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authorSascha Hauer <s.hauer@pengutronix.de>2015-11-10 12:36:38 +0100
committerSascha Hauer <s.hauer@pengutronix.de>2015-11-23 10:23:38 +0100
commitd9ba9c92b72b1c795da524becd41859450aafc1a (patch)
treefea51c336a23f602adda2036f64a584ebd914c59 /drivers/reset
parent97a92f0d86e74dfe153c30ecefc480e0c7e08569 (diff)
downloadbarebox-d9ba9c92b72b1c795da524becd41859450aafc1a.tar.gz
reset: Add gpio reset support
If a device has the reset-gpios property we can support this through the reset controller API, so drivers do not have to open code the support for this property each time themselves as done a few dozen times in the kernel. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/reset')
-rw-r--r--drivers/reset/core.c80
1 files changed, 79 insertions, 1 deletions
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 1821283..0f900a9 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -9,7 +9,9 @@
* (at your option) any later version.
*/
#include <common.h>
+#include <gpio.h>
#include <malloc.h>
+#include <of_gpio.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/reset.h>
@@ -26,6 +28,10 @@ static LIST_HEAD(reset_controller_list);
*/
struct reset_control {
struct reset_controller_dev *rcdev;
+
+ int gpio;
+ int gpio_active_high;
+
struct device_d *dev;
unsigned int id;
};
@@ -103,6 +109,9 @@ int reset_control_assert(struct reset_control *rstc)
if (!rstc)
return 0;
+ if (rstc->gpio >= 0)
+ return gpio_direction_output(rstc->gpio, rstc->gpio_active_high);
+
if (rstc->rcdev->ops->assert)
return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
@@ -119,6 +128,9 @@ int reset_control_deassert(struct reset_control *rstc)
if (!rstc)
return 0;
+ if (rstc->gpio >= 0)
+ return gpio_direction_output(rstc->gpio, !rstc->gpio_active_high);
+
if (rstc->rcdev->ops->deassert)
return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
@@ -183,6 +195,29 @@ struct reset_control *of_reset_control_get(struct device_node *node,
}
EXPORT_SYMBOL_GPL(of_reset_control_get);
+struct reset_control *gpio_reset_control_get(struct device_d *dev, const char *id)
+{
+ struct reset_control *rc;
+ int gpio;
+ enum of_gpio_flags flags;
+
+ if (id)
+ return ERR_PTR(-EINVAL);
+
+ if (!of_get_property(dev->device_node, "reset-gpios", NULL))
+ return NULL;
+
+ gpio = of_get_named_gpio_flags(dev->device_node, "reset-gpios", 0, &flags);
+ if (gpio < 0)
+ return ERR_PTR(gpio);
+
+ rc = xzalloc(sizeof(*rc));
+ rc->gpio = gpio;
+ rc->gpio_active_high = !(flags & OF_GPIO_ACTIVE_LOW);
+
+ return rc;
+}
+
/**
* reset_control_get - Lookup and obtain a reference to a reset controller.
* @dev: device to be reset by the controller
@@ -203,6 +238,16 @@ struct reset_control *reset_control_get(struct device_d *dev, const char *id)
if (IS_ERR(rstc))
return ERR_CAST(rstc);
+ /*
+ * If there is no dedicated reset controller device, check if we have
+ * a reset line controlled by a GPIO instead.
+ */
+ if (!rstc) {
+ rstc = gpio_reset_control_get(dev, id);
+ if (IS_ERR(rstc))
+ return ERR_CAST(rstc);
+ }
+
if (!rstc)
return NULL;
@@ -241,8 +286,12 @@ int device_reset(struct device_d *dev)
int ret;
rstc = reset_control_get(dev, NULL);
- if (IS_ERR(rstc))
+ if (IS_ERR(rstc)) {
+ if (PTR_ERR(rstc) == -ENOENT)
+ return 0;
+
return PTR_ERR(rstc);
+ }
ret = reset_control_reset(rstc);
@@ -251,3 +300,32 @@ int device_reset(struct device_d *dev)
return ret;
}
EXPORT_SYMBOL_GPL(device_reset);
+
+int device_reset_us(struct device_d *dev, int us)
+{
+ struct reset_control *rstc;
+ int ret;
+
+ rstc = reset_control_get(dev, NULL);
+ if (IS_ERR(rstc)) {
+ if (PTR_ERR(rstc) == -ENOENT)
+ return 0;
+
+ return PTR_ERR(rstc);
+ }
+
+ ret = reset_control_assert(rstc);
+ if (ret)
+ return ret;
+
+ udelay(us);
+
+ ret = reset_control_deassert(rstc);
+ if (ret)
+ return ret;
+
+ reset_control_put(rstc);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(device_reset_us);