thermal: tsens: Check if the IP is correctly enabled by firmware

The SROT registers are initialised by the secure firmware at boot. We
don't have write access to the registers. Check if the block is enabled
before continuing.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
index 0b8a793f15f4b439de1cbb0f5e1edfe136945add..3be4be2e046598a494e48c41392c89913ff3ce70 100644 (file)
--- a/drivers/thermal/qcom/tsens-common.c
+++ b/drivers/thermal/qcom/tsens-common.c
@@ -12,6 +12,10 @@
 #include <linux/regmap.h>
 #include "tsens.h"
 
+/* SROT */
+#define TSENS_EN               BIT(0)
+
+/* TM */
 #define STATUS_OFFSET          0x30
 #define SN_ADDR_OFFSET         0x4
 #define SN_ST_TEMP_MASK                0x3ff
@@ -119,7 +123,10 @@ int __init init_common(struct tsens_device *tmdev)
 {
        void __iomem *tm_base, *srot_base;
        struct resource *res;
+       u32 code;
+       int ret;
        struct platform_device *op = of_find_device_by_node(tmdev->dev->of_node);
+       u16 ctrl_offset = tmdev->reg_offsets[SROT_CTRL_OFFSET];
 
        if (!op)
                return -EINVAL;
@@ -151,5 +158,15 @@ int __init init_common(struct tsens_device *tmdev)
        if (IS_ERR(tmdev->tm_map))
                return PTR_ERR(tmdev->tm_map);
 
+       if (tmdev->srot_map) {
+               ret = regmap_read(tmdev->srot_map, ctrl_offset, &code);
+               if (ret)
+                       return ret;
+               if (!(code & TSENS_EN)) {
+                       dev_err(tmdev->dev, "tsens device is not enabled\n");
+                       return -ENODEV;
+               }
+       }
+
        return 0;
 }