thermal: qcom: add support for adc-tm5 PMIC thermal monitor

Add support for Thermal Monitoring part of PMIC5. This part is closely
coupled with ADC, using it's channels directly. ADC-TM support
generating interrupts on ADC value crossing low or high voltage bounds,
which is used to support thermal trip points.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210205000118.493610-3-dmitry.baryshkov@linaro.org

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

@@ -368,6 +368,28 @@ static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
 	return 0;
 }
 
+static s32 qcom_vadc_map_temp_voltage(const struct vadc_map_pt *pts,
+				      u32 tablesize, int input)
+{
+	u32 i = 0;
+
+	/*
+	 * Table must be sorted, find the interval of 'y' which contains value
+	 * 'input' and map it to proper 'x' value
+	 */
+	while (i < tablesize && pts[i].y < input)
+		i++;
+
+	if (i == 0)
+		return pts[0].x;
+	if (i == tablesize)
+		return pts[tablesize - 1].x;
+
+	/* interpolate linearly */
+	return fixp_linear_interpolate(pts[i - 1].y, pts[i - 1].x,
+			pts[i].y, pts[i].x, input);
+}
+
 static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,
 				  u16 adc_code,
 				  bool absolute,
@@ -463,6 +485,21 @@ static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
 	return 0;
 }
 
+/* convert voltage to ADC code, using 1.875V reference */
+static u16 qcom_vadc_scale_voltage_code(s32 voltage,
+					const struct vadc_prescale_ratio *prescale,
+					const u32 full_scale_code_volt,
+					unsigned int factor)
+{
+	s64 volt = voltage;
+	s64 adc_vdd_ref_mv = 1875; /* reference voltage */
+
+	volt *= prescale->num * factor * full_scale_code_volt;
+	volt = div64_s64(volt, (s64)prescale->den * adc_vdd_ref_mv * 1000);
+
+	return volt;
+}
+
 static int qcom_vadc_scale_code_voltage_factor(u16 adc_code,
 				const struct vadc_prescale_ratio *prescale,
 				const struct adc5_data *data,
@@ -627,6 +664,19 @@ int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 }
 EXPORT_SYMBOL(qcom_vadc_scale);
 
+u16 qcom_adc_tm5_temp_volt_scale(unsigned int prescale_ratio,
+				 u32 full_scale_code_volt, int temp)
+{
+	const struct vadc_prescale_ratio *prescale = &adc5_prescale_ratios[prescale_ratio];
+	s32 voltage;
+
+	voltage = qcom_vadc_map_temp_voltage(adcmap_100k_104ef_104fb_1875_vref,
+					     ARRAY_SIZE(adcmap_100k_104ef_104fb_1875_vref),
+					     temp);
+	return qcom_vadc_scale_voltage_code(voltage, prescale, full_scale_code_volt, 1000);
+}
+EXPORT_SYMBOL(qcom_adc_tm5_temp_volt_scale);
+
 int qcom_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
 		    unsigned int prescale_ratio,
 		    const struct adc5_data *data,

drivers/thermal/qcom/Kconfig

@@ -10,6 +10,17 @@ config QCOM_TSENS
 	  Also able to set threshold temperature for both hot and cold and update
 	  when a threshold is reached.
 
+config QCOM_SPMI_ADC_TM5
+	tristate "Qualcomm SPMI PMIC Thermal Monitor ADC5"
+	depends on OF && SPMI && IIO
+	select REGMAP_SPMI
+	select QCOM_VADC_COMMON
+	help
+	  This enables the thermal driver for the ADC thermal monitoring
+	  device. It shows up as a thermal zone with multiple trip points.
+	  Thermal client sets threshold temperature for both warm and cool and
+	  gets updated when a threshold is reached.
+
 config QCOM_SPMI_TEMP_ALARM
 	tristate "Qualcomm SPMI PMIC Temperature Alarm"
 	depends on OF && SPMI && IIO

drivers/thermal/qcom/Makefile

@@ -3,4 +3,5 @@ obj-$(CONFIG_QCOM_TSENS)	+= qcom_tsens.o
 
 qcom_tsens-y			+= tsens.o tsens-v2.o tsens-v1.o tsens-v0_1.o \
 				   tsens-8960.o
+obj-$(CONFIG_QCOM_SPMI_ADC_TM5)	+= qcom-spmi-adc-tm5.o
 obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM)	+= qcom-spmi-temp-alarm.o

include/linux/iio/adc/qcom-vadc-common.h

@@ -158,6 +158,9 @@ int qcom_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
 		    const struct adc5_data *data,
 		    u16 adc_code, int *result_mdec);
 
+u16 qcom_adc_tm5_temp_volt_scale(unsigned int prescale_ratio,
+				 u32 full_scale_code_volt, int temp);
+
 int qcom_adc5_prescaling_from_dt(u32 num, u32 den);
 
 int qcom_adc5_hw_settle_time_from_dt(u32 value, const unsigned int *hw_settle);