commit 91492a44b998cf762150de8f1b40bda1902e8ea7
author Rabin Vincent <rabin@rab.in> Wed Jul 22 15:05:18 2015 +0200
committer Linus Walleij <linus.walleij@linaro.org> Mon Jul 27 15:01:05 2015 +0200
tree 31ca1c400a6e8d0921125fbe20b156eb35db25de
parent 1296fba1a397b173d45534885a0934a7c005d7e3

gpio: generic: support input-only chips

Allow chips to indicates that they are input-only and thus cannot set
the output value.  This will be used by the gpio-etraxfs driver.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-generic.c

diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index 802e6d2..a3f0753 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -153,6 +153,10 @@
 	return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
 }
 
+static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+}
+
 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct bgpio_chip *bgc = to_bgpio_chip(gc);
@@ -279,6 +283,12 @@
 	return 0;
 }
 
+static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
+				int val)
+{
+	return -EINVAL;
+}
+
 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
 				int val)
 {
@@ -460,6 +470,9 @@
 		bgc->reg_set = set;
 		bgc->gc.set = bgpio_set_set;
 		bgc->gc.set_multiple = bgpio_set_multiple_set;
+	} else if (flags & BGPIOF_NO_OUTPUT) {
+		bgc->gc.set = bgpio_set_none;
+		bgc->gc.set_multiple = NULL;
 	} else {
 		bgc->gc.set = bgpio_set;
 		bgc->gc.set_multiple = bgpio_set_multiple;
@@ -476,7 +489,8 @@
 
 static int bgpio_setup_direction(struct bgpio_chip *bgc,
 				 void __iomem *dirout,
-				 void __iomem *dirin)
+				 void __iomem *dirin,
+				 unsigned long flags)
 {
 	if (dirout && dirin) {
 		return -EINVAL;
@@ -491,7 +505,10 @@
 		bgc->gc.direction_input = bgpio_dir_in_inv;
 		bgc->gc.get_direction = bgpio_get_dir_inv;
 	} else {
-		bgc->gc.direction_output = bgpio_simple_dir_out;
+		if (flags & BGPIOF_NO_OUTPUT)
+			bgc->gc.direction_output = bgpio_dir_out_err;
+		else
+			bgc->gc.direction_output = bgpio_simple_dir_out;
 		bgc->gc.direction_input = bgpio_simple_dir_in;
 	}
 
@@ -543,7 +560,7 @@
 	if (ret)
 		return ret;
 
-	ret = bgpio_setup_direction(bgc, dirout, dirin);
+	ret = bgpio_setup_direction(bgc, dirout, dirin, flags);
 	if (ret)
 		return ret;