From: NeilBrown <neilb@xxxxxxx>
Add a 'continuous' option for usb charging which enables
the "linear" charging mode of the twl4030.
Linear charging does a good job with not-so-reliable power sources.
Auto mode does not work well as it switches off when voltage drops
momentarily. Care must be taken not to over-charge.
It was used with a bike hub dynamo since a year or so. In that case
there are automatically charging stops when the cyclist needs a break.
Orignal-by: Andreas Kemnade <andreas@xxxxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
.../ABI/testing/sysfs-class-power-twl4030 | 9 +++
drivers/power/twl4030_charger.c | 55 ++++++++++++++++++--
2 files changed, 59 insertions(+), 5 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-class-power-twl4030 b/Documentation/ABI/testing/sysfs-class-power-twl4030
index 390db7a55231..c27e8ca8c9db 100644
--- a/Documentation/ABI/testing/sysfs-class-power-twl4030
+++ b/Documentation/ABI/testing/sysfs-class-power-twl4030
@@ -24,3 +24,12 @@ Description:
"auto" - draw power as appropriate for detected
power source and battery status.
"off" - do not draw any power.
+ "continuous"
+ - activate mode described as "linear" in
+ TWL data sheets. This uses whatever
+ current is available and doesn't switch off
+ when voltage drops.
+
+ This is useful for unstable power sources
+ such as bicycle dynamo, but care should
+ be taken that battery is not over-charged.
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index 802cdd6d3e00..2c8d85102def 100644
--- a/drivers/power/twl4030_charger.c
+++ b/drivers/power/twl4030_charger.c
@@ -24,6 +24,8 @@
#include <linux/usb/otg.h>
#include <linux/i2c/twl4030-madc.h>
+#define TWL4030_BCIMDEN 0x00
+#define TWL4030_BCIMDKEY 0x01
#define TWL4030_BCIMSTATEC 0x02
#define TWL4030_BCIICHG 0x08
#define TWL4030_BCIVAC 0x0a
@@ -35,13 +37,16 @@
#define TWL4030_BCIIREF1 0x27
#define TWL4030_BCIIREF2 0x28
#define TWL4030_BCIMFKEY 0x11
+#define TWL4030_BCIMFEN3 0x14
#define TWL4030_BCIMFTH8 0x1d
#define TWL4030_BCIMFTH9 0x1e
+#define TWL4030_BCIWDKEY 0x21
#define TWL4030_BCIMFSTS1 0x01
#define TWL4030_BCIAUTOWEN BIT(5)
#define TWL4030_CONFIG_DONE BIT(4)
+#define TWL4030_CVENAC BIT(2)
#define TWL4030_BCIAUTOUSB BIT(1)
#define TWL4030_BCIAUTOAC BIT(0)
#define TWL4030_CGAIN BIT(5)
@@ -112,12 +117,13 @@ struct twl4030_bci {
int usb_mode; /* charging mode requested */
#define CHARGE_OFF 0
#define CHARGE_AUTO 1
+#define CHARGE_LINEAR 2
unsigned long event;
};
/* strings for 'usb_mode' values */
-static char *modes[] = { "off", "auto" };
+static char *modes[] = { "off", "auto", "continuous" };
/*
* clear and set bits on an given register on a given module
@@ -404,16 +410,42 @@ static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
bci->usb_enabled = 1;
}
- /* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */
- ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB);
- if (ret < 0)
- return ret;
+ if (bci->usb_mode == CHARGE_AUTO)
+ /* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */
+ ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB);
/* forcing USBFASTMCHG(BCIMFSTS4[2]) to 1 */
ret = twl4030_clear_set(TWL_MODULE_MAIN_CHARGE, 0,
TWL4030_USBFASTMCHG, TWL4030_BCIMFSTS4);
+ if (bci->usb_mode == CHARGE_LINEAR) {
+ twl4030_clear_set_boot_bci(TWL4030_BCIAUTOAC|TWL4030_CVENAC, 0);
+ /* Watch dog key: WOVF acknowledge */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x33,
+ TWL4030_BCIWDKEY);
+ /* 0x24 + EKEY6: off mode */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a,
+ TWL4030_BCIMDKEY);
+ /* EKEY2: Linear charge: USB path */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x26,
+ TWL4030_BCIMDKEY);
+ /* WDKEY5: stop watchdog count */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf3,
+ TWL4030_BCIWDKEY);
+ /* enable MFEN3 access */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x9c,
+ TWL4030_BCIMFKEY);
+ /* ICHGEOCEN - end-of-charge monitor (current < 80mA)
+ * (charging continues)
+ * ICHGLOWEN - current level monitor (charge continues)
+ * don't monitor over-current or heat save
+ */
+ ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf0,
+ TWL4030_BCIMFEN3);
+ }
} else {
ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOUSB, 0);
+ ret |= twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a,
+ TWL4030_BCIMDKEY);
if (bci->usb_enabled) {
pm_runtime_mark_last_busy(bci->transceiver->dev);
pm_runtime_put_autosuspend(bci->transceiver->dev);
@@ -657,6 +689,8 @@ twl4030_bci_mode_store(struct device *dev, struct device_attribute *attr,
mode = 0;
else if (sysfs_streq(buf, modes[1]))
mode = 1;
+ else if (sysfs_streq(buf, modes[2]))
+ mode = 2;
else
return -EINVAL;
twl4030_charger_enable_usb(bci, false);
@@ -755,6 +789,17 @@ static int twl4030_bci_get_property(struct power_supply *psy,
is_charging = state & TWL4030_MSTATEC_USB;
else
is_charging = state & TWL4030_MSTATEC_AC;
+ if (!is_charging) {
+ u8 s;
+ twl4030_bci_read(TWL4030_BCIMDEN, &s);
+ if (psy->type == POWER_SUPPLY_TYPE_USB)
+ is_charging = s & 1;
+ else
+ is_charging = s & 2;
+ if (is_charging)
+ /* A little white lie */
+ state = TWL4030_MSTATEC_QUICK1;
+ }
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
--
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