ab8500_charger: Charger current step-up/down
There is no state machine in the AB to step up/down the charger
current to avoid dips and spikes on VBUS and VBAT when charging
is started. Instead this is implemented in SW.
Signed-off-by: Johan Bjornstedt <johan.bjornstedt@stericsson.com>
Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Karl KOMIEROWSKI <karl.komierowski@stericsson.com>
diff --git a/drivers/power/ab8500_charger.c b/drivers/power/ab8500_charger.c
index dddc947..d27dd7f 100644
--- a/drivers/power/ab8500_charger.c
+++ b/drivers/power/ab8500_charger.c
@@ -79,6 +79,9 @@
/* Lowest charger voltage is 3.39V -> 0x4E */
#define LOW_VOLT_REG 0x4E
+/* Step up/down delay in us */
+#define STEP_UDELAY 1000
+
/* UsbLineStatus register - usb types */
enum ab8500_charger_link_status {
USB_STAT_NOT_CONFIGURED,
@@ -936,6 +939,88 @@
}
/**
+ * ab8500_charger_set_current() - set charger current
+ * @di: pointer to the ab8500_charger structure
+ * @ich: charger current, in mA
+ * @reg: select what charger register to set
+ *
+ * Set charger current.
+ * There is no state machine in the AB to step up/down the charger
+ * current to avoid dips and spikes on MAIN, VBUS and VBAT when
+ * charging is started. Instead we need to implement
+ * this charger current step-up/down here.
+ * Returns error code in case of failure else 0(on success)
+ */
+static int ab8500_charger_set_current(struct ab8500_charger *di,
+ int ich, int reg)
+{
+ int ret, i;
+ int curr_index, prev_curr_index, shift_value;
+ u8 reg_value;
+
+ switch (reg) {
+ case AB8500_MCH_IPT_CURLVL_REG:
+ shift_value = MAIN_CH_INPUT_CURR_SHIFT;
+ curr_index = ab8500_current_to_regval(ich);
+ break;
+ case AB8500_USBCH_IPT_CRNTLVL_REG:
+ shift_value = VBUS_IN_CURR_LIM_SHIFT;
+ curr_index = ab8500_vbus_in_curr_to_regval(ich);
+ break;
+ case AB8500_CH_OPT_CRNTLVL_REG:
+ shift_value = 0;
+ curr_index = ab8500_current_to_regval(ich);
+ break;
+ default:
+ dev_err(di->dev, "%s current register not valid\n", __func__);
+ return -ENXIO;
+ }
+
+ if (curr_index < 0) {
+ dev_err(di->dev, "requested current limit out-of-range\n");
+ return -ENXIO;
+ }
+
+ ret = abx500_get_register_interruptible(di->dev, AB8500_CHARGER,
+ reg, ®_value);
+ if (ret < 0) {
+ dev_err(di->dev, "%s read failed\n", __func__);
+ return ret;
+ }
+ prev_curr_index = (reg_value >> shift_value);
+
+ /* only update current if it's been changed */
+ if (prev_curr_index == curr_index)
+ return 0;
+
+ dev_dbg(di->dev, "%s set charger current: %d mA for reg: 0x%02x\n",
+ __func__, ich, reg);
+
+ if (prev_curr_index > curr_index) {
+ for (i = prev_curr_index - 1; i >= curr_index; i--) {
+ ret = abx500_set_register_interruptible(di->dev,
+ AB8500_CHARGER, reg, (u8) i << shift_value);
+ if (ret) {
+ dev_err(di->dev, "%s write failed\n", __func__);
+ return ret;
+ }
+ usleep_range(STEP_UDELAY, STEP_UDELAY * 2);
+ }
+ } else {
+ for (i = prev_curr_index + 1; i <= curr_index; i++) {
+ ret = abx500_set_register_interruptible(di->dev,
+ AB8500_CHARGER, reg, (u8) i << shift_value);
+ if (ret) {
+ dev_err(di->dev, "%s write failed\n", __func__);
+ return ret;
+ }
+ usleep_range(STEP_UDELAY, STEP_UDELAY * 2);
+ }
+ }
+ return ret;
+}
+
+/**
* ab8500_charger_set_vbus_in_curr() - set VBUS input current limit
* @di: pointer to the ab8500_charger structure
* @ich_in: charger input current limit
@@ -946,8 +1031,6 @@
static int ab8500_charger_set_vbus_in_curr(struct ab8500_charger *di,
int ich_in)
{
- int ret;
- int input_curr_index;
int min_value;
/* We should always use to lowest current limit */
@@ -966,19 +1049,38 @@
break;
}
- input_curr_index = ab8500_vbus_in_curr_to_regval(min_value);
- if (input_curr_index < 0) {
- dev_err(di->dev, "VBUS input current limit too high\n");
- return -ENXIO;
- }
+ return ab8500_charger_set_current(di, min_value,
+ AB8500_USBCH_IPT_CRNTLVL_REG);
+}
- ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
- AB8500_USBCH_IPT_CRNTLVL_REG,
- input_curr_index << VBUS_IN_CURR_LIM_SHIFT);
- if (ret)
- dev_err(di->dev, "%s write failed\n", __func__);
+/**
+ * ab8500_charger_set_main_in_curr() - set main charger input current
+ * @di: pointer to the ab8500_charger structure
+ * @ich_in: input charger current, in mA
+ *
+ * Set main charger input current.
+ * Returns error code in case of failure else 0(on success)
+ */
+static int ab8500_charger_set_main_in_curr(struct ab8500_charger *di,
+ int ich_in)
+{
+ return ab8500_charger_set_current(di, ich_in,
+ AB8500_MCH_IPT_CURLVL_REG);
+}
- return ret;
+/**
+ * ab8500_charger_set_output_curr() - set charger output current
+ * @di: pointer to the ab8500_charger structure
+ * @ich_out: output charger current, in mA
+ *
+ * Set charger output current.
+ * Returns error code in case of failure else 0(on success)
+ */
+static int ab8500_charger_set_output_curr(struct ab8500_charger *di,
+ int ich_out)
+{
+ return ab8500_charger_set_current(di, ich_out,
+ AB8500_CH_OPT_CRNTLVL_REG);
}
/**
@@ -1090,18 +1192,19 @@
return ret;
}
/* MainChInputCurr: current that can be drawn from the charger*/
- ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
- AB8500_MCH_IPT_CURLVL_REG,
- input_curr_index << MAIN_CH_INPUT_CURR_SHIFT);
+ ret = ab8500_charger_set_main_in_curr(di,
+ di->bat->chg_params->ac_curr_max);
if (ret) {
- dev_err(di->dev, "%s write failed\n", __func__);
+ dev_err(di->dev, "%s Failed to set MainChInputCurr\n",
+ __func__);
return ret;
}
/* ChOutputCurentLevel: protected output current */
- ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
- AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
+ ret = ab8500_charger_set_output_curr(di, iset);
if (ret) {
- dev_err(di->dev, "%s write failed\n", __func__);
+ dev_err(di->dev, "%s "
+ "Failed to set ChOutputCurentLevel\n",
+ __func__);
return ret;
}
@@ -1158,12 +1261,11 @@
return ret;
}
- ret = abx500_set_register_interruptible(di->dev,
- AB8500_CHARGER,
- AB8500_CH_OPT_CRNTLVL_REG, CH_OP_CUR_LVL_0P1);
+ ret = ab8500_charger_set_output_curr(di, 0);
if (ret) {
- dev_err(di->dev,
- "%s write failed\n", __func__);
+ dev_err(di->dev, "%s "
+ "Failed to set ChOutputCurentLevel\n",
+ __func__);
return ret;
}
} else {
@@ -1266,10 +1368,11 @@
return ret;
}
/* ChOutputCurentLevel: protected output current */
- ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
- AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
+ ret = ab8500_charger_set_output_curr(di, ich_out);
if (ret) {
- dev_err(di->dev, "%s write failed\n", __func__);
+ dev_err(di->dev, "%s "
+ "Failed to set ChOutputCurentLevel\n",
+ __func__);
return ret;
}
/* Check if VBAT overshoot control should be enabled */
@@ -1366,7 +1469,6 @@
int ich_out)
{
int ret;
- int curr_index;
struct ab8500_charger *di;
if (charger->psy.type == POWER_SUPPLY_TYPE_MAINS)
@@ -1376,18 +1478,11 @@
else
return -ENXIO;
- curr_index = ab8500_current_to_regval(ich_out);
- if (curr_index < 0) {
- dev_err(di->dev,
- "Charger current too high, "
- "charging not started\n");
- return -ENXIO;
- }
-
- ret = abx500_set_register_interruptible(di->dev, AB8500_CHARGER,
- AB8500_CH_OPT_CRNTLVL_REG, (u8) curr_index);
+ ret = ab8500_charger_set_output_curr(di, ich_out);
if (ret) {
- dev_err(di->dev, "%s write failed\n", __func__);
+ dev_err(di->dev, "%s "
+ "Failed to set ChOutputCurentLevel\n",
+ __func__);
return ret;
}