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authorLinus Walleij <linus.walleij@linaro.org>2018-10-12 14:54:12 +0200
committerMark Brown <broonie@kernel.org>2018-10-12 18:55:02 +0200
commitb0ce7b29bfcd090ddba476f45a75ec0a797b048a (patch)
treeb689c014f8e3423d4db5a5355ec81c548eba3ae1 /drivers/gpio
parentbef9391cbec547351c6a13e52f3a26bb2d271ec7 (diff)
downloadlinux-b0ce7b29bfcd090ddba476f45a75ec0a797b048a.tar.bz2
regulator/gpio: Allow nonexclusive GPIO access
This allows nonexclusive (simultaneous) access to a single GPIO line for the fixed regulator enable line. This happens when several regulators use the same GPIO for enabling and disabling a regulator, and all need a handle on their GPIO descriptor. This solution with a special flag is not entirely elegant and should ideally be replaced by something more careful as this makes it possible for several consumers to enable/disable the same GPIO line to the left and right without any consistency. The current use inside the regulator core should however be fine as it takes special care to handle this. For the state of the GPIO backend, this is still the lesser evil compared to going back to global GPIO numbers. Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Jon Hunter <jonathanh@nvidia.com> Fixes: efdfeb079cc3 ("regulator: fixed: Convert to use GPIO descriptor only") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpiolib.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e8f8a1999393..8228306aba46 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3908,8 +3908,23 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
* the device name as label
*/
status = gpiod_request(desc, con_id ? con_id : devname);
- if (status < 0)
- return ERR_PTR(status);
+ if (status < 0) {
+ if (status == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
+ /*
+ * This happens when there are several consumers for
+ * the same GPIO line: we just return here without
+ * further initialization. It is a bit if a hack.
+ * This is necessary to support fixed regulators.
+ *
+ * FIXME: Make this more sane and safe.
+ */
+ dev_info(dev, "nonexclusive access to GPIO for %s\n",
+ con_id ? con_id : devname);
+ return desc;
+ } else {
+ return ERR_PTR(status);
+ }
+ }
status = gpiod_configure_flags(desc, con_id, lookupflags, flags);
if (status < 0) {