[PATCH v2 3/4] usb: dwc3: of-simple: Add support to get resets for the device

From: Vivek Gautam
Date: Mon Apr 03 2017 - 09:42:53 EST


Add support to get a list of resets available for the device.
These resets must be kept de-asserted until the device is
in use.

Cc: Felipe Balbi <balbi@xxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
---

Changes since v1:
- Using new APIs for reset control array.
- Using the *_get_exclusive() API.
- Added reset_control_array_put() to error and driver removal path.

drivers/usb/dwc3/dwc3-of-simple.c | 45 +++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
index fe414e7a9c78..96786f5ede0b 100644
--- a/drivers/usb/dwc3/dwc3-of-simple.c
+++ b/drivers/usb/dwc3/dwc3-of-simple.c
@@ -29,13 +29,48 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>

struct dwc3_of_simple {
struct device *dev;
struct clk **clks;
int num_clocks;
+ int num_resets;
+ struct reset_control_array *resets;
};

+static int dwc3_of_simple_reset_init(struct dwc3_of_simple *simple, int count)
+{
+ struct device *dev = simple->dev;
+ int ret;
+
+ /* Not all platforms have resets, so don't return a failure */
+ if (count < 0)
+ return 0;
+
+ simple->num_resets = count;
+
+ simple->resets = devm_kcalloc(dev, count, sizeof(simple->resets),
+ GFP_KERNEL);
+ if (!simple->resets)
+ return -ENOMEM;
+
+ ret = of_reset_control_array_get_exclusive(dev->of_node, count,
+ simple->resets);
+ if (ret) {
+ dev_err(dev, "failed to get device resets\n");
+ return ret;
+ }
+
+ ret = reset_control_array_deassert(count, simple->resets);
+ if (ret) {
+ reset_control_array_put(count, simple->resets);
+ return ret;
+ }
+
+ return 0;
+}
+
static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count)
{
struct device *dev = simple->dev;
@@ -100,6 +135,10 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
if (ret)
return ret;

+ ret = dwc3_of_simple_reset_init(simple, of_reset_control_get_count(np));
+ if (ret)
+ return ret;
+
ret = of_platform_populate(np, NULL, NULL, dev);
if (ret) {
for (i = 0; i < simple->num_clocks; i++) {
@@ -107,6 +146,9 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
clk_put(simple->clks[i]);
}

+ reset_control_array_assert(simple->num_resets, simple->resets);
+ reset_control_array_put(simple->num_resets, simple->resets);
+
return ret;
}

@@ -128,6 +170,9 @@ static int dwc3_of_simple_remove(struct platform_device *pdev)
clk_put(simple->clks[i]);
}

+ reset_control_array_assert(simple->num_resets, simple->resets);
+ reset_control_array_put(simple->num_resets, simple->resets);
+
of_platform_depopulate(dev);

pm_runtime_put_sync(dev);
--
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