twl4030_charger: add software controlled linear charging mode.
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.
Original-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index 6fa928e..de5430d 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 @@
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 @@
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);
@@ -652,6 +684,8 @@
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);
@@ -750,6 +784,17 @@
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->desc->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: