iio: adc: Add QCOM SPMI PMIC5 ADC driver

This patch adds support for QCOM SPMI PMIC5 family
of ADC driver that supports hardware based offset and
gain compensation. The ADC peripheral can measure both
voltage and current channels whose input signal is
connected to the PMIC ADC AMUX.

The register set and configuration has been refreshed
compared to the prior QCOM PMIC ADC family. Register
ADC5 as part of the IIO framework.
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -596,6 +596,26 @@ config QCOM_SPMI_VADC
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-spmi-vadc.
 
+config QCOM_SPMI_ADC5
+	tristate "Qualcomm Technologies Inc. SPMI PMIC5 ADC"
+	depends on SPMI
+	select REGMAP_SPMI
+	select QCOM_VADC_COMMON
+	help
+	  This is the IIO Voltage PMIC5 ADC driver for Qualcomm Technologies Inc.
+
+	  The driver supports multiple channels read. The ADC is a 16-bit
+	  sigma-delta ADC. The hardware supports calibrated results for
+	  conversion requests and clients include reading voltage phone
+	  power, on board system thermistors connected to the PMIC ADC,
+	  PMIC die temperature, charger temperature, battery current, USB voltage
+	  input, voltage signals connected to supported PMIC GPIO inputs. The
+	  hardware supports internal pull-up for thermistors and can choose between
+	  a 100k, 30k and 400k pull up using the ADC channels.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called qcom-spmi-adc5.
+
 config RCAR_GYRO_ADC
 	tristate "Renesas R-Car GyroADC driver"
 	depends on ARCH_RCAR_GEN2 || COMPILE_TEST

drivers/iio/adc/Makefile

@@ -53,6 +53,7 @@ obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
 obj-$(CONFIG_MXS_LRADC_ADC) += mxs-lradc-adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
+obj-$(CONFIG_QCOM_SPMI_ADC5) += qcom-spmi-adc5.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
 obj-$(CONFIG_QCOM_VADC_COMMON) += qcom-vadc-common.o
 obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o

drivers/iio/adc/qcom-vadc-common.c

@@ -47,8 +47,79 @@ static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
 	{44,	125}
 };
 
+/*
+ * Voltage to temperature table for 100k pull up for NTCG104EF104 with
+ * 1.875V reference.
+ */
+static const struct vadc_map_pt adcmap_100k_104ef_104fb_1875_vref[] = {
+	{ 1831,	-40000 },
+	{ 1814,	-35000 },
+	{ 1791,	-30000 },
+	{ 1761,	-25000 },
+	{ 1723,	-20000 },
+	{ 1675,	-15000 },
+	{ 1616,	-10000 },
+	{ 1545,	-5000 },
+	{ 1463,	0 },
+	{ 1370,	5000 },
+	{ 1268,	10000 },
+	{ 1160,	15000 },
+	{ 1049,	20000 },
+	{ 937,	25000 },
+	{ 828,	30000 },
+	{ 726,	35000 },
+	{ 630,	40000 },
+	{ 544,	45000 },
+	{ 467,	50000 },
+	{ 399,	55000 },
+	{ 340,	60000 },
+	{ 290,	65000 },
+	{ 247,	70000 },
+	{ 209,	75000 },
+	{ 179,	80000 },
+	{ 153,	85000 },
+	{ 130,	90000 },
+	{ 112,	95000 },
+	{ 96,	100000 },
+	{ 82,	105000 },
+	{ 71,	110000 },
+	{ 62,	115000 },
+	{ 53,	120000 },
+	{ 46,	125000 },
+};
+
+static int qcom_vadc_scale_hw_calib_volt(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_uv);
+static int qcom_vadc_scale_hw_calib_therm(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec);
+static int qcom_vadc_scale_hw_smb_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec);
+static int qcom_vadc_scale_hw_chg5_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec);
+static int qcom_vadc_scale_hw_calib_die_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec);
+
+static struct qcom_adc5_scale_type scale_adc5_fn[] = {
+	[SCALE_HW_CALIB_DEFAULT] = {qcom_vadc_scale_hw_calib_volt},
+	[SCALE_HW_CALIB_THERM_100K_PULLUP] = {qcom_vadc_scale_hw_calib_therm},
+	[SCALE_HW_CALIB_XOTHERM] = {qcom_vadc_scale_hw_calib_therm},
+	[SCALE_HW_CALIB_PMIC_THERM] = {qcom_vadc_scale_hw_calib_die_temp},
+	[SCALE_HW_CALIB_PM5_CHG_TEMP] = {qcom_vadc_scale_hw_chg5_temp},
+	[SCALE_HW_CALIB_PM5_SMB_TEMP] = {qcom_vadc_scale_hw_smb_temp},
+};
+
 static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
-				      u32 tablesize, s32 input, s64 *output)
+				      u32 tablesize, s32 input, int *output)
 {
 	bool descending = 1;
 	u32 i = 0;
@@ -128,7 +199,7 @@ static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
 				 bool absolute, u16 adc_code,
 				 int *result_mdec)
 {
-	s64 voltage = 0, result = 0;
+	s64 voltage = 0;
 	int ret;
 
 	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
@@ -138,12 +209,11 @@ static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
 
 	ret = qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
 					 ARRAY_SIZE(adcmap_100k_104ef_104fb),
-					 voltage, &result);
+					 voltage, result_mdec);
 	if (ret)
 		return ret;
 
-	result *= 1000;
-	*result_mdec = result;
+	*result_mdec *= 1000;
 
 	return 0;
 }
@@ -191,6 +261,99 @@ static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
 	return 0;
 }
 
+static int qcom_vadc_scale_code_voltage_factor(u16 adc_code,
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				unsigned int factor)
+{
+	s64 voltage, temp, adc_vdd_ref_mv = 1875;
+
+	/*
+	 * The normal data range is between 0V to 1.875V. On cases where
+	 * we read low voltage values, the ADC code can go beyond the
+	 * range and the scale result is incorrect so we clamp the values
+	 * for the cases where the code represents a value below 0V
+	 */
+	if (adc_code > VADC5_MAX_CODE)
+		adc_code = 0;
+
+	/* (ADC code * vref_vadc (1.875V)) / full_scale_code */
+	voltage = (s64) adc_code * adc_vdd_ref_mv * 1000;
+	voltage = div64_s64(voltage, data->full_scale_code_volt);
+	if (voltage > 0) {
+		voltage *= prescale->den;
+		temp = prescale->num * factor;
+		voltage = div64_s64(voltage, temp);
+	} else {
+		voltage = 0;
+	}
+
+	return (int) voltage;
+}
+
+static int qcom_vadc_scale_hw_calib_volt(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_uv)
+{
+	*result_uv = qcom_vadc_scale_code_voltage_factor(adc_code,
+				prescale, data, 1);
+
+	return 0;
+}
+
+static int qcom_vadc_scale_hw_calib_therm(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec)
+{
+	int voltage;
+
+	voltage = qcom_vadc_scale_code_voltage_factor(adc_code,
+				prescale, data, 1000);
+
+	/* Map voltage to temperature from look-up table */
+	return qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb_1875_vref,
+				 ARRAY_SIZE(adcmap_100k_104ef_104fb_1875_vref),
+				 voltage, result_mdec);
+}
+
+static int qcom_vadc_scale_hw_calib_die_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec)
+{
+	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code,
+				prescale, data, 2);
+	*result_mdec -= KELVINMIL_CELSIUSMIL;
+
+	return 0;
+}
+
+static int qcom_vadc_scale_hw_smb_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec)
+{
+	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code * 100,
+				prescale, data, PMIC5_SMB_TEMP_SCALE_FACTOR);
+	*result_mdec = PMIC5_SMB_TEMP_CONSTANT - *result_mdec;
+
+	return 0;
+}
+
+static int qcom_vadc_scale_hw_chg5_temp(
+				const struct vadc_prescale_ratio *prescale,
+				const struct adc5_data *data,
+				u16 adc_code, int *result_mdec)
+{
+	*result_mdec = qcom_vadc_scale_code_voltage_factor(adc_code,
+				prescale, data, 4);
+	*result_mdec = PMIC5_CHG_TEMP_SCALE_FACTOR - *result_mdec;
+
+	return 0;
+}
+
 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 		    const struct vadc_linear_graph *calib_graph,
 		    const struct vadc_prescale_ratio *prescale,
@@ -221,6 +384,22 @@ int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 }
 EXPORT_SYMBOL(qcom_vadc_scale);
 
+int qcom_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
+		    const struct vadc_prescale_ratio *prescale,
+		    const struct adc5_data *data,
+		    u16 adc_code, int *result)
+{
+	if (!(scaletype >= SCALE_HW_CALIB_DEFAULT &&
+		scaletype < SCALE_HW_CALIB_INVALID)) {
+		pr_err("Invalid scale type %d\n", scaletype);
+		return -EINVAL;
+	}
+
+	return scale_adc5_fn[scaletype].scale_fn(prescale, data,
+					adc_code, result);
+}
+EXPORT_SYMBOL(qcom_adc5_hw_scale);
+
 int qcom_vadc_decimation_from_dt(u32 value)
 {
 	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||

drivers/iio/adc/qcom-vadc-common.h

@@ -25,15 +25,31 @@
 
 #define VADC_DECIMATION_MIN			512
 #define VADC_DECIMATION_MAX			4096
+#define ADC5_DEF_VBAT_PRESCALING		1 /* 1:3 */
+#define ADC5_DECIMATION_SHORT			250
+#define ADC5_DECIMATION_MEDIUM			420
+#define ADC5_DECIMATION_LONG			840
+/* Default decimation - 1024 for rev2, 840 for pmic5 */
+#define ADC5_DECIMATION_DEFAULT			2
+#define ADC5_DECIMATION_SAMPLES_MAX		3
 
 #define VADC_HW_SETTLE_DELAY_MAX		10000
+#define VADC_HW_SETTLE_SAMPLES_MAX		16
 #define VADC_AVG_SAMPLES_MAX			512
+#define ADC5_AVG_SAMPLES_MAX			16
 
 #define KELVINMIL_CELSIUSMIL			273150
+#define PMIC5_CHG_TEMP_SCALE_FACTOR		377500
+#define PMIC5_SMB_TEMP_CONSTANT			419400
+#define PMIC5_SMB_TEMP_SCALE_FACTOR		356
 
 #define PMI_CHG_SCALE_1				-138890
 #define PMI_CHG_SCALE_2				391750000000LL
 
+#define VADC5_MAX_CODE				0x7fff
+#define ADC5_FULL_SCALE_CODE			0x70e4
+#define ADC5_USR_DATA_CHECK			0x8000
+
 /**
  * struct vadc_map_pt - Map the graph representation for ADC channel
  * @x: Represent the ADC digitized code.
@@ -89,6 +105,18 @@ struct vadc_prescale_ratio {
  * SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.
  * SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.
  * SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp
+ * SCALE_HW_CALIB_DEFAULT: Default scaling to convert raw adc code to
+ *	voltage (uV) with hardware applied offset/slope values to adc code.
+ * SCALE_HW_CALIB_THERM_100K_PULLUP: Returns temperature in millidegC using
+ *	lookup table. The hardware applies offset/slope to adc code.
+ * SCALE_HW_CALIB_XOTHERM: Returns XO thermistor voltage in millidegC using
+ *	100k pullup. The hardware applies offset/slope to adc code.
+ * SCALE_HW_CALIB_PMIC_THERM: Returns result in milli degree's Centigrade.
+ *	The hardware applies offset/slope to adc code.
+ * SCALE_HW_CALIB_PM5_CHG_TEMP: Returns result in millidegrees for PMIC5
+ *	charger temperature.
+ * SCALE_HW_CALIB_PM5_SMB_TEMP: Returns result in millidegrees for PMIC5
+ *	SMB1390 temperature.
  */
 enum vadc_scale_fn_type {
 	SCALE_DEFAULT = 0,
@@ -96,6 +124,22 @@ enum vadc_scale_fn_type {
 	SCALE_PMIC_THERM,
 	SCALE_XOTHERM,
 	SCALE_PMI_CHG_TEMP,
+	SCALE_HW_CALIB_DEFAULT,
+	SCALE_HW_CALIB_THERM_100K_PULLUP,
+	SCALE_HW_CALIB_XOTHERM,
+	SCALE_HW_CALIB_PMIC_THERM,
+	SCALE_HW_CALIB_PM5_CHG_TEMP,
+	SCALE_HW_CALIB_PM5_SMB_TEMP,
+	SCALE_HW_CALIB_INVALID,
+};
+
+struct adc5_data {
+	const u32	full_scale_code_volt;
+	const u32	full_scale_code_cur;
+	const struct adc5_channels *adc_chans;
+	unsigned int	*decimation;
+	unsigned int	*hw_settle_1;
+	unsigned int	*hw_settle_2;
 };
 
 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
@@ -104,6 +148,16 @@ int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 		    bool absolute,
 		    u16 adc_code, int *result_mdec);
 
+struct qcom_adc5_scale_type {
+	int (*scale_fn)(const struct vadc_prescale_ratio *prescale,
+		const struct adc5_data *data, u16 adc_code, int *result);
+};
+
+int qcom_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
+		    const struct vadc_prescale_ratio *prescale,
+		    const struct adc5_data *data,
+		    u16 adc_code, int *result_mdec);
+
 int qcom_vadc_decimation_from_dt(u32 value);
 
 #endif /* QCOM_VADC_COMMON_H */