linux-kernel - Re: [PATCH 14/21] usb: chipidea: msm: Add proper clk and reset support

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Message-ID: <20160629070212.GI25236@shlinux2>
Date:	Wed, 29 Jun 2016 15:02:12 +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 14/21] usb: chipidea: msm: Add proper clk and reset
 support

On Sun, Jun 26, 2016 at 12:28:31AM -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 read/write the ULPI phy registers. Some ULPI phys drive
> this clk themselves and so it isn't necessary to turn on to probe
> a ULPI device, but the HSIC phy doesn't provide one itself, so we
> must turn it on here.
> 
> 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 | 58 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/usb/chipidea/ci_hdrc_msm.c b/drivers/usb/chipidea/ci_hdrc_msm.c
> index 07cccd24a87f..40249b0e3e93 100644
> --- a/drivers/usb/chipidea/ci_hdrc_msm.c
> +++ b/drivers/usb/chipidea/ci_hdrc_msm.c
> @@ -10,11 +10,19 @@
>  #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;
> +};
> +
>  static void ci_hdrc_msm_notify_event(struct ci_hdrc *ci, unsigned event)
>  {
>  	struct device *dev = ci->gadget.dev.parent;
> @@ -43,34 +51,76 @@ 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 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);
> +
> +	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);

You say it has three clocks in commit log, why it is only two in the code?
> +
> +	reset_control_assert(reset);
> +	usleep_range(10000, 12000);
> +	reset_control_deassert(reset);
> +
> +	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);
ci->plat_ci(or ci) = ...

Delete the local variable plat_ci

>  	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;

[...]


-- 

Best Regards,
Peter Chen