Minor enhancements to axp173 driver

- Added register names to reduce usage of magic numbers
- Added function to control max charging current, needed for USB
- Corrected comment about axp173, since FiiO M3K has an axp192

Change-Id: I6604ce8d44e5a2ee84061cf042d17ccc4734ac57

4 files changed, 120 insertions, 32 deletions

diff --git a/firmware/drivers/axp173.c b/firmware/drivers/axp173.c
index 22417650fc..0c9b9c81a4 100644
--- a/firmware/drivers/axp173.c
+++ b/firmware/drivers/axp173.c
@@ -35,21 +35,22 @@ static const struct axp173_adc_info {
     uint8_t en_reg;
     uint8_t en_bit;
 } axp173_adc_info[NUM_ADC_CHANNELS] = {
-    {0x56, 0x82, 5},    /* ACIN_VOLTAGE */
-    {0x58, 0x82, 4},    /* ACIN_CURRENT */
-    {0x5a, 0x82, 3},    /* VBUS_VOLTAGE */
-    {0x5c, 0x82, 2},    /* VBUS_CURRENT */
-    {0x5e, 0x83, 7},    /* INTERNAL_TEMP */
-    {0x62, 0x82, 1},    /* TS_INPUT */
-    {0x78, 0x82, 7},    /* BATTERY_VOLTAGE */
-    {0x7a, 0x82, 6},    /* CHARGE_CURRENT */
-    {0x7c, 0x82, 6},    /* DISCHARGE_CURRENT */
-    {0x7e, 0x82, 1},    /* APS_VOLTAGE */
-    {0x70, 0xff, 0},    /* BATTERY_POWER */
+    {0x56, AXP173_REG_ADCENABLE1, 5}, /* ACIN_VOLTAGE */
+    {0x58, AXP173_REG_ADCENABLE1, 4}, /* ACIN_CURRENT */
+    {0x5a, AXP173_REG_ADCENABLE1, 3}, /* VBUS_VOLTAGE */
+    {0x5c, AXP173_REG_ADCENABLE1, 2}, /* VBUS_CURRENT */
+    {0x5e, AXP173_REG_ADCENABLE2, 7}, /* INTERNAL_TEMP */
+    {0x62, AXP173_REG_ADCENABLE1, 1}, /* TS_INPUT */
+    {0x78, AXP173_REG_ADCENABLE1, 7}, /* BATTERY_VOLTAGE */
+    {0x7a, AXP173_REG_ADCENABLE1, 6}, /* CHARGE_CURRENT */
+    {0x7c, AXP173_REG_ADCENABLE1, 6}, /* DISCHARGE_CURRENT */
+    {0x7e, AXP173_REG_ADCENABLE1, 1}, /* APS_VOLTAGE */
+    {0x70, 0xff, 0},                  /* BATTERY_POWER */
 };
 
 static struct axp173 {
     int adc_enable;
+    int chargecurrent_setting;
 } axp173;
 
 static void axp173_init_enabled_adcs(void)
@@ -58,7 +59,8 @@ static void axp173_init_enabled_adcs(void)
 
     /* Read enabled ADCs from the hardware */
     uint8_t regs[2];
-    int rc = i2c_reg_read(AXP173_BUS, AXP173_ADDR, 0x82, 2, &regs[0]);
+    int rc = i2c_reg_read(AXP173_BUS, AXP173_ADDR,
+                          AXP173_REG_ADCENABLE1, 2, &regs[0]);
     if(rc != I2C_STATUS_OK)
         return;
 
@@ -68,7 +70,7 @@ static void axp173_init_enabled_adcs(void)
         if(info[i].en_reg == 0xff)
             continue;
 
-        if(regs[info[i].en_reg - 0x82] & info[i].en_bit)
+        if(regs[info[i].en_reg - AXP173_REG_ADCENABLE1] & info[i].en_bit)
             axp173.adc_enable |= 1 << i;
     }
 
@@ -87,12 +89,16 @@ void axp173_init(void)
     int bits = axp173.adc_enable;
     bits |= (1 << ADC_DISCHARGE_CURRENT);
     axp173_adc_set_enabled(bits);
+
+    /* Read the maximum charging current */
+    int value = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, AXP173_REG_CHARGECONTROL1);
+    axp173.chargecurrent_setting = (value < 0) ? -1 : value;
 }
 
 /* TODO: this can STILL indicate some false positives! */
 int axp173_battery_status(void)
 {
-    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, 0x00);
+    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, AXP173_REG_POWERSTATUS);
     if(r >= 0) {
         /* Charging bit indicates we're currently charging */
         if((r & 0x04) != 0)
@@ -124,7 +130,7 @@ int axp173_input_status(void)
     int input_status = AXP173_INPUT_BATTERY;
 #endif
 
-    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, 0x00);
+    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, AXP173_REG_POWERSTATUS);
     if(r < 0)
         return input_status;
 
@@ -138,7 +144,7 @@ int axp173_input_status(void)
 
 #ifdef HAVE_BATTERY_SWITCH
     /* Check for battery presence if target defines it as removable */
-    r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, 0x01);
+    r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, AXP173_REG_CHARGESTATUS);
     if(r >= 0 && (r & 0x20) != 0)
         input_status |= AXP173_INPUT_BATTERY;
 #endif
@@ -251,13 +257,13 @@ void axp173_adc_set_enabled(int adc_bits)
     }
 
     /* Update the configuration */
-    i2c_reg_write(AXP173_BUS, AXP173_ADDR, 0x82, 2, &regs[0]);
+    i2c_reg_write(AXP173_BUS, AXP173_ADDR, AXP173_REG_ADCENABLE1, 2, &regs[0]);
     axp173.adc_enable = adc_bits;
 }
 
 int axp173_adc_get_rate(void)
 {
-    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, 0x84);
+    int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, AXP173_REG_ADCSAMPLERATE);
     if(r < 0)
         return AXP173_ADC_RATE_100HZ; /* an arbitrary value */
 
@@ -266,7 +272,7 @@ int axp173_adc_get_rate(void)
 
 void axp173_adc_set_rate(int rate)
 {
-    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR, 0x84,
+    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR, AXP173_REG_ADCSAMPLERATE,
                     0xc0, (rate & 3) << 6, NULL);
 }
 
@@ -278,7 +284,8 @@ static uint32_t axp173_cc_parse(const uint8_t* buf)
 void axp173_cc_read(uint32_t* charge, uint32_t* discharge)
 {
     uint8_t buf[8];
-    int rc = i2c_reg_read(AXP173_BUS, AXP173_ADDR, 0xb0, 8, &buf[0]);
+    int rc = i2c_reg_read(AXP173_BUS, AXP173_ADDR,
+                          AXP173_REG_COULOMBCOUNTERBASE, 8, &buf[0]);
     if(rc != I2C_STATUS_OK) {
         if(charge)
             *charge = 0;
@@ -295,19 +302,63 @@ void axp173_cc_read(uint32_t* charge, uint32_t* discharge)
 
 void axp173_cc_clear(void)
 {
-    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR, 0xb8, 5, 1, NULL);
+    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_COULOMBCOUNTERCTRL, 5, 1, NULL);
 }
 
 void axp173_cc_enable(bool en)
 {
-    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR, 0xb8, 7, en ? 1 : 0, NULL);
+    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_COULOMBCOUNTERCTRL, 7, en ? 1 : 0, NULL);
+}
+
+static const int chargecurrent_tbl[] = {
+    100,  190,  280,  360,
+    450,  550,  630,  700,
+    780,  880,  960,  1000,
+    1080, 1160, 1240, 1320,
+};
+
+static const int chargecurrent_tblsz = sizeof(chargecurrent_tbl)/sizeof(int);
+
+void axp173_set_charge_current(int maxcurrent)
+{
+    /* Find the charge current just higher than maxcurrent */
+    int value = 0;
+    while(value < chargecurrent_tblsz &&
+          chargecurrent_tbl[value] <= maxcurrent)
+        ++value;
+
+    /* Select the next lower current, the greatest current <= maxcurrent */
+    if(value >= chargecurrent_tblsz)
+        value = chargecurrent_tblsz - 1;
+    else if(value > 0)
+        --value;
+
+    /* Don't issue i2c write if desired setting is already in use */
+    if(value == axp173.chargecurrent_setting)
+        return;
+
+    /* Update register */
+    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_CHARGECONTROL1, 0x0f, value, NULL);
+    axp173.chargecurrent_setting = value;
+}
+
+int axp173_get_charge_current(void)
+{
+    if(axp173.chargecurrent_setting < 0)
+        return chargecurrent_tbl[0];
+    else
+        return chargecurrent_tbl[axp173.chargecurrent_setting];
 }
 
 #ifndef BOOTLOADER
 #define AXP173_DEBUG_BATTERY_STATUS 0
 #define AXP173_DEBUG_INPUT_STATUS   1
-#define AXP173_DEBUG_ADC_RATE       2
-#define AXP173_DEBUG_FIRST_ADC      3
+#define AXP173_DEBUG_CHARGE_CURRENT 2
+#define AXP173_DEBUG_ADC_RATE       3
+#define AXP173_DEBUG_FIRST_ADC      4
 #define AXP173_DEBUG_ENTRIES        (AXP173_DEBUG_FIRST_ADC + NUM_ADC_CHANNELS)
 
 static int axp173_debug_menu_cb(int action, struct gui_synclist* lists)
@@ -377,6 +428,12 @@ static const char* axp173_debug_menu_get_name(int item, void* data,
         return buf;
     } break;
 
+    case AXP173_DEBUG_CHARGE_CURRENT: {
+        int current = axp173_get_charge_current();
+        snprintf(buf, buflen, "Max charge current: %d mA", current);
+        return buf;
+    } break;
+
     case AXP173_DEBUG_ADC_RATE: {
         int rate = 25 << axp173_adc_get_rate();
         snprintf(buf, buflen, "ADC sample rate: %d Hz", rate);
diff --git a/firmware/export/axp173.h b/firmware/export/axp173.h
index 60519138e1..34f0c2ec19 100644
--- a/firmware/export/axp173.h
+++ b/firmware/export/axp173.h
@@ -25,6 +25,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+/* ADC channels */
 #define ADC_ACIN_VOLTAGE        0
 #define ADC_ACIN_CURRENT        1
 #define ADC_VBUS_VOLTAGE        2
@@ -55,6 +56,25 @@
 #define AXP173_INPUT_BATTERY    (1 << 2)
 #define AXP173_INPUT_EXTERNAL   (AXP173_INPUT_AC|AXP173_INPUT_USB)
 
+/* Registers -- common to AXP173 and AXP192 (incomplete listing) */
+#define AXP173_REG_POWERSTATUS          0x00
+#define AXP173_REG_CHARGESTATUS         0x01
+#define AXP173_REG_PWROUTPUTCTRL        0x12
+#define AXP173_REG_SHUTDOWNLEDCTRL      0x32
+#define AXP173_REG_CHARGECONTROL1       0x33
+#define AXP173_REG_DCDCWORKINGMODE      0x80
+#define AXP173_REG_ADCENABLE1           0x82
+#define AXP173_REG_ADCENABLE2           0x83
+#define AXP173_REG_ADCSAMPLERATE        0x84
+#define AXP173_REG_COULOMBCOUNTERBASE   0xb0
+#define AXP173_REG_COULOMBCOUNTERCTRL   0xb8
+
+/* AXP192-only registers (incomplete listing) */
+#define AXP192_REG_GPIO0FUNCTION        0x90
+#define AXP192_REG_GPIO1FUNCTION        0x92
+#define AXP192_REG_GPIO2FUNCTION        0x93
+#define AXP192_REG_GPIOSTATE1           0x94
+
 /* Must be called from power_init() to initialize the driver state */
 extern void axp173_init(void);
 
@@ -88,6 +108,10 @@ extern void axp173_cc_read(uint32_t* charge, uint32_t* discharge);
 extern void axp173_cc_clear(void);
 extern void axp173_cc_enable(bool en);
 
+/* Set/get maximum charging current in milliamps */
+extern void axp173_set_charge_current(int maxcurrent);
+extern int axp173_get_charge_current(void);
+
 /* Debug menu */
 extern bool axp173_debug_menu(void);
 
diff --git a/firmware/target/mips/ingenic_x1000/fiiom3k/button-fiiom3k.c b/firmware/target/mips/ingenic_x1000/fiiom3k/button-fiiom3k.c
index db5ece10b0..e27e0be464 100644
--- a/firmware/target/mips/ingenic_x1000/fiiom3k/button-fiiom3k.c
+++ b/firmware/target/mips/ingenic_x1000/fiiom3k/button-fiiom3k.c
@@ -23,13 +23,14 @@
 #include "kernel.h"
 #include "backlight.h"
 #include "panic.h"
-#include "lcd.h"
+#include "axp173.h"
 #include "gpio-x1000.h"
 #include "i2c-x1000.h"
 #include <string.h>
 #include <stdbool.h>
 
 #ifndef BOOTLOADER
+# include "lcd.h"
 # include "font.h"
 #endif
 
@@ -409,7 +410,7 @@ static int hp_detect_tmo_cb(struct timeout* tmo)
 static void hp_detect_init(void)
 {
     static struct timeout tmo;
-    static const uint8_t gpio_reg = 0x94;
+    static const uint8_t gpio_reg = AXP192_REG_GPIOSTATE1;
     static i2c_descriptor desc = {
         .slave_addr = AXP173_ADDR,
         .bus_cond = I2C_START | I2C_STOP,
@@ -423,9 +424,8 @@ static void hp_detect_init(void)
         .next = NULL,
     };
 
-    /* Headphone detect is wired to an undocumented GPIO on the AXP173.
-     * This sets it to input mode so we can see the pin state. */
-    i2c_reg_write1(AXP173_BUS, AXP173_ADDR, 0x93, 0x01);
+    /* Headphone detect is wired to AXP192 GPIO: set it to input state */
+    i2c_reg_write1(AXP173_BUS, AXP173_ADDR, AXP192_REG_GPIO2FUNCTION, 0x01);
 
     /* Get an initial reading before startup */
     int r = i2c_reg_read1(AXP173_BUS, AXP173_ADDR, gpio_reg);
diff --git a/firmware/target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c b/firmware/target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c
index b4923835aa..a3760d145a 100644
--- a/firmware/target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c
+++ b/firmware/target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c
@@ -68,8 +68,14 @@ void power_init(void)
     axp173_adc_set_enabled(bits);
 
     /* Turn on all power outputs */
-    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR, 0x12, 0, 0x5f, NULL);
-    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR, 0x80, 0, 0xc0, NULL);
+    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_PWROUTPUTCTRL, 0, 0x5f, NULL);
+    i2c_reg_modify1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_DCDCWORKINGMODE, 0, 0xc0, NULL);
+
+    /* Set the default charging current. This is the same as the
+     * OF's setting, although it's not strictly within the USB spec. */
+    axp173_set_charge_current(780);
 
     /* Short delay to give power outputs time to stabilize */
     mdelay(5);
@@ -82,7 +88,8 @@ void adc_init(void)
 void power_off(void)
 {
     /* Set the shutdown bit */
-    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR, 0x32, 7, 1, NULL);
+    i2c_reg_setbit1(AXP173_BUS, AXP173_ADDR,
+                    AXP173_REG_SHUTDOWNLEDCTRL, 7, 1, NULL);
     while(1);
 }