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authorCharles Keepax <ckeepax@opensource.wolfsonmicro.com>2017-04-05 16:50:46 +0100
committerLinus Walleij <linus.walleij@linaro.org>2017-04-07 12:14:04 +0200
commit11598d1740500e3c1848122f3e77ab017aa38b77 (patch)
treef8897a4c50430564183dbf3b0555b443d85771bf /drivers/gpio
parente1e37d6c4a78bb6fb9b67115f497337cb38de503 (diff)
downloadlinux-11598d1740500e3c1848122f3e77ab017aa38b77.tar.bz2
gpio: arizona: Correct handling for reading input GPIOs
The GPIO register is cached since all the configuration resides within it, however, this means for input GPIOs the driver will not return the actual state but the last value written to the register cache. To correct this in the case of reading an input GPIO resume the CODEC and drop the cache for the input register to ensure an actual hardware read takes place. Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpio-arizona.c30
1 files changed, 28 insertions, 2 deletions
diff --git a/drivers/gpio/gpio-arizona.c b/drivers/gpio/gpio-arizona.c
index 1f91557717a6..60b3102279f3 100644
--- a/drivers/gpio/gpio-arizona.c
+++ b/drivers/gpio/gpio-arizona.c
@@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include <linux/mfd/arizona/core.h>
@@ -41,13 +42,38 @@ static int arizona_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
struct arizona *arizona = arizona_gpio->arizona;
- unsigned int val;
+ unsigned int reg, val;
int ret;
- ret = regmap_read(arizona->regmap, ARIZONA_GPIO1_CTRL + offset, &val);
+ reg = ARIZONA_GPIO1_CTRL + offset;
+ ret = regmap_read(arizona->regmap, reg, &val);
if (ret < 0)
return ret;
+ /* Resume to read actual registers for input pins */
+ if (!(val & ARIZONA_GPN_DIR)) {
+ ret = pm_runtime_get_sync(chip->parent);
+ if (ret < 0) {
+ dev_err(chip->parent, "Failed to resume: %d\n", ret);
+ return ret;
+ }
+
+ /* Register is cached, drop it to ensure a physical read */
+ ret = regcache_drop_region(arizona->regmap, reg, reg);
+ if (ret < 0) {
+ dev_err(chip->parent, "Failed to drop cache: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = regmap_read(arizona->regmap, reg, &val);
+ if (ret < 0)
+ return ret;
+
+ pm_runtime_mark_last_busy(chip->parent);
+ pm_runtime_put_autosuspend(chip->parent);
+ }
+
if (val & ARIZONA_GPN_LVL)
return 1;
else