pinctrl: cy8c95x0: Avoid accessing reserved registers

The checks for vrtual registers in the cy8c95x0_readable_register()
and cy8c95x0_writeable_register() are not aligned and broken.

Fix that by explicitly avoiding reserved registers to be accessed.

Fixes: 71e4001 ("pinctrl: pinctrl-cy8c95x0: Fix regcache")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/20250203131506.3318201-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: andy-shev

drivers/pinctrl/pinctrl-cy8c95x0.c

@@ -328,14 +328,14 @@ static int cypress_get_pin_mask(struct cy8c95x0_pinctrl *chip, unsigned int pin)
 static bool cy8c95x0_readable_register(struct device *dev, unsigned int reg)
 {
 	/*
-	 * Only 12 registers are present per port (see Table 6 in the
-	 * datasheet).
+	 * Only 12 registers are present per port (see Table 6 in the datasheet).
 	 */
-	if (reg >= CY8C95X0_VIRTUAL && (reg % MUXED_STRIDE) < 12)
-		return true;
+	if (reg >= CY8C95X0_VIRTUAL && (reg % MUXED_STRIDE) >= 12)
+		return false;
 
 	switch (reg) {
 	case 0x24 ... 0x27:
+	case 0x31 ... 0x3f:
 		return false;
 	default:
 		return true;
@@ -344,15 +344,19 @@ static bool cy8c95x0_readable_register(struct device *dev, unsigned int reg)
 
 static bool cy8c95x0_writeable_register(struct device *dev, unsigned int reg)
 {
-	if (reg >= CY8C95X0_VIRTUAL)
-		return true;
+	/*
+	 * Only 12 registers are present per port (see Table 6 in the datasheet).
+	 */
+	if (reg >= CY8C95X0_VIRTUAL && (reg % MUXED_STRIDE) >= 12)
+		return false;
 
 	switch (reg) {
 	case CY8C95X0_INPUT_(0) ... CY8C95X0_INPUT_(7):
 		return false;
 	case CY8C95X0_DEVID:
 		return false;
 	case 0x24 ... 0x27:
+	case 0x31 ... 0x3f:
 		return false;
 	default:
 		return true;