iio:adc: add iio driver for Palmas (twl6035/7) gpadc

This driver code was found as:

https://android.googlesource.com/kernel/tegra/+/aaabb2e045f31e5a970109ffdaae900dd403d17e/drivers/staging/iio/adc

Fixed various compilation issues and test this driver on omap5 evm.
Signed-off-by: NPradeep Goudagunta <pgoudagunta@nvidia.com>
Signed-off-by: NH. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: NMarek Belisko <marek@goldelico.com>
Acked-by: NLaxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/iio/adc/Kconfig

@@ -275,6 +275,14 @@ config NAU7802
 	  To compile this driver as a module, choose M here: the
 	  module will be called nau7802.
 
+config PALMAS_GPADC
+	tristate "TI Palmas General Purpose ADC"
+	depends on MFD_PALMAS
+	help
+	  Palmas series pmic chip by Texas Instruments (twl6035/6037)
+	  is used in smartphones and tablets and supports a 16 channel
+	  general purpose ADC.
+
 config QCOM_SPMI_IADC
 	tristate "Qualcomm SPMI PMIC current ADC"
 	depends on SPMI

drivers/iio/adc/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
 obj-$(CONFIG_MCP3422) += mcp3422.o
 obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
+obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o

include/linux/mfd/palmas.h

@@ -134,21 +134,32 @@ struct palmas_pmic_driver_data {
 			    struct regulator_config config);
 };
 
+struct palmas_adc_wakeup_property {
+	int adc_channel_number;
+	int adc_high_threshold;
+	int adc_low_threshold;
+};
+
 struct palmas_gpadc_platform_data {
 	/* Channel 3 current source is only enabled during conversion */
-	int ch3_current;
+	int ch3_current;	/* 0: off; 1: 10uA; 2: 400uA; 3: 800 uA */
 
 	/* Channel 0 current source can be used for battery detection.
 	 * If used for battery detection this will cause a permanent current
 	 * consumption depending on current level set here.
 	 */
-	int ch0_current;
+	int ch0_current;	/* 0: off; 1: 5uA; 2: 15uA; 3: 20 uA */
+	bool extended_delay;	/* use extended delay for conversion */
 
 	/* default BAT_REMOVAL_DAT setting on device probe */
 	int bat_removal;
 
 	/* Sets the START_POLARITY bit in the RT_CTRL register */
 	int start_polarity;
+
+	int auto_conversion_period_ms;
+	struct palmas_adc_wakeup_property *adc_wakeup1_data;
+	struct palmas_adc_wakeup_property *adc_wakeup2_data;
 };
 
 struct palmas_reg_init {
@@ -405,28 +416,7 @@ struct palmas_gpadc_calibration {
 	s32 offset_error;
 };
 
-struct palmas_gpadc {
-	struct device *dev;
-	struct palmas *palmas;
-
-	int ch3_current;
-	int ch0_current;
-
-	int gpadc_force;
-
-	int bat_removal;
-
-	struct mutex reading_lock;
-	struct completion irq_complete;
-
-	int eoc_sw_irq;
-
-	struct palmas_gpadc_calibration *palmas_cal_tbl;
-
-	int conv0_channel;
-	int conv1_channel;
-	int rt_channel;
-};
+#define PALMAS_DATASHEET_NAME(_name)	"palmas-gpadc-chan-"#_name
 
 struct palmas_gpadc_result {
 	s32 raw_code;
@@ -520,6 +510,43 @@ enum palmas_irqs {
 	PALMAS_NUM_IRQ,
 };
 
+/* Palmas GPADC Channels */
+enum {
+	PALMAS_ADC_CH_IN0,
+	PALMAS_ADC_CH_IN1,
+	PALMAS_ADC_CH_IN2,
+	PALMAS_ADC_CH_IN3,
+	PALMAS_ADC_CH_IN4,
+	PALMAS_ADC_CH_IN5,
+	PALMAS_ADC_CH_IN6,
+	PALMAS_ADC_CH_IN7,
+	PALMAS_ADC_CH_IN8,
+	PALMAS_ADC_CH_IN9,
+	PALMAS_ADC_CH_IN10,
+	PALMAS_ADC_CH_IN11,
+	PALMAS_ADC_CH_IN12,
+	PALMAS_ADC_CH_IN13,
+	PALMAS_ADC_CH_IN14,
+	PALMAS_ADC_CH_IN15,
+	PALMAS_ADC_CH_MAX,
+};
+
+/* Palmas GPADC Channel0 Current Source */
+enum {
+	PALMAS_ADC_CH0_CURRENT_SRC_0,
+	PALMAS_ADC_CH0_CURRENT_SRC_5,
+	PALMAS_ADC_CH0_CURRENT_SRC_15,
+	PALMAS_ADC_CH0_CURRENT_SRC_20,
+};
+
+/* Palmas GPADC Channel3 Current Source */
+enum {
+	PALMAS_ADC_CH3_CURRENT_SRC_0,
+	PALMAS_ADC_CH3_CURRENT_SRC_10,
+	PALMAS_ADC_CH3_CURRENT_SRC_400,
+	PALMAS_ADC_CH3_CURRENT_SRC_800,
+};
+
 struct palmas_pmic {
 	struct palmas *palmas;
 	struct device *dev;