1 files changed, 380 insertions, 0 deletions
diff --git a/arch/arm/mach-s3c/pm-gpio.c b/arch/arm/mach-s3c/pm-gpio.c
new file mode 100644
index 0000000000..cfdbc23379
--- /dev/null
+++ b/arch/arm/mach-s3c/pm-gpio.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// Copyright 2008 Openmoko, Inc.
+// Copyright 2008 Simtec Electronics
+//	Ben Dooks <ben@simtec.co.uk>
+//	http://armlinux.simtec.co.uk/
+//
+// S3C series GPIO PM code
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+
+#include "gpio-samsung.h"
+
+#include "gpio-core.h"
+#include "pm.h"
+
+/* PM GPIO helpers */
+
+#define OFFS_CON	(0x00)
+#define OFFS_DAT	(0x04)
+#define OFFS_UP		(0x08)
+
+static void samsung_gpio_pm_1bit_save(struct samsung_gpio_chip *chip)
+{
+	chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
+	chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
+}
+
+static void samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip *chip)
+{
+	void __iomem *base = chip->base;
+	u32 old_gpcon = __raw_readl(base + OFFS_CON);
+	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
+	u32 gps_gpcon = chip->pm_save[0];
+	u32 gps_gpdat = chip->pm_save[1];
+	u32 gpcon;
+
+	/* GPACON only has one bit per control / data and no PULLUPs.
+	 * GPACON[x] = 0 => Output, 1 => SFN */
+
+	/* first set all SFN bits to SFN */
+
+	gpcon = old_gpcon | gps_gpcon;
+	__raw_writel(gpcon, base + OFFS_CON);
+
+	/* now set all the other bits */
+
+	__raw_writel(gps_gpdat, base + OFFS_DAT);
+	__raw_writel(gps_gpcon, base + OFFS_CON);
+
+	S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
+		  chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
+}
+
+struct samsung_gpio_pm samsung_gpio_pm_1bit = {
+	.save	= samsung_gpio_pm_1bit_save,
+	.resume = samsung_gpio_pm_1bit_resume,
+};
+
+static void samsung_gpio_pm_2bit_save(struct samsung_gpio_chip *chip)
+{
+	chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
+	chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
+	chip->pm_save[2] = __raw_readl(chip->base + OFFS_UP);
+}
+
+/* Test whether the given masked+shifted bits of an GPIO configuration
+ * are one of the SFN (special function) modes. */
+
+static inline int is_sfn(unsigned long con)
+{
+	return con >= 2;
+}
+
+/* Test if the given masked+shifted GPIO configuration is an input */
+
+static inline int is_in(unsigned long con)
+{
+	return con == 0;
+}
+
+/* Test if the given masked+shifted GPIO configuration is an output */
+
+static inline int is_out(unsigned long con)
+{
+	return con == 1;
+}
+
+/**
+ * samsung_gpio_pm_2bit_resume() - restore the given GPIO bank
+ * @chip: The chip information to resume.
+ *
+ * Restore one of the GPIO banks that was saved during suspend. This is
+ * not as simple as once thought, due to the possibility of glitches
+ * from the order that the CON and DAT registers are set in.
+ *
+ * The three states the pin can be are {IN,OUT,SFN} which gives us 9
+ * combinations of changes to check. Three of these, if the pin stays
+ * in the same configuration can be discounted. This leaves us with
+ * the following:
+ *
+ * { IN => OUT }  Change DAT first
+ * { IN => SFN }  Change CON first
+ * { OUT => SFN } Change CON first, so new data will not glitch
+ * { OUT => IN }  Change CON first, so new data will not glitch
+ * { SFN => IN }  Change CON first
+ * { SFN => OUT } Change DAT first, so new data will not glitch [1]
+ *
+ * We do not currently deal with the UP registers as these control
+ * weak resistors, so a small delay in change should not need to bring
+ * these into the calculations.
+ *
+ * [1] this assumes that writing to a pin DAT whilst in SFN will set the
+ *     state for when it is next output.
+ */
+static void samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip *chip)
+{
+	void __iomem *base = chip->base;
+	u32 old_gpcon = __raw_readl(base + OFFS_CON);
+	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
+	u32 gps_gpcon = chip->pm_save[0];
+	u32 gps_gpdat = chip->pm_save[1];
+	u32 gpcon, old, new, mask;
+	u32 change_mask = 0x0;
+	int nr;
+
+	/* restore GPIO pull-up settings */
+	__raw_writel(chip->pm_save[2], base + OFFS_UP);
+
+	/* Create a change_mask of all the items that need to have
+	 * their CON value changed before their DAT value, so that
+	 * we minimise the work between the two settings.
+	 */
+
+	for (nr = 0, mask = 0x03; nr < 32; nr += 2, mask <<= 2) {
+		old = (old_gpcon & mask) >> nr;
+		new = (gps_gpcon & mask) >> nr;
+
+		/* If there is no change, then skip */
+
+		if (old == new)
+			continue;
+
+		/* If both are special function, then skip */
+
+		if (is_sfn(old) && is_sfn(new))
+			continue;
+
+		/* Change is IN => OUT, do not change now */
+
+		if (is_in(old) && is_out(new))
+			continue;
+
+		/* Change is SFN => OUT, do not change now */
+
+		if (is_sfn(old) && is_out(new))
+			continue;
+
+		/* We should now be at the case of IN=>SFN,
+		 * OUT=>SFN, OUT=>IN, SFN=>IN. */
+
+		change_mask |= mask;
+	}
+
+
+	/* Write the new CON settings */
+
+	gpcon = old_gpcon & ~change_mask;
+	gpcon |= gps_gpcon & change_mask;
+
+	__raw_writel(gpcon, base + OFFS_CON);
+
+	/* Now change any items that require DAT,CON */
+
+	__raw_writel(gps_gpdat, base + OFFS_DAT);
+	__raw_writel(gps_gpcon, base + OFFS_CON);
+
+	S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
+		  chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
+}
+
+struct samsung_gpio_pm samsung_gpio_pm_2bit = {
+	.save	= samsung_gpio_pm_2bit_save,
+	.resume = samsung_gpio_pm_2bit_resume,
+};
+
+#if defined(CONFIG_ARCH_S3C64XX)
+static void samsung_gpio_pm_4bit_save(struct samsung_gpio_chip *chip)
+{
+	chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
+	chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
+	chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);
+
+	if (chip->chip.ngpio > 8)
+		chip->pm_save[0] = __raw_readl(chip->base - 4);
+}
+
+static u32 samsung_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
+{
+	u32 old, new, mask;
+	u32 change_mask = 0x0;
+	int nr;
+
+	for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
+		old = (old_gpcon & mask) >> nr;
+		new = (gps_gpcon & mask) >> nr;
+
+		/* If there is no change, then skip */
+
+		if (old == new)
+			continue;
+
+		/* If both are special function, then skip */
+
+		if (is_sfn(old) && is_sfn(new))
+			continue;
+
+		/* Change is IN => OUT, do not change now */
+
+		if (is_in(old) && is_out(new))
+			continue;
+
+		/* Change is SFN => OUT, do not change now */
+
+		if (is_sfn(old) && is_out(new))
+			continue;
+
+		/* We should now be at the case of IN=>SFN,
+		 * OUT=>SFN, OUT=>IN, SFN=>IN. */
+
+		change_mask |= mask;
+	}
+
+	return change_mask;
+}
+
+static void samsung_gpio_pm_4bit_con(struct samsung_gpio_chip *chip, int index)
+{
+	void __iomem *con = chip->base + (index * 4);
+	u32 old_gpcon = __raw_readl(con);
+	u32 gps_gpcon = chip->pm_save[index + 1];
+	u32 gpcon, mask;
+
+	mask = samsung_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);
+
+	gpcon = old_gpcon & ~mask;
+	gpcon |= gps_gpcon & mask;
+
+	__raw_writel(gpcon, con);
+}
+
+static void samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip *chip)
+{
+	void __iomem *base = chip->base;
+	u32 old_gpcon[2];
+	u32 old_gpdat = __raw_readl(base + OFFS_DAT);
+	u32 gps_gpdat = chip->pm_save[2];
+
+	/* First, modify the CON settings */
+
+	old_gpcon[0] = 0;
+	old_gpcon[1] = __raw_readl(base + OFFS_CON);
+
+	samsung_gpio_pm_4bit_con(chip, 0);
+	if (chip->chip.ngpio > 8) {
+		old_gpcon[0] = __raw_readl(base - 4);
+		samsung_gpio_pm_4bit_con(chip, -1);
+	}
+
+	/* Now change the configurations that require DAT,CON */
+
+	__raw_writel(chip->pm_save[2], base + OFFS_DAT);
+	__raw_writel(chip->pm_save[1], base + OFFS_CON);
+	if (chip->chip.ngpio > 8)
+		__raw_writel(chip->pm_save[0], base - 4);
+
+	__raw_writel(chip->pm_save[2], base + OFFS_DAT);
+	__raw_writel(chip->pm_save[3], base + OFFS_UP);
+
+	if (chip->chip.ngpio > 8) {
+		S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
+			  chip->chip.label, old_gpcon[0], old_gpcon[1],
+			  __raw_readl(base - 4),
+			  __raw_readl(base + OFFS_CON),
+			  old_gpdat, gps_gpdat);
+	} else
+		S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
+			  chip->chip.label, old_gpcon[1],
+			  __raw_readl(base + OFFS_CON),
+			  old_gpdat, gps_gpdat);
+}
+
+struct samsung_gpio_pm samsung_gpio_pm_4bit = {
+	.save	= samsung_gpio_pm_4bit_save,
+	.resume = samsung_gpio_pm_4bit_resume,
+};
+#endif /* CONFIG_ARCH_S3C64XX */
+
+/**
+ * samsung_pm_save_gpio() - save gpio chip data for suspend
+ * @ourchip: The chip for suspend.
+ */
+static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
+{
+	struct samsung_gpio_pm *pm = ourchip->pm;
+
+	if (pm == NULL || pm->save == NULL)
+		S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
+	else
+		pm->save(ourchip);
+}
+
+/**
+ * samsung_pm_save_gpios() - Save the state of the GPIO banks.
+ *
+ * For all the GPIO banks, save the state of each one ready for going
+ * into a suspend mode.
+ */
+void samsung_pm_save_gpios(void)
+{
+	struct samsung_gpio_chip *ourchip;
+	unsigned int gpio_nr;
+
+	for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
+		ourchip = samsung_gpiolib_getchip(gpio_nr);
+		if (!ourchip) {
+			gpio_nr++;
+			continue;
+		}
+
+		samsung_pm_save_gpio(ourchip);
+
+		S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
+			  ourchip->chip.label,
+			  ourchip->pm_save[0],
+			  ourchip->pm_save[1],
+			  ourchip->pm_save[2],
+			  ourchip->pm_save[3]);
+
+		gpio_nr += ourchip->chip.ngpio;
+		gpio_nr += CONFIG_S3C_GPIO_SPACE;
+	}
+}
+
+/**
+ * samsung_pm_resume_gpio() - restore gpio chip data after suspend
+ * @ourchip: The suspended chip.
+ */
+static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
+{
+	struct samsung_gpio_pm *pm = ourchip->pm;
+
+	if (pm == NULL || pm->resume == NULL)
+		S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
+	else
+		pm->resume(ourchip);
+}
+
+void samsung_pm_restore_gpios(void)
+{
+	struct samsung_gpio_chip *ourchip;
+	unsigned int gpio_nr;
+
+	for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
+		ourchip = samsung_gpiolib_getchip(gpio_nr);
+		if (!ourchip) {
+			gpio_nr++;
+			continue;
+		}
+
+		samsung_pm_resume_gpio(ourchip);
+
+		gpio_nr += ourchip->chip.ngpio;
+		gpio_nr += CONFIG_S3C_GPIO_SPACE;
+	}
+}