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Commit f8e96dff authored by Johan Bjornstedt's avatar Johan Bjornstedt Committed by Lee Jones
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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: default avatarJohan Bjornstedt <johan.bjornstedt@stericsson.com>
Signed-off-by: default avatarMattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Reviewed-by: default avatarKarl KOMIEROWSKI <karl.komierowski@stericsson.com>
parent f5695a39

drivers/power/ab8500_charger.c

+135 −40
Original line number Diff line number Diff line
@@ -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,
@@ -935,6 +938,88 @@ static int ab8500_charger_get_usb_cur(struct ab8500_charger *di) 
	return 0;

}



/**

 * 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, &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
@@ -946,8 +1031,6 @@ static int ab8500_charger_get_usb_cur(struct ab8500_charger *di) 
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 @@ static int ab8500_charger_set_vbus_in_curr(struct ab8500_charger *di, 
		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 @@ static int ab8500_charger_ac_en(struct ux500_charger *charger, 
			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 @@ static int ab8500_charger_ac_en(struct ux500_charger *charger, 
				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 @@ static int ab8500_charger_usb_en(struct ux500_charger *charger, 
			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 @@ static int ab8500_charger_update_charger_current(struct ux500_charger *charger, 
		int ich_out)

{

	int ret;

	int curr_index;

	struct ab8500_charger *di;



	if (charger->psy.type == POWER_SUPPLY_TYPE_MAINS)
@@ -1376,18 +1478,11 @@ static int ab8500_charger_update_charger_current(struct ux500_charger *charger, 
	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;

	}