[PATCH 5/7] usb: ohci-platform: Enable optional use of reset controller

Maxime Ripard
2014-05-07T03:50:21Z

The OHCI controllers used in the Allwinner A31 are asserted in reset using a
global reset controller.

Add optional support for such a controller in the OHCI platform driver.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
Documentation/devicetree/bindings/usb/usb-ohci.txt | 1 +
drivers/usb/host/ohci-platform.c | 25 +++++++++++++++++++++-
2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/usb/usb-ohci.txt b/Documentation/devicetree/bindings/usb/usb-ohci.txt
index 45f67d91e888..b968a1aea995 100644
--- a/Documentation/devicetree/bindings/usb/usb-ohci.txt
+++ b/Documentation/devicetree/bindings/usb/usb-ohci.txt
@@ -12,6 +12,7 @@ Optional properties:
- clocks : a list of phandle + clock specifier pairs
- phys : phandle + phy specifier pair
- phy-names : "usb"
+- resets : phandle + reset specifier pair

Example:

diff --git a/drivers/usb/host/ohci-platform.c b/drivers/usb/host/ohci-platform.c
index b6002c951c5c..55f6c87628eb 100644
--- a/drivers/usb/host/ohci-platform.c
+++ b/drivers/usb/host/ohci-platform.c
@@ -24,6 +24,7 @@
#include <linux/err.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
+#include <linux/reset.h>
#include <linux/usb/ohci_pdriver.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
@@ -36,6 +37,7 @@

struct ohci_platform_priv {
struct clk *clks[OHCI_MAX_CLKS];
+ struct reset_control *rst;
struct phy *phy;
};

@@ -67,10 +69,16 @@ static int ohci_platform_power_on(struct platform_device *dev)
goto err_disable_clks;
}

+ if (priv->rst) {
+ ret = reset_control_deassert(priv->rst);
+ if (ret)
+ goto err_disable_clks;
+ }
+
if (priv->phy) {
ret = phy_init(priv->phy);
if (ret)
- goto err_disable_clks;
+ goto err_assert_rst;

ret = phy_power_on(priv->phy);
if (ret)
@@ -81,6 +89,9 @@ static int ohci_platform_power_on(struct platform_device *dev)

err_exit_phy:
phy_exit(priv->phy);
+err_assert_rst:
+ if (priv->rst)
+ reset_control_assert(priv->rst);
err_disable_clks:
while (--clk >= 0)
clk_disable_unprepare(priv->clks[clk]);
@@ -99,6 +110,9 @@ static void ohci_platform_power_off(struct platform_device *dev)
phy_exit(priv->phy);
}

+ if (priv->rst)
+ reset_control_assert(priv->rst);
+
for (clk = OHCI_MAX_CLKS - 1; clk >= 0; clk--)
if (priv->clks[clk])
clk_disable_unprepare(priv->clks[clk]);
@@ -191,6 +205,15 @@ static int ohci_platform_probe(struct platform_device *dev)
break;
}
}
+
+ priv->rst = devm_reset_control_get_optional(&dev->dev,
+ NULL);
+ if (IS_ERR(priv->rst)) {
+ err = PTR_ERR(priv->rst);
+ if (err == -EPROBE_DEFER)
+ goto err_put_clks;
+ priv->rst = NULL;
+ }
}

if (pdata->big_endian_desc)
--
1.9.1