nct6775: Don't report VID if not supported

VID support is configured with CR2a on NCT6775 and NCT6776, so we can detect
if it is enabled. NCT6779 does not support VID at all.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/nct6775.c b/nct6775.c
index 955c7fbdb1bc960481f74b86bf223b3cae581120..8ac2477b7943b3f75d21f81afd3318a76436e79f 100644 (file)
--- a/nct6775.c
+++ b/nct6775.c
@@ -3401,6 +3401,8 @@ static int nct6775_probe(struct platform_device *pdev)
        const u16 *reg_temp, *reg_temp_over, *reg_temp_hyst, *reg_temp_config;
        const u16 *reg_temp_alternate, *reg_temp_crit;
        int num_reg_temp;
+       bool have_vid = false;
+       u8 cr2a;
 
        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!devm_request_region(&pdev->dev, res->start, IOREGION_LENGTH,
@@ -3769,17 +3771,31 @@ static int nct6775_probe(struct platform_device *pdev)
        /* Initialize the chip */
        nct6775_init_device(data);
 
-       data->vrm = vid_which_vrm();
        err = superio_enter(sio_data->sioreg);
        if (err)
                return err;
 
+       cr2a = superio_inb(sio_data->sioreg, 0x2a);
+       switch (data->kind) {
+       case nct6775:
+               have_vid = (cr2a & 0x40);
+               break;
+       case nct6776:
+               have_vid = (cr2a & 0x60) == 0x40;
+               break;
+       case nct6779:
+               break;
+       }
+
        /*
         * Read VID value
         * We can get the VID input values directly at logical device D 0xe3.
         */
-       superio_select(sio_data->sioreg, NCT6775_LD_VID);
-       data->vid = superio_inb(sio_data->sioreg, 0xe3);
+       if (have_vid) {
+               superio_select(sio_data->sioreg, NCT6775_LD_VID);
+               data->vid = superio_inb(sio_data->sioreg, 0xe3);
+               data->vrm = vid_which_vrm();
+       }
 
        if (fan_debounce) {
                u8 tmp;
@@ -3804,9 +3820,11 @@ static int nct6775_probe(struct platform_device *pdev)
 
        superio_exit(sio_data->sioreg);
 
-       err = device_create_file(dev, &dev_attr_cpu0_vid);
-       if (err)
-               return err;
+       if (have_vid) {
+               err = device_create_file(dev, &dev_attr_cpu0_vid);
+               if (err)
+                       return err;
+       }
 
        err = nct6775_check_fan_inputs(sio_data, data);
        if (err)