1 files changed, 522 insertions, 0 deletions

diff --git a/drivers/staging/greybus/arche-apb-ctrl.c b/drivers/staging/greybus/arche-apb-ctrl.c
new file mode 100644
index 0000000..70323aa
--- /dev/null
+++ b/drivers/staging/greybus/arche-apb-ctrl.c
@@ -0,0 +1,522 @@
+/*
+ * Arche Platform driver to control APB.
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spinlock.h>
+#include "arche_platform.h"
+
+
+struct arche_apb_ctrl_drvdata {
+	/* Control GPIO signals to and from AP <=> AP Bridges */
+	int resetn_gpio;
+	int boot_ret_gpio;
+	int pwroff_gpio;
+	int wake_in_gpio;
+	int wake_out_gpio;
+	int pwrdn_gpio;
+
+	enum arche_platform_state state;
+	bool init_disabled;
+
+	struct regulator *vcore;
+	struct regulator *vio;
+
+	int clk_en_gpio;
+	struct clk *clk;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pin_default;
+
+	/* V2: SPI Bus control  */
+	int spi_en_gpio;
+	bool spi_en_polarity_high;
+};
+
+/*
+ * Note that these low level api's are active high
+ */
+static inline void deassert_reset(unsigned int gpio)
+{
+	gpio_set_value(gpio, 1);
+}
+
+static inline void assert_reset(unsigned int gpio)
+{
+	gpio_set_value(gpio, 0);
+}
+
+/*
+ * Note: Please do not modify the below sequence, as it is as per the spec
+ */
+static int coldboot_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret;
+
+	if (apb->init_disabled ||
+			apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
+		return 0;
+
+	/* Hold APB in reset state */
+	assert_reset(apb->resetn_gpio);
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/* Enable power to APB */
+	if (!IS_ERR(apb->vcore)) {
+		ret = regulator_enable(apb->vcore);
+		if (ret) {
+			dev_err(dev, "failed to enable core regulator\n");
+			return ret;
+		}
+	}
+
+	if (!IS_ERR(apb->vio)) {
+		ret = regulator_enable(apb->vio);
+		if (ret) {
+			dev_err(dev, "failed to enable IO regulator\n");
+			return ret;
+		}
+	}
+
+	apb_bootret_deassert(dev);
+
+	/* On DB3 clock was not mandatory */
+	if (gpio_is_valid(apb->clk_en_gpio))
+		gpio_set_value(apb->clk_en_gpio, 1);
+
+	usleep_range(100, 200);
+
+	/* deassert reset to APB : Active-low signal */
+	deassert_reset(apb->resetn_gpio);
+
+	apb->state = ARCHE_PLATFORM_STATE_ACTIVE;
+
+	return 0;
+}
+
+static int fw_flashing_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret;
+
+	if (apb->init_disabled ||
+			apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+		return 0;
+
+	ret = regulator_enable(apb->vcore);
+	if (ret) {
+		dev_err(dev, "failed to enable core regulator\n");
+		return ret;
+	}
+
+	ret = regulator_enable(apb->vio);
+	if (ret) {
+		dev_err(dev, "failed to enable IO regulator\n");
+		return ret;
+	}
+
+	if (gpio_is_valid(apb->spi_en_gpio)) {
+		unsigned long flags;
+
+		if (apb->spi_en_polarity_high)
+			flags = GPIOF_OUT_INIT_HIGH;
+		else
+			flags = GPIOF_OUT_INIT_LOW;
+
+		ret = devm_gpio_request_one(dev, apb->spi_en_gpio,
+				flags, "apb_spi_en");
+		if (ret) {
+			dev_err(dev, "Failed requesting SPI bus en gpio %d\n",
+				apb->spi_en_gpio);
+			return ret;
+		}
+	}
+
+	/* for flashing device should be in reset state */
+	assert_reset(apb->resetn_gpio);
+	apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
+
+	return 0;
+}
+
+static int standby_boot_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+
+	if (apb->init_disabled)
+		return 0;
+
+	/* Even if it is in OFF state, then we do not want to change the state */
+	if (apb->state == ARCHE_PLATFORM_STATE_STANDBY ||
+			apb->state == ARCHE_PLATFORM_STATE_OFF)
+		return 0;
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/*
+	 * As per WDM spec, do nothing
+	 *
+	 * Pasted from WDM spec,
+	 *  - A falling edge on POWEROFF_L is detected (a)
+	 *  - WDM enters standby mode, but no output signals are changed
+	 * */
+
+	/* TODO: POWEROFF_L is input to WDM module  */
+	apb->state = ARCHE_PLATFORM_STATE_STANDBY;
+	return 0;
+}
+
+static void poweroff_seq(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+
+	if (apb->init_disabled || apb->state == ARCHE_PLATFORM_STATE_OFF)
+		return;
+
+	if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING &&
+			gpio_is_valid(apb->spi_en_gpio))
+		devm_gpio_free(dev, apb->spi_en_gpio);
+
+	/* disable the clock */
+	if (gpio_is_valid(apb->clk_en_gpio))
+		gpio_set_value(apb->clk_en_gpio, 0);
+
+	if (!IS_ERR(apb->vcore) && regulator_is_enabled(apb->vcore) > 0)
+		regulator_disable(apb->vcore);
+
+	if (!IS_ERR(apb->vio) && regulator_is_enabled(apb->vio) > 0)
+		regulator_disable(apb->vio);
+
+	/* As part of exit, put APB back in reset state */
+	assert_reset(apb->resetn_gpio);
+	apb->state = ARCHE_PLATFORM_STATE_OFF;
+
+	/* TODO: May have to send an event to SVC about this exit */
+}
+
+void apb_bootret_assert(struct device *dev)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	gpio_set_value(apb->boot_ret_gpio, 1);
+}
+
+void apb_bootret_deassert(struct device *dev)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	gpio_set_value(apb->boot_ret_gpio, 0);
+}
+
+int apb_ctrl_coldboot(struct device *dev)
+{
+	return coldboot_seq(to_platform_device(dev));
+}
+
+int apb_ctrl_fw_flashing(struct device *dev)
+{
+	return fw_flashing_seq(to_platform_device(dev));
+}
+
+int apb_ctrl_standby_boot(struct device *dev)
+{
+	return standby_boot_seq(to_platform_device(dev));
+}
+
+void apb_ctrl_poweroff(struct device *dev)
+{
+	poweroff_seq(to_platform_device(dev));
+}
+
+static ssize_t state_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
+	int ret = 0;
+	bool is_disabled;
+
+	if (sysfs_streq(buf, "off")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_OFF)
+			return count;
+
+		poweroff_seq(pdev);
+	} else if (sysfs_streq(buf, "active")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
+			return count;
+
+		poweroff_seq(pdev);
+		is_disabled = apb->init_disabled;
+		apb->init_disabled = false;
+		ret = coldboot_seq(pdev);
+		if (ret)
+			apb->init_disabled = is_disabled;
+	} else if (sysfs_streq(buf, "standby")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_STANDBY)
+			return count;
+
+		ret = standby_boot_seq(pdev);
+	} else if (sysfs_streq(buf, "fw_flashing")) {
+		if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
+			return count;
+
+		/* First we want to make sure we power off everything
+		 * and then enter FW flashing state */
+		poweroff_seq(pdev);
+		ret = fw_flashing_seq(pdev);
+	} else {
+		dev_err(dev, "unknown state\n");
+		ret = -EINVAL;
+	}
+
+	return ret ? ret : count;
+}
+
+static ssize_t state_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
+
+	switch (apb->state) {
+	case ARCHE_PLATFORM_STATE_OFF:
+		return sprintf(buf, "off%s\n",
+				apb->init_disabled ? ",disabled" : "");
+	case ARCHE_PLATFORM_STATE_ACTIVE:
+		return sprintf(buf, "active\n");
+	case ARCHE_PLATFORM_STATE_STANDBY:
+		return sprintf(buf, "standby\n");
+	case ARCHE_PLATFORM_STATE_FW_FLASHING:
+		return sprintf(buf, "fw_flashing\n");
+	default:
+		return sprintf(buf, "unknown state\n");
+	}
+}
+
+static DEVICE_ATTR_RW(state);
+
+static int apb_ctrl_get_devtree_data(struct platform_device *pdev,
+		struct arche_apb_ctrl_drvdata *apb)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	apb->resetn_gpio = of_get_named_gpio(np, "reset-gpios", 0);
+	if (apb->resetn_gpio < 0) {
+		dev_err(dev, "failed to get reset gpio\n");
+		return apb->resetn_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->resetn_gpio,
+			GPIOF_OUT_INIT_LOW, "apb-reset");
+	if (ret) {
+		dev_err(dev, "Failed requesting reset gpio %d\n",
+				apb->resetn_gpio);
+		return ret;
+	}
+
+	apb->boot_ret_gpio = of_get_named_gpio(np, "boot-ret-gpios", 0);
+	if (apb->boot_ret_gpio < 0) {
+		dev_err(dev, "failed to get boot retention gpio\n");
+		return apb->boot_ret_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->boot_ret_gpio,
+			GPIOF_OUT_INIT_LOW, "boot retention");
+	if (ret) {
+		dev_err(dev, "Failed requesting bootret gpio %d\n",
+				apb->boot_ret_gpio);
+		return ret;
+	}
+
+	/* It's not mandatory to support power management interface */
+	apb->pwroff_gpio = of_get_named_gpio(np, "pwr-off-gpios", 0);
+	if (apb->pwroff_gpio < 0) {
+		dev_err(dev, "failed to get power off gpio\n");
+		return apb->pwroff_gpio;
+	}
+	ret = devm_gpio_request_one(dev, apb->pwroff_gpio,
+			GPIOF_IN, "pwroff_n");
+	if (ret) {
+		dev_err(dev, "Failed requesting pwroff_n gpio %d\n",
+				apb->pwroff_gpio);
+		return ret;
+	}
+
+	/* Do not make clock mandatory as of now (for DB3) */
+	apb->clk_en_gpio = of_get_named_gpio(np, "clock-en-gpio", 0);
+	if (apb->clk_en_gpio < 0) {
+		dev_warn(dev, "failed to get clock en gpio\n");
+	} else if (gpio_is_valid(apb->clk_en_gpio)) {
+		ret = devm_gpio_request_one(dev, apb->clk_en_gpio,
+				GPIOF_OUT_INIT_LOW, "apb_clk_en");
+		if (ret) {
+			dev_warn(dev, "Failed requesting APB clock en gpio %d\n",
+					apb->clk_en_gpio);
+			return ret;
+		}
+	}
+
+	apb->pwrdn_gpio = of_get_named_gpio(np, "pwr-down-gpios", 0);
+	if (apb->pwrdn_gpio < 0)
+		dev_warn(dev, "failed to get power down gpio\n");
+
+	/* Regulators are optional, as we may have fixed supply coming in */
+	apb->vcore = devm_regulator_get(dev, "vcore");
+	if (IS_ERR(apb->vcore))
+		dev_warn(dev, "no core regulator found\n");
+
+	apb->vio = devm_regulator_get(dev, "vio");
+	if (IS_ERR(apb->vio))
+		dev_warn(dev, "no IO regulator found\n");
+
+	apb->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(apb->pinctrl)) {
+		dev_err(&pdev->dev, "could not get pinctrl handle\n");
+		return PTR_ERR(apb->pinctrl);
+	}
+	apb->pin_default = pinctrl_lookup_state(apb->pinctrl, "default");
+	if (IS_ERR(apb->pin_default)) {
+		dev_err(&pdev->dev, "could not get default pin state\n");
+		return PTR_ERR(apb->pin_default);
+	}
+
+	/* Only applicable for platform >= V2 */
+	apb->spi_en_gpio = of_get_named_gpio(np, "spi-en-gpio", 0);
+	if (apb->spi_en_gpio >= 0) {
+		if (of_property_read_bool(pdev->dev.of_node,
+					"spi-en-active-high"))
+			apb->spi_en_polarity_high = true;
+	}
+
+	return 0;
+}
+
+static int arche_apb_ctrl_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct arche_apb_ctrl_drvdata *apb;
+	struct device *dev = &pdev->dev;
+
+	apb = devm_kzalloc(&pdev->dev, sizeof(*apb), GFP_KERNEL);
+	if (!apb)
+		return -ENOMEM;
+
+	ret = apb_ctrl_get_devtree_data(pdev, apb);
+	if (ret) {
+		dev_err(dev, "failed to get apb devicetree data %d\n", ret);
+		return ret;
+	}
+
+	/* Initially set APB to OFF state */
+	apb->state = ARCHE_PLATFORM_STATE_OFF;
+	/* Check whether device needs to be enabled on boot */
+	if (of_property_read_bool(pdev->dev.of_node, "arche,init-disable"))
+		apb->init_disabled = true;
+
+	platform_set_drvdata(pdev, apb);
+
+	/* Create sysfs interface to allow user to change state dynamically */
+	ret = device_create_file(dev, &dev_attr_state);
+	if (ret) {
+		dev_err(dev, "failed to create state file in sysfs\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "Device registered successfully\n");
+	return 0;
+}
+
+static int arche_apb_ctrl_remove(struct platform_device *pdev)
+{
+	device_remove_file(&pdev->dev, &dev_attr_state);
+	poweroff_seq(pdev);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static int arche_apb_ctrl_suspend(struct device *dev)
+{
+	/*
+	 * If timing profile permits, we may shutdown bridge
+	 * completely
+	 *
+	 * TODO: sequence ??
+	 *
+	 * Also, need to make sure we meet precondition for unipro suspend
+	 * Precondition: Definition ???
+	 */
+	return 0;
+}
+
+static int arche_apb_ctrl_resume(struct device *dev)
+{
+	/*
+	 * Atleast for ES2 we have to meet the delay requirement between
+	 * unipro switch and AP bridge init, depending on whether bridge is in
+	 * OFF state or standby state.
+	 *
+	 * Based on whether bridge is in standby or OFF state we may have to
+	 * assert multiple signals. Please refer to WDM spec, for more info.
+	 *
+	 */
+	return 0;
+}
+
+static void arche_apb_ctrl_shutdown(struct platform_device *pdev)
+{
+	apb_ctrl_poweroff(&pdev->dev);
+}
+
+static SIMPLE_DEV_PM_OPS(arche_apb_ctrl_pm_ops, arche_apb_ctrl_suspend,
+			 arche_apb_ctrl_resume);
+
+static const struct of_device_id arche_apb_ctrl_of_match[] = {
+	{ .compatible = "usbffff,2", },
+	{ },
+};
+
+static struct platform_driver arche_apb_ctrl_device_driver = {
+	.probe		= arche_apb_ctrl_probe,
+	.remove		= arche_apb_ctrl_remove,
+	.shutdown	= arche_apb_ctrl_shutdown,
+	.driver		= {
+		.name	= "arche-apb-ctrl",
+		.pm	= &arche_apb_ctrl_pm_ops,
+		.of_match_table = arche_apb_ctrl_of_match,
+	}
+};
+
+int __init arche_apb_init(void)
+{
+	return platform_driver_register(&arche_apb_ctrl_device_driver);
+}
+
+void __exit arche_apb_exit(void)
+{
+	platform_driver_unregister(&arche_apb_ctrl_device_driver);
+}