ b/firmware/target/arm/imx233/adc-imx233.h
@@ -29,6 +29,10 @@
 #define IMX233_ADC_BATTERY      -1 /* Battery voltage (mV) */
 #define IMX233_ADC_DIE_TEMP     -2 /* Die temperature (°C) */
 #define IMX233_ADC_VDDIO        -3 /* VddIO voltage (mV) */
+#define IMX233_ADC_VDD5V        -4 /* Vdd5V voltage (mV) */
+#ifdef IMX233_ADC_BATT_TEMP_SENSOR
+#define IMX233_ADC_BATT_TEMP    -5 /* Battery temperature (°C) */
+#endif
 
 /* Channel mapping */
 extern int imx233_adc_mapping[];
diff --git a/firmware/target/arm/imx233/lradc-imx233.c b/firmware/target/arm/imx233/lradc-imx233.c
index 432d1c1035..4d309b0875 100644
--- a/firmware/target/arm/imx233/lradc-imx233.c
+++ b/firmware/target/arm/imx233/lradc-imx233.c
@@ -27,6 +27,9 @@
 static struct channel_arbiter_t channel_arbiter;
 /* delay channels */
 static struct channel_arbiter_t delay_arbiter;
+/* battery is very special, dedicate a channel and a delay to it */
+static int battery_chan;
+static int battery_delay_chan;
 
 void imx233_lradc_setup_channel(int channel, bool div2, bool acc, int nr_samples, int src)
 {
@@ -111,6 +114,8 @@ void imx233_lradc_reserve_delay(int channel)
 
 int imx233_lradc_sense_die_temperature(int nmos_chan, int pmos_chan)
 {
+    imx233_lradc_setup_channel(nmos_chan, false, false, 0, HW_LRADC_CHANNEL_NMOS_THIN);
+    imx233_lradc_setup_channel(pmos_chan, false, false, 0, HW_LRADC_CHANNEL_PMOS_THIN);
     // mux sensors
     __REG_CLR(HW_LRADC_CTRL2) = HW_LRADC_CTRL2__TEMPSENSE_PWD;
     imx233_lradc_clear_channel(nmos_chan);
@@ -129,6 +134,60 @@ int imx233_lradc_sense_die_temperature(int nmos_chan, int pmos_chan)
     return (diff * 1012) / 4000;
 }
 
+/* set to 0 to disable current source */
+static void imx233_lradc_set_temp_isrc(int sensor, int value)
+{
+    if(sensor < 0 || sensor > 1)
+        panicf("imx233_lradc_set_temp_isrc: invalid sensor");
+    unsigned mask = HW_LRADC_CTRL2__TEMP_ISRCx_BM(sensor);
+    unsigned bp = HW_LRADC_CTRL2__TEMP_ISRCx_BP(sensor);
+    unsigned en = HW_LRADC_CTRL2__TEMP_SENSOR_IENABLEx(sensor);
+
+    __REG_CLR(HW_LRADC_CTRL2) = mask;
+    __REG_SET(HW_LRADC_CTRL2) = value << bp;
+    if(value != 0)
+    {
+        __REG_SET(HW_LRADC_CTRL2) = en;
+        udelay(100);
+    }
+    else
+        __REG_CLR(HW_LRADC_CTRL2) = en;
+}
+
+int imx233_lradc_sense_ext_temperature(int chan, int sensor)
+{
+#define EXT_TEMP_ACC_COUNT  5
+    /* setup channel */
+    imx233_lradc_setup_channel(chan, false, false, 0, sensor);
+    /* set current source to 300µA */
+    imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__300uA);
+    /* read value and accumulate */
+    int a = 0;
+    for(int i = 0; i < EXT_TEMP_ACC_COUNT; i++)
+    {
+        imx233_lradc_clear_channel(chan);
+        imx233_lradc_kick_channel(chan);
+        imx233_lradc_wait_channel(chan);
+        a += imx233_lradc_read_channel(chan);
+    }
+    /* setup channel for small accumulation */
+    /* set current source to 20µA */
+    imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__20uA);
+    /* read value */
+    int b = 0;
+    for(int i = 0; i < EXT_TEMP_ACC_COUNT; i++)
+    {
+        imx233_lradc_clear_channel(chan);
+        imx233_lradc_kick_channel(chan);
+        imx233_lradc_wait_channel(chan);
+        b += imx233_lradc_read_channel(chan);
+    }
+    /* disable sensor current */
+    imx233_lradc_set_temp_isrc(sensor, HW_LRADC_CTRL2__TEMP_ISRC__0uA);
+    
+    return (b - a) / EXT_TEMP_ACC_COUNT;
+}
+
 void imx233_lradc_setup_battery_conversion(bool automatic, unsigned long scale_factor)
 {
     __REG_CLR(HW_LRADC_CONVERSION) = HW_LRADC_CONVERSION__SCALE_FACTOR_BM;
@@ -159,4 +218,20 @@ void imx233_lradc_init(void)
     // set frequency
     __REG_CLR(HW_LRADC_CTRL3) = HW_LRADC_CTRL3__CYCLE_TIME_BM;
     __REG_SET(HW_LRADC_CTRL3) = HW_LRADC_CTRL3__CYCLE_TIME__6MHz;
+    // setup battery
+    battery_chan = 7;
+    imx233_lradc_reserve_channel(battery_chan);
+    /* setup them for the simplest use: no accumulation, no division*/
+    imx233_lradc_setup_channel(battery_chan, false, false, 0, HW_LRADC_CHANNEL_BATTERY);
+    /* setup delay channel for battery for automatic reading and scaling */
+    battery_delay_chan = 0;
+    imx233_lradc_reserve_delay(battery_delay_chan);
+    /* setup delay to trigger battery channel and retrigger itself.
+     * The counter runs at 2KHz so a delay of 200 will trigger 10
+     * conversions per seconds */
+    imx233_lradc_setup_delay(battery_delay_chan, 1 << battery_chan,
+        1 << battery_delay_chan, 0, 200);
+    imx233_lradc_kick_delay(battery_delay_chan);
+    /* enable automatic conversion, use Li-Ion type battery */
+    imx233_lradc_setup_battery_conversion(true, HW_LRADC_CONVERSION__SCALE_FACTOR__LI_ION);
 }
diff --git a/firmware/target/arm/imx233/lradc-imx233.h b/firmware/target/arm/imx233/lradc-imx233.h
index d79ebe0eff..b661fa8aa4 100644
--- a/firmware/target/arm/imx233/lradc-imx233.h
+++ b/firmware/target/arm/imx233/lradc-imx233.h
@@ -43,8 +43,14 @@
 #define HW_LRADC_CTRL2__TEMP_ISRC1_BM           0xf0
 #define HW_LRADC_CTRL2__TEMP_ISRC0_BP           0
 #define HW_LRADC_CTRL2__TEMP_ISRC0_BM           0xf
+#define HW_LRADC_CTRL2__TEMP_ISRCx_BP(x)        (4 * (x))
+#define HW_LRADC_CTRL2__TEMP_ISRCx_BM(x)        (0xf << (4 * (x)))
+#define HW_LRADC_CTRL2__TEMP_ISRC__0uA          0
+#define HW_LRADC_CTRL2__TEMP_ISRC__20uA         1
+#define HW_LRADC_CTRL2__TEMP_ISRC__300uA        15
 #define HW_LRADC_CTRL2__TEMP_SENSOR_IENABLE0    (1 << 8)
 #define HW_LRADC_CTRL2__TEMP_SENSOR_IENABLE1    (1 << 9)
+#define HW_LRADC_CTRL2__TEMP_SENSOR_IENABLEx(x) (1 << (8 + (x)))
 #define HW_LRADC_CTRL2__TEMPSENSE_PWD           (1 << 15)
 #define HW_LRADC_CTRL2__DIVIDE_BY_TWO(x)        (1 << ((x) + 24))
 
@@ -59,7 +65,7 @@
 #define HW_LRADC_STATUS     (*(volatile uint32_t *)(HW_LRADC_BASE + 0x40))
 
 #define HW_LRADC_CHx(x)     (*(volatile uint32_t *)(HW_LRADC_BASE + 0x50 + (x) * 0x10))
-#define HW_LRADC_CHx__NUM_SAMPLES_BM    (0xf << 24)
+#define HW_LRADC_CHx__NUM_SAMPLES_BM    (0x1f << 24)
 #define HW_LRADC_CHx__NUM_SAMPLES_BP    24
 #define HW_LRADC_CHx__ACCUMULATE        29
 #define HW_LRADC_CHx__VALUE_BM          0x3ffff
@@ -127,8 +133,11 @@ void imx233_lradc_reserve_delay(int dchannel);
 void imx233_lradc_release_delay(int dchan);
 
 /* enable sensing and return temperature in kelvin,
- * channels must already be configured as nmos and pmos */
+ * channels needs not to be configured */
 int imx233_lradc_sense_die_temperature(int nmos_chan, int pmos_chan);
+/* return *raw* external temperature, might need some transformation
+ * channel needs not to be configured */
+int imx233_lradc_sense_ext_temperature(int chan, int sensor);
 
 void imx233_lradc_setup_battery_conversion(bool automatic, unsigned long scale_factor);
 // read scaled voltage, only available after proper setup
diff --git a/firmware/target/arm/imx233/sansa-fuzeplus/adc-fuzeplus.c b/firmware/target/arm/imx233/sansa-fuzeplus/adc-fuzeplus.c
index 7207e5f8a8..cf420ae84f 100644
--- a/firmware/target/arm/imx233/sansa-fuzeplus/adc-fuzeplus.c
+++ b/firmware/target/arm/imx233/sansa-fuzeplus/adc-fuzeplus.c
@@ -26,7 +26,8 @@ int imx233_adc_mapping[] =
     [ADC_BATTERY] = IMX233_ADC_BATTERY,
     [ADC_DIE_TEMP] = IMX233_ADC_DIE_TEMP,
     [ADC_VDDIO] = IMX233_ADC_VDDIO,
-    [ADC_5V] = HW_LRADC_CHANNEL_5V,
+    [ADC_5V] = IMX233_ADC_VDD5V,
+    [ADC_BATT_TEMP] = IMX233_ADC_BATT_TEMP,
     [ADC_CH2] = HW_LRADC_CHANNEL(2),
 };
 
@@ -34,7 +35,8 @@ const char *imx233_adc_channel_name[] =
 {
     "Battery(raw)",
     "Die temperature(°C)",
-    "VddIO",
-    "Vdd5V",
+    "VddIO(mV)",
+    "Vdd5V(mV)",
+    "Battery temperature(raw)",
     "Channel 2",
 };
diff --git a/firmware/target/arm/imx233/sansa-fuzeplus/adc-target.h b/firmware/target/arm/imx233/sansa-fuzeplus/adc-target.h
index e9c6f5d00e..5907eefdc2 100644
--- a/firmware/target/arm/imx233/sansa-fuzeplus/adc-target.h
+++ b/firmware/target/arm/imx233/sansa-fuzeplus/adc-target.h
@@ -21,12 +21,15 @@
 #ifndef _ADC_TARGET_H_
 #define _ADC_TARGET_H_
 
-#define NUM_ADC_CHANNELS    5
+#define NUM_ADC_CHANNELS    6
 
 #define ADC_BATTERY         0
 #define ADC_DIE_TEMP        1
 #define ADC_VDDIO           2
 #define ADC_5V              3
-#define ADC_CH2             4
+#define ADC_BATT_TEMP       4
+#define ADC_CH2             5
+
+#define IMX233_ADC_BATT_TEMP_SENSOR     0
 
 #endif
diff --git a/firmware/target/arm/imx233/system-imx233.c b/firmware/target/arm/imx233/system-imx233.c
index 63bd91998d..7519687568 100644
--- a/firmware/target/arm/imx233/system-imx233.c
+++ b/firmware/target/arm/imx233/system-imx233.c
@@ -31,6 +31,7 @@
 #include "ssp-imx233.h"
 #include "i2c-imx233.h"
 #include "dcp-imx233.h"
+#include "lradc-imx233.h"
 #include "lcd.h"
 #include "backlight-target.h"
 #include "button.h"
@@ -214,6 +215,7 @@ void system_init(void)
     imx233_dma_init();
     imx233_ssp_init();
     imx233_dcp_init();
+    imx233_lradc_init();
     imx233_i2c_init();
 #if defined(SANSA_FUZEPLUS) && !defined(BOOTLOADER)
     fmradio_i2c_init();