linux-kernel - Re: [PATCH 2/2] phy: bcm-ns-usb2: support updated DT binding with the CRU syscon

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Message-ID: <1e1d2151-87b1-668a-f63d-162054a67a90@broadcom.com>
Date:   Mon, 7 Jan 2019 10:47:35 -0800
From:   Ray Jui <ray.jui@...adcom.com>
To:     Rafał Miłecki <zajec5@...il.com>,
        Kishon Vijay Abraham I <kishon@...com>
Cc:     linux-kernel@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org, Hauke Mehrtens <hauke@...ke-m.de>,
        bcm-kernel-feedback-list@...adcom.com,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: Re: [PATCH 2/2] phy: bcm-ns-usb2: support updated DT binding with the
 CRU syscon



On 1/7/2019 12:25 AM, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@...ecki.pl>
> 
> This adds support for the "syscon-cru" DT property which simply requires
> using regmap to access CRU registers.
> 
> The old binding has been deprecated and stays as a fallback method.
> 
> Signed-off-by: Rafał Miłecki <rafal@...ecki.pl>
> ---
>  drivers/phy/broadcom/phy-bcm-ns-usb2.c | 44 +++++++++++++++++++++++++++-------
>  1 file changed, 35 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/phy/broadcom/phy-bcm-ns-usb2.c b/drivers/phy/broadcom/phy-bcm-ns-usb2.c
> index 58dff80e9386..8dc6835b941c 100644
> --- a/drivers/phy/broadcom/phy-bcm-ns-usb2.c
> +++ b/drivers/phy/broadcom/phy-bcm-ns-usb2.c
> @@ -13,17 +13,23 @@
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/err.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/module.h>
>  #include <linux/of_address.h>
>  #include <linux/of_platform.h>
> +#include <linux/regmap.h>

alphabetical order, so after platform_device.h

>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  
> +#define CRU_USB2_CONTROL			0x64
> +#define CRU_CLKSET_KEY				0x80
> +
>  struct bcm_ns_usb2 {
>  	struct device *dev;
>  	struct clk *ref_clk;
>  	struct phy *phy;
> +	struct regmap *cru;
>  	void __iomem *dmu;
>  };
>  
> @@ -31,6 +37,7 @@ static int bcm_ns_usb2_phy_init(struct phy *phy)
>  {
>  	struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
>  	struct device *dev = usb2->dev;
> +	struct regmap *cru = usb2->cru;
>  	void __iomem *dmu = usb2->dmu;
>  	u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
>  	int err = 0;
> @@ -48,7 +55,10 @@ static int bcm_ns_usb2_phy_init(struct phy *phy)
>  		goto err_clk_off;
>  	}
>  
> -	usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
> +	if (cru)
> +		regmap_read(cru, CRU_USB2_CONTROL, &usb2ctl);
> +	else
> +		usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);

Do you think it's cleaner to use a read/write wrapper to handle both the
syscon based case and the plain readl/writel? I thought that would make
the code much more readable.

>  
>  	if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
>  		usb_pll_pdiv = usb2ctl;
> @@ -62,15 +72,24 @@ static int bcm_ns_usb2_phy_init(struct phy *phy)
>  	usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
>  
>  	/* Unlock DMU PLL settings with some magic value */
> -	writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
> +	if (cru)
> +		regmap_write(cru, CRU_CLKSET_KEY, 0x0000ea68);
> +	else
> +		writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
>  
>  	/* Write USB 2.0 PLL control setting */
>  	usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
>  	usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
> -	writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
> +	if (cru)
> +		regmap_write(cru, CRU_USB2_CONTROL, usb2ctl);
> +	else
> +		writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
>  
>  	/* Lock DMU PLL settings */
> -	writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
> +	if (cru)
> +		regmap_write(cru, CRU_CLKSET_KEY, 0x00000000);
> +	else
> +		writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
>  
>  err_clk_off:
>  	clk_disable_unprepare(usb2->ref_clk);
> @@ -86,6 +105,7 @@ static const struct phy_ops ops = {
>  static int bcm_ns_usb2_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	struct device_node *cru_np;
>  	struct bcm_ns_usb2 *usb2;
>  	struct resource *res;
>  	struct phy_provider *phy_provider;
> @@ -95,11 +115,17 @@ static int bcm_ns_usb2_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  	usb2->dev = dev;
>  
> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
> -	usb2->dmu = devm_ioremap_resource(dev, res);
> -	if (IS_ERR(usb2->dmu)) {
> -		dev_err(dev, "Failed to map DMU regs\n");
> -		return PTR_ERR(usb2->dmu);
> +	cru_np = of_parse_phandle(dev->of_node, "syscon-cru", 0);
> +	usb2->cru = syscon_node_to_regmap(cru_np);

just use 'syscon_regmap_lookup_by_phandle'

> +	if (IS_ERR(usb2->cru)) {
> +		usb2->cru = NULL;
> +
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
> +		usb2->dmu = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(usb2->dmu)) {
> +			dev_err(dev, "Failed to map DMU regs\n");
> +			return PTR_ERR(usb2->dmu);
> +		}
>  	}
>  
>  	usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
>