// SPDX-License-Identifier: GPL-2.0
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/*
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* Arche Platform driver to control APB.
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*
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* Copyright 2014-2015 Google Inc.
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* Copyright 2014-2015 Linaro Ltd.
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/interrupt.h>
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#include <linux/of_irq.h>
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#include <linux/module.h>
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#include <linux/pinctrl/consumer.h>
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#include <linux/platform_device.h>
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#include <linux/pm.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spinlock.h>
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#include "arche_platform.h"
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static void apb_bootret_deassert(struct device *dev);
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struct arche_apb_ctrl_drvdata {
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/* Control GPIO signals to and from AP <=> AP Bridges */
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struct gpio_desc *resetn;
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struct gpio_desc *boot_ret;
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struct gpio_desc *pwroff;
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struct gpio_desc *wake_in;
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struct gpio_desc *wake_out;
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struct gpio_desc *pwrdn;
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enum arche_platform_state state;
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bool init_disabled;
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struct regulator *vcore;
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struct regulator *vio;
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struct gpio_desc *clk_en;
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struct clk *clk;
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struct pinctrl *pinctrl;
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struct pinctrl_state *pin_default;
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/* V2: SPI Bus control */
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struct gpio_desc *spi_en;
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bool spi_en_polarity_high;
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};
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/*
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* Note that these low level api's are active high
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*/
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static inline void deassert_reset(struct gpio_desc *gpio)
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{
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gpiod_set_raw_value(gpio, 1);
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}
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static inline void assert_reset(struct gpio_desc *gpio)
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{
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gpiod_set_raw_value(gpio, 0);
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}
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/*
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* Note: Please do not modify the below sequence, as it is as per the spec
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*/
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static int coldboot_seq(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
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int ret;
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if (apb->init_disabled ||
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apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
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return 0;
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/* Hold APB in reset state */
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assert_reset(apb->resetn);
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if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
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devm_gpiod_put(dev, apb->spi_en);
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/* Enable power to APB */
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if (!IS_ERR(apb->vcore)) {
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ret = regulator_enable(apb->vcore);
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if (ret) {
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dev_err(dev, "failed to enable core regulator\n");
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return ret;
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}
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}
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if (!IS_ERR(apb->vio)) {
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ret = regulator_enable(apb->vio);
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if (ret) {
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dev_err(dev, "failed to enable IO regulator\n");
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return ret;
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}
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}
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apb_bootret_deassert(dev);
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/* On DB3 clock was not mandatory */
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if (apb->clk_en)
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gpiod_set_value(apb->clk_en, 1);
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usleep_range(100, 200);
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/* deassert reset to APB : Active-low signal */
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deassert_reset(apb->resetn);
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apb->state = ARCHE_PLATFORM_STATE_ACTIVE;
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return 0;
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}
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static int fw_flashing_seq(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
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int ret;
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if (apb->init_disabled ||
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apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
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return 0;
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ret = regulator_enable(apb->vcore);
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if (ret) {
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dev_err(dev, "failed to enable core regulator\n");
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return ret;
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}
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ret = regulator_enable(apb->vio);
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if (ret) {
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dev_err(dev, "failed to enable IO regulator\n");
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return ret;
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}
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if (apb->spi_en) {
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unsigned long flags;
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if (apb->spi_en_polarity_high)
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flags = GPIOD_OUT_HIGH;
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else
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flags = GPIOD_OUT_LOW;
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apb->spi_en = devm_gpiod_get(dev, "spi-en", flags);
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if (IS_ERR(apb->spi_en)) {
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ret = PTR_ERR(apb->spi_en);
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dev_err(dev, "Failed requesting SPI bus en GPIO: %d\n",
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ret);
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return ret;
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}
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}
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/* for flashing device should be in reset state */
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assert_reset(apb->resetn);
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apb->state = ARCHE_PLATFORM_STATE_FW_FLASHING;
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return 0;
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}
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static int standby_boot_seq(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
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if (apb->init_disabled)
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return 0;
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/*
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* Even if it is in OFF state,
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* then we do not want to change the state
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*/
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if (apb->state == ARCHE_PLATFORM_STATE_STANDBY ||
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apb->state == ARCHE_PLATFORM_STATE_OFF)
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return 0;
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if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
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devm_gpiod_put(dev, apb->spi_en);
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/*
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* As per WDM spec, do nothing
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*
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* Pasted from WDM spec,
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* - A falling edge on POWEROFF_L is detected (a)
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* - WDM enters standby mode, but no output signals are changed
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*/
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/* TODO: POWEROFF_L is input to WDM module */
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apb->state = ARCHE_PLATFORM_STATE_STANDBY;
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return 0;
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}
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static void poweroff_seq(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
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if (apb->init_disabled || apb->state == ARCHE_PLATFORM_STATE_OFF)
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return;
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if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING && apb->spi_en)
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devm_gpiod_put(dev, apb->spi_en);
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/* disable the clock */
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if (apb->clk_en)
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gpiod_set_value(apb->clk_en, 0);
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if (!IS_ERR(apb->vcore) && regulator_is_enabled(apb->vcore) > 0)
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regulator_disable(apb->vcore);
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if (!IS_ERR(apb->vio) && regulator_is_enabled(apb->vio) > 0)
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regulator_disable(apb->vio);
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/* As part of exit, put APB back in reset state */
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assert_reset(apb->resetn);
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apb->state = ARCHE_PLATFORM_STATE_OFF;
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/* TODO: May have to send an event to SVC about this exit */
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}
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static void apb_bootret_deassert(struct device *dev)
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{
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struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
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gpiod_set_value(apb->boot_ret, 0);
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}
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int apb_ctrl_coldboot(struct device *dev)
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{
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return coldboot_seq(to_platform_device(dev));
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}
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int apb_ctrl_fw_flashing(struct device *dev)
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{
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return fw_flashing_seq(to_platform_device(dev));
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}
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int apb_ctrl_standby_boot(struct device *dev)
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{
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return standby_boot_seq(to_platform_device(dev));
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}
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void apb_ctrl_poweroff(struct device *dev)
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{
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poweroff_seq(to_platform_device(dev));
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}
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static ssize_t state_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct arche_apb_ctrl_drvdata *apb = platform_get_drvdata(pdev);
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int ret = 0;
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bool is_disabled;
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if (sysfs_streq(buf, "off")) {
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if (apb->state == ARCHE_PLATFORM_STATE_OFF)
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return count;
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poweroff_seq(pdev);
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} else if (sysfs_streq(buf, "active")) {
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if (apb->state == ARCHE_PLATFORM_STATE_ACTIVE)
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return count;
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poweroff_seq(pdev);
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is_disabled = apb->init_disabled;
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apb->init_disabled = false;
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ret = coldboot_seq(pdev);
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if (ret)
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apb->init_disabled = is_disabled;
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} else if (sysfs_streq(buf, "standby")) {
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if (apb->state == ARCHE_PLATFORM_STATE_STANDBY)
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return count;
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ret = standby_boot_seq(pdev);
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} else if (sysfs_streq(buf, "fw_flashing")) {
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if (apb->state == ARCHE_PLATFORM_STATE_FW_FLASHING)
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return count;
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/*
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* First we want to make sure we power off everything
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* and then enter FW flashing state
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*/
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poweroff_seq(pdev);
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ret = fw_flashing_seq(pdev);
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} else {
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dev_err(dev, "unknown state\n");
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ret = -EINVAL;
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}
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return ret ? ret : count;
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}
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static ssize_t state_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct arche_apb_ctrl_drvdata *apb = dev_get_drvdata(dev);
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switch (apb->state) {
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case ARCHE_PLATFORM_STATE_OFF:
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return sprintf(buf, "off%s\n",
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apb->init_disabled ? ",disabled" : "");
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case ARCHE_PLATFORM_STATE_ACTIVE:
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return sprintf(buf, "active\n");
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case ARCHE_PLATFORM_STATE_STANDBY:
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return sprintf(buf, "standby\n");
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case ARCHE_PLATFORM_STATE_FW_FLASHING:
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return sprintf(buf, "fw_flashing\n");
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default:
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return sprintf(buf, "unknown state\n");
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}
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}
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static DEVICE_ATTR_RW(state);
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static int apb_ctrl_get_devtree_data(struct platform_device *pdev,
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struct arche_apb_ctrl_drvdata *apb)
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{
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struct device *dev = &pdev->dev;
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int ret;
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apb->resetn = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
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if (IS_ERR(apb->resetn)) {
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ret = PTR_ERR(apb->resetn);
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dev_err(dev, "Failed requesting reset GPIO: %d\n", ret);
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return ret;
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}
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apb->boot_ret = devm_gpiod_get(dev, "boot-ret", GPIOD_OUT_LOW);
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if (IS_ERR(apb->boot_ret)) {
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ret = PTR_ERR(apb->boot_ret);
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dev_err(dev, "Failed requesting bootret GPIO: %d\n", ret);
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return ret;
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}
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/* It's not mandatory to support power management interface */
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apb->pwroff = devm_gpiod_get_optional(dev, "pwr-off", GPIOD_IN);
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if (IS_ERR(apb->pwroff)) {
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ret = PTR_ERR(apb->pwroff);
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dev_err(dev, "Failed requesting pwroff_n GPIO: %d\n", ret);
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return ret;
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}
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/* Do not make clock mandatory as of now (for DB3) */
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apb->clk_en = devm_gpiod_get_optional(dev, "clock-en", GPIOD_OUT_LOW);
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if (IS_ERR(apb->clk_en)) {
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ret = PTR_ERR(apb->clk_en);
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dev_err(dev, "Failed requesting APB clock en GPIO: %d\n", ret);
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return ret;
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}
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apb->pwrdn = devm_gpiod_get(dev, "pwr-down", GPIOD_OUT_LOW);
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if (IS_ERR(apb->pwrdn)) {
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ret = PTR_ERR(apb->pwrdn);
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dev_warn(dev, "Failed requesting power down GPIO: %d\n", ret);
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return ret;
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}
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/* Regulators are optional, as we may have fixed supply coming in */
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apb->vcore = devm_regulator_get(dev, "vcore");
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if (IS_ERR(apb->vcore))
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dev_warn(dev, "no core regulator found\n");
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apb->vio = devm_regulator_get(dev, "vio");
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if (IS_ERR(apb->vio))
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dev_warn(dev, "no IO regulator found\n");
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apb->pinctrl = devm_pinctrl_get(&pdev->dev);
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if (IS_ERR(apb->pinctrl)) {
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dev_err(&pdev->dev, "could not get pinctrl handle\n");
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return PTR_ERR(apb->pinctrl);
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}
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apb->pin_default = pinctrl_lookup_state(apb->pinctrl, "default");
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if (IS_ERR(apb->pin_default)) {
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dev_err(&pdev->dev, "could not get default pin state\n");
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return PTR_ERR(apb->pin_default);
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}
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/* Only applicable for platform >= V2 */
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if (of_property_read_bool(pdev->dev.of_node, "gb,spi-en-active-high"))
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apb->spi_en_polarity_high = true;
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return 0;
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}
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static int arche_apb_ctrl_probe(struct platform_device *pdev)
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{
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int ret;
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struct arche_apb_ctrl_drvdata *apb;
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struct device *dev = &pdev->dev;
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apb = devm_kzalloc(&pdev->dev, sizeof(*apb), GFP_KERNEL);
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if (!apb)
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return -ENOMEM;
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ret = apb_ctrl_get_devtree_data(pdev, apb);
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if (ret) {
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dev_err(dev, "failed to get apb devicetree data %d\n", ret);
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return ret;
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}
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/* Initially set APB to OFF state */
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apb->state = ARCHE_PLATFORM_STATE_OFF;
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/* Check whether device needs to be enabled on boot */
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if (of_property_read_bool(pdev->dev.of_node, "arche,init-disable"))
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apb->init_disabled = true;
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platform_set_drvdata(pdev, apb);
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/* Create sysfs interface to allow user to change state dynamically */
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ret = device_create_file(dev, &dev_attr_state);
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if (ret) {
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dev_err(dev, "failed to create state file in sysfs\n");
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return ret;
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}
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dev_info(&pdev->dev, "Device registered successfully\n");
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return 0;
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}
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static int arche_apb_ctrl_remove(struct platform_device *pdev)
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{
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device_remove_file(&pdev->dev, &dev_attr_state);
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poweroff_seq(pdev);
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platform_set_drvdata(pdev, NULL);
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return 0;
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}
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static int __maybe_unused arche_apb_ctrl_suspend(struct device *dev)
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{
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/*
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* If timing profile permits, we may shutdown bridge
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* completely
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*
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* TODO: sequence ??
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*
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* Also, need to make sure we meet precondition for unipro suspend
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* Precondition: Definition ???
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*/
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return 0;
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}
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static int __maybe_unused arche_apb_ctrl_resume(struct device *dev)
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{
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/*
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* Atleast for ES2 we have to meet the delay requirement between
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* unipro switch and AP bridge init, depending on whether bridge is in
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* OFF state or standby state.
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*
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* Based on whether bridge is in standby or OFF state we may have to
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* assert multiple signals. Please refer to WDM spec, for more info.
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*
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*/
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return 0;
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}
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static void arche_apb_ctrl_shutdown(struct platform_device *pdev)
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{
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apb_ctrl_poweroff(&pdev->dev);
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}
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static SIMPLE_DEV_PM_OPS(arche_apb_ctrl_pm_ops, arche_apb_ctrl_suspend,
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arche_apb_ctrl_resume);
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static const struct of_device_id arche_apb_ctrl_of_match[] = {
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{ .compatible = "usbffff,2", },
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{ },
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};
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static struct platform_driver arche_apb_ctrl_device_driver = {
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.probe = arche_apb_ctrl_probe,
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.remove = arche_apb_ctrl_remove,
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.shutdown = arche_apb_ctrl_shutdown,
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.driver = {
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.name = "arche-apb-ctrl",
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.pm = &arche_apb_ctrl_pm_ops,
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.of_match_table = arche_apb_ctrl_of_match,
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}
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};
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int __init arche_apb_init(void)
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{
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return platform_driver_register(&arche_apb_ctrl_device_driver);
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}
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void __exit arche_apb_exit(void)
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{
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platform_driver_unregister(&arche_apb_ctrl_device_driver);
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}
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