diff options
Diffstat (limited to 'arch/arm/plat-s3c/pm-gpio.c')
| -rw-r--r-- | arch/arm/plat-s3c/pm-gpio.c | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c/pm-gpio.c b/arch/arm/plat-s3c/pm-gpio.c new file mode 100644 index 000000000000..cfd326a8b693 --- /dev/null +++ b/arch/arm/plat-s3c/pm-gpio.c @@ -0,0 +1,380 @@ + +/* linux/arch/arm/plat-s3c/pm-gpio.c + * + * Copyright 2008 Openmoko, Inc. + * Copyright 2008 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * http://armlinux.simtec.co.uk/ + * + * S3C series GPIO PM code + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#include <linux/kernel.h> +#include <linux/sysdev.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/gpio.h> + +#include <mach/gpio-core.h> +#include <plat/pm.h> + +/* PM GPIO helpers */ + +#define OFFS_CON (0x00) +#define OFFS_DAT (0x04) +#define OFFS_UP (0x08) + +static void s3c_gpio_pm_1bit_save(struct s3c_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 s3c_gpio_pm_1bit_resume(struct s3c_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 s3c_gpio_pm s3c_gpio_pm_1bit = { + .save = s3c_gpio_pm_1bit_save, + .resume = s3c_gpio_pm_1bit_resume, +}; + +static void s3c_gpio_pm_2bit_save(struct s3c_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; +} + +/** + * s3c_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 s3c_gpio_pm_2bit_resume(struct s3c_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 s3c_gpio_pm s3c_gpio_pm_2bit = { + .save = s3c_gpio_pm_2bit_save, + .resume = s3c_gpio_pm_2bit_resume, +}; + +#ifdef CONFIG_ARCH_S3C64XX +static void s3c_gpio_pm_4bit_save(struct s3c_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 s3c_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 s3c_gpio_pm_4bit_con(struct s3c_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 = s3c_gpio_pm_4bit_mask(old_gpcon, gps_gpcon); + + gpcon = old_gpcon & ~mask; + gpcon |= gps_gpcon & mask; + + __raw_writel(gpcon, con); +} + +static void s3c_gpio_pm_4bit_resume(struct s3c_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); + + s3c_gpio_pm_4bit_con(chip, 0); + if (chip->chip.ngpio > 8) { + old_gpcon[0] = __raw_readl(base - 4); + s3c_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 s3c_gpio_pm s3c_gpio_pm_4bit = { + .save = s3c_gpio_pm_4bit_save, + .resume = s3c_gpio_pm_4bit_resume, +}; +#endif /* CONFIG_ARCH_S3C64XX */ + +/** + * s3c_pm_save_gpio() - save gpio chip data for suspend + * @ourchip: The chip for suspend. + */ +static void s3c_pm_save_gpio(struct s3c_gpio_chip *ourchip) +{ + struct s3c_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); +} + +/** + * s3c_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 s3c_pm_save_gpios(void) +{ + struct s3c_gpio_chip *ourchip; + unsigned int gpio_nr; + + for (gpio_nr = 0; gpio_nr < S3C_GPIO_END; gpio_nr++) { + ourchip = s3c_gpiolib_getchip(gpio_nr); + if (!ourchip) + continue; + + s3c_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; + } +} + +/** + * s3c_pm_resume_gpio() - restore gpio chip data after suspend + * @ourchip: The suspended chip. + */ +static void s3c_pm_resume_gpio(struct s3c_gpio_chip *ourchip) +{ + struct s3c_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 s3c_pm_restore_gpios(void) +{ + struct s3c_gpio_chip *ourchip; + unsigned int gpio_nr; + + for (gpio_nr = 0; gpio_nr < S3C_GPIO_END; gpio_nr++) { + ourchip = s3c_gpiolib_getchip(gpio_nr); + if (!ourchip) + continue; + + s3c_pm_resume_gpio(ourchip); + + gpio_nr += ourchip->chip.ngpio; + gpio_nr += CONFIG_S3C_GPIO_SPACE; + } +} |