thermal: qoriq: Add hwmon support

Expose thermal readings as a HWMON device, so that it could be
accessed using lm-sensors.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Lucas Stach <l.stach@pengutronix.de>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Angus Ainslie (Purism) <angus@akkea.ca>
Cc: linux-imx@nxp.com
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191210164153.10463-13-andrew.smirnov@gmail.com

drivers/thermal/qoriq_thermal.c

@@ -14,6 +14,7 @@
 #include <linux/thermal.h>
 
 #include "thermal_core.h"
+#include "thermal_hwmon.h"
 
 #define SITES_MAX		16
 #define TMR_DISABLE		0x0
@@ -140,6 +141,11 @@ static int qoriq_tmu_register_tmu_zone(struct device *dev,
 			regmap_write(qdata->regmap, REGS_TMR, TMR_DISABLE);
 			return ret;
 		}
+
+		if (devm_thermal_add_hwmon_sysfs(tzd))
+			dev_warn(dev,
+				 "Failed to add hwmon sysfs attributes\n");
+
 	}
 
 	return 0;