staging: OMAP4+: thermal: introduce bandgap temperature sensor

In the System Control Module, OMAP supplies a voltage reference
and a temperature sensor feature that are gathered in the band
gap voltage and temperature sensor (VBGAPTS) module. The band
gap provides current and voltage reference for its internal
circuits and other analog IP blocks. The analog-to-digital
converter (ADC) produces an output value that is proportional
to the silicon temperature.

This patch provides a platform driver which expose this feature.
It is moduled as a MFD child of the System Control Module core
MFD driver.

This driver provides only APIs to access the device properties,
like temperature, thresholds and update rate.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: J Keerthy <j-keerthy@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/Kconfig

@@ -134,4 +134,6 @@ source "drivers/staging/gdm72xx/Kconfig"
 
 source "drivers/staging/csr/Kconfig"
 
+source "drivers/staging/omap-thermal/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

@@ -59,3 +59,4 @@ obj-$(CONFIG_USB_WPAN_HCD)	+= ozwpan/
 obj-$(CONFIG_USB_G_CCG)		+= ccg/
 obj-$(CONFIG_WIMAX_GDM72XX)	+= gdm72xx/
 obj-$(CONFIG_CSR_WIFI)		+= csr/
+obj-$(CONFIG_OMAP_BANDGAP)	+= omap-thermal/

drivers/staging/omap-thermal/Kconfig

@@ -0,0 +1,11 @@
+config OMAP_BANDGAP
+	tristate "Texas Instruments OMAP4+ temperature sensor driver"
+	depends on THERMAL
+	depends on ARCH_OMAP4 || SOC_OMAP5
+	help
+	  If you say yes here you get support for the Texas Instruments
+	  OMAP4460+ on die bandgap temperature sensor support. The register
+	  set is part of system control module.
+
+	  This includes alert interrupts generation and also the TSHUT
+	  support.

drivers/staging/omap-thermal/Makefile

@@ -0,0 +1,2 @@
+obj-$(CONFIG_OMAP_BANDGAP)	+= omap-thermal.o
+omap-thermal-y			:= omap-bandgap.o

drivers/staging/omap-thermal/TODO

@@ -0,0 +1,28 @@
+List of TODOs (by Eduardo Valentin)
+
+on omap-bandgap.c:
+- Rework locking
+- Improve driver code by adding usage of regmap-mmio
+- Test every exposed API to userland
+- Add support to hwmon
+- Review and revisit all API exposed
+- Revisit PM support
+- Revisit data structures and simplify them
+- Once SCM-core api settles, update this driver accordingly
+
+on omap-thermal-common.c/omap-thermal.h:
+- Revisit extrapolation constants for O4/O5
+- Revisit need for locking
+- Revisit trips and its definitions
+- Revisit trending
+
+on omap5-thermal.c
+- Add support for GPU cooling
+
+generally:
+- write Kconfig dependencies so that omap variants are covered
+- make checkpatch.pl and sparse happy
+- make sure this code works on OMAP4430, OMAP4460 and OMAP5430
+- update documentation
+
+Copy patches to Eduardo Valentin <eduardo.valentin@ti.com>

drivers/staging/omap-thermal/omap-bandgap.h

@@ -0,0 +1,425 @@
+/*
+ * OMAP4 Bandgap temperature sensor driver
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
+ * Contact:
+ *   Eduardo Valentin <eduardo.valentin@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+#ifndef __OMAP_BANDGAP_H
+#define __OMAP_BANDGAP_H
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/err.h>
+
+/* TEMP_SENSOR OMAP4430 */
+#define OMAP4430_BGAP_TSHUT_SHIFT			11
+#define OMAP4430_BGAP_TSHUT_MASK			(1 << 11)
+
+/* TEMP_SENSOR OMAP4430 */
+#define OMAP4430_BGAP_TEMPSOFF_SHIFT			12
+#define OMAP4430_BGAP_TEMPSOFF_MASK			(1 << 12)
+#define OMAP4430_SINGLE_MODE_SHIFT			10
+#define OMAP4430_SINGLE_MODE_MASK			(1 << 10)
+#define OMAP4430_BGAP_TEMP_SENSOR_SOC_SHIFT		9
+#define OMAP4430_BGAP_TEMP_SENSOR_SOC_MASK		(1 << 9)
+#define OMAP4430_BGAP_TEMP_SENSOR_EOCZ_SHIFT		8
+#define OMAP4430_BGAP_TEMP_SENSOR_EOCZ_MASK		(1 << 8)
+#define OMAP4430_BGAP_TEMP_SENSOR_DTEMP_SHIFT		0
+#define OMAP4430_BGAP_TEMP_SENSOR_DTEMP_MASK		(0xff << 0)
+
+#define OMAP4430_ADC_START_VALUE			0
+#define OMAP4430_ADC_END_VALUE				127
+#define OMAP4430_MAX_FREQ				32768
+#define OMAP4430_MIN_FREQ				32768
+#define OMAP4430_MIN_TEMP				-40000
+#define OMAP4430_MAX_TEMP				125000
+#define OMAP4430_HYST_VAL				5000
+
+/* TEMP_SENSOR OMAP4460 */
+#define OMAP4460_BGAP_TEMPSOFF_SHIFT			13
+#define OMAP4460_BGAP_TEMPSOFF_MASK			(1 << 13)
+#define OMAP4460_BGAP_TEMP_SENSOR_SOC_SHIFT		11
+#define OMAP4460_BGAP_TEMP_SENSOR_SOC_MASK		(1 << 11)
+#define OMAP4460_BGAP_TEMP_SENSOR_EOCZ_SHIFT		10
+#define OMAP4460_BGAP_TEMP_SENSOR_EOCZ_MASK		(1 << 10)
+#define OMAP4460_BGAP_TEMP_SENSOR_DTEMP_SHIFT		0
+#define OMAP4460_BGAP_TEMP_SENSOR_DTEMP_MASK		(0x3ff << 0)
+
+/* BANDGAP_CTRL */
+#define OMAP4460_SINGLE_MODE_SHIFT			31
+#define OMAP4460_SINGLE_MODE_MASK			(1 << 31)
+#define OMAP4460_MASK_HOT_SHIFT				1
+#define OMAP4460_MASK_HOT_MASK				(1 << 1)
+#define OMAP4460_MASK_COLD_SHIFT			0
+#define OMAP4460_MASK_COLD_MASK				(1 << 0)
+
+/* BANDGAP_COUNTER */
+#define OMAP4460_COUNTER_SHIFT				0
+#define OMAP4460_COUNTER_MASK				(0xffffff << 0)
+
+/* BANDGAP_THRESHOLD */
+#define OMAP4460_T_HOT_SHIFT				16
+#define OMAP4460_T_HOT_MASK				(0x3ff << 16)
+#define OMAP4460_T_COLD_SHIFT				0
+#define OMAP4460_T_COLD_MASK				(0x3ff << 0)
+
+/* TSHUT_THRESHOLD */
+#define OMAP4460_TSHUT_HOT_SHIFT			16
+#define OMAP4460_TSHUT_HOT_MASK				(0x3ff << 16)
+#define OMAP4460_TSHUT_COLD_SHIFT			0
+#define OMAP4460_TSHUT_COLD_MASK			(0x3ff << 0)
+
+/* BANDGAP_STATUS */
+#define OMAP4460_CLEAN_STOP_SHIFT			3
+#define OMAP4460_CLEAN_STOP_MASK			(1 << 3)
+#define OMAP4460_BGAP_ALERT_SHIFT			2
+#define OMAP4460_BGAP_ALERT_MASK			(1 << 2)
+#define OMAP4460_HOT_FLAG_SHIFT				1
+#define OMAP4460_HOT_FLAG_MASK				(1 << 1)
+#define OMAP4460_COLD_FLAG_SHIFT			0
+#define OMAP4460_COLD_FLAG_MASK				(1 << 0)
+
+/* TEMP_SENSOR OMAP5430 */
+#define OMAP5430_BGAP_TEMP_SENSOR_SOC_SHIFT		12
+#define OMAP5430_BGAP_TEMP_SENSOR_SOC_MASK		(1 << 12)
+#define OMAP5430_BGAP_TEMPSOFF_SHIFT			11
+#define OMAP5430_BGAP_TEMPSOFF_MASK			(1 << 11)
+#define OMAP5430_BGAP_TEMP_SENSOR_EOCZ_SHIFT		10
+#define OMAP5430_BGAP_TEMP_SENSOR_EOCZ_MASK		(1 << 10)
+#define OMAP5430_BGAP_TEMP_SENSOR_DTEMP_SHIFT		0
+#define OMAP5430_BGAP_TEMP_SENSOR_DTEMP_MASK		(0x3ff << 0)
+
+/* BANDGAP_CTRL */
+#define OMAP5430_MASK_HOT_CORE_SHIFT			5
+#define OMAP5430_MASK_HOT_CORE_MASK			(1 << 5)
+#define OMAP5430_MASK_COLD_CORE_SHIFT			4
+#define OMAP5430_MASK_COLD_CORE_MASK			(1 << 4)
+#define OMAP5430_MASK_HOT_MM_SHIFT			3
+#define OMAP5430_MASK_HOT_MM_MASK			(1 << 3)
+#define OMAP5430_MASK_COLD_MM_SHIFT			2
+#define OMAP5430_MASK_COLD_MM_MASK			(1 << 2)
+#define OMAP5430_MASK_HOT_MPU_SHIFT			1
+#define OMAP5430_MASK_HOT_MPU_MASK			(1 << 1)
+#define OMAP5430_MASK_COLD_MPU_SHIFT			0
+#define OMAP5430_MASK_COLD_MPU_MASK			(1 << 0)
+
+/* BANDGAP_COUNTER */
+#define OMAP5430_REPEAT_MODE_SHIFT			31
+#define OMAP5430_REPEAT_MODE_MASK			(1 << 31)
+#define OMAP5430_COUNTER_SHIFT				0
+#define OMAP5430_COUNTER_MASK				(0xffffff << 0)
+
+/* BANDGAP_THRESHOLD */
+#define OMAP5430_T_HOT_SHIFT				16
+#define OMAP5430_T_HOT_MASK				(0x3ff << 16)
+#define OMAP5430_T_COLD_SHIFT				0
+#define OMAP5430_T_COLD_MASK				(0x3ff << 0)
+
+/* TSHUT_THRESHOLD */
+#define OMAP5430_TSHUT_HOT_SHIFT			16
+#define OMAP5430_TSHUT_HOT_MASK				(0x3ff << 16)
+#define OMAP5430_TSHUT_COLD_SHIFT			0
+#define OMAP5430_TSHUT_COLD_MASK			(0x3ff << 0)
+
+/* BANDGAP_STATUS */
+#define OMAP5430_BGAP_ALERT_SHIFT			31
+#define OMAP5430_BGAP_ALERT_MASK			(1 << 31)
+#define OMAP5430_HOT_CORE_FLAG_SHIFT			5
+#define OMAP5430_HOT_CORE_FLAG_MASK			(1 << 5)
+#define OMAP5430_COLD_CORE_FLAG_SHIFT			4
+#define OMAP5430_COLD_CORE_FLAG_MASK			(1 << 4)
+#define OMAP5430_HOT_MM_FLAG_SHIFT			3
+#define OMAP5430_HOT_MM_FLAG_MASK			(1 << 3)
+#define OMAP5430_COLD_MM_FLAG_SHIFT			2
+#define OMAP5430_COLD_MM_FLAG_MASK			(1 << 2)
+#define OMAP5430_HOT_MPU_FLAG_SHIFT			1
+#define OMAP5430_HOT_MPU_FLAG_MASK			(1 << 1)
+#define OMAP5430_COLD_MPU_FLAG_SHIFT			0
+#define OMAP5430_COLD_MPU_FLAG_MASK			(1 << 0)
+
+/* Offsets from the base of temperature sensor registers */
+
+/* 4430 - All goes relative to OPP_BGAP */
+#define OMAP4430_FUSE_OPP_BGAP				0x0
+#define OMAP4430_TEMP_SENSOR_CTRL_OFFSET		0xCC
+
+/* 4460 - All goes relative to OPP_BGAP */
+#define OMAP4460_FUSE_OPP_BGAP				0x0
+#define OMAP4460_TEMP_SENSOR_CTRL_OFFSET		0xCC
+#define OMAP4460_BGAP_CTRL_OFFSET			0x118
+#define OMAP4460_BGAP_COUNTER_OFFSET			0x11C
+#define OMAP4460_BGAP_THRESHOLD_OFFSET			0x120
+#define OMAP4460_BGAP_TSHUT_OFFSET			0x124
+#define OMAP4460_BGAP_STATUS_OFFSET			0x128
+
+/* 5430 - All goes relative to OPP_BGAP_GPU */
+#define OMAP5430_FUSE_OPP_BGAP_GPU			0x0
+#define OMAP5430_TEMP_SENSOR_GPU_OFFSET			0x150
+#define OMAP5430_BGAP_COUNTER_GPU_OFFSET		0x1C0
+#define OMAP5430_BGAP_THRESHOLD_GPU_OFFSET		0x1A8
+#define OMAP5430_BGAP_TSHUT_GPU_OFFSET			0x1B4
+
+#define OMAP5430_FUSE_OPP_BGAP_MPU			0x4
+#define OMAP5430_TEMP_SENSOR_MPU_OFFSET			0x14C
+#define OMAP5430_BGAP_CTRL_OFFSET			0x1A0
+#define OMAP5430_BGAP_COUNTER_MPU_OFFSET		0x1BC
+#define OMAP5430_BGAP_THRESHOLD_MPU_OFFSET		0x1A4
+#define OMAP5430_BGAP_TSHUT_MPU_OFFSET			0x1B0
+#define OMAP5430_BGAP_STATUS_OFFSET			0x1C8
+
+#define OMAP5430_FUSE_OPP_BGAP_CORE			0x8
+#define OMAP5430_TEMP_SENSOR_CORE_OFFSET		0x154
+#define OMAP5430_BGAP_COUNTER_CORE_OFFSET		0x1C4
+#define OMAP5430_BGAP_THRESHOLD_CORE_OFFSET		0x1AC
+#define OMAP5430_BGAP_TSHUT_CORE_OFFSET			0x1B8
+
+#define OMAP4460_TSHUT_HOT				900	/* 122 deg C */
+#define OMAP4460_TSHUT_COLD				895	/* 100 deg C */
+#define OMAP4460_T_HOT					800	/* 73 deg C */
+#define OMAP4460_T_COLD					795	/* 71 deg C */
+#define OMAP4460_MAX_FREQ				1500000
+#define OMAP4460_MIN_FREQ				1000000
+#define OMAP4460_MIN_TEMP				-40000
+#define OMAP4460_MAX_TEMP				123000
+#define OMAP4460_HYST_VAL				5000
+#define OMAP4460_ADC_START_VALUE			530
+#define OMAP4460_ADC_END_VALUE				932
+
+#define OMAP5430_MPU_TSHUT_HOT				915
+#define OMAP5430_MPU_TSHUT_COLD				900
+#define OMAP5430_MPU_T_HOT				800
+#define OMAP5430_MPU_T_COLD				795
+#define OMAP5430_MPU_MAX_FREQ				1500000
+#define OMAP5430_MPU_MIN_FREQ				1000000
+#define OMAP5430_MPU_MIN_TEMP				-40000
+#define OMAP5430_MPU_MAX_TEMP				125000
+#define OMAP5430_MPU_HYST_VAL				5000
+#define OMAP5430_ADC_START_VALUE			532
+#define OMAP5430_ADC_END_VALUE				934
+
+
+#define OMAP5430_GPU_TSHUT_HOT				915
+#define OMAP5430_GPU_TSHUT_COLD				900
+#define OMAP5430_GPU_T_HOT				800
+#define OMAP5430_GPU_T_COLD				795
+#define OMAP5430_GPU_MAX_FREQ				1500000
+#define OMAP5430_GPU_MIN_FREQ				1000000
+#define OMAP5430_GPU_MIN_TEMP				-40000
+#define OMAP5430_GPU_MAX_TEMP				125000
+#define OMAP5430_GPU_HYST_VAL				5000
+
+#define OMAP5430_CORE_TSHUT_HOT				915
+#define OMAP5430_CORE_TSHUT_COLD			900
+#define OMAP5430_CORE_T_HOT				800
+#define OMAP5430_CORE_T_COLD				795
+#define OMAP5430_CORE_MAX_FREQ				1500000
+#define OMAP5430_CORE_MIN_FREQ				1000000
+#define OMAP5430_CORE_MIN_TEMP				-40000
+#define OMAP5430_CORE_MAX_TEMP				125000
+#define OMAP5430_CORE_HYST_VAL				5000
+
+/**
+ * The register offsets and bit fields might change across
+ * OMAP versions hence populating them in this structure.
+ */
+
+struct temp_sensor_registers {
+	u32	temp_sensor_ctrl;
+	u32	bgap_tempsoff_mask;
+	u32	bgap_soc_mask;
+	u32	bgap_eocz_mask;
+	u32	bgap_dtemp_mask;
+
+	u32	bgap_mask_ctrl;
+	u32	mask_hot_mask;
+	u32	mask_cold_mask;
+
+	u32	bgap_mode_ctrl;
+	u32	mode_ctrl_mask;
+
+	u32	bgap_counter;
+	u32	counter_mask;
+
+	u32	bgap_threshold;
+	u32	threshold_thot_mask;
+	u32	threshold_tcold_mask;
+
+	u32	tshut_threshold;
+	u32	tshut_hot_mask;
+	u32	tshut_cold_mask;
+
+	u32	bgap_status;
+	u32	status_clean_stop_mask;
+	u32	status_bgap_alert_mask;
+	u32	status_hot_mask;
+	u32	status_cold_mask;
+
+	u32	bgap_efuse;
+};
+
+/**
+ * The thresholds and limits for temperature sensors.
+ */
+struct temp_sensor_data {
+	u32	tshut_hot;
+	u32	tshut_cold;
+	u32	t_hot;
+	u32	t_cold;
+	u32	min_freq;
+	u32	max_freq;
+	int     max_temp;
+	int     min_temp;
+	int     hyst_val;
+	u32     adc_start_val;
+	u32     adc_end_val;
+	u32     update_int1;
+	u32     update_int2;
+};
+
+struct omap_bandgap_data;
+
+/**
+ * struct omap_bandgap - bandgap device structure
+ * @dev: device pointer
+ * @conf: platform data with sensor data
+ * @fclock: pointer to functional clock of temperature sensor
+ * @div_clk: pointer to parent clock of temperature sensor fclk
+ * @conv_table: Pointer to adc to temperature conversion table
+ * @bg_mutex: Mutex for sysfs, irq and PM
+ * @irq: MPU Irq number for thermal alert
+ * @tshut_gpio: GPIO where Tshut signal is routed
+ * @clk_rate: Holds current clock rate
+ */
+struct omap_bandgap {
+	struct device			*dev;
+	void __iomem			*base;
+	struct omap_bandgap_data	*conf;
+	struct clk			*fclock;
+	struct clk			*div_clk;
+	const int			*conv_table;
+	struct mutex			bg_mutex; /* Mutex for irq and PM */
+	int				irq;
+	int				tshut_gpio;
+	u32				clk_rate;
+};
+
+/**
+ * struct temp_sensor_regval - temperature sensor register values
+ * @bg_mode_ctrl: temp sensor control register value
+ * @bg_ctrl: bandgap ctrl register value
+ * @bg_counter: bandgap counter value
+ * @bg_threshold: bandgap threshold register value
+ * @tshut_threshold: bandgap tshut register value
+ */
+struct temp_sensor_regval {
+	u32			bg_mode_ctrl;
+	u32			bg_ctrl;
+	u32			bg_counter;
+	u32			bg_threshold;
+	u32			tshut_threshold;
+};
+
+/**
+ * struct thermal_cooling_conf - description on how to cool a thermal zone
+ * @freq_clip_count: size of freq_data
+ */
+struct thermal_cooling_conf {
+	int freq_clip_count;
+};
+
+/**
+ * struct omap_temp_sensor - bandgap temperature sensor platform data
+ * @ts_data: pointer to struct with thresholds, limits of temperature sensor
+ * @registers: pointer to the list of register offsets and bitfields
+ * @regval: temperature sensor register values
+ * @domain: the name of the domain where the sensor is located
+ * @cooling_data: description on how the zone should be cooled off.
+ * @slope: sensor gradient slope info for hotspot extrapolation
+ * @const: sensor gradient const info for hotspot extrapolation
+ * @slope_pcb: sensor gradient slope info for hotspot extrapolation
+ *             with no external influence
+ * @const_pcb: sensor gradient const info for hotspot extrapolation
+ *             with no external influence
+ * @data: private data
+ * @register_cooling: function to describe how this sensor is going to be cooled
+ * @unregister_cooling: function to release cooling data
+ */
+struct omap_temp_sensor {
+	struct temp_sensor_data		*ts_data;
+	struct temp_sensor_registers	*registers;
+	struct temp_sensor_regval	regval;
+	char				*domain;
+	struct thermal_cooling_conf	cooling_data;
+	/* for hotspot extrapolation */
+	const int			slope;
+	const int			constant;
+	const int			slope_pcb;
+	const int			constant_pcb;
+	void				*data;
+	int (*register_cooling)(struct omap_bandgap *bg_ptr, int id);
+	int (*unregister_cooling)(struct omap_bandgap *bg_ptr, int id);
+};
+
+/**
+ * struct omap_bandgap_data - bandgap platform data structure
+ * @features: a bitwise flag set to describe the device features
+ * @conv_table: Pointer to adc to temperature conversion table
+ * @fclock_name: clock name of the functional clock
+ * @div_ck_nme: clock name of the clock divisor
+ * @sensor_count: count of temperature sensor device in scm
+ * @sensors: array of sensors present in this bandgap instance
+ * @expose_sensor: callback to export sensor to thermal API
+ */
+struct omap_bandgap_data {
+#define OMAP_BANDGAP_FEATURE_TSHUT		(1 << 0)
+#define OMAP_BANDGAP_FEATURE_TSHUT_CONFIG	(1 << 1)
+#define OMAP_BANDGAP_FEATURE_TALERT		(1 << 2)
+#define OMAP_BANDGAP_FEATURE_MODE_CONFIG	(1 << 3)
+#define OMAP_BANDGAP_FEATURE_COUNTER		(1 << 4)
+#define OMAP_BANDGAP_FEATURE_POWER_SWITCH	(1 << 5)
+#define OMAP_BANDGAP_HAS(b, f)			\
+			((b)->conf->features & OMAP_BANDGAP_FEATURE_ ## f)
+	unsigned int			features;
+	const int			*conv_table;
+	char				*fclock_name;
+	char				*div_ck_name;
+	int				sensor_count;
+	int (*report_temperature)(struct omap_bandgap *bg_ptr, int id);
+	int (*expose_sensor)(struct omap_bandgap *bg_ptr, int id, char *domain);
+	int (*remove_sensor)(struct omap_bandgap *bg_ptr, int id);
+
+	/* this needs to be at the end */
+	struct omap_temp_sensor		sensors[];
+};
+
+int omap_bandgap_read_thot(struct omap_bandgap *bg_ptr, int id, int *thot);
+int omap_bandgap_write_thot(struct omap_bandgap *bg_ptr, int id, int val);
+int omap_bandgap_read_tcold(struct omap_bandgap *bg_ptr, int id, int *tcold);
+int omap_bandgap_write_tcold(struct omap_bandgap *bg_ptr, int id, int val);
+int omap_bandgap_read_update_interval(struct omap_bandgap *bg_ptr, int id,
+				      int *interval);
+int omap_bandgap_write_update_interval(struct omap_bandgap *bg_ptr, int id,
+				       u32 interval);
+int omap_bandgap_read_temperature(struct omap_bandgap *bg_ptr, int id,
+				  int *temperature);
+int omap_bandgap_set_sensor_data(struct omap_bandgap *bg_ptr, int id,
+				 void *data);
+void *omap_bandgap_get_sensor_data(struct omap_bandgap *bg_ptr, int id);
+
+#endif

drivers/staging/omap-thermal/omap_bandgap.txt

@@ -0,0 +1,30 @@
+* Texas Instrument OMAP SCM bandgap bindings
+
+In the System Control Module, OMAP supplies a voltage reference
+and a temperature sensor feature that are gathered in the band
+gap voltage and temperature sensor (VBGAPTS) module. The band
+gap provides current and voltage reference for its internal
+circuits and other analog IP blocks. The analog-to-digital
+converter (ADC) produces an output value that is proportional
+to the silicon temperature.
+
+Required properties:
+- compatible : Should be:
+  - "ti,omap4460-control-bandgap" : for OMAP4460 bandgap
+  - "ti,omap5430-control-bandgap" : for OMAP5430 bandgap
+- interrupts : this entry should indicate which interrupt line
+the talert signal is routed to;
+Specific:
+- ti,tshut-gpio : this entry should be used to inform which GPIO
+line the tshut signal is routed to;
+
+Example:
+
+bandgap {
+	reg = <0x4a002260 0x4
+		0x4a00232C 0x4
+		0x4a002378 0x18>;
+	compatible = "ti,omap4460-control-bandgap";
+	interrupts = <0 126 4>; /* talert */
+	ti,tshut-gpio = <86>;
+};