[U-Boot] [PATCH v5] gpio: dwapb_gpio: Add reset ctrl to driver

[Ley Foon Tan]

Add code to reset all reset signals as in gpio DT node. A reset property
is an optional feature, so only print out a warning and do not fail if a
reset property is not present.

If a reset property is discovered, then use it to deassert, thus
bringing the IP out of reset.

Signed-off-by: Ley Foon Tan <ley.foon....@intel.com>

---
v5:
- Move dev_warn() when return error.

v4:
- Add struct gpio_dwapb_priv

v3:
- Add .remove function.
- Add error handling when return non-zero from reset_get_bulk().

v2:
- Move reset to probe() function.
---
 drivers/gpio/dwapb_gpio.c |   51 +++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
index 7cf2d47..0f6574d 100644
--- a/drivers/gpio/dwapb_gpio.c
+++ b/drivers/gpio/dwapb_gpio.c
@@ -15,6 +15,7 @@
 #include <dm/lists.h>
 #include <dm/root.h>
 #include <errno.h>
+#include <reset.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -29,6 +30,10 @@ DECLARE_GLOBAL_DATA_PTR;
 #define GPIO_PORTA_EOI         0x4c
 #define GPIO_EXT_PORT(p)       (0x50 + (p) * 4)
 
+struct gpio_dwapb_priv {
+       struct reset_ctl_bulk   resets;
+};
+
 struct gpio_dwapb_platdata {
        const char      *name;
        int             bank;
@@ -99,13 +104,42 @@ static const struct dm_gpio_ops gpio_dwapb_ops = {
        .get_function           = dwapb_gpio_get_function,
 };
 
+static int gpio_dwapb_reset(struct udevice *dev)
+{
+       int ret;
+       struct gpio_dwapb_priv *priv = dev_get_priv(dev);
+
+       ret = reset_get_bulk(dev, &priv->resets);
+       if (ret) {
+               /* Return 0 if error due to !CONFIG_DM_RESET and reset
+                * DT property is not present.
+                */
+               if (ret == -ENOENT || ret == -ENOTSUPP)
+                       return 0;
+
+               dev_warn(dev, "Can't get reset: %d\n", ret);
+               return ret;
+       }
+
+       ret = reset_deassert_bulk(&priv->resets);
+       if (ret) {
+               reset_release_bulk(&priv->resets);
+               dev_err(dev, "Failed to reset: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
 static int gpio_dwapb_probe(struct udevice *dev)
 {
        struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
        struct gpio_dwapb_platdata *plat = dev->platdata;
 
-       if (!plat)
-               return 0;
+       if (!plat) {
+               /* Reset on parent device only */
+               return gpio_dwapb_reset(dev);
+       }
 
        priv->gpio_count = plat->pins;
        priv->bank_name = plat->name;
@@ -166,6 +200,17 @@ err:
        return ret;
 }
 
+static int gpio_dwapb_remove(struct udevice *dev)
+{
+       struct gpio_dwapb_platdata *plat = dev_get_platdata(dev);
+       struct gpio_dwapb_priv *priv = dev_get_priv(dev);
+
+       if (!plat && priv)
+               return reset_release_bulk(&priv->resets);
+
+       return 0;
+}
+
 static const struct udevice_id gpio_dwapb_ids[] = {
        { .compatible = "snps,dw-apb-gpio" },
        { }
@@ -178,4 +223,6 @@ U_BOOT_DRIVER(gpio_dwapb) = {
        .ops            = &gpio_dwapb_ops,
        .bind           = gpio_dwapb_bind,
        .probe          = gpio_dwapb_probe,
+       .remove         = gpio_dwapb_remove,
+       .priv_auto_alloc_size   = sizeof(struct gpio_dwapb_priv),
 };
-- 
1.7.1

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