usb: chipidea: udc: add maximum-speed = full-speed option

This patch makes it possible to set the chipidea udc into full-speed only mode.
It is set by the oftree property "maximum-speed = full-speed".

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/usb/ci13xxx-imx.txt b/Documentation/devicetree/bindings/usb/ci13xxx-imx.txt
index 8d58c8ce91ca..881901a59604 100644
--- a/Documentation/devicetree/bindings/usb/ci13xxx-imx.txt
+++ b/Documentation/devicetree/bindings/usb/ci13xxx-imx.txt
@@ -30,6 +30,7 @@ at imx6 SoC series
 - osc-clkgate-delay: the delay between powering up the xtal 24MHz clock
   and release the clock to the digital logic inside the analog block,
   0 <= osc-clkgate-delay <= 7.
+- maximum-speed: limit the maximum connection speed to "full-speed".
 
 Examples:
 usb@02184000 { /* USB OTG */
@@ -46,4 +47,5 @@ usb@02184000 { /* USB OTG */
         pinctrl-0 = <&pinctrl_usbh2_1>;
         pinctrl-1 = <&pinctrl_usbh2_2>;
         osc-clkgate-delay = <0x3>;
+        maximum-speed = "full-speed";
 };
diff --git a/drivers/usb/chipidea/bits.h b/drivers/usb/chipidea/bits.h
index 9f936a361f95..aa82c8517bcd 100644
--- a/drivers/usb/chipidea/bits.h
+++ b/drivers/usb/chipidea/bits.h
@@ -50,12 +50,14 @@
 #define PORTSC_PTC            (0x0FUL << 16)
 #define PORTSC_PHCD(d)        ((d) ? BIT(22) : BIT(23))
 /* PTS and PTW for non lpm version only */
+#define PORTSC_PFSC           BIT(24)
 #define PORTSC_PTS(d)                                           \
         ((((d) & 0x3) << 30) | (((d) & 0x4) ? BIT(25) : 0))
 #define PORTSC_PTW            BIT(28)
 #define PORTSC_STS            BIT(29)
 
 /* DEVLC */
+#define DEVLC_PFSC            BIT(23)
 #define DEVLC_PSPD            (0x03UL << 25)
 #define DEVLC_PSPD_HS         (0x02UL << 25)
 #define DEVLC_PTW             BIT(27)
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 798598ed8791..36cada7ae4c6 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -64,6 +64,7 @@
 #include <linux/usb/otg.h>
 #include <linux/usb/chipidea.h>
 #include <linux/usb/of.h>
+#include <linux/of.h>
 #include <linux/phy.h>
 #include <linux/regulator/consumer.h>
 
@@ -310,6 +311,13 @@ int hw_device_reset(struct ci_hdrc *ci, u32 mode)
         if (ci->platdata->flags & CI_HDRC_DISABLE_STREAMING)
                 hw_write(ci, OP_USBMODE, USBMODE_CI_SDIS, USBMODE_CI_SDIS);
 
+        if (ci->platdata->flags & CI_HDRC_FORCE_FULLSPEED) {
+                if (ci->hw_bank.lpm)
+                        hw_write(ci, OP_DEVLC, DEVLC_PFSC, DEVLC_PFSC);
+                else
+                        hw_write(ci, OP_PORTSC, PORTSC_PFSC, PORTSC_PFSC);
+        }
+
         /* USBMODE should be configured step by step */
         hw_write(ci, OP_USBMODE, USBMODE_CM, USBMODE_CM_IDLE);
         hw_write(ci, OP_USBMODE, USBMODE_CM, mode);
@@ -431,6 +439,9 @@ static int ci_get_platdata(struct device *dev,
                 }
         }
 
+        if (of_usb_get_maximum_speed(dev->of_node) == USB_SPEED_FULL)
+                platdata->flags |= CI_HDRC_FORCE_FULLSPEED;
+
         return 0;
 }
 
diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h
index 8820c88621df..f0328724e2e4 100644
--- a/include/linux/usb/chipidea.h
+++ b/include/linux/usb/chipidea.h
@@ -28,6 +28,7 @@ struct ci_hdrc_platform_data {
 #define CI_HDRC_IMX28_WRITE_FIX         BIT(5)
 #define CI_HDRC_IMX_EHCI_QUIRK          BIT(6)
 #define CI_HDRC_IMX_IS_HSIC             BIT(7)
+#define CI_HDRC_FORCE_FULLSPEED         BIT(8)
         enum usb_dr_mode        dr_mode;
 #define CI_HDRC_CONTROLLER_RESET_EVENT          0
 #define CI_HDRC_CONTROLLER_STOPPED_EVENT        1