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Message-ID: <1299321997-6865-1-git-send-email-linus.walleij@stericsson.com>
Date: Sat, 5 Mar 2011 11:46:37 +0100
From: Linus Walleij <linus.walleij@...ricsson.com>
To: Samuel Ortiz <sameo@...ux.intel.com>,
<linux-kernel@...r.kernel.org>
Cc: Lee Jones <lee.jones@...aro.org>,
Johan Palsson <johan.palsson@...ricsson.com>,
Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH 4/5] mfd: calibrate ab8500 gpadc using OTP values
From: Johan Palsson <johan.palsson@...ricsson.com>
The GPADC found in the AB8500 needs to be calibrated to work
properly. This is done by writing a number of special OTP
(one-time-programmable) registers at production. This patch
makes sure that these values are used to calibrate the returned
value from the GPADC so that it is correct.
Signed-off-by: Johan Palsson <johan.palsson@...ricsson.com>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
---
drivers/mfd/ab8500-gpadc.c | 286 +++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 281 insertions(+), 5 deletions(-)
diff --git a/drivers/mfd/ab8500-gpadc.c b/drivers/mfd/ab8500-gpadc.c
index b5b75b7..a70201a 100644
--- a/drivers/mfd/ab8500-gpadc.c
+++ b/drivers/mfd/ab8500-gpadc.c
@@ -4,6 +4,7 @@
* License Terms: GNU General Public License v2
* Author: Arun R Murthy <arun.murthy@...ricsson.com>
* Author: Daniel Willerud <daniel.willerud@...ricsson.com>
+ * Author: Johan Palsson <johan.palsson@...ricsson.com>
*/
#include <linux/init.h>
#include <linux/module.h>
@@ -36,6 +37,18 @@
#define AB8500_GPADC_AUTODATAH_REG 0x08
#define AB8500_GPADC_MUX_CTRL_REG 0x09
+/*
+ * OTP register offsets
+ * Bank : 0x15
+ */
+#define AB8500_GPADC_CAL_1 0x0F
+#define AB8500_GPADC_CAL_2 0x10
+#define AB8500_GPADC_CAL_3 0x11
+#define AB8500_GPADC_CAL_4 0x12
+#define AB8500_GPADC_CAL_5 0x13
+#define AB8500_GPADC_CAL_6 0x14
+#define AB8500_GPADC_CAL_7 0x15
+
/* gpadc constants */
#define EN_VINTCORE12 0x04
#define EN_VTVOUT 0x02
@@ -47,8 +60,46 @@
#define DIS_ZERO 0x00
#define GPADC_BUSY 0x01
+/* GPADC constants from AB8500 spec, UM0836 */
+#define ADC_RESOLUTION 1024
+#define ADC_CH_BTEMP_MIN 0
+#define ADC_CH_BTEMP_MAX 1350
+#define ADC_CH_DIETEMP_MIN 0
+#define ADC_CH_DIETEMP_MAX 1350
+#define ADC_CH_CHG_V_MIN 0
+#define ADC_CH_CHG_V_MAX 20030
+#define ADC_CH_ACCDET2_MIN 0
+#define ADC_CH_ACCDET2_MAX 2500
+#define ADC_CH_VBAT_MIN 2300
+#define ADC_CH_VBAT_MAX 4800
+#define ADC_CH_CHG_I_MIN 0
+#define ADC_CH_CHG_I_MAX 1500
+#define ADC_CH_BKBAT_MIN 0
+#define ADC_CH_BKBAT_MAX 3200
+
+/* This is used to not lose precision when dividing to get gain and offset */
+#define CALIB_SCALE 1000
+
+enum cal_channels {
+ ADC_INPUT_VMAIN = 0,
+ ADC_INPUT_BTEMP,
+ ADC_INPUT_VBAT,
+ NBR_CAL_INPUTS,
+};
+
+/**
+ * struct adc_cal_data - Table for storing gain and offset for the calibrated
+ * ADC channels
+ * @gain: Gain of the ADC channel
+ * @offset: Offset of the ADC channel
+ */
+struct adc_cal_data {
+ u64 gain;
+ u64 offset;
+};
+
/**
- * struct ab8500_gpadc - ab8500 GPADC device information
+ * struct ab8500_gpadc - AB8500 GPADC device information
* @dev: pointer to the struct device
* @node: a list of AB8500 GPADCs, hence prepared for
reentrance
@@ -57,6 +108,7 @@
* @ab8500_gpadc_lock: structure of type mutex
* @regu: pointer to the struct regulator
* @irq: interrupt number that is used by gpadc
+ * @cal_data array of ADC calibration data structs
*/
struct ab8500_gpadc {
struct device *dev;
@@ -65,6 +117,7 @@ struct ab8500_gpadc {
struct mutex ab8500_gpadc_lock;
struct regulator *regu;
int irq;
+ struct adc_cal_data cal_data[NBR_CAL_INPUTS];
};
static LIST_HEAD(ab8500_gpadc_list);
@@ -86,13 +139,102 @@ struct ab8500_gpadc *ab8500_gpadc_get(char *name)
}
EXPORT_SYMBOL(ab8500_gpadc_get);
+static int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc, u8 input,
+ int ad_value)
+{
+ int res;
+
+ switch (input) {
+ case MAIN_CHARGER_V:
+ /* For some reason we don't have calibrated data */
+ if (!gpadc->cal_data[ADC_INPUT_VMAIN].gain) {
+ res = ADC_CH_CHG_V_MIN + (ADC_CH_CHG_V_MAX -
+ ADC_CH_CHG_V_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+ }
+ /* Here we can use the calibrated data */
+ res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_VMAIN].gain +
+ gpadc->cal_data[ADC_INPUT_VMAIN].offset) / CALIB_SCALE;
+ break;
+
+ case BAT_CTRL:
+ case BTEMP_BALL:
+ case ACC_DETECT1:
+ case ADC_AUX1:
+ case ADC_AUX2:
+ /* For some reason we don't have calibrated data */
+ if (!gpadc->cal_data[ADC_INPUT_BTEMP].gain) {
+ res = ADC_CH_BTEMP_MIN + (ADC_CH_BTEMP_MAX -
+ ADC_CH_BTEMP_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+ }
+ /* Here we can use the calibrated data */
+ res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_BTEMP].gain +
+ gpadc->cal_data[ADC_INPUT_BTEMP].offset) / CALIB_SCALE;
+ break;
+
+ case MAIN_BAT_V:
+ /* For some reason we don't have calibrated data */
+ if (!gpadc->cal_data[ADC_INPUT_VBAT].gain) {
+ res = ADC_CH_VBAT_MIN + (ADC_CH_VBAT_MAX -
+ ADC_CH_VBAT_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+ }
+ /* Here we can use the calibrated data */
+ res = (int) (ad_value * gpadc->cal_data[ADC_INPUT_VBAT].gain +
+ gpadc->cal_data[ADC_INPUT_VBAT].offset) / CALIB_SCALE;
+ break;
+
+ case DIE_TEMP:
+ res = ADC_CH_DIETEMP_MIN +
+ (ADC_CH_DIETEMP_MAX - ADC_CH_DIETEMP_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+
+ case ACC_DETECT2:
+ res = ADC_CH_ACCDET2_MIN +
+ (ADC_CH_ACCDET2_MAX - ADC_CH_ACCDET2_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+
+ case VBUS_V:
+ res = ADC_CH_CHG_V_MIN +
+ (ADC_CH_CHG_V_MAX - ADC_CH_CHG_V_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+
+ case MAIN_CHARGER_C:
+ case USB_CHARGER_C:
+ res = ADC_CH_CHG_I_MIN +
+ (ADC_CH_CHG_I_MAX - ADC_CH_CHG_I_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+
+ case BK_BAT_V:
+ res = ADC_CH_BKBAT_MIN +
+ (ADC_CH_BKBAT_MAX - ADC_CH_BKBAT_MIN) * ad_value /
+ ADC_RESOLUTION;
+ break;
+
+ default:
+ dev_err(gpadc->dev,
+ "unknown channel, not possible to convert\n");
+ res = -EINVAL;
+ break;
+
+ }
+ return res;
+}
+
/**
* ab8500_gpadc_convert() - gpadc conversion
* @input: analog input to be converted to digital data
*
* This function converts the selected analog i/p to digital
- * data. Thereafter calibration has to be made to obtain the
- * data in the required quantity measurement.
+ * data.
*/
int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
{
@@ -189,7 +331,8 @@ int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
/* Disable VTVout LDO this is required for GPADC */
regulator_disable(gpadc->regu);
mutex_unlock(&gpadc->ab8500_gpadc_lock);
- return data;
+ ret = ab8500_gpadc_ad_to_voltage(gpadc, input, data);
+ return ret;
out:
/*
@@ -227,6 +370,138 @@ static irqreturn_t ab8500_bm_gpswadcconvend_handler(int irq, void *_gpadc)
return IRQ_HANDLED;
}
+static int otp_cal_regs[] = {
+ AB8500_GPADC_CAL_1,
+ AB8500_GPADC_CAL_2,
+ AB8500_GPADC_CAL_3,
+ AB8500_GPADC_CAL_4,
+ AB8500_GPADC_CAL_5,
+ AB8500_GPADC_CAL_6,
+ AB8500_GPADC_CAL_7,
+};
+
+static void ab8500_gpadc_read_calibration_data(struct ab8500_gpadc *gpadc)
+{
+ int i;
+ int ret[ARRAY_SIZE(otp_cal_regs)];
+ u8 gpadc_cal[ARRAY_SIZE(otp_cal_regs)];
+
+ int vmain_high, vmain_low;
+ int btemp_high, btemp_low;
+ int vbat_high, vbat_low;
+
+ /* First we read all OTP registers and store the error code */
+ for (i = 0; i < ARRAY_SIZE(otp_cal_regs); i++) {
+ ret[i] = abx500_get_register_interruptible(gpadc->dev,
+ AB8500_OTP_EMUL, otp_cal_regs[i], &gpadc_cal[i]);
+ if (ret[i] < 0)
+ dev_err(gpadc->dev, "%s: read otp reg 0x%02x failed\n",
+ __func__, otp_cal_regs[i]);
+ }
+
+ /*
+ * The ADC calibration data is stored in OTP registers.
+ * The layout of the calibration data is outlined below and a more
+ * detailed description can be found in UM0836
+ *
+ * vm_h/l = vmain_high/low
+ * bt_h/l = btemp_high/low
+ * vb_h/l = vbat_high/low
+ *
+ * Data bits:
+ * | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | | vm_h9 | vm_h8
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
+ * |.......|.......|.......|.......|.......|.......|.......|.......
+ *
+ *
+ * Ideal output ADC codes corresponding to injected input voltages
+ * during manufacturing is:
+ *
+ * vmain_high: Vin = 19500mV / ADC ideal code = 997
+ * vmain_low: Vin = 315mV / ADC ideal code = 16
+ * btemp_high: Vin = 1300mV / ADC ideal code = 985
+ * btemp_low: Vin = 21mV / ADC ideal code = 16
+ * vbat_high: Vin = 4700mV / ADC ideal code = 982
+ * vbat_low: Vin = 2380mV / ADC ideal code = 33
+ */
+
+ /* Calculate gain and offset for VMAIN if all reads succeeded */
+ if (!(ret[0] < 0 || ret[1] < 0 || ret[2] < 0)) {
+ vmain_high = (((gpadc_cal[0] & 0x03) << 8) |
+ ((gpadc_cal[1] & 0x3F) << 2) |
+ ((gpadc_cal[2] & 0xC0) >> 6));
+
+ vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);
+
+ gpadc->cal_data[ADC_INPUT_VMAIN].gain = CALIB_SCALE *
+ (19500 - 315) / (vmain_high - vmain_low);
+
+ gpadc->cal_data[ADC_INPUT_VMAIN].offset = CALIB_SCALE * 19500 -
+ (CALIB_SCALE * (19500 - 315) /
+ (vmain_high - vmain_low)) * vmain_high;
+ } else {
+ gpadc->cal_data[ADC_INPUT_VMAIN].gain = 0;
+ }
+
+ /* Calculate gain and offset for BTEMP if all reads succeeded */
+ if (!(ret[2] < 0 || ret[3] < 0 || ret[4] < 0)) {
+ btemp_high = (((gpadc_cal[2] & 0x01) << 9) |
+ (gpadc_cal[3] << 1) |
+ ((gpadc_cal[4] & 0x80) >> 7));
+
+ btemp_low = ((gpadc_cal[4] & 0x7C) >> 2);
+
+ gpadc->cal_data[ADC_INPUT_BTEMP].gain =
+ CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low);
+
+ gpadc->cal_data[ADC_INPUT_BTEMP].offset = CALIB_SCALE * 1300 -
+ (CALIB_SCALE * (1300 - 21) /
+ (btemp_high - btemp_low)) * btemp_high;
+ } else {
+ gpadc->cal_data[ADC_INPUT_BTEMP].gain = 0;
+ }
+
+ /* Calculate gain and offset for VBAT if all reads succeeded */
+ if (!(ret[4] < 0 || ret[5] < 0 || ret[6] < 0)) {
+ vbat_high = (((gpadc_cal[4] & 0x03) << 8) | gpadc_cal[5]);
+ vbat_low = ((gpadc_cal[6] & 0xFC) >> 2);
+
+ gpadc->cal_data[ADC_INPUT_VBAT].gain = CALIB_SCALE *
+ (4700 - 2380) / (vbat_high - vbat_low);
+
+ gpadc->cal_data[ADC_INPUT_VBAT].offset = CALIB_SCALE * 4700 -
+ (CALIB_SCALE * (4700 - 2380) /
+ (vbat_high - vbat_low)) * vbat_high;
+ } else {
+ gpadc->cal_data[ADC_INPUT_VBAT].gain = 0;
+ }
+
+ dev_dbg(gpadc->dev, "VMAIN gain %llu offset %llu\n",
+ gpadc->cal_data[ADC_INPUT_VMAIN].gain,
+ gpadc->cal_data[ADC_INPUT_VMAIN].offset);
+
+ dev_dbg(gpadc->dev, "BTEMP gain %llu offset %llu\n",
+ gpadc->cal_data[ADC_INPUT_BTEMP].gain,
+ gpadc->cal_data[ADC_INPUT_BTEMP].offset);
+
+ dev_dbg(gpadc->dev, "VBAT gain %llu offset %llu\n",
+ gpadc->cal_data[ADC_INPUT_VBAT].gain,
+ gpadc->cal_data[ADC_INPUT_VBAT].offset);
+}
+
static int __devinit ab8500_gpadc_probe(struct platform_device *pdev)
{
int ret = 0;
@@ -269,6 +544,7 @@ static int __devinit ab8500_gpadc_probe(struct platform_device *pdev)
dev_err(gpadc->dev, "failed to get vtvout LDO\n");
goto fail_irq;
}
+ ab8500_gpadc_read_calibration_data(gpadc);
list_add_tail(&gpadc->node, &ab8500_gpadc_list);
dev_dbg(gpadc->dev, "probe success\n");
return 0;
@@ -318,6 +594,6 @@ subsys_initcall_sync(ab8500_gpadc_init);
module_exit(ab8500_gpadc_exit);
MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Arun R Murthy, Daniel Willerud");
+MODULE_AUTHOR("Arun R Murthy, Daniel Willerud, Johan Palsson");
MODULE_ALIAS("platform:ab8500_gpadc");
MODULE_DESCRIPTION("AB8500 GPADC driver");
--
1.7.3.2
--
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