gpio: htc-egpio: read output value from cache

When the hardware is in output mode, reading the value from the
hardware is not giving the correct value back. Instead read the
value from the cache so we get the right value.

Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/gpio/gpio-htc-egpio.c b/drivers/gpio/gpio-htc-egpio.c
index 27af52850927..271356effb2e 100644
--- a/drivers/gpio/gpio-htc-egpio.c
+++ b/drivers/gpio/gpio-htc-egpio.c
@@ -160,10 +160,14 @@ static int egpio_get(struct gpio_chip *chip, unsigned offset)
         bit   = egpio_bit(ei, offset);
         reg   = egpio->reg_start + egpio_pos(ei, offset);
 
-        value = egpio_readw(ei, reg);
-        pr_debug("readw(%p + %x) = %x\n",
-                        ei->base_addr, reg << ei->bus_shift, value);
-        return !!(value & bit);
+        if (test_bit(offset, &egpio->is_out)) {
+                return !!(egpio->cached_values & (1 << offset));
+        } else {
+                value = egpio_readw(ei, reg);
+                pr_debug("readw(%p + %x) = %x\n",
+                         ei->base_addr, reg << ei->bus_shift, value);
+                return !!(value & bit);
+        }
 }
 
 static int egpio_direction_input(struct gpio_chip *chip, unsigned offset)