USB: s3c-hsotg: Add support for external USB clock

The PLL that drives the USB clock supports 3 input clocks: 12, 24 and 48Mhz.
This patch adds support to the USB driver for setting the correct register bit
according to the given clock.

This depends on the following patch:
[PATCH] ARM: S3C64XX: Add USB external clock definition

Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index 825b6ca6294..a4e0b0fa019 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -25,6 +25,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/clk.h>
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
@@ -2798,6 +2799,7 @@ static void __devinit s3c_hsotg_initep(struct s3c_hsotg *hsotg,
  */
 static void s3c_hsotg_otgreset(struct s3c_hsotg *hsotg)
 {
+        struct clk *xusbxti;
         u32 osc;
 
         writel(0, S3C_PHYPWR);
@@ -2805,6 +2807,23 @@ static void s3c_hsotg_otgreset(struct s3c_hsotg *hsotg)
 
         osc = hsotg->plat->is_osc ? S3C_PHYCLK_EXT_OSC : 0;
 
+        xusbxti = clk_get(hsotg->dev, "xusbxti");
+        if (xusbxti && !IS_ERR(xusbxti)) {
+                switch (clk_get_rate(xusbxti)) {
+                case 12*MHZ:
+                        osc |= S3C_PHYCLK_CLKSEL_12M;
+                        break;
+                case 24*MHZ:
+                        osc |= S3C_PHYCLK_CLKSEL_24M;
+                        break;
+                default:
+                case 48*MHZ:
+                        /* default reference clock */
+                        break;
+                }
+                clk_put(xusbxti);
+        }
+
         writel(osc | 0x10, S3C_PHYCLK);
 
         /* issue a full set of resets to the otg and core */