Re: [PATCH 2/2] usb: dwc3: add clock and resets

[Masami Hiramatsu]

On Thu, 15 Mar 2018 20:39:58 +0900
Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote:

> dwc3-of-simple.c only handles arbitrary number of clocks and resets.
> They are both generic enough to be put into the dwc3 core.  For simple
> cases, a nested node structure like follows:
> 
>   dwc3-glue {
>           compatible = "foo,dwc3";
>           clocks = ...;
>           resets = ...;
>           ...
> 
>           dwc3 {
>                   compatible = "snps,dwc3";
>                   ...
>           };
>   }
> 
> would be turned into a single node:
> 
>   dwc3 {
>           compatible = "foo,dwc3", "snps,dwc3";
>           clocks = ...;
>           resets = ...;
>           ...
>   }
> 
> I inserted reset_control_deassert() and clk_enable() before the first
> register access, i.e. dwc3_cache_hwparams().

This looks good to me. 

Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Thanks!

> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
> 
>  Documentation/devicetree/bindings/usb/dwc3.txt |   2 +
>  drivers/usb/dwc3/core.c                        | 127 ++++++++++++++++++++++++-
>  drivers/usb/dwc3/core.h                        |   5 +
>  3 files changed, 132 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
> index 44e8bab..67e9cfb 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
> @@ -9,12 +9,14 @@ Required properties:
>   - interrupts: Interrupts used by the dwc3 controller.
>  
>  Optional properties:
> + - clocks: list of phandle and clock specifier pairs
>   - usb-phy : array of phandle for the PHY device.  The first element
>     in the array is expected to be a handle to the USB2/HS PHY and
>     the second element is expected to be a handle to the USB3/SS PHY
>   - phys: from the *Generic PHY* bindings
>   - phy-names: from the *Generic PHY* bindings; supported names are "usb2-phy"
>  	or "usb3-phy".
> + - resets: list of phandle and reset specifier pairs
>   - snps,usb3_lpm_capable: determines if platform is USB3 LPM capable
>   - snps,disable_scramble_quirk: true when SW should disable data scrambling.
>  	Only really useful for FPGA builds.
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index e9083a3..f17e4a9 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -8,6 +8,7 @@
>   *	    Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>   */
>  
> +#include <linux/clk.h>
>  #include <linux/version.h>
>  #include <linux/module.h>
>  #include <linux/kernel.h>
> @@ -24,6 +25,7 @@
>  #include <linux/of.h>
>  #include <linux/acpi.h>
>  #include <linux/pinctrl/consumer.h>
> +#include <linux/reset.h>
>  
>  #include <linux/usb/ch9.h>
>  #include <linux/usb/gadget.h>
> @@ -240,6 +242,74 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
>  	return -ETIMEDOUT;
>  }
>  
> +static int dwc3_core_get_clks(struct dwc3 *dwc)
> +{
> +	struct device *dev = dwc->dev;
> +	struct device_node *node = dev->of_node;
> +	struct clk *clk;
> +	int num_clks, i;
> +
> +	num_clks = of_count_phandle_with_args(node, "clocks", "#clock-cells");
> +	if (num_clks <= 0)
> +		return 0;
> +
> +	dwc->num_clks = num_clks;
> +
> +	dwc->clks = devm_kcalloc(dev, num_clks, sizeof(*dwc->clks), GFP_KERNEL);
> +	if (!dwc->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_clks; i++) {
> +		clk = of_clk_get(node, i);
> +		if (IS_ERR(clk))
> +			goto put_clks;
> +		dwc->clks[i] = clk;
> +	}
> +
> +	return 0;
> +
> +put_clks:
> +	while (--i >= 0)
> +		clk_put(dwc->clks[i]);
> +
> +	return PTR_ERR(clk);
> +}
> +
> +static void dwc3_core_put_clks(struct dwc3 *dwc)
> +{
> +	int i;
> +
> +	for (i = dwc->num_clks - 1; i >= 0; i--)
> +		clk_put(dwc->clks[i]);
> +}
> +
> +static int dwc3_core_enable_clks(struct dwc3 *dwc)
> +{
> +	int ret, i;
> +
> +	for (i = 0; i < dwc->num_clks; i++) {
> +		ret = clk_prepare_enable(dwc->clks[i]);
> +		if (ret)
> +			goto disable_clks;
> +	}
> +
> +	return 0;
> +
> +disable_clks:
> +	while (--i >= 0)
> +		clk_disable_unprepare(dwc->clks[i]);
> +
> +	return ret;
> +}
> +
> +static void dwc3_core_disable_clks(struct dwc3 *dwc)
> +{
> +	int i;
> +
> +	for (i = dwc->num_clks - 1; i >= 0; i--)
> +		clk_disable_unprepare(dwc->clks[i]);
> +}
> +
>  /*
>   * dwc3_frame_length_adjustment - Adjusts frame length if required
>   * @dwc3: Pointer to our controller context structure
> @@ -641,6 +711,8 @@ static void dwc3_core_exit(struct dwc3 *dwc)
>  	usb_phy_set_suspend(dwc->usb3_phy, 1);
>  	phy_power_off(dwc->usb2_generic_phy);
>  	phy_power_off(dwc->usb3_generic_phy);
> +	dwc3_core_disable_clks(dwc);
> +	reset_control_assert(dwc->resets);
>  }
>  
>  static bool dwc3_core_is_valid(struct dwc3 *dwc)
> @@ -1205,6 +1277,22 @@ static int dwc3_probe(struct platform_device *pdev)
>  
>  	dwc3_get_properties(dwc);
>  
> +	dwc->resets = devm_reset_control_array_get_optional_shared(dev);
> +	if (IS_ERR(dwc->resets))
> +		return PTR_ERR(dwc->resets);
> +
> +	ret = dwc3_core_get_clks(dwc);
> +	if (ret)
> +		return ret;
> +
> +	ret = reset_control_deassert(dwc->resets);
> +	if (ret)
> +		goto put_clks;
> +
> +	ret = dwc3_core_enable_clks(dwc);
> +	if (ret)
> +		goto assert_resets;
> +
>  	platform_set_drvdata(pdev, dwc);
>  	dwc3_cache_hwparams(dwc);
>  
> @@ -1268,6 +1356,14 @@ static int dwc3_probe(struct platform_device *pdev)
>  	pm_runtime_put_sync(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  
> +	dwc3_core_disable_clks(dwc);
> +
> +assert_resets:
> +	reset_control_assert(dwc->resets);
> +
> +put_clks:
> +	dwc3_core_put_clks(dwc);
> +
>  	return ret;
>  }
>  
> @@ -1289,11 +1385,38 @@ static int dwc3_remove(struct platform_device *pdev)
>  
>  	dwc3_free_event_buffers(dwc);
>  	dwc3_free_scratch_buffers(dwc);
> +	dwc3_core_put_clks(dwc);
>  
>  	return 0;
>  }
>  
>  #ifdef CONFIG_PM
> +static int dwc3_core_init_for_resume(struct dwc3 *dwc)
> +{
> +	int ret;
> +
> +	ret = reset_control_deassert(dwc->resets);
> +	if (ret)
> +		return ret;
> +
> +	ret = dwc3_core_enable_clks(dwc);
> +	if (ret)
> +		goto assert_resets;
> +
> +	ret = dwc3_core_init(dwc);
> +	if (ret)
> +		goto disable_clks;
> +
> +	return 0;
> +
> +disable_clks:
> +	dwc3_core_disable_clks(dwc);
> +assert_resets:
> +	reset_control_assert(dwc->resets);
> +
> +	return ret;
> +}
> +
>  static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>  {
>  	unsigned long	flags;
> @@ -1325,7 +1448,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
>  
>  	switch (dwc->current_dr_role) {
>  	case DWC3_GCTL_PRTCAP_DEVICE:
> -		ret = dwc3_core_init(dwc);
> +		ret = dwc3_core_init_for_resume(dwc);
>  		if (ret)
>  			return ret;
>  
> @@ -1336,7 +1459,7 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
>  	case DWC3_GCTL_PRTCAP_HOST:
>  		/* nothing to do on host runtime_resume */
>  		if (!PMSG_IS_AUTO(msg)) {
> -			ret = dwc3_core_init(dwc);
> +			ret = dwc3_core_init_for_resume(dwc);
>  			if (ret)
>  				return ret;
>  		}
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 860d2bc..14cd335 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -891,6 +891,11 @@ struct dwc3 {
>  	struct usb_gadget	gadget;
>  	struct usb_gadget_driver *gadget_driver;
>  
> +	struct clk		**clks;
> +	int			num_clks;
> +
> +	struct reset_control	*resets;
> +
>  	struct usb_phy		*usb2_phy;
>  	struct usb_phy		*usb3_phy;
>  
> -- 
> 2.7.4
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>