drivers/power/reset/at91-sama5d2_shdwc.c - kernel/quantenna - Git at Google

 /*
  * Atmel SAMA5D2-Compatible Shutdown Controller (SHDWC) driver.
  * Found on some SoCs as the sama5d2 (obviously).
  *
  * Copyright (C) 2015 Atmel Corporation,
  *                    Nicolas Ferre <nicolas.ferre@atmel.com>
  *
  * Evolved from driver at91-poweroff.c.
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2.  This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  *
  * TODO:
  * - addition to status of other wake-up inputs [1 - 15]
  * - Analog Comparator wake-up alarm
  * - Serial RX wake-up alarm
  * - low power debouncer
  */

 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/printk.h>

 #define SLOW_CLOCK_FREQ	32768

 #define AT91_SHDW_CR	0x00		/* Shut Down Control Register */
 #define AT91_SHDW_SHDW		BIT(0)			/* Shut Down command */
 #define AT91_SHDW_KEY		(0xa5UL << 24)		/* KEY Password */

 #define AT91_SHDW_MR	0x04		/* Shut Down Mode Register */
 #define AT91_SHDW_WKUPDBC_SHIFT	24
 #define AT91_SHDW_WKUPDBC_MASK	GENMASK(31, 16)
 #define AT91_SHDW_WKUPDBC(x)	(((x) << AT91_SHDW_WKUPDBC_SHIFT) \
 						& AT91_SHDW_WKUPDBC_MASK)

 #define AT91_SHDW_SR	0x08		/* Shut Down Status Register */
 #define AT91_SHDW_WKUPIS_SHIFT	16
 #define AT91_SHDW_WKUPIS_MASK	GENMASK(31, 16)
 #define AT91_SHDW_WKUPIS(x)	((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
 						& AT91_SHDW_WKUPIS_MASK)

 #define AT91_SHDW_WUIR	0x0c		/* Shutdown Wake-up Inputs Register */
 #define AT91_SHDW_WKUPEN_MASK	GENMASK(15, 0)
 #define AT91_SHDW_WKUPEN(x)	((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
 #define AT91_SHDW_WKUPT_SHIFT	16
 #define AT91_SHDW_WKUPT_MASK	GENMASK(31, 16)
 #define AT91_SHDW_WKUPT(x)	((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
 						& AT91_SHDW_WKUPT_MASK)

 #define SHDW_WK_PIN(reg, cfg)	((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
 #define SHDW_RTCWK(reg, cfg)	(((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
 #define SHDW_RTCWKEN(cfg)	(1 << ((cfg)->mr_rtcwk_shift))

 #define DBC_PERIOD_US(x)	DIV_ROUND_UP_ULL((1000000 * (x)), \
 							SLOW_CLOCK_FREQ)

 struct shdwc_config {
 	u8 wkup_pin_input;
 	u8 mr_rtcwk_shift;
 	u8 sr_rtcwk_shift;
 };

 struct shdwc {
 	struct shdwc_config *cfg;
 	void __iomem *at91_shdwc_base;
 };

 /*
  * Hold configuration here, cannot be more than one instance of the driver
  * since pm_power_off itself is global.
  */
 static struct shdwc *at91_shdwc;
 static struct clk *sclk;

 static const unsigned long long sdwc_dbc_period[] = {
 	0, 3, 32, 512, 4096, 32768,
 };

 static void __init at91_wakeup_status(struct platform_device *pdev)
 {
 	struct shdwc *shdw = platform_get_drvdata(pdev);
 	u32 reg;
 	char *reason = "unknown";

 	reg = readl(shdw->at91_shdwc_base + AT91_SHDW_SR);

 	dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);

 	/* Simple power-on, just bail out */
 	if (!reg)
 		return;

 	if (SHDW_WK_PIN(reg, shdw->cfg))
 		reason = "WKUP pin";
 	else if (SHDW_RTCWK(reg, shdw->cfg))
 		reason = "RTC";

 	pr_info("AT91: Wake-Up source: %s\n", reason);
 }

 static void at91_poweroff(void)
 {
 	writel(AT91_SHDW_KEY | AT91_SHDW_SHDW,
 	       at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);
 }

 static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
 				      u32 in_period_us)
 {
 	int i;
 	int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
 	unsigned long long period_us;
 	unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);

 	if (in_period_us > max_period_us) {
 		dev_warn(&pdev->dev,
 			 "debouncer period %u too big, reduced to %llu us\n",
 			 in_period_us, max_period_us);
 		return max_idx;
 	}

 	for (i = max_idx - 1; i > 0; i--) {
 		period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
 		dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
 						__func__, i, period_us);
 		if (in_period_us > period_us)
 			break;
 	}

 	return i + 1;
 }

 static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
 				       struct device_node *np)
 {
 	struct device_node *cnp;
 	u32 wk_input_mask;
 	u32 wuir = 0;
 	u32 wk_input;

 	for_each_child_of_node(np, cnp) {
 		if (of_property_read_u32(cnp, "reg", &wk_input)) {
 			dev_warn(&pdev->dev, "reg property is missing for %s\n",
 				 cnp->full_name);
 			continue;
 		}

 		wk_input_mask = 1 << wk_input;
 		if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
 			dev_warn(&pdev->dev,
 				 "wake-up input %d out of bounds ignore\n",
 				 wk_input);
 			continue;
 		}
 		wuir |= wk_input_mask;

 		if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
 			wuir |= AT91_SHDW_WKUPT(wk_input);

 		dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
 						__func__, wk_input, wuir);
 	}

 	return wuir;
 }

 static void at91_shdwc_dt_configure(struct platform_device *pdev)
 {
 	struct shdwc *shdw = platform_get_drvdata(pdev);
 	struct device_node *np = pdev->dev.of_node;
 	u32 mode = 0, tmp, input;

 	if (!np) {
 		dev_err(&pdev->dev, "device node not found\n");
 		return;
 	}

 	if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
 		mode |= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));

 	if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
 		mode |= SHDW_RTCWKEN(shdw->cfg);

 	dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
 	writel(mode, shdw->at91_shdwc_base + AT91_SHDW_MR);

 	input = at91_shdwc_get_wakeup_input(pdev, np);
 	writel(input, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
 }

 static const struct shdwc_config sama5d2_shdwc_config = {
 	.wkup_pin_input = 0,
 	.mr_rtcwk_shift = 17,
 	.sr_rtcwk_shift = 5,
 };

 static const struct of_device_id at91_shdwc_of_match[] = {
 	{
 		.compatible = "atmel,sama5d2-shdwc",
 		.data = &sama5d2_shdwc_config,
 	}, {
 		/*sentinel*/
 	}
 };
 MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);

 static int __init at91_shdwc_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	const struct of_device_id *match;
 	int ret;

 	if (!pdev->dev.of_node)
 		return -ENODEV;

 	at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
 	if (!at91_shdwc)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, at91_shdwc);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	at91_shdwc->at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(at91_shdwc->at91_shdwc_base)) {
 		dev_err(&pdev->dev, "Could not map reset controller address\n");
 		return PTR_ERR(at91_shdwc->at91_shdwc_base);
 	}

 	match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
 	at91_shdwc->cfg = (struct shdwc_config *)(match->data);

 	sclk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(sclk))
 		return PTR_ERR(sclk);

 	ret = clk_prepare_enable(sclk);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not enable slow clock\n");
 		return ret;
 	}

 	at91_wakeup_status(pdev);

 	at91_shdwc_dt_configure(pdev);

 	pm_power_off = at91_poweroff;

 	return 0;
 }

 static int __exit at91_shdwc_remove(struct platform_device *pdev)
 {
 	struct shdwc *shdw = platform_get_drvdata(pdev);

 	if (pm_power_off == at91_poweroff)
 		pm_power_off = NULL;

 	/* Reset values to disable wake-up features  */
 	writel(0, shdw->at91_shdwc_base + AT91_SHDW_MR);
 	writel(0, shdw->at91_shdwc_base + AT91_SHDW_WUIR);

 	clk_disable_unprepare(sclk);

 	return 0;
 }

 static struct platform_driver at91_shdwc_driver = {
 	.remove = __exit_p(at91_shdwc_remove),
 	.driver = {
 		.name = "at91-shdwc",
 		.of_match_table = at91_shdwc_of_match,
 	},
 };
 module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);

 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
 MODULE_DESCRIPTION("Atmel shutdown controller driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Atmel SAMA5D2-Compatible Shutdown Controller (SHDWC) driver.
	* Found on some SoCs as the sama5d2 (obviously).
	*
	* Copyright (C) 2015 Atmel Corporation,
	* Nicolas Ferre <nicolas.ferre@atmel.com>
	*
	* Evolved from driver at91-poweroff.c.
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*
	* TODO:
	* - addition to status of other wake-up inputs [1 - 15]
	* - Analog Comparator wake-up alarm
	* - Serial RX wake-up alarm
	* - low power debouncer
	*/

	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/printk.h>

	#define SLOW_CLOCK_FREQ 32768

	#define AT91_SHDW_CR 0x00 /* Shut Down Control Register */
	#define AT91_SHDW_SHDW BIT(0) /* Shut Down command */
	#define AT91_SHDW_KEY (0xa5UL << 24) /* KEY Password */

	#define AT91_SHDW_MR 0x04 /* Shut Down Mode Register */
	#define AT91_SHDW_WKUPDBC_SHIFT 24
	#define AT91_SHDW_WKUPDBC_MASK GENMASK(31, 16)
	#define AT91_SHDW_WKUPDBC(x) (((x) << AT91_SHDW_WKUPDBC_SHIFT) \
	& AT91_SHDW_WKUPDBC_MASK)

	#define AT91_SHDW_SR 0x08 /* Shut Down Status Register */
	#define AT91_SHDW_WKUPIS_SHIFT 16
	#define AT91_SHDW_WKUPIS_MASK GENMASK(31, 16)
	#define AT91_SHDW_WKUPIS(x) ((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
	& AT91_SHDW_WKUPIS_MASK)

	#define AT91_SHDW_WUIR 0x0c /* Shutdown Wake-up Inputs Register */
	#define AT91_SHDW_WKUPEN_MASK GENMASK(15, 0)
	#define AT91_SHDW_WKUPEN(x) ((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
	#define AT91_SHDW_WKUPT_SHIFT 16
	#define AT91_SHDW_WKUPT_MASK GENMASK(31, 16)
	#define AT91_SHDW_WKUPT(x) ((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
	& AT91_SHDW_WKUPT_MASK)

	#define SHDW_WK_PIN(reg, cfg) ((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
	#define SHDW_RTCWK(reg, cfg) (((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
	#define SHDW_RTCWKEN(cfg) (1 << ((cfg)->mr_rtcwk_shift))

	#define DBC_PERIOD_US(x) DIV_ROUND_UP_ULL((1000000 * (x)), \
	SLOW_CLOCK_FREQ)

	struct shdwc_config {
	u8 wkup_pin_input;
	u8 mr_rtcwk_shift;
	u8 sr_rtcwk_shift;
	};

	struct shdwc {
	struct shdwc_config *cfg;
	void __iomem *at91_shdwc_base;
	};

	/*
	* Hold configuration here, cannot be more than one instance of the driver
	* since pm_power_off itself is global.
	*/
	static struct shdwc *at91_shdwc;
	static struct clk *sclk;

	static const unsigned long long sdwc_dbc_period[] = {
	0, 3, 32, 512, 4096, 32768,
	};

	static void __init at91_wakeup_status(struct platform_device *pdev)
	{
	struct shdwc *shdw = platform_get_drvdata(pdev);
	u32 reg;
	char *reason = "unknown";

	reg = readl(shdw->at91_shdwc_base + AT91_SHDW_SR);

	dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);

	/* Simple power-on, just bail out */
	if (!reg)
	return;

	if (SHDW_WK_PIN(reg, shdw->cfg))
	reason = "WKUP pin";
	else if (SHDW_RTCWK(reg, shdw->cfg))
	reason = "RTC";

	pr_info("AT91: Wake-Up source: %s\n", reason);
	}

	static void at91_poweroff(void)
	{
	writel(AT91_SHDW_KEY \| AT91_SHDW_SHDW,
	at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);
	}

	static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
	u32 in_period_us)
	{
	int i;
	int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
	unsigned long long period_us;
	unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);

	if (in_period_us > max_period_us) {
	dev_warn(&pdev->dev,
	"debouncer period %u too big, reduced to %llu us\n",
	in_period_us, max_period_us);
	return max_idx;
	}

	for (i = max_idx - 1; i > 0; i--) {
	period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
	dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
	__func__, i, period_us);
	if (in_period_us > period_us)
	break;
	}

	return i + 1;
	}

	static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
	struct device_node *np)
	{
	struct device_node *cnp;
	u32 wk_input_mask;
	u32 wuir = 0;
	u32 wk_input;

	for_each_child_of_node(np, cnp) {
	if (of_property_read_u32(cnp, "reg", &wk_input)) {
	dev_warn(&pdev->dev, "reg property is missing for %s\n",
	cnp->full_name);
	continue;
	}

	wk_input_mask = 1 << wk_input;
	if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
	dev_warn(&pdev->dev,
	"wake-up input %d out of bounds ignore\n",
	wk_input);
	continue;
	}
	wuir \|= wk_input_mask;

	if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
	wuir \|= AT91_SHDW_WKUPT(wk_input);

	dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
	__func__, wk_input, wuir);
	}

	return wuir;
	}

	static void at91_shdwc_dt_configure(struct platform_device *pdev)
	{
	struct shdwc *shdw = platform_get_drvdata(pdev);
	struct device_node *np = pdev->dev.of_node;
	u32 mode = 0, tmp, input;

	if (!np) {
	dev_err(&pdev->dev, "device node not found\n");
	return;
	}

	if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
	mode \|= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));

	if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
	mode \|= SHDW_RTCWKEN(shdw->cfg);

	dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
	writel(mode, shdw->at91_shdwc_base + AT91_SHDW_MR);

	input = at91_shdwc_get_wakeup_input(pdev, np);
	writel(input, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
	}

	static const struct shdwc_config sama5d2_shdwc_config = {
	.wkup_pin_input = 0,
	.mr_rtcwk_shift = 17,
	.sr_rtcwk_shift = 5,
	};

	static const struct of_device_id at91_shdwc_of_match[] = {
	{
	.compatible = "atmel,sama5d2-shdwc",
	.data = &sama5d2_shdwc_config,
	}, {
	/sentinel/
	}
	};
	MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);

	static int __init at91_shdwc_probe(struct platform_device *pdev)
	{
	struct resource *res;
	const struct of_device_id *match;
	int ret;

	if (!pdev->dev.of_node)
	return -ENODEV;

	at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
	if (!at91_shdwc)
	return -ENOMEM;

	platform_set_drvdata(pdev, at91_shdwc);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	at91_shdwc->at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(at91_shdwc->at91_shdwc_base)) {
	dev_err(&pdev->dev, "Could not map reset controller address\n");
	return PTR_ERR(at91_shdwc->at91_shdwc_base);
	}

	match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
	at91_shdwc->cfg = (struct shdwc_config *)(match->data);

	sclk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(sclk))
	return PTR_ERR(sclk);

	ret = clk_prepare_enable(sclk);
	if (ret) {
	dev_err(&pdev->dev, "Could not enable slow clock\n");
	return ret;
	}

	at91_wakeup_status(pdev);

	at91_shdwc_dt_configure(pdev);

	pm_power_off = at91_poweroff;

	return 0;
	}

	static int __exit at91_shdwc_remove(struct platform_device *pdev)
	{
	struct shdwc *shdw = platform_get_drvdata(pdev);

	if (pm_power_off == at91_poweroff)
	pm_power_off = NULL;

	/* Reset values to disable wake-up features */
	writel(0, shdw->at91_shdwc_base + AT91_SHDW_MR);
	writel(0, shdw->at91_shdwc_base + AT91_SHDW_WUIR);

	clk_disable_unprepare(sclk);

	return 0;
	}

	static struct platform_driver at91_shdwc_driver = {
	.remove = __exit_p(at91_shdwc_remove),
	.driver = {
	.name = "at91-shdwc",
	.of_match_table = at91_shdwc_of_match,
	},
	};
	module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);

	MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
	MODULE_DESCRIPTION("Atmel shutdown controller driver");
	MODULE_LICENSE("GPL v2");