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Commit c2fda30f authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

USB: ice40-hcd: Add XO clock support 



The bridge chip require a 19.2MHz clock for USB operations.
It is supplied by the PMIC on MSM8916. Add the XO clock.
The XO clock can operate either in pin-control or direct
mode. When it operates in pin-control mode, the clk-en gpio
also needs to be asserted to enable the clock.

Change-Id: Id181fd5edfe22c57f3c958e081454b4fe987a097
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent b5c75c4d

Documentation/devicetree/bindings/usb/ice40-hcd.txt

+6 −0
Original line number Diff line number Diff line
@@ -19,6 +19,9 @@ Required properties: 


Optional properties:

- interrupts: IRQ lines used by this controller

- clocks: List of clock phandles.

- clock-names: List of clock names. Supported clock name string is

  "xo"

- clk-en-gpio: gpio used to enable the 19.2 MHZ clock to the bridge

  chip. If it is not present, assume that the clock is available on

  the bridge chip board.
@@ -41,5 +44,8 @@ Optional properties: 
			lattice,slave-select-gpio = <&msmgpio 118 0>;

			lattice,config-done-gpio = <&msmgpio 115 0>;

			lattice,vcc-en-gpio = <&msmgpio 117 0>;



			clocks = <&clock_rpm clk_bb_clk2_pin>;

			clock-names = "xo";

		};

	};

drivers/usb/host/ice40-hcd.c

+50 −2
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/uaccess.h>

#include <linux/debugfs.h>

#include <linux/pm_runtime.h>

#include <linux/clk.h>

#include <linux/regulator/consumer.h>

#include <linux/gpio.h>

#include <linux/of_gpio.h>
@@ -151,6 +152,8 @@ struct ice40_hcd { 
	struct workqueue_struct *wq;

	struct work_struct async_work;



	struct clk *xo_clk;



	int reset_gpio;

	int slave_select_gpio;

	int config_done_gpio;
@@ -1368,6 +1371,8 @@ static void ice40_spi_power_off(struct ice40_hcd *ihcd) 
		regulator_disable(ihcd->gpio_vcc);

	if (ihcd->clk_en_gpio)

		gpio_direction_output(ihcd->clk_en_gpio, 0);

	if (ihcd->xo_clk)

		clk_disable_unprepare(ihcd->xo_clk);



	ihcd->powered = false;

}
@@ -1376,11 +1381,19 @@ static int ice40_spi_power_up(struct ice40_hcd *ihcd) 
{

	int ret;



	if (ihcd->xo_clk) {

		ret = clk_prepare_enable(ihcd->xo_clk);

		if (ret < 0) {

			pr_err("fail to enable xo clk %d\n", ret);

			goto out;

		}

	}



	if (ihcd->clk_en_gpio) {

		ret = gpio_direction_output(ihcd->clk_en_gpio, 1);

		if (ret < 0) {

			pr_err("fail to enabel clk %d\n", ret);

			goto out;

			pr_err("fail to enable clk %d\n", ret);

			goto disable_xo;

		}

	}
@@ -1424,6 +1437,9 @@ disable_gpio_vcc: 
disable_clk:

	if (ihcd->clk_en_gpio)

		gpio_direction_output(ihcd->clk_en_gpio, 0);

disable_xo:

	if (ihcd->xo_clk)

		clk_disable_unprepare(ihcd->xo_clk);

out:

	return ret;

}
@@ -1599,6 +1615,32 @@ out: 
	return ret;

}



static int ice40_spi_init_clocks(struct ice40_hcd *ihcd)

{

	int ret = 0;



	/*

	 * XO clock is the only supported clock. So no need to parse

	 * the clock-names string. If there is no clock-names property,

	 * there will not be XO clock.

	 *

	 * This XO clock can be either direct clock or pin control clock.

	 * if it is pin control clock, clk_en gpio is used to control

	 * the clock.

	 */

	if (!of_get_property(ihcd->spi->dev.of_node, "clock-names", NULL))

		return 0;



	ihcd->xo_clk = devm_clk_get(&ihcd->spi->dev, "xo");

	if (IS_ERR(ihcd->xo_clk)) {

		ret = PTR_ERR(ihcd->xo_clk);

		if (ret != -EPROBE_DEFER)

			pr_err("fail to get xo clk %d\n", ret);

	}



	return ret;

}



static int ice40_spi_init_regulators(struct ice40_hcd *ihcd)

{

	int ret;
@@ -1952,6 +1994,12 @@ static int ice40_spi_probe(struct spi_device *spi) 
		goto out;

	}



	ret = ice40_spi_init_clocks(ihcd);

	if (ret) {

		pr_err("fail to init clocks\n");

		goto out;

	}



	ret = ice40_spi_init_regulators(ihcd);

	if (ret) {

		pr_err("fail to init regulators\n");