Re: [PATCH v2] usb: phy: samsung: Add support to set pmu isolation
From: Sylwester Nawrocki
Date: Tue Dec 18 2012 - 18:25:43 EST
Hi Vivek,
On 12/18/2012 02:56 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>
---
Changes from v1:
- Changed the name of property for phy handler from'samsung,usb-phyctrl'
to 'samsung,usb-phyhandle' to make it look more generic.
- Similarly 'samsung,phyctrl-reg' is changed to 'samsung,phyhandle-reg'
- Added a check for 'samsung,usb-phyhandle' before getting node from
phandle.
- Putting the node using 'of_node_put()' which had been missed.
- Adding necessary check for the pointer in 'samsung_usbphy_set_isolation()'
to avoid any NULL pointer dereferencing.
- Unmapping the register ioremapped in 'samsung_usbphy_parse_dt_param()'.
.../devicetree/bindings/usb/samsung-usbphy.txt | 12 +++
drivers/usb/phy/samsung-usbphy.c | 94 ++++++++++++++++++--
2 files changed, 98 insertions(+), 8 deletions(-)
diff --git a/Documentation/devicetree/bindings/usb/samsung-usbphy.txt b/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
index 7b26e2d..a7b28b2 100644
--- a/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
+++ b/Documentation/devicetree/bindings/usb/samsung-usbphy.txt
@@ -9,3 +9,15 @@ Required properties:
- compatible : should be "samsung,exynos4210-usbphy"
- reg : base physical address of the phy registers and length of memory mapped
region.
+
+Optional properties:
+- samsung,usb-phyhandle : should point to usb-phyhandle sub-node which provides
+ binding data to enable/disable device PHY handled by
+ PMU register.
+
+ Required properties:
+ - compatible : should be "samsung,usbdev-phyctrl" for
+ DEVICE type phy.
+ - samsung,phyhandle-reg: base physical address of
+ PHY_CONTROL register in PMU.
+- samsung,enable-mask : should be '1'
This should only be 1 for Exynos4210+ SoCs, right ?
S5PV210 uses bit 0 for OTG and bit1 for USB host, doesn't it ? And for
s3c64xx
it seems to be bit 16.
How about deriving this information from 'compatible' property instead ?
Maybe you could just encode the USB PMU registers (I assume those aren't
touched by anything but the usb drivers) in a regular 'reg' property in
an usbphy subnode. Then the driver could interpret it also with help
of 'compatible' property. And you could just use of_iomap(). E.g.
usbphy@12130000 {
compatible = "samsung,exynos5250-usbphy";
reg = <0x12130000 0x100>, <0x12100000 0x100>;
usbphy-pmu {
/* USB device and host PHY_CONTROL registers */
reg = <0x10040704 8>;
};
};
Your "samsung,usb-phyhandle" approach seems over-engineered to me.
I might be missing something though.
diff --git a/drivers/usb/phy/samsung-usbphy.c b/drivers/usb/phy/samsung-usbphy.c
index 5c5e1bb5..4ceabe3 100644
--- a/drivers/usb/phy/samsung-usbphy.c
+++ b/drivers/usb/phy/samsung-usbphy.c
@@ -72,6 +72,8 @@ enum samsung_cpu_type {
* @dev: The parent device supplied to the probe function
* @clk: usb phy clock
* @regs: usb phy register memory base
+ * @devctrl_reg: usb device phy-control pmu register memory base
hum, this name is not really helpful in understanding what's going
on here.
Looking at arch/arm/mach-s5pv210/setup-usb-phy.c, there is only one
PHY_CONTROL (Power Management Unit) register for both OTG and USB host
PHYs. So are you really taking care of that case as well ?
+ * @en_mask: enable mask
* @ref_clk_freq: reference clock frequency selection
* @cpu_type: machine identifier
*/
@@ -81,12 +83,73 @@ struct samsung_usbphy {
struct device *dev;
struct clk *clk;
void __iomem *regs;
+ void __iomem *devctrl_reg;
+ u32 en_mask;
int ref_clk_freq;
int cpu_type;
};
#define phy_to_sphy(x) container_of((x), struct samsung_usbphy, phy)
+static int samsung_usbphy_parse_dt_param(struct samsung_usbphy *sphy)
+{
+ struct device_node *usb_phyctrl;
+ u32 reg;
+ int lenp;
+
+ if (!sphy->dev->of_node) {
+ sphy->devctrl_reg = NULL;
+ return -ENODEV;
+ }
+
+ if (of_get_property(sphy->dev->of_node, "samsung,usb-phyhandle",&lenp)) {
+ usb_phyctrl = of_parse_phandle(sphy->dev->of_node,
+ "samsung,usb-phyhandle", 0);
+ if (!usb_phyctrl) {
+ dev_warn(sphy->dev, "Can't get usb-phy handle\n");
+ sphy->devctrl_reg = NULL;
+ }
+
+ of_property_read_u32(usb_phyctrl, "samsung,phyhandle-reg",®);
+
+ sphy->devctrl_reg = ioremap(reg, SZ_4);
What happens if invalid address value is assigned to
'samsung,phyhandle-reg' ?
+ of_property_read_u32(sphy->dev->of_node, "samsung,enable-mask",
+ &sphy->en_mask);
+ of_node_put(usb_phyctrl);
+ } else {
+ dev_warn(sphy->dev, "Can't get usb-phy handle\n");
+ sphy->devctrl_reg = NULL;
+ }
+
+ 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)
+{
+ void __iomem *usb_phyctrl_reg;
+ u32 en_mask = sphy->en_mask;
+ u32 reg;
+
+ usb_phyctrl_reg = sphy->devctrl_reg;
+
+ if (!usb_phyctrl_reg) {
+ dev_warn(sphy->dev, "Can't set pmu isolation\n");
+ return;
+ }
+
+ reg = readl(usb_phyctrl_reg);
+
+ if (on)
+ writel(reg& ~en_mask, usb_phyctrl_reg);
+ else
+ writel(reg | en_mask, usb_phyctrl_reg);
+}
+
/*
* Returns reference clock frequency selection value
*/
@@ -199,6 +262,8 @@ 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);
@@ -228,6 +293,8 @@ 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);
}
@@ -249,17 +316,12 @@ static inline int samsung_usbphy_get_driver_data(struct platform_device *pdev)
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 +345,20 @@ static int __devinit samsung_usbphy_probe(struct platform_device *pdev)
return PTR_ERR(clk);
}
- sphy->dev =&pdev->dev;
+ sphy->dev =&pdev->dev;
sphy->dev = dev;
+
+ ret = samsung_usbphy_parse_dt_param(sphy);
+ if (ret) {
+ /* fallback to pdata */
+ if (!pdata) {
+ dev_err(&pdev->dev,
+ "%s: no device data found\n", __func__);
I find term "device data" a bit confusing here.
+ return -ENODEV;
In the original code -EINVAL was returned when platform_data was not set.
+ } else {
+ sphy->plat = pdata;
+ }
+ }
+
How about rewriting this to:
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;
}
}
This way we won't be obfuscating any error code returned from the
OF parsing function.
sphy->plat = pdata;
sphy->regs = phy_base;
sphy->clk = clk;
@@ -305,6 +380,9 @@ static int __exit samsung_usbphy_remove(struct platform_device *pdev)
usb_remove_phy(&sphy->phy);
+ if (sphy->devctrl_reg)
+ iounmap(sphy->devctrl_reg);
+
return 0;
}
--
Regards,
Sylwester
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