thermal: of: improve of-thermal sensor registration API

Different drivers request API extensions in of-thermal. For this reason,
additional callbacks are required to fit the new drivers needs.

The current API implementation expects the registering sensor driver
to provide a get_temp and get_trend callbacks as function parameters.
As the amount of callbacks is growing, this patch changes the existing
implementation to use a .ops field to hold all the of thermal callbacks
to sensor drivers.

This patch also changes the existing of-thermal users to fit the new
API design. No functional change is introduced in this patch.

Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Cc: lm-sensors@lm-sensors.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
Reviewed-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index 5171995..ba9f478 100644
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -158,6 +158,10 @@
 #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
 #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
 
+static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
+	.get_temp = tmp102_read_temp,
+};
+
 static int tmp102_probe(struct i2c_client *client,
 				  const struct i2c_device_id *id)
 {
@@ -215,7 +219,7 @@
 	}
 	tmp102->hwmon_dev = hwmon_dev;
 	tmp102->tz = thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
-						     tmp102_read_temp, NULL);
+						     &tmp102_of_thermal_ops);
 	if (IS_ERR(tmp102->tz))
 		tmp102->tz = NULL;