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Commit 657d898a authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Greg Kroah-Hartman
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usb: usb5303: add support for reference clock specified in device tree 



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: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6fecd4f2

Documentation/devicetree/bindings/usb/usb3503.txt

+8 −0
Original line number Diff line number Diff line
@@ -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 {

drivers/usb/misc/usb3503.c

+57 −2
Original line number Diff line number Diff line
@@ -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",