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usb: usb5303: add support for reference clock specified in device tree

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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@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marek Szyprowski 2014-05-22 13:21:38 +02:00 committed by Greg Kroah-Hartman
parent 6fecd4f2a5
commit 657d898a93
2 changed files with 65 additions and 2 deletions
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8
Documentation/devicetree/bindings/usb/usb3503.txt
View file

@ -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 {

59
drivers/usb/misc/usb3503.c
View file

@ -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",