On 04/19/2017 04:02 PM, Philipp Zabel wrote:
On Tue, 2017-04-18 at 16:51 +0530, Vivek Gautam wrote:
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>
---
drivers/usb/dwc3/dwc3-of-simple.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c
index fe414e7a9c78..9116df649f0b 100644
--- a/drivers/usb/dwc3/dwc3-of-simple.c
+++ b/drivers/usb/dwc3/dwc3-of-simple.c
@@ -29,13 +29,39 @@
#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;
+ struct reset_control_array *resets;
};
+static int dwc3_of_simple_reset_init(struct dwc3_of_simple *simple)
+{
+ struct device *dev = simple->dev;
+ int ret;
+
+ simple->resets = of_reset_control_array_get_exclusive(dev->of_node);
+ if (IS_ERR(simple->resets)) {
+ ret = PTR_ERR(simple->resets);
+ if (ret == -ENOENT)
+ /* not all controllers required resets */
+ return 0;
If you use the of_reset_control_array_get_optional_exclusive variant,
you can remove the three lines directly above.
No, it's a little tricky here.
of_reset_control_get_count() returns an error code, that we then return from
of_reset_control_array_get().
This is something that tegra/pmc driver required (return errorno in case
count
of reset controls is zero.
So we handle that error separately here.
+ dev_err(dev, "failed to get device resets\n");
It would be nice to print the error code here.
Sure.
+ return ret;
+ }
+
+ ret = reset_control_array_deassert(simple->resets);
+ if (ret) {
+ reset_control_array_put(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 +126,10 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
if (ret)
return ret;
+ ret = dwc3_of_simple_reset_init(simple);
+ if (ret)
+ return ret;
+
I would just move the contents of dwc3_of_simple_reset_init here and add
a goto error path at the end of dwc3_of_simple_clk_init to handle the
reset control cleanup as needed.
Okay, i can restructure it.
ret = of_platform_populate(np, NULL, NULL, dev);
if (ret) {
for (i = 0; i < simple->num_clocks; i++) {
@@ -107,6 +137,9 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
clk_put(simple->clks[i]);
}
+ reset_control_array_assert(simple->resets);
+ reset_control_array_put(simple->resets);
+
return ret;
}
@@ -128,6 +161,9 @@ static int dwc3_of_simple_remove(struct platform_device *pdev)
clk_put(simple->clks[i]);
}
+ reset_control_array_assert(simple->resets);
+ reset_control_array_put(simple->resets);
+
Must the reset be asserted before of_platform_depopulate?
Right, the order must be taken care of here. Will change this.
of_platform_depopulate(dev);
Given the order above, I'd expect the reset cleanup here.
Sure.
pm_runtime_put_sync(dev);
regards
Philipp
Thanks for reviewing.
Best Regards
Vivek
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