hwmon: (nct6775) Restore hardware monitoring logical device status on resume

After a suspend/resume cycle it is not guaranteed that the hardware monitoring
device is still enabled. Ensure that this is the case after resume.

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

diff --git a/drivers/hwmon/nct6775.c b/drivers/hwmon/nct6775.c
index db6a68efc3895da547d2d80f33a1d17f68fa5dbc..0445a52379e7229ba9e01c2ca0c54271d36d1c19 100644 (file)
--- a/drivers/hwmon/nct6775.c
+++ b/drivers/hwmon/nct6775.c
@@ -885,6 +885,7 @@ struct nct6775_data {
        u8 vbat;
        u8 fandiv1;
        u8 fandiv2;
+       u8 sio_reg_enable;
 };
 
 struct nct6775_sio_data {
@@ -3177,6 +3178,10 @@ nct6775_check_fan_inputs(struct nct6775_data *data)
        int sioreg = data->sioreg;
        int regval;
 
+       /* Store SIO_REG_ENABLE for use during resume */
+       superio_select(sioreg, NCT6775_LD_HWM);
+       data->sio_reg_enable = superio_inb(sioreg, SIO_REG_ENABLE);
+
        /* fan4 and fan5 share some pins with the GPIO and serial flash */
        if (data->kind == nct6775) {
                regval = superio_inb(sioreg, 0x2c);
@@ -3195,20 +3200,17 @@ nct6775_check_fan_inputs(struct nct6775_data *data)
        } else if (data->kind == nct6776) {
                bool gpok = superio_inb(sioreg, 0x27) & 0x80;
 
-               superio_select(sioreg, NCT6775_LD_HWM);
-               regval = superio_inb(sioreg, SIO_REG_ENABLE);
-
-               if (regval & 0x80)
+               if (data->sio_reg_enable & 0x80)
                        fan3pin = gpok;
                else
                        fan3pin = !(superio_inb(sioreg, 0x24) & 0x40);
 
-               if (regval & 0x40)
+               if (data->sio_reg_enable & 0x40)
                        fan4pin = gpok;
                else
                        fan4pin = superio_inb(sioreg, 0x1C) & 0x01;
 
-               if (regval & 0x20)
+               if (data->sio_reg_enable & 0x20)
                        fan5pin = gpok;
                else
                        fan5pin = superio_inb(sioreg, 0x1C) & 0x02;
@@ -4006,19 +4008,26 @@ static int __maybe_unused nct6775_suspend(struct device *dev)
 static int __maybe_unused nct6775_resume(struct device *dev)
 {
        struct nct6775_data *data = dev_get_drvdata(dev);
+       int sioreg = data->sioreg;
        int i, j, err = 0;
+       u8 reg;
 
        mutex_lock(&data->update_lock);
        data->bank = 0xff;              /* Force initial bank selection */
 
-       if (data->kind == nct6791 || data->kind == nct6792) {
-               err = superio_enter(data->sioreg);
-               if (err)
-                       goto abort;
+       err = superio_enter(sioreg);
+       if (err)
+               goto abort;
 
-               nct6791_enable_io_mapping(data->sioreg);
-               superio_exit(data->sioreg);
-       }
+       superio_select(sioreg, NCT6775_LD_HWM);
+       reg = superio_inb(sioreg, SIO_REG_ENABLE);
+       if (reg != data->sio_reg_enable)
+               superio_outb(sioreg, SIO_REG_ENABLE, data->sio_reg_enable);
+
+       if (data->kind == nct6791 || data->kind == nct6792)
+               nct6791_enable_io_mapping(sioreg);
+
+       superio_exit(sioreg);
 
        /* Restore limits */
        for (i = 0; i < data->in_num; i++) {