i2c: i801: Use MMIO if available

Newer versions of supported chips support MMIO in addition to legacy
PMIO register access. Probe the MMIO PCI BAR and use faster MMIO
register access if available.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/b4748b7a-aac5-445c-b813-20c4d2c23ec3@gmail.com

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index bf5702ccb93abe153318d99e7d28573823efa16a..48e1af544b75a3ff62b9bed4c525486d8a5fd2e3 100644 (file)
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -144,6 +144,7 @@
 #define SMBNTFDADD(p)  (20 + (p)->smba)        /* ICH3 and later */
 
 /* PCI Address Constants */
+#define SMBBAR_MMIO    0
 #define SMBBAR         4
 #define SMBHSTCFG      0x040
 #define TCOBASE                0x050
@@ -1522,7 +1523,7 @@ static void i801_restore_regs(struct i801_priv *priv)
 
 static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
-       int err, i;
+       int err, i, bar = SMBBAR;
        struct i801_priv *priv;
 
        priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
@@ -1570,10 +1571,13 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
        if (i801_acpi_probe(priv))
                return -ENODEV;
 
-       priv->smba = pcim_iomap_region(dev, SMBBAR, DRV_NAME);
+       if (pci_resource_flags(dev, SMBBAR_MMIO) & IORESOURCE_MEM)
+               bar = SMBBAR_MMIO;
+
+       priv->smba = pcim_iomap_region(dev, bar, DRV_NAME);
        if (IS_ERR(priv->smba)) {
                pci_err(dev, "Failed to request SMBus region %pr\n",
-                       pci_resource_n(dev, SMBBAR));
+                       pci_resource_n(dev, bar));
                i801_acpi_remove(priv);
                return PTR_ERR(priv->smba);
        }