Re: [PATCH v4] usb: phy: samsung: Add support to set pmu isolation

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On 12/26/2012 01:28 PM, Vivek Gautam wrote:
Adding support to parse device node data in order to get
required properties to set pmu isolation for usb-phy.

Signed-off-by: Vivek Gautam<gautam.vivek@xxxxxxxxxxx>
---
  .../devicetree/bindings/usb/samsung-usbphy.txt     |   31 ++++
  drivers/usb/phy/samsung-usbphy.c                   |  145 +++++++++++++++++---
  2 files changed, 155 insertions(+), 21 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/samsung-usbphy.txt b/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
index 7b26e2d..6b873fd 100644
--- a/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
+++ b/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
@@ -9,3 +9,34 @@ Required properties:
  - compatible : should be "samsung,exynos4210-usbphy"
  - reg : base physical address of the phy registers and length of memory mapped
  	region.
+
+Optional properties:
+- #address-cells: should be '1' when usbphy node has a child node with 'reg'
+		  property.
+- #size-cells: should be '1' when usbphy node has a child node with 'reg'
+	       property.
+
+- The child node 'usbphy-pmu' to the node usbphy should provide the following
+  information required by usb-phy controller to enable/disable the phy.
+   - reg : base physical address of PHY control register in PMU which
+           enables/disables the phy controller.
+           The size of this register is the total sum of size of all phy-control
+           registers that the SoC has. For example, the size will be
+           '0x4' in case we have only one phy-control register (like in S3C64XX) or
+           '0x8' in case we have two phy-control registers (like in Exynos4210)
+           and so on.
+
+Example:
+ - Exysno4210

s/Exysno/Exynos

+
+	usbphy@125B0000 {
+		#address-cells =<1>;
+		#size-cells =<1>;
+		compatible = "samsung,exynos4210-usbphy";
+		reg =<0x125B0000 0x100>;
+
+		usbphy-pmu {
+			/* USB device and host PHY_CONTROL registers */
+			reg =<0x10020704 0x8>;
+		};
+	};
diff --git a/drivers/usb/phy/samsung-usbphy.c b/drivers/usb/phy/samsung-usbphy.c
index 5c5e1bb5..b9f4f42 100644
--- a/drivers/usb/phy/samsung-usbphy.c
+++ b/drivers/usb/phy/samsung-usbphy.c
@@ -60,20 +60,42 @@
  #define MHZ (1000*1000)
  #endif

+#define S3C64XX_USBPHY_ENABLE			(0x1<<  16)
+#define EXYNOS_USBPHY_ENABLE			(0x1<<  0)
+
  enum samsung_cpu_type {
  	TYPE_S3C64XX,
  	TYPE_EXYNOS4210,
  };

  /*
+ * struct samsung_usbphy_drvdata - driver data for various SoC variants
+ * @cpu_type: machine identifier
+ * @devphy_en_mask: device phy enable mask for PHY CONTROL register
+ *
+ *	Here we have a separate mask for device type phy.
+ *	Having different masks for host and device type phy helps
+ *	in setting independent masks in case of SoCs like S5PV210,
+ *	in which PHY0 and PHY1 enable bits belong to same register
+ *	placed at [0] and [1] respectively.

"and are placed at positions 0 and 1 respectively" ?

+ *	Although for newer SoCs like exynos these bits belong to
+ *	different registers altogether placed at [0].
+ */
+struct samsung_usbphy_drvdata {
+	int cpu_type;
+	int devphy_en_mask;
+};
+
+/*
   * struct samsung_usbphy - transceiver driver state
   * @phy: transceiver structure
   * @plat: platform data
   * @dev: The parent device supplied to the probe function
   * @clk: usb phy clock
   * @regs: usb phy register memory base
+ * @phyctrl_pmureg: usb device phy-control pmu register memory base

nit: Perhaps we could just call it "pmureg' ?

   * @ref_clk_freq: reference clock frequency selection
- * @cpu_type: machine identifier
+ * @drv_data: driver data available for different cpu types

Actually it's for different SoCs, not CPUs, right ?

   */
  struct samsung_usbphy {
  	struct usb_phy	phy;
@@ -81,12 +103,67 @@ struct samsung_usbphy {
  	struct device	*dev;
  	struct clk	*clk;
  	void __iomem	*regs;
+	void __iomem	*phyctrl_pmureg;
  	int		ref_clk_freq;
-	int		cpu_type;
+	const struct samsung_usbphy_drvdata *drv_data;
  };

  #define phy_to_sphy(x)		container_of((x), struct samsung_usbphy, phy)

+static int samsung_usbphy_parse_dt_param(struct samsung_usbphy *sphy)

nit: s/samsung_usbphy_parse_dt_param/samsung_usbphy_parse_dt ?

+{
+	struct device_node *usbphy_pmu;
+	u32 reg[2];
+	int ret;
+
+	if (!sphy->dev->of_node) {
+		dev_err(sphy->dev, "Can't get usb-phy node\n");
+		return -ENODEV;

The function is called only when dev->of_node is not NULL, so this path
is never executed, AFAICS. I would just drop this redundant check.

+	}
+
+	usbphy_pmu = of_get_child_by_name(sphy->dev->of_node, "usbphy-pmu");
+	if (!usbphy_pmu)
+		dev_warn(sphy->dev, "Can't get usb-phy pmu control node\n");

+	ret = of_property_read_u32_array(usbphy_pmu, "reg", reg,
+						ARRAY_SIZE(reg));
+	if (!ret)
+		sphy->phyctrl_pmureg = ioremap(reg[0], reg[1]);

I don't think this is correct. reg is not really an array of u32 type,
it's an array of address/size tuples. I thought you would use of_iomap()
here. Any reason why you didn't do so ? It would also make it easier to
handle multiple address/size pairs if required.

+
+	of_node_put(usbphy_pmu);
+
+	if (IS_ERR_OR_NULL(sphy->phyctrl_pmureg)) {

When is sphy->phyctrl_pmureg assigned a ERR_PTR() value ? Wouldn't it
be enough to simply check for NULL ?

+		dev_err(sphy->dev, "Can't get usb-phy pmu control register\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * Set isolation here for phy.
+ * SOCs control this by controlling corresponding PMU registers
+ */
+static void samsung_usbphy_set_isolation(struct samsung_usbphy *sphy, int on)
+{
+	u32 reg;
+	int en_mask;
+
+	if (!sphy->phyctrl_pmureg) {
+		dev_warn(sphy->dev, "Can't set pmu isolation\n");
+		return;
+	}
+
+	reg = readl(sphy->phyctrl_pmureg);

To make it more generic maybe it's worth to store an offset to the actual
register somewhere, e.g. in the driver_data struct ? This function is
supposed to handle both device and host PHYs, isn't it ?

+	en_mask = sphy->drv_data->devphy_en_mask;
+
+	if (on)
+		writel(reg&  ~en_mask, sphy->phyctrl_pmureg);
+	else
+		writel(reg | en_mask, sphy->phyctrl_pmureg);

nit: This could be also written as:

	reg = on ? reg & ~mask : reg | mask;
	writel(reg, sphy->phyctrl_pmureg);
+}
+
  /*
   * Returns reference clock frequency selection value
   */
@@ -112,7 +189,7 @@ static int samsung_usbphy_get_refclk_freq(struct samsung_usbphy *sphy)
  		refclk_freq = PHYCLK_CLKSEL_48M;
  		break;
  	default:
-		if (sphy->cpu_type == TYPE_S3C64XX)
+		if (sphy->drv_data->cpu_type == TYPE_S3C64XX)
  			refclk_freq = PHYCLK_CLKSEL_48M;
  		else
  			refclk_freq = PHYCLK_CLKSEL_24M;
@@ -135,7 +212,7 @@ static void samsung_usbphy_enable(struct samsung_usbphy *sphy)
  	phypwr = readl(regs + SAMSUNG_PHYPWR);
  	rstcon = readl(regs + SAMSUNG_RSTCON);

-	switch (sphy->cpu_type) {
+	switch (sphy->drv_data->cpu_type) {
  	case TYPE_S3C64XX:
  		phyclk&= ~PHYCLK_COMMON_ON_N;
  		phypwr&= ~PHYPWR_NORMAL_MASK;
@@ -165,7 +242,7 @@ static void samsung_usbphy_disable(struct samsung_usbphy *sphy)

  	phypwr = readl(regs + SAMSUNG_PHYPWR);

-	switch (sphy->cpu_type) {
+	switch (sphy->drv_data->cpu_type) {
  	case TYPE_S3C64XX:
  		phypwr |= PHYPWR_NORMAL_MASK;
  		break;
@@ -199,6 +276,8 @@ static int samsung_usbphy_init(struct usb_phy *phy)
  	/* Disable phy isolation */
  	if (sphy->plat&&  sphy->plat->pmu_isolation)
  		sphy->plat->pmu_isolation(false);
+	else
+		samsung_usbphy_set_isolation(sphy, false);

  	/* Initialize usb phy registers */
  	samsung_usbphy_enable(sphy);
@@ -228,38 +307,37 @@ static void samsung_usbphy_shutdown(struct usb_phy *phy)
  	/* Enable phy isolation */
  	if (sphy->plat&&  sphy->plat->pmu_isolation)
  		sphy->plat->pmu_isolation(true);
+	else
+		samsung_usbphy_set_isolation(sphy, true);

  	clk_disable_unprepare(sphy->clk);
  }

  static const struct of_device_id samsung_usbphy_dt_match[];

-static inline int samsung_usbphy_get_driver_data(struct platform_device *pdev)
+static inline struct samsung_usbphy_drvdata
+*samsung_usbphy_get_driver_data(struct platform_device *pdev)
  {
  	if (pdev->dev.of_node) {
  		const struct of_device_id *match;
  		match = of_match_node(samsung_usbphy_dt_match,
  							pdev->dev.of_node);
-		return (int) match->data;
+		return (struct samsung_usbphy_drvdata *) match->data;
  	}

-	return platform_get_device_id(pdev)->driver_data;
+	return (struct samsung_usbphy_drvdata *)
+				platform_get_device_id(pdev)->driver_data;
  }

  static int __devinit samsung_usbphy_probe(struct platform_device *pdev)
  {
  	struct samsung_usbphy *sphy;
-	struct samsung_usbphy_data *pdata;
+	struct samsung_usbphy_data *pdata = pdev->dev.platform_data;
  	struct device *dev =&pdev->dev;
  	struct resource *phy_mem;
  	void __iomem	*phy_base;
  	struct clk *clk;
-
-	pdata = pdev->dev.platform_data;
-	if (!pdata) {
-		dev_err(&pdev->dev, "%s: no platform data defined\n", __func__);
-		return -EINVAL;
-	}
+	int ret;

  	phy_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!phy_mem) {
@@ -283,7 +361,19 @@ static int __devinit samsung_usbphy_probe(struct platform_device *pdev)
  		return PTR_ERR(clk);
  	}

-	sphy->dev		=&pdev->dev;
+	sphy->dev = dev;
+
+	if (dev->of_node) {
+		ret = samsung_usbphy_parse_dt_param(sphy);
+		if (ret<  0)
+			return ret;
+	} else {
+		if (!pdata) {
+			dev_err(dev, "no platform data specified\n");
+			return -EINVAL;
+		}
+	}
+
  	sphy->plat		= pdata;
  	sphy->regs		= phy_base;
  	sphy->clk		= clk;

--

Thanks,
Sylwester
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