mfd: Add ADC support to the DA9052/53 core

This patch adds ADC support to the DA9052/53 core.

Tested on smdkv6410 and i.mx53 QS boards.
Signed-off-by: NAshish Jangam <ashish.jangam@kpitcummins.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

drivers/mfd/da9052-core.c

@@ -318,6 +318,135 @@ static bool da9052_reg_volatile(struct device *dev, unsigned int reg)
 	}
 }
 
+/*
+ * TBAT look-up table is computed from the R90 reg (8 bit register)
+ * reading as below. The battery temperature is in milliCentigrade
+ * TBAT = (1/(t1+1/298) - 273) * 1000 mC
+ * where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255))
+ * Default values are R25 = 10e3, B = 3380, ITBAT = 50e-6
+ * Example:
+ * R25=10E3, B=3380, ITBAT=50e-6, ADCVAL=62d calculates
+ * TBAT = 20015 mili degrees Centrigrade
+ *
+*/
+static const int32_t tbat_lookup[255] = {
+	183258, 144221, 124334, 111336, 101826, 94397, 88343, 83257,
+	78889, 75071, 71688, 68656, 65914, 63414, 61120, 59001,
+	570366, 55204, 53490, 51881, 50364, 48931, 47574, 46285,
+	45059, 43889, 42772, 41703, 40678, 39694, 38748, 37838,
+	36961, 36115, 35297, 34507, 33743, 33002, 32284, 31588,
+	30911, 30254, 29615, 28994, 28389, 27799, 27225, 26664,
+	26117, 25584, 25062, 24553, 24054, 23567, 23091, 22624,
+	22167, 21719, 21281, 20851, 20429, 20015, 19610, 19211,
+	18820, 18436, 18058, 17688, 17323, 16965, 16612, 16266,
+	15925, 15589, 15259, 14933, 14613, 14298, 13987, 13681,
+	13379, 13082, 12788, 12499, 12214, 11933, 11655, 11382,
+	11112, 10845, 10582, 10322, 10066, 9812, 9562, 9315,
+	9071, 8830, 8591, 8356, 8123, 7893, 7665, 7440,
+	7218, 6998, 6780, 6565, 6352, 6141, 5933, 5726,
+	5522, 5320, 5120, 4922, 4726, 4532, 4340, 4149,
+	3961, 3774, 3589, 3406, 3225, 3045, 2867, 2690,
+	2516, 2342, 2170, 2000, 1831, 1664, 1498, 1334,
+	1171, 1009, 849, 690, 532, 376, 221, 67,
+	-84, -236, -386, -535, -683, -830, -975, -1119,
+	-1263, -1405, -1546, -1686, -1825, -1964, -2101, -2237,
+	-2372, -2506, -2639, -2771, -2902, -3033, -3162, -3291,
+	-3418, -3545, -3671, -3796, -3920, -4044, -4166, -4288,
+	-4409, -4529, -4649, -4767, -4885, -5002, -5119, -5235,
+	-5349, -5464, -5577, -5690, -5802, -5913, -6024, -6134,
+	-6244, -6352, -6461, -6568, -6675, -6781, -6887, -6992,
+	-7096, -7200, -7303, -7406, -7508, -7609, -7710, -7810,
+	-7910, -8009, -8108, -8206, -8304, -8401, -8497, -8593,
+	-8689, -8784, -8878, -8972, -9066, -9159, -9251, -9343,
+	-9435, -9526, -9617, -9707, -9796, -9886, -9975, -10063,
+	-10151, -10238, -10325, -10412, -10839, -10923, -11007, -11090,
+	-11173, -11256, -11338, -11420, -11501, -11583, -11663, -11744,
+	-11823, -11903, -11982
+};
+
+static const u8 chan_mux[DA9052_ADC_VBBAT + 1] = {
+	[DA9052_ADC_VDDOUT]	= DA9052_ADC_MAN_MUXSEL_VDDOUT,
+	[DA9052_ADC_ICH]	= DA9052_ADC_MAN_MUXSEL_ICH,
+	[DA9052_ADC_TBAT]	= DA9052_ADC_MAN_MUXSEL_TBAT,
+	[DA9052_ADC_VBAT]	= DA9052_ADC_MAN_MUXSEL_VBAT,
+	[DA9052_ADC_IN4]	= DA9052_ADC_MAN_MUXSEL_AD4,
+	[DA9052_ADC_IN5]	= DA9052_ADC_MAN_MUXSEL_AD5,
+	[DA9052_ADC_IN6]	= DA9052_ADC_MAN_MUXSEL_AD6,
+	[DA9052_ADC_VBBAT]	= DA9052_ADC_MAN_MUXSEL_VBBAT
+};
+
+int da9052_adc_manual_read(struct da9052 *da9052, unsigned char channel)
+{
+	int ret;
+	unsigned short calc_data;
+	unsigned short data;
+	unsigned char mux_sel;
+
+	if (channel > DA9052_ADC_VBBAT)
+		return -EINVAL;
+
+	mutex_lock(&da9052->auxadc_lock);
+
+	/* Channel gets activated on enabling the Conversion bit */
+	mux_sel = chan_mux[channel] | DA9052_ADC_MAN_MAN_CONV;
+
+	ret = da9052_reg_write(da9052, DA9052_ADC_MAN_REG, mux_sel);
+	if (ret < 0)
+		goto err;
+
+	/* Wait for an interrupt */
+	if (!wait_for_completion_timeout(&da9052->done,
+					 msecs_to_jiffies(500))) {
+		dev_err(da9052->dev,
+			"timeout waiting for ADC conversion interrupt\n");
+		ret = -ETIMEDOUT;
+		goto err;
+	}
+
+	ret = da9052_reg_read(da9052, DA9052_ADC_RES_H_REG);
+	if (ret < 0)
+		goto err;
+
+	calc_data = (unsigned short)ret;
+	data = calc_data << 2;
+
+	ret = da9052_reg_read(da9052, DA9052_ADC_RES_L_REG);
+	if (ret < 0)
+		goto err;
+
+	calc_data = (unsigned short)(ret & DA9052_ADC_RES_LSB);
+	data |= calc_data;
+
+	ret = data;
+
+err:
+	mutex_unlock(&da9052->auxadc_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(da9052_adc_manual_read);
+
+static irqreturn_t da9052_auxadc_irq(int irq, void *irq_data)
+{
+	struct da9052 *da9052 = irq_data;
+
+	complete(&da9052->done);
+
+	return IRQ_HANDLED;
+}
+
+int da9052_adc_read_temp(struct da9052 *da9052)
+{
+	int tbat;
+
+	tbat = da9052_reg_read(da9052, DA9052_TBAT_RES_REG);
+	if (tbat <= 0)
+		return tbat;
+
+	/* ARRAY_SIZE check is not needed since TBAT is a 8-bit register */
+	return tbat_lookup[tbat - 1];
+}
+EXPORT_SYMBOL_GPL(da9052_adc_read_temp);
+
 static struct resource da9052_rtc_resource = {
 	.name = "ALM",
 	.start = DA9052_IRQ_ALARM,
@@ -646,6 +775,9 @@ int __devinit da9052_device_init(struct da9052 *da9052, u8 chip_id)
 	struct irq_desc *desc;
 	int ret;
 
+	mutex_init(&da9052->auxadc_lock);
+	init_completion(&da9052->done);
+
 	if (pdata && pdata->init != NULL)
 		pdata->init(da9052);
 
@@ -666,6 +798,12 @@ int __devinit da9052_device_init(struct da9052 *da9052, u8 chip_id)
 	desc = irq_to_desc(da9052->chip_irq);
 	da9052->irq_base = regmap_irq_chip_get_base(desc->action->dev_id);
 
+	ret = request_threaded_irq(DA9052_IRQ_ADC_EOM, NULL, da9052_auxadc_irq,
+				   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+				   "adc irq", da9052);
+	if (ret != 0)
+		dev_err(da9052->dev, "DA9052 ADC IRQ failed ret=%d\n", ret);
+
 	ret = mfd_add_devices(da9052->dev, -1, da9052_subdev_info,
 			      ARRAY_SIZE(da9052_subdev_info), NULL, 0);
 	if (ret)
@@ -674,6 +812,7 @@ int __devinit da9052_device_init(struct da9052 *da9052, u8 chip_id)
 	return 0;
 
 err:
+	free_irq(DA9052_IRQ_ADC_EOM, da9052);
 	mfd_remove_devices(da9052->dev);
 regmap_err:
 	return ret;
@@ -681,6 +820,7 @@ int __devinit da9052_device_init(struct da9052 *da9052, u8 chip_id)
 
 void da9052_device_exit(struct da9052 *da9052)
 {
+	free_irq(DA9052_IRQ_ADC_EOM, da9052);
 	regmap_del_irq_chip(da9052->chip_irq,
 			    irq_get_irq_data(da9052->irq_base)->chip_data);
 	mfd_remove_devices(da9052->dev);

include/linux/mfd/da9052/da9052.h

@@ -33,6 +33,18 @@
 
 #include <linux/mfd/da9052/reg.h>
 
+/* Common - HWMON Channel Definations */
+#define DA9052_ADC_VDDOUT	0
+#define DA9052_ADC_ICH		1
+#define DA9052_ADC_TBAT	2
+#define DA9052_ADC_VBAT	3
+#define DA9052_ADC_IN4		4
+#define DA9052_ADC_IN5		5
+#define DA9052_ADC_IN6		6
+#define DA9052_ADC_TSI		7
+#define DA9052_ADC_TJUNC	8
+#define DA9052_ADC_VBBAT	9
+
 #define DA9052_IRQ_DCIN	0
 #define DA9052_IRQ_VBUS	1
 #define DA9052_IRQ_DCINREM	2
@@ -79,12 +91,19 @@ struct da9052 {
 	struct device *dev;
 	struct regmap *regmap;
 
+	struct mutex auxadc_lock;
+	struct completion done;
+
 	int irq_base;
 	u8 chip_id;
 
 	int chip_irq;
 };
 
+/* ADC API */
+int da9052_adc_manual_read(struct da9052 *da9052, unsigned char channel);
+int da9052_adc_read_temp(struct da9052 *da9052);
+
 /* Device I/O API */
 static inline int da9052_reg_read(struct da9052 *da9052, unsigned char reg)
 {