[PATCH] gpio: gpio-dwapb: add optional reset

[Alan Tull]

Some platforms require reset to be released to allow register
access.

Signed-off-by: Alan Tull <at...@kernel.org>
---
v2: Request shared controller
    return all errors from reset controller request
    drop conditions on asserting/deasserting reset
---
 drivers/gpio/gpio-dwapb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpio/gpio-dwapb.c b/drivers/gpio/gpio-dwapb.c
index f051c45..0df8cdf 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>
@@ -97,6 +98,7 @@ 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)
@@ -608,6 +610,12 @@ 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)
@@ -659,6 +667,7 @@ static int dwapb_gpio_remove(struct platform_device *pdev)
 
        dwapb_gpio_unregister(gpio);
        dwapb_irq_teardown(gpio);
+       reset_control_assert(gpio->rst);
 
        return 0;
 }
-- 
2.7.4