linux-kernel - Re: [PATCH v2 14/22] usb: chipidea: msm: Add proper clk and reset support

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Date:	Mon, 11 Jul 2016 12:32:49 +0800
From:	Peter Chen <hzpeterchen@...il.com>
To:	Stephen Boyd <stephen.boyd@...aro.org>
Cc:	linux-usb@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	Andy Gross <andy.gross@...aro.org>,
	Bjorn Andersson <bjorn.andersson@...aro.org>,
	Neil Armstrong <narmstrong@...libre.com>,
	Arnd Bergmann <arnd@...db.de>, Felipe Balbi <balbi@...nel.org>,
	Peter Chen <peter.chen@....com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v2 14/22] usb: chipidea: msm: Add proper clk and reset
 support

On Thu, Jul 07, 2016 at 03:21:05PM -0700, Stephen Boyd wrote:
> The msm chipidea controller uses two main clks, an AHB clk to
> read/write the MMIO registers and a core clk called the system
> clk that drives the controller itself. Add support for these clks
> as they're required in all designs.
> 
> Also add support for an optional third clk that we need to turn
> on to reset the controller and wrapper logic and other
> "housekeeping" things. This clk was removed in later revisions of
> the hardware because the reset methodology no longer required
> clks to be enabled to propagate resets.
> 
> Cc: Peter Chen <peter.chen@....com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@...aro.org>
> ---
>  drivers/usb/chipidea/ci_hdrc_msm.c | 72 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 68 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/ci_hdrc_msm.c b/drivers/usb/chipidea/ci_hdrc_msm.c
> index b282a717bf8c..7e870a253f55 100644
> --- a/drivers/usb/chipidea/ci_hdrc_msm.c
> +++ b/drivers/usb/chipidea/ci_hdrc_msm.c
> @@ -10,11 +10,20 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/usb/gadget.h>
>  #include <linux/usb/chipidea.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
>  
>  #include "ci.h"
>  
>  #define HS_PHY_AHB_MODE			0x0098
>  
> +struct ci_hdrc_msm {
> +	struct platform_device *ci;
> +	struct clk *core_clk;
> +	struct clk *iface_clk;
> +	struct clk *fs_clk;
> +};
> +
>  static void ci_hdrc_msm_notify_event(struct ci_hdrc *ci, unsigned event)
>  {
>  	struct device *dev = ci->gadget.dev.parent;
> @@ -52,11 +61,20 @@ static struct ci_hdrc_platform_data ci_hdrc_msm_platdata = {
>  
>  static int ci_hdrc_msm_probe(struct platform_device *pdev)
>  {
> +	struct ci_hdrc_msm *ci;
>  	struct platform_device *plat_ci;
>  	struct usb_phy *phy;
> +	struct clk *clk;
> +	struct reset_control *reset;
> +	int ret;
>  
>  	dev_dbg(&pdev->dev, "ci_hdrc_msm_probe\n");
>  
> +	ci = devm_kzalloc(&pdev->dev, sizeof(*ci), GFP_KERNEL);
> +	if (!ci)
> +		return -ENOMEM;
> +	platform_set_drvdata(pdev, ci);
> +
>  	/*
>  	 * OTG(PHY) driver takes care of PHY initialization, clock management,
>  	 * powering up VBUS, mapping of registers address space and power
> @@ -68,29 +86,75 @@ static int ci_hdrc_msm_probe(struct platform_device *pdev)
>  
>  	ci_hdrc_msm_platdata.usb_phy = phy;
>  
> +	reset = devm_reset_control_get(&pdev->dev, "core");
> +	if (IS_ERR(reset))
> +		return PTR_ERR(reset);
> +
> +	ci->core_clk = clk = devm_clk_get(&pdev->dev, "core");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	ci->iface_clk = clk = devm_clk_get(&pdev->dev, "iface");
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	ci->fs_clk = clk = devm_clk_get(&pdev->dev, "fs");
> +	if (IS_ERR(clk)) {
> +		if (PTR_ERR(clk) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		ci->fs_clk = NULL;
> +	}
> +
> +	ret = clk_prepare_enable(ci->fs_clk);
> +	if (ret)
> +		return ret;
> +
> +	reset_control_assert(reset);
> +	usleep_range(10000, 12000);
> +	reset_control_deassert(reset);
> +
> +	clk_disable_unprepare(ci->fs_clk);
> +
> +	ret = clk_prepare_enable(ci->core_clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(ci->iface_clk);
> +	if (ret)
> +		goto err_iface;
> +
>  	plat_ci = ci_hdrc_add_device(&pdev->dev,
>  				pdev->resource, pdev->num_resources,
>  				&ci_hdrc_msm_platdata);
>  	if (IS_ERR(plat_ci)) {
>  		dev_err(&pdev->dev, "ci_hdrc_add_device failed!\n");
> -		return PTR_ERR(plat_ci);
> +		ret = PTR_ERR(plat_ci);
> +		goto err_mux;
>  	}
>  
> -	platform_set_drvdata(pdev, plat_ci);
> +	ci->ci = plat_ci;
>  
>  	pm_runtime_set_active(&pdev->dev);
>  	pm_runtime_no_callbacks(&pdev->dev);
>  	pm_runtime_enable(&pdev->dev);
>  
>  	return 0;
> +
> +err_mux:
> +	clk_disable_unprepare(ci->iface_clk);
> +err_iface:
> +	clk_disable_unprepare(ci->core_clk);
> +	return ret;
>  }
>  
>  static int ci_hdrc_msm_remove(struct platform_device *pdev)
>  {
> -	struct platform_device *plat_ci = platform_get_drvdata(pdev);
> +	struct ci_hdrc_msm *ci = platform_get_drvdata(pdev);
>  
>  	pm_runtime_disable(&pdev->dev);
> -	ci_hdrc_remove_device(plat_ci);
> +	ci_hdrc_remove_device(ci->ci);
> +	clk_disable_unprepare(ci->iface_clk);
> +	clk_disable_unprepare(ci->core_clk);
>  
>  	return 0;
>  }
> -- 

Acked-by: Peter Chen <peter.chen@....com>

-- 

Best Regards,
Peter Chen