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Release 4.14 drivers/power/reset/at91-sama5d2_shdwc.c

/*
 * 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/of_address.h>
#include <linux/platform_device.h>
#include <linux/printk.h>

#include <soc/at91/at91sam9_ddrsdr.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 void __iomem *mpddrc_base;


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); }

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

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static void at91_lpddr_poweroff(void) { asm volatile( /* Align to cache lines */ ".balign 32\n\t" /* Ensure AT91_SHDW_CR is in the TLB by reading it */ " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t" /* Power down SDRAM0 */ " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t" /* Shutdown CPU */ " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t" " b .\n\t" : : "r" (mpddrc_base), "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF), "r" (at91_shdwc->at91_shdwc_base), "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW) : "r6"); }

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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; }

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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 %pOF\n", cnp); 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; }

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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); }

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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; struct device_node *np; u32 ddr_type; 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; np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc"); if (!np) return 0; mpddrc_base = of_iomap(np, 0); of_node_put(np); if (!mpddrc_base) return 0; ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD; if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) || (ddr_type == AT91_DDRSDRC_MD_LPDDR3)) pm_power_off = at91_lpddr_poweroff; else iounmap(mpddrc_base); return 0; }

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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 == at91_lpddr_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; }

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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");

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