USB3503 chip supports 8 values of reference clock. The value is
specified by REF_SEL[1:0] pins and INT_N line. This patch add support
for getting 'refclk' clock, enabling it and setting INT_N line according
to the value of the gathered clock. If no clock has been specified,
driver defaults to the old behaviour (assuming that clock has been
specified by REF_SEL pins from primary reference clock frequencies
table).
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
Hello,
This extension to USB3503 driver is needed to add support for OdroidU3
board, which uses 24MHz reference clock, sourced directly from CLKOUT
line from Exynos4412 SoC.
Changelog:
v2
- fixed issues pointed by Mark Brown
- added optional refclk-frequency property, clock rate is read from DT
instead of getting it from clock
v1
- initial version
Best regards
Marek Szyprowski
Samsung R&D Institute Poland
---
Documentation/devicetree/bindings/usb/usb3503.txt | 8 +++
drivers/usb/misc/usb3503.c | 59 ++++++++++++++++++++++-
2 files changed, 65 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/usb/usb3503.txt b/Documentation/devicetree/bindings/usb/usb3503.txt
index a018da4a7ad7..221ac0dbc678 100644
--- a/Documentation/devicetree/bindings/usb/usb3503.txt
+++ b/Documentation/devicetree/bindings/usb/usb3503.txt
@@ -15,6 +15,14 @@ Optional properties:
- reset-gpios: Should specify GPIO for reset.
- initial-mode: Should specify initial mode.
(1 for HUB mode, 2 for STANDBY mode)
+- refclk: Clock used for driving REFCLK signal (optional, if not provided
+ the driver assumes that clock signal is always available, its
+ rate is specified by REF_SEL pins and a value from the primary
+ reference clock frequencies table is used)
+- refclk-frequency: Frequency of the REFCLK signal as defined by REF_SEL
+ pins (optional, if not provided, driver will not set rate of the
+ REFCLK signal and assume that a value from the primary reference
+ clock frequencies table is used)
Examples:
usb3503@08 {
diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
index a31641e18d19..f43c61989cef 100644
--- a/drivers/usb/misc/usb3503.c
+++ b/drivers/usb/misc/usb3503.c
@@ -18,6 +18,7 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/delay.h>
@@ -57,10 +58,12 @@ struct usb3503 {
enum usb3503_mode mode;
struct regmap *regmap;
struct device *dev;
+ struct clk *clk;
u8 port_off_mask;
int gpio_intn;
int gpio_reset;
int gpio_connect;
+ bool secondary_ref_clk;
};
static int usb3503_reset(struct usb3503 *hub, int state)
@@ -184,8 +187,58 @@ static int usb3503_probe(struct usb3503 *hub)
hub->gpio_reset = pdata->gpio_reset;
hub->mode = pdata->initial_mode;
} else if (np) {
+ struct clk *clk;
hub->port_off_mask = 0;
+ clk = devm_clk_get(dev, "refclk");
+ if (IS_ERR(clk) && PTR_ERR(clk) != -ENOENT) {
+ dev_err(dev, "unable to request refclk (%d)\n", err);
+ return PTR_ERR(clk);
+ }
+
+ if (!IS_ERR(clk)) {
+ u32 rate = 0;
+ hub->clk = clk;
+
+ if (!of_property_read_u32(np, "refclk-frequency",
+ &rate)) {
+
+ switch (rate) {
+ case 38400000:
+ case 26000000:
+ case 19200000:
+ case 12000000:
+ hub->secondary_ref_clk = 0;
+ break;
+ case 24000000:
+ case 27000000:
+ case 25000000:
+ case 50000000:
+ hub->secondary_ref_clk = 1;
+ break;
+ default:
+ dev_err(dev,
+ "unsupported reference clock rate (%d)\n",
+ (int) rate);
+ return -EINVAL;
+ }
+ err = clk_set_rate(hub->clk, rate);
+ if (err) {
+ dev_err(dev,
+ "unable to set reference clock rate to %d\n",
+ (int) rate);
+ return err;
+ }
+ }
+
+ err = clk_prepare_enable(hub->clk);
+ if (err) {
+ dev_err(dev,
+ "unable to enable reference clock\n");
+ return err;
+ }
+ }
+
property = of_get_property(np, "disabled-ports", &len);
if (property && (len / sizeof(u32)) > 0) {
int i;
@@ -213,8 +266,10 @@ static int usb3503_probe(struct usb3503 *hub)
dev_err(dev, "Ports disabled with no control interface\n");
if (gpio_is_valid(hub->gpio_intn)) {
- err = devm_gpio_request_one(dev, hub->gpio_intn,
- GPIOF_OUT_INIT_HIGH, "usb3503 intn");
+ int val = hub->secondary_ref_clk ? GPIOF_OUT_INIT_LOW :
+ GPIOF_OUT_INIT_HIGH;
+ err = devm_gpio_request_one(dev, hub->gpio_intn, val,
+ "usb3503 intn");
if (err) {
dev_err(dev,
"unable to request GPIO %d as connect pin (%d)\n",
--
1.9.2
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
