gpio: gpio-dwapb: add optional reset
Some platforms require reset to be released to allow register
access.
Signed-off-by: Alan Tull <atull@kernel.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
[Added DT bindings oneliner for standard reset binding]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index 5cdb7bc..d782ad1 100644
--- a/drivers/gpio/gpio-dwapb.c
+++ b/drivers/gpio/gpio-dwapb.c
@@ -25,6 +25,7 @@
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/property.h>
+#include <linux/reset.h>
#include <linux/spinlock.h>
#include <linux/platform_data/gpio-dwapb.h>
#include <linux/slab.h>
@@ -98,6 +99,7 @@ struct dwapb_gpio {
unsigned int nr_ports;
struct irq_domain *domain;
unsigned int flags;
+ struct reset_control *rst;
};
static inline u32 gpio_reg_v2_convert(unsigned int offset)
@@ -629,6 +631,12 @@ static int dwapb_gpio_probe(struct platform_device *pdev)
gpio->dev = &pdev->dev;
gpio->nr_ports = pdata->nports;
+ gpio->rst = devm_reset_control_get_optional_shared(dev, NULL);
+ if (IS_ERR(gpio->rst))
+ return PTR_ERR(gpio->rst);
+
+ reset_control_deassert(gpio->rst);
+
gpio->ports = devm_kcalloc(&pdev->dev, gpio->nr_ports,
sizeof(*gpio->ports), GFP_KERNEL);
if (!gpio->ports)
@@ -680,6 +688,7 @@ static int dwapb_gpio_remove(struct platform_device *pdev)
dwapb_gpio_unregister(gpio);
dwapb_irq_teardown(gpio);
+ reset_control_assert(gpio->rst);
return 0;
}