power: supply: cpcap-charger: Update charge current table and add comments

Turns out a similar battery charger hardware is documented for NXP MC13783
PMIC in "MC13783 Power Management and Audio Circuit Users's Guide" named
MC13783UG.pdf. Looks like the CPCAP charge current table matches that, so
let's start using the nominal values from it.

While at it, let's also add comments to some of the mystery CPCAP charger
registers based on the MC13783UG.pdf documentation.

Note that this patch does not contain any functional changes, the register
values being used stay the same.

Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

diff --git a/drivers/power/supply/cpcap-charger.c b/drivers/power/supply/cpcap-charger.c
index 26a2dc7ac9a2777643ec2b3abda2e19af0b7ea50..adb9767adc8ab39410fc49f0954a50b946a77f19 100644 (file)
--- a/drivers/power/supply/cpcap-charger.c
+++ b/drivers/power/supply/cpcap-charger.c
@@ -38,20 +38,27 @@
 #include <linux/iio/consumer.h>
 #include <linux/mfd/motorola-cpcap.h>
 
-/* CPCAP_REG_CRM register bits */
+/*
+ * CPCAP_REG_CRM register bits. For documentation of somewhat similar hardware,
+ * see NXP "MC13783 Power Management and Audio Circuit Users's Guide"
+ * MC13783UG.pdf chapter "8.5 Battery Interface Register Summary". The registers
+ * and values for CPCAP are different, but some of the internal components seem
+ * similar. Also see the Motorola Linux kernel cpcap-regbits.h. CPCAP_REG_CHRGR_1
+ * bits that seem to describe the CRM register.
+ */
 #define CPCAP_REG_CRM_UNUSED_641_15    BIT(15) /* 641 = register number */
 #define CPCAP_REG_CRM_UNUSED_641_14    BIT(14) /* 641 = register number */
-#define CPCAP_REG_CRM_CHRG_LED_EN      BIT(13)
-#define CPCAP_REG_CRM_RVRSMODE         BIT(12)
-#define CPCAP_REG_CRM_ICHRG_TR1                BIT(11)
+#define CPCAP_REG_CRM_CHRG_LED_EN      BIT(13) /* Charger LED */
+#define CPCAP_REG_CRM_RVRSMODE         BIT(12) /* USB VBUS output enable */
+#define CPCAP_REG_CRM_ICHRG_TR1                BIT(11) /* Trickle charge current */
 #define CPCAP_REG_CRM_ICHRG_TR0                BIT(10)
-#define CPCAP_REG_CRM_FET_OVRD         BIT(9)
-#define CPCAP_REG_CRM_FET_CTRL         BIT(8)
-#define CPCAP_REG_CRM_VCHRG3           BIT(7)
+#define CPCAP_REG_CRM_FET_OVRD         BIT(9)  /* 0 = hardware, 1 = FET_CTRL */
+#define CPCAP_REG_CRM_FET_CTRL         BIT(8)  /* BPFET 1 if FET_OVRD set */
+#define CPCAP_REG_CRM_VCHRG3           BIT(7)  /* Charge voltage bits */
 #define CPCAP_REG_CRM_VCHRG2           BIT(6)
 #define CPCAP_REG_CRM_VCHRG1           BIT(5)
 #define CPCAP_REG_CRM_VCHRG0           BIT(4)
-#define CPCAP_REG_CRM_ICHRG3           BIT(3)
+#define CPCAP_REG_CRM_ICHRG3           BIT(3)  /* Charge current bits */
 #define CPCAP_REG_CRM_ICHRG2           BIT(2)
 #define CPCAP_REG_CRM_ICHRG1           BIT(1)
 #define CPCAP_REG_CRM_ICHRG0           BIT(0)
@@ -82,23 +89,27 @@
 #define CPCAP_REG_CRM_VCHRG_4V42       CPCAP_REG_CRM_VCHRG(0xe)
 #define CPCAP_REG_CRM_VCHRG_4V44       CPCAP_REG_CRM_VCHRG(0xf)
 
-/* CPCAP_REG_CRM charge currents */
+/*
+ * CPCAP_REG_CRM charge currents. These seem to match MC13783UG.pdf
+ * values in "Table 8-3. Charge Path Regulator Current Limit
+ * Characteristics" for the nominal values.
+ */
 #define CPCAP_REG_CRM_ICHRG(val)       (((val) & 0xf) << 0)
 #define CPCAP_REG_CRM_ICHRG_0A000      CPCAP_REG_CRM_ICHRG(0x0)
 #define CPCAP_REG_CRM_ICHRG_0A070      CPCAP_REG_CRM_ICHRG(0x1)
-#define CPCAP_REG_CRM_ICHRG_0A176      CPCAP_REG_CRM_ICHRG(0x2)
-#define CPCAP_REG_CRM_ICHRG_0A264      CPCAP_REG_CRM_ICHRG(0x3)
-#define CPCAP_REG_CRM_ICHRG_0A352      CPCAP_REG_CRM_ICHRG(0x4)
-#define CPCAP_REG_CRM_ICHRG_0A440      CPCAP_REG_CRM_ICHRG(0x5)
-#define CPCAP_REG_CRM_ICHRG_0A528      CPCAP_REG_CRM_ICHRG(0x6)
-#define CPCAP_REG_CRM_ICHRG_0A616      CPCAP_REG_CRM_ICHRG(0x7)
-#define CPCAP_REG_CRM_ICHRG_0A704      CPCAP_REG_CRM_ICHRG(0x8)
-#define CPCAP_REG_CRM_ICHRG_0A792      CPCAP_REG_CRM_ICHRG(0x9)
-#define CPCAP_REG_CRM_ICHRG_0A880      CPCAP_REG_CRM_ICHRG(0xa)
-#define CPCAP_REG_CRM_ICHRG_0A968      CPCAP_REG_CRM_ICHRG(0xb)
-#define CPCAP_REG_CRM_ICHRG_1A056      CPCAP_REG_CRM_ICHRG(0xc)
-#define CPCAP_REG_CRM_ICHRG_1A144      CPCAP_REG_CRM_ICHRG(0xd)
-#define CPCAP_REG_CRM_ICHRG_1A584      CPCAP_REG_CRM_ICHRG(0xe)
+#define CPCAP_REG_CRM_ICHRG_0A177      CPCAP_REG_CRM_ICHRG(0x2)
+#define CPCAP_REG_CRM_ICHRG_0A266      CPCAP_REG_CRM_ICHRG(0x3)
+#define CPCAP_REG_CRM_ICHRG_0A355      CPCAP_REG_CRM_ICHRG(0x4)
+#define CPCAP_REG_CRM_ICHRG_0A443      CPCAP_REG_CRM_ICHRG(0x5)
+#define CPCAP_REG_CRM_ICHRG_0A532      CPCAP_REG_CRM_ICHRG(0x6)
+#define CPCAP_REG_CRM_ICHRG_0A621      CPCAP_REG_CRM_ICHRG(0x7)
+#define CPCAP_REG_CRM_ICHRG_0A709      CPCAP_REG_CRM_ICHRG(0x8)
+#define CPCAP_REG_CRM_ICHRG_0A798      CPCAP_REG_CRM_ICHRG(0x9)
+#define CPCAP_REG_CRM_ICHRG_0A886      CPCAP_REG_CRM_ICHRG(0xa)
+#define CPCAP_REG_CRM_ICHRG_0A975      CPCAP_REG_CRM_ICHRG(0xb)
+#define CPCAP_REG_CRM_ICHRG_1A064      CPCAP_REG_CRM_ICHRG(0xc)
+#define CPCAP_REG_CRM_ICHRG_1A152      CPCAP_REG_CRM_ICHRG(0xd)
+#define CPCAP_REG_CRM_ICHRG_1A596      CPCAP_REG_CRM_ICHRG(0xe)
 #define CPCAP_REG_CRM_ICHRG_NO_LIMIT   CPCAP_REG_CRM_ICHRG(0xf)
 
 enum {
@@ -428,9 +439,9 @@ static void cpcap_usb_detect(struct work_struct *work)
                int max_current;
 
                if (cpcap_charger_battery_found(ddata))
-                       max_current = CPCAP_REG_CRM_ICHRG_1A584;
+                       max_current = CPCAP_REG_CRM_ICHRG_1A596;
                else
-                       max_current = CPCAP_REG_CRM_ICHRG_0A528;
+                       max_current = CPCAP_REG_CRM_ICHRG_0A532;
 
                error = cpcap_charger_set_state(ddata,
                                                CPCAP_REG_CRM_VCHRG_4V35,