hwmon: (it87) Reapply probe path chip registers settings after resume

After a suspend / resume cycle we possibly need to reapply chip registers
settings that we had set or fixed in a probe path, since they might have
been reset to default values or set incorrectly by a BIOS again.

Tested on a Gigabyte M720-US3 board, which requires routing internal VCCH5V
to in7 (and had it wrong again on resume from S3).

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
[groeck: Return value from it87_resume_sio() is unused; make it void]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 74 insertions, 2 deletions

diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 818f123ac475..f8499cb95fec 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -497,12 +497,14 @@ static const struct it87_devices it87_devices[] = {
 #define has_vin3_5v(data)       ((data)->features & FEAT_VIN3_5V)
 
 struct it87_sio_data {
+        int sioaddr;
         enum chips type;
         /* Values read from Super-I/O config space */
         u8 revision;
         u8 vid_value;
         u8 beep_pin;
         u8 internal;    /* Internal sensors can be labeled */
+        bool need_in7_reroute;
         /* Features skipped based on config or DMI */
         u16 skip_in;
         u8 skip_vid;
@@ -517,6 +519,7 @@ struct it87_sio_data {
  */
 struct it87_data {
         const struct attribute_group *groups[7];
+        int sioaddr;
         enum chips type;
         u32 features;
         u8 peci_mask;
@@ -532,6 +535,7 @@ struct it87_data {
         u16 in_internal;        /* Bitfield, internal sensors (for labels) */
         u16 has_in;             /* Bitfield, voltage sensors enabled */
         u8 in[NUM_VIN][3];              /* [nr][0]=in, [1]=min, [2]=max */
+        bool need_in7_reroute;
         u8 has_fan;             /* Bitfield, fans enabled */
         u16 fan[NUM_FAN][2];    /* Register values, [nr][0]=fan, [1]=min */
         u8 has_temp;            /* Bitfield, temp sensors enabled */
@@ -2487,6 +2491,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
         }
 
         err = 0;
+        sio_data->sioaddr = sioaddr;
         sio_data->revision = superio_inb(sioaddr, DEVREV) & 0x0f;
         pr_info("Found IT%04x%s chip at 0x%x, revision %d\n", chip_type,
                 it87_devices[sio_data->type].suffix,
@@ -2575,6 +2580,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
                                 reg2c |= BIT(1);
                                 superio_outb(sioaddr, IT87_SIO_PINX2_REG,
                                              reg2c);
+                                sio_data->need_in7_reroute = true;
                                 pr_notice("Routing internal VCCH5V to in7.\n");
                         }
                         pr_notice("in7 routed to internal voltage divider, with external pin disabled.\n");
@@ -2777,6 +2783,7 @@ static int __init it87_find(int sioaddr, unsigned short *address,
                 if ((sio_data->type == it8720 || uart6) && !(reg & BIT(1))) {
                         reg |= BIT(1);
                         superio_outb(sioaddr, IT87_SIO_PINX2_REG, reg);
+                        sio_data->need_in7_reroute = true;
                         pr_notice("Routing internal VCCH5V to in7\n");
                 }
                 if (reg & BIT(0))
@@ -3024,8 +3031,6 @@ static int it87_check_pwm(struct device *dev)
                                  "PWM configuration is too broken to be fixed\n");
                 }
 
-                dev_info(dev,
-                         "Detected broken BIOS defaults, disabling PWM interface\n");
                 return 0;
         } else if (fix_pwm_polarity) {
                 dev_info(dev,
@@ -3058,6 +3063,7 @@ static int it87_probe(struct platform_device *pdev)
                 return -ENOMEM;
 
         data->addr = res->start;
+        data->sioaddr = sio_data->sioaddr;
         data->type = sio_data->type;
         data->features = it87_devices[sio_data->type].features;
         data->peci_mask = it87_devices[sio_data->type].peci_mask;
@@ -3096,6 +3102,9 @@ static int it87_probe(struct platform_device *pdev)
 
         /* Check PWM configuration */
         enable_pwm_interface = it87_check_pwm(dev);
+        if (!enable_pwm_interface)
+                dev_info(dev,
+                         "Detected broken BIOS defaults, disabling PWM interface\n");
 
         /* Starting with IT8721F, we handle scaling of internal voltages */
         if (has_12mv_adc(data)) {
@@ -3123,6 +3132,7 @@ static int it87_probe(struct platform_device *pdev)
         }
 
         data->in_internal = sio_data->internal;
+        data->need_in7_reroute = sio_data->need_in7_reroute;
         data->has_in = 0x3ff & ~sio_data->skip_in;
 
         if (has_six_temp(data)) {
@@ -3178,9 +3188,71 @@ static int it87_probe(struct platform_device *pdev)
         return PTR_ERR_OR_ZERO(hwmon_dev);
 }
 
+static void __maybe_unused it87_resume_sio(struct platform_device *pdev)
+{
+        struct it87_data *data = dev_get_drvdata(&pdev->dev);
+        int err;
+        int reg2c;
+
+        if (!data->need_in7_reroute)
+                return;
+
+        err = superio_enter(data->sioaddr);
+        if (err) {
+                dev_warn(&pdev->dev,
+                         "Unable to enter Super I/O to reroute in7 (%d)",
+                         err);
+                return;
+        }
+
+        superio_select(data->sioaddr, GPIO);
+
+        reg2c = superio_inb(data->sioaddr, IT87_SIO_PINX2_REG);
+        if (!(reg2c & BIT(1))) {
+                dev_dbg(&pdev->dev,
+                        "Routing internal VCCH5V to in7 again");
+
+                reg2c |= BIT(1);
+                superio_outb(data->sioaddr, IT87_SIO_PINX2_REG,
+                             reg2c);
+        }
+
+        superio_exit(data->sioaddr);
+}
+
+static int __maybe_unused it87_resume(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct it87_data *data = dev_get_drvdata(dev);
+
+        it87_resume_sio(pdev);
+
+        mutex_lock(&data->update_lock);
+
+        it87_check_pwm(dev);
+        it87_check_limit_regs(data);
+        it87_check_voltage_monitors_reset(data);
+        it87_check_tachometers_reset(pdev);
+        it87_check_tachometers_16bit_mode(pdev);
+
+        it87_start_monitoring(data);
+
+        /* force update */
+        data->valid = 0;
+
+        mutex_unlock(&data->update_lock);
+
+        it87_update_device(dev);
+
+        return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(it87_dev_pm_ops, NULL, it87_resume);
+
 static struct platform_driver it87_driver = {
         .driver = {
                 .name   = DRVNAME,
+                .pm     = &it87_dev_pm_ops,
         },
         .probe  = it87_probe,
 };