drm/i915/gmbus: combine gmbus pin lookups to one function

Combine the platform specific if ladders for array lookup and size
checks into one. This is cleaner and avoids duplication, but hopefully
also helps any static analyzers that seem to have trouble with the
bounds checks.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220303181931.1661767-1-jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_gmbus.c

@@ -106,51 +106,47 @@ static const struct gmbus_pin gmbus_pins_dg2[] = {
 	[GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ },
 };
 
-/* pin is expected to be valid */
-static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *dev_priv,
+static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *i915,
 					     unsigned int pin)
 {
-	if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG2)
-		return &gmbus_pins_dg2[pin];
-	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
-		return &gmbus_pins_dg1[pin];
-	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
-		return &gmbus_pins_icp[pin];
-	else if (HAS_PCH_CNP(dev_priv))
-		return &gmbus_pins_cnp[pin];
-	else if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
-		return &gmbus_pins_bxt[pin];
-	else if (DISPLAY_VER(dev_priv) == 9)
-		return &gmbus_pins_skl[pin];
-	else if (IS_BROADWELL(dev_priv))
-		return &gmbus_pins_bdw[pin];
-	else
-		return &gmbus_pins[pin];
-}
-
-bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
-			      unsigned int pin)
-{
-	unsigned int size;
+	const struct gmbus_pin *pins;
+	size_t size;
 
-	if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG2)
+	if (INTEL_PCH_TYPE(i915) >= PCH_DG2) {
+		pins = gmbus_pins_dg2;
 		size = ARRAY_SIZE(gmbus_pins_dg2);
-	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
+	} else if (INTEL_PCH_TYPE(i915) >= PCH_DG1) {
+		pins = gmbus_pins_dg1;
 		size = ARRAY_SIZE(gmbus_pins_dg1);
-	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
+	} else if (INTEL_PCH_TYPE(i915) >= PCH_ICP) {
+		pins = gmbus_pins_icp;
 		size = ARRAY_SIZE(gmbus_pins_icp);
-	else if (HAS_PCH_CNP(dev_priv))
+	} else if (HAS_PCH_CNP(i915)) {
+		pins = gmbus_pins_cnp;
 		size = ARRAY_SIZE(gmbus_pins_cnp);
-	else if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
+	} else if (IS_GEMINILAKE(i915) || IS_BROXTON(i915)) {
+		pins = gmbus_pins_bxt;
 		size = ARRAY_SIZE(gmbus_pins_bxt);
-	else if (DISPLAY_VER(dev_priv) == 9)
+	} else if (DISPLAY_VER(i915) == 9) {
+		pins = gmbus_pins_skl;
 		size = ARRAY_SIZE(gmbus_pins_skl);
-	else if (IS_BROADWELL(dev_priv))
+	} else if (IS_BROADWELL(i915)) {
+		pins = gmbus_pins_bdw;
 		size = ARRAY_SIZE(gmbus_pins_bdw);
-	else
+	} else {
+		pins = gmbus_pins;
 		size = ARRAY_SIZE(gmbus_pins);
+	}
+
+	if (pin >= size || !pins[pin].name)
+		return NULL;
 
-	return pin < size && get_gmbus_pin(dev_priv, pin)->name;
+	return &pins[pin];
+}
+
+bool intel_gmbus_is_valid_pin(struct drm_i915_private *i915, unsigned int pin)
+{
+	return get_gmbus_pin(i915, pin);
 }
 
 /* Intel GPIO access functions */