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.
> + dev_err(dev, "failed to get device resets\n");
It would be nice to print the error code here.
> + 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.
> 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?
> of_platform_depopulate(dev);
Given the order above, I'd expect the reset cleanup here.
> pm_runtime_put_sync(dev);
regards
Philipp
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