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

From: Sylwester Nawrocki
Date: Wed Dec 26 2012 - 17:57:45 EST

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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