diff options
Diffstat (limited to 'arch/powerpc/platforms/52xx/mpc52xx_gpt.c')
| -rw-r--r-- | arch/powerpc/platforms/52xx/mpc52xx_gpt.c | 780 |
1 files changed, 780 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c new file mode 100644 index 000000000..581059527 --- /dev/null +++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c @@ -0,0 +1,780 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * MPC5200 General Purpose Timer device driver + * + * Copyright (c) 2009 Secret Lab Technologies Ltd. + * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix + * + * This file is a driver for the General Purpose Timer (gpt) devices + * found on the MPC5200 SoC. Each timer has an IO pin which can be used + * for GPIO or can be used to raise interrupts. The timer function can + * be used independently from the IO pin, or it can be used to control + * output signals or measure input signals. + * + * This driver supports the GPIO and IRQ controller functions of the GPT + * device. Timer functions are not yet supported. + * + * The timer gpt0 can be used as watchdog (wdt). If the wdt mode is used, + * this prevents the use of any gpt0 gpt function (i.e. they will fail with + * -EBUSY). Thus, the safety wdt function always has precedence over the gpt + * function. If the kernel has been compiled with CONFIG_WATCHDOG_NOWAYOUT, + * this means that gpt0 is locked in wdt mode until the next reboot - this + * may be a requirement in safety applications. + * + * To use the GPIO function, the following two properties must be added + * to the device tree node for the gpt device (typically in the .dts file + * for the board): + * gpio-controller; + * #gpio-cells = < 2 >; + * This driver will register the GPIO pin if it finds the gpio-controller + * property in the device tree. + * + * To use the IRQ controller function, the following two properties must + * be added to the device tree node for the gpt device: + * interrupt-controller; + * #interrupt-cells = < 1 >; + * The IRQ controller binding only uses one cell to specify the interrupt, + * and the IRQ flags are encoded in the cell. A cell is not used to encode + * the IRQ number because the GPT only has a single IRQ source. For flags, + * a value of '1' means rising edge sensitive and '2' means falling edge. + * + * The GPIO and the IRQ controller functions can be used at the same time, + * but in this use case the IO line will only work as an input. Trying to + * use it as a GPIO output will not work. + * + * When using the GPIO line as an output, it can either be driven as normal + * IO, or it can be an Open Collector (OC) output. At the moment it is the + * responsibility of either the bootloader or the platform setup code to set + * the output mode. This driver does not change the output mode setting. + */ + +#include <linux/irq.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/kernel.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/watchdog.h> +#include <linux/miscdevice.h> +#include <linux/uaccess.h> +#include <linux/module.h> +#include <asm/div64.h> +#include <asm/mpc52xx.h> + +MODULE_DESCRIPTION("Freescale MPC52xx gpt driver"); +MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß"); +MODULE_LICENSE("GPL"); + +/** + * struct mpc52xx_gpt - Private data structure for MPC52xx GPT driver + * @dev: pointer to device structure + * @regs: virtual address of GPT registers + * @lock: spinlock to coordinate between different functions. + * @gc: gpio_chip instance structure; used when GPIO is enabled + * @irqhost: Pointer to irq_domain instance; used when IRQ mode is supported + * @wdt_mode: only relevant for gpt0: bit 0 (MPC52xx_GPT_CAN_WDT) indicates + * if the gpt may be used as wdt, bit 1 (MPC52xx_GPT_IS_WDT) indicates + * if the timer is actively used as wdt which blocks gpt functions + */ +struct mpc52xx_gpt_priv { + struct list_head list; /* List of all GPT devices */ + struct device *dev; + struct mpc52xx_gpt __iomem *regs; + raw_spinlock_t lock; + struct irq_domain *irqhost; + u32 ipb_freq; + u8 wdt_mode; + +#if defined(CONFIG_GPIOLIB) + struct gpio_chip gc; +#endif +}; + +LIST_HEAD(mpc52xx_gpt_list); +DEFINE_MUTEX(mpc52xx_gpt_list_mutex); + +#define MPC52xx_GPT_MODE_MS_MASK (0x07) +#define MPC52xx_GPT_MODE_MS_IC (0x01) +#define MPC52xx_GPT_MODE_MS_OC (0x02) +#define MPC52xx_GPT_MODE_MS_PWM (0x03) +#define MPC52xx_GPT_MODE_MS_GPIO (0x04) + +#define MPC52xx_GPT_MODE_GPIO_MASK (0x30) +#define MPC52xx_GPT_MODE_GPIO_OUT_LOW (0x20) +#define MPC52xx_GPT_MODE_GPIO_OUT_HIGH (0x30) + +#define MPC52xx_GPT_MODE_COUNTER_ENABLE (0x1000) +#define MPC52xx_GPT_MODE_CONTINUOUS (0x0400) +#define MPC52xx_GPT_MODE_OPEN_DRAIN (0x0200) +#define MPC52xx_GPT_MODE_IRQ_EN (0x0100) +#define MPC52xx_GPT_MODE_WDT_EN (0x8000) + +#define MPC52xx_GPT_MODE_ICT_MASK (0x030000) +#define MPC52xx_GPT_MODE_ICT_RISING (0x010000) +#define MPC52xx_GPT_MODE_ICT_FALLING (0x020000) +#define MPC52xx_GPT_MODE_ICT_TOGGLE (0x030000) + +#define MPC52xx_GPT_MODE_WDT_PING (0xa5) + +#define MPC52xx_GPT_STATUS_IRQMASK (0x000f) + +#define MPC52xx_GPT_CAN_WDT (1 << 0) +#define MPC52xx_GPT_IS_WDT (1 << 1) + + +/* --------------------------------------------------------------------- + * Cascaded interrupt controller hooks + */ + +static void mpc52xx_gpt_irq_unmask(struct irq_data *d) +{ + struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); + unsigned long flags; + + raw_spin_lock_irqsave(&gpt->lock, flags); + setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); + raw_spin_unlock_irqrestore(&gpt->lock, flags); +} + +static void mpc52xx_gpt_irq_mask(struct irq_data *d) +{ + struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); + unsigned long flags; + + raw_spin_lock_irqsave(&gpt->lock, flags); + clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); + raw_spin_unlock_irqrestore(&gpt->lock, flags); +} + +static void mpc52xx_gpt_irq_ack(struct irq_data *d) +{ + struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); + + out_be32(&gpt->regs->status, MPC52xx_GPT_STATUS_IRQMASK); +} + +static int mpc52xx_gpt_irq_set_type(struct irq_data *d, unsigned int flow_type) +{ + struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); + unsigned long flags; + u32 reg; + + dev_dbg(gpt->dev, "%s: virq=%i type=%x\n", __func__, d->irq, flow_type); + + raw_spin_lock_irqsave(&gpt->lock, flags); + reg = in_be32(&gpt->regs->mode) & ~MPC52xx_GPT_MODE_ICT_MASK; + if (flow_type & IRQF_TRIGGER_RISING) + reg |= MPC52xx_GPT_MODE_ICT_RISING; + if (flow_type & IRQF_TRIGGER_FALLING) + reg |= MPC52xx_GPT_MODE_ICT_FALLING; + out_be32(&gpt->regs->mode, reg); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + + return 0; +} + +static struct irq_chip mpc52xx_gpt_irq_chip = { + .name = "MPC52xx GPT", + .irq_unmask = mpc52xx_gpt_irq_unmask, + .irq_mask = mpc52xx_gpt_irq_mask, + .irq_ack = mpc52xx_gpt_irq_ack, + .irq_set_type = mpc52xx_gpt_irq_set_type, +}; + +static void mpc52xx_gpt_irq_cascade(struct irq_desc *desc) +{ + struct mpc52xx_gpt_priv *gpt = irq_desc_get_handler_data(desc); + u32 status; + + status = in_be32(&gpt->regs->status) & MPC52xx_GPT_STATUS_IRQMASK; + if (status) + generic_handle_domain_irq(gpt->irqhost, 0); +} + +static int mpc52xx_gpt_irq_map(struct irq_domain *h, unsigned int virq, + irq_hw_number_t hw) +{ + struct mpc52xx_gpt_priv *gpt = h->host_data; + + dev_dbg(gpt->dev, "%s: h=%p, virq=%i\n", __func__, h, virq); + irq_set_chip_data(virq, gpt); + irq_set_chip_and_handler(virq, &mpc52xx_gpt_irq_chip, handle_edge_irq); + + return 0; +} + +static int mpc52xx_gpt_irq_xlate(struct irq_domain *h, struct device_node *ct, + const u32 *intspec, unsigned int intsize, + irq_hw_number_t *out_hwirq, + unsigned int *out_flags) +{ + struct mpc52xx_gpt_priv *gpt = h->host_data; + + dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]); + + if ((intsize < 1) || (intspec[0] > 3)) { + dev_err(gpt->dev, "bad irq specifier in %pOF\n", ct); + return -EINVAL; + } + + *out_hwirq = 0; /* The GPT only has 1 IRQ line */ + *out_flags = intspec[0]; + + return 0; +} + +static const struct irq_domain_ops mpc52xx_gpt_irq_ops = { + .map = mpc52xx_gpt_irq_map, + .xlate = mpc52xx_gpt_irq_xlate, +}; + +static void +mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) +{ + int cascade_virq; + unsigned long flags; + u32 mode; + + cascade_virq = irq_of_parse_and_map(node, 0); + if (!cascade_virq) + return; + + gpt->irqhost = irq_domain_add_linear(node, 1, &mpc52xx_gpt_irq_ops, gpt); + if (!gpt->irqhost) { + dev_err(gpt->dev, "irq_domain_add_linear() failed\n"); + return; + } + + irq_set_handler_data(cascade_virq, gpt); + irq_set_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade); + + /* If the GPT is currently disabled, then change it to be in Input + * Capture mode. If the mode is non-zero, then the pin could be + * already in use for something. */ + raw_spin_lock_irqsave(&gpt->lock, flags); + mode = in_be32(&gpt->regs->mode); + if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0) + out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + + dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq); +} + + +/* --------------------------------------------------------------------- + * GPIOLIB hooks + */ +#if defined(CONFIG_GPIOLIB) +static int mpc52xx_gpt_gpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); + + return (in_be32(&gpt->regs->status) >> 8) & 1; +} + +static void +mpc52xx_gpt_gpio_set(struct gpio_chip *gc, unsigned int gpio, int v) +{ + struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); + unsigned long flags; + u32 r; + + dev_dbg(gpt->dev, "%s: gpio:%d v:%d\n", __func__, gpio, v); + r = v ? MPC52xx_GPT_MODE_GPIO_OUT_HIGH : MPC52xx_GPT_MODE_GPIO_OUT_LOW; + + raw_spin_lock_irqsave(&gpt->lock, flags); + clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK, r); + raw_spin_unlock_irqrestore(&gpt->lock, flags); +} + +static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) +{ + struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); + unsigned long flags; + + dev_dbg(gpt->dev, "%s: gpio:%d\n", __func__, gpio); + + raw_spin_lock_irqsave(&gpt->lock, flags); + clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + + return 0; +} + +static int +mpc52xx_gpt_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) +{ + mpc52xx_gpt_gpio_set(gc, gpio, val); + return 0; +} + +static void mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *gpt) +{ + int rc; + + /* Only setup GPIO if the device claims the GPT is a GPIO controller */ + if (!device_property_present(gpt->dev, "gpio-controller")) + return; + + gpt->gc.label = kasprintf(GFP_KERNEL, "%pfw", dev_fwnode(gpt->dev)); + if (!gpt->gc.label) { + dev_err(gpt->dev, "out of memory\n"); + return; + } + + gpt->gc.ngpio = 1; + gpt->gc.direction_input = mpc52xx_gpt_gpio_dir_in; + gpt->gc.direction_output = mpc52xx_gpt_gpio_dir_out; + gpt->gc.get = mpc52xx_gpt_gpio_get; + gpt->gc.set = mpc52xx_gpt_gpio_set; + gpt->gc.base = -1; + gpt->gc.parent = gpt->dev; + + /* Setup external pin in GPIO mode */ + clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK, + MPC52xx_GPT_MODE_MS_GPIO); + + rc = gpiochip_add_data(&gpt->gc, gpt); + if (rc) + dev_err(gpt->dev, "gpiochip_add_data() failed; rc=%i\n", rc); + + dev_dbg(gpt->dev, "%s() complete.\n", __func__); +} +#else /* defined(CONFIG_GPIOLIB) */ +static void mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *gpt) { } +#endif /* defined(CONFIG_GPIOLIB) */ + +/*********************************************************************** + * Timer API + */ + +/** + * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number + * @irq: irq of timer. + */ +struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq) +{ + struct mpc52xx_gpt_priv *gpt; + struct list_head *pos; + + /* Iterate over the list of timers looking for a matching device */ + mutex_lock(&mpc52xx_gpt_list_mutex); + list_for_each(pos, &mpc52xx_gpt_list) { + gpt = container_of(pos, struct mpc52xx_gpt_priv, list); + if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) { + mutex_unlock(&mpc52xx_gpt_list_mutex); + return gpt; + } + } + mutex_unlock(&mpc52xx_gpt_list_mutex); + + return NULL; +} +EXPORT_SYMBOL(mpc52xx_gpt_from_irq); + +static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period, + int continuous, int as_wdt) +{ + u32 clear, set; + u64 clocks; + u32 prescale; + unsigned long flags; + + clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS; + set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE; + if (as_wdt) { + clear |= MPC52xx_GPT_MODE_IRQ_EN; + set |= MPC52xx_GPT_MODE_WDT_EN; + } else if (continuous) + set |= MPC52xx_GPT_MODE_CONTINUOUS; + + /* Determine the number of clocks in the requested period. 64 bit + * arithmetic is done here to preserve the precision until the value + * is scaled back down into the u32 range. Period is in 'ns', bus + * frequency is in Hz. */ + clocks = period * (u64)gpt->ipb_freq; + do_div(clocks, 1000000000); /* Scale it down to ns range */ + + /* This device cannot handle a clock count greater than 32 bits */ + if (clocks > 0xffffffff) + return -EINVAL; + + /* Calculate the prescaler and count values from the clocks value. + * 'clocks' is the number of clock ticks in the period. The timer + * has 16 bit precision and a 16 bit prescaler. Prescaler is + * calculated by integer dividing the clocks by 0x10000 (shifting + * down 16 bits) to obtain the smallest possible divisor for clocks + * to get a 16 bit count value. + * + * Note: the prescale register is '1' based, not '0' based. ie. a + * value of '1' means divide the clock by one. 0xffff divides the + * clock by 0xffff. '0x0000' does not divide by zero, but wraps + * around and divides by 0x10000. That is why prescale must be + * a u32 variable, not a u16, for this calculation. */ + prescale = (clocks >> 16) + 1; + do_div(clocks, prescale); + if (clocks > 0xffff) { + pr_err("calculation error; prescale:%x clocks:%llx\n", + prescale, clocks); + return -EINVAL; + } + + /* Set and enable the timer, reject an attempt to use a wdt as gpt */ + raw_spin_lock_irqsave(&gpt->lock, flags); + if (as_wdt) + gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; + else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { + raw_spin_unlock_irqrestore(&gpt->lock, flags); + return -EBUSY; + } + out_be32(&gpt->regs->count, prescale << 16 | clocks); + clrsetbits_be32(&gpt->regs->mode, clear, set); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + + return 0; +} + +/** + * mpc52xx_gpt_start_timer - Set and enable the GPT timer + * @gpt: Pointer to gpt private data structure + * @period: period of timer in ns; max. ~130s @ 33MHz IPB clock + * @continuous: set to 1 to make timer continuous free running + * + * An interrupt will be generated every time the timer fires + */ +int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, u64 period, + int continuous) +{ + return mpc52xx_gpt_do_start(gpt, period, continuous, 0); +} +EXPORT_SYMBOL(mpc52xx_gpt_start_timer); + +/** + * mpc52xx_gpt_stop_timer - Stop a gpt + * @gpt: Pointer to gpt private data structure + * + * Returns an error if attempting to stop a wdt + */ +int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt) +{ + unsigned long flags; + + /* reject the operation if the timer is used as watchdog (gpt 0 only) */ + raw_spin_lock_irqsave(&gpt->lock, flags); + if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { + raw_spin_unlock_irqrestore(&gpt->lock, flags); + return -EBUSY; + } + + clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + return 0; +} +EXPORT_SYMBOL(mpc52xx_gpt_stop_timer); + +/** + * mpc52xx_gpt_timer_period - Read the timer period + * @gpt: Pointer to gpt private data structure + * + * Returns the timer period in ns + */ +u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt) +{ + u64 period; + u64 prescale; + unsigned long flags; + + raw_spin_lock_irqsave(&gpt->lock, flags); + period = in_be32(&gpt->regs->count); + raw_spin_unlock_irqrestore(&gpt->lock, flags); + + prescale = period >> 16; + period &= 0xffff; + if (prescale == 0) + prescale = 0x10000; + period = period * prescale * 1000000000ULL; + do_div(period, gpt->ipb_freq); + return period; +} +EXPORT_SYMBOL(mpc52xx_gpt_timer_period); + +#if defined(CONFIG_MPC5200_WDT) +/*********************************************************************** + * Watchdog API for gpt0 + */ + +#define WDT_IDENTITY "mpc52xx watchdog on GPT0" + +/* wdt_is_active stores whether or not the /dev/watchdog device is opened */ +static unsigned long wdt_is_active; + +/* wdt-capable gpt */ +static struct mpc52xx_gpt_priv *mpc52xx_gpt_wdt; + +/* low-level wdt functions */ +static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&gpt_wdt->lock, flags); + out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING); + raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags); +} + +/* wdt misc device api */ +static ssize_t mpc52xx_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + mpc52xx_gpt_wdt_ping(gpt_wdt); + return 0; +} + +static const struct watchdog_info mpc5200_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = WDT_IDENTITY, +}; + +static long mpc52xx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + int __user *data = (int __user *)arg; + int timeout; + u64 real_timeout; + int ret = 0; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user(data, &mpc5200_wdt_info, + sizeof(mpc5200_wdt_info)); + if (ret) + ret = -EFAULT; + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, data); + break; + + case WDIOC_KEEPALIVE: + mpc52xx_gpt_wdt_ping(gpt_wdt); + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(timeout, data); + if (ret) + break; + real_timeout = (u64) timeout * 1000000000ULL; + ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1); + if (ret) + break; + /* fall through and return the timeout */ + fallthrough; + + case WDIOC_GETTIMEOUT: + /* we need to round here as to avoid e.g. the following + * situation: + * - timeout requested is 1 second; + * - real timeout @33MHz is 999997090ns + * - the int divide by 10^9 will return 0. + */ + real_timeout = + mpc52xx_gpt_timer_period(gpt_wdt) + 500000000ULL; + do_div(real_timeout, 1000000000ULL); + timeout = (int) real_timeout; + ret = put_user(timeout, data); + break; + + default: + ret = -ENOTTY; + } + return ret; +} + +static int mpc52xx_wdt_open(struct inode *inode, struct file *file) +{ + int ret; + + /* sanity check */ + if (!mpc52xx_gpt_wdt) + return -ENODEV; + + /* /dev/watchdog can only be opened once */ + if (test_and_set_bit(0, &wdt_is_active)) + return -EBUSY; + + /* Set and activate the watchdog with 30 seconds timeout */ + ret = mpc52xx_gpt_do_start(mpc52xx_gpt_wdt, 30ULL * 1000000000ULL, + 0, 1); + if (ret) { + clear_bit(0, &wdt_is_active); + return ret; + } + + file->private_data = mpc52xx_gpt_wdt; + return stream_open(inode, file); +} + +static int mpc52xx_wdt_release(struct inode *inode, struct file *file) +{ + /* note: releasing the wdt in NOWAYOUT-mode does not stop it */ +#if !defined(CONFIG_WATCHDOG_NOWAYOUT) + struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; + unsigned long flags; + + raw_spin_lock_irqsave(&gpt_wdt->lock, flags); + clrbits32(&gpt_wdt->regs->mode, + MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN); + gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT; + raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags); +#endif + clear_bit(0, &wdt_is_active); + return 0; +} + + +static const struct file_operations mpc52xx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = mpc52xx_wdt_write, + .unlocked_ioctl = mpc52xx_wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = mpc52xx_wdt_open, + .release = mpc52xx_wdt_release, +}; + +static struct miscdevice mpc52xx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &mpc52xx_wdt_fops, +}; + +static int mpc52xx_gpt_wdt_init(void) +{ + int err; + + /* try to register the watchdog misc device */ + err = misc_register(&mpc52xx_wdt_miscdev); + if (err) + pr_err("%s: cannot register watchdog device\n", WDT_IDENTITY); + else + pr_info("%s: watchdog device registered\n", WDT_IDENTITY); + return err; +} + +static int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, + const u32 *period) +{ + u64 real_timeout; + + /* remember the gpt for the wdt operation */ + mpc52xx_gpt_wdt = gpt; + + /* configure the wdt if the device tree contained a timeout */ + if (!period || *period == 0) + return 0; + + real_timeout = (u64) *period * 1000000000ULL; + if (mpc52xx_gpt_do_start(gpt, real_timeout, 0, 1)) + dev_warn(gpt->dev, "starting as wdt failed\n"); + else + dev_info(gpt->dev, "watchdog set to %us timeout\n", *period); + return 0; +} + +#else + +static int mpc52xx_gpt_wdt_init(void) +{ + return 0; +} + +static inline int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, + const u32 *period) +{ + return 0; +} + +#endif /* CONFIG_MPC5200_WDT */ + +/* --------------------------------------------------------------------- + * of_platform bus binding code + */ +static int mpc52xx_gpt_probe(struct platform_device *ofdev) +{ + struct mpc52xx_gpt_priv *gpt; + + gpt = devm_kzalloc(&ofdev->dev, sizeof *gpt, GFP_KERNEL); + if (!gpt) + return -ENOMEM; + + raw_spin_lock_init(&gpt->lock); + gpt->dev = &ofdev->dev; + gpt->ipb_freq = mpc5xxx_get_bus_frequency(&ofdev->dev); + gpt->regs = of_iomap(ofdev->dev.of_node, 0); + if (!gpt->regs) + return -ENOMEM; + + dev_set_drvdata(&ofdev->dev, gpt); + + mpc52xx_gpt_gpio_setup(gpt); + mpc52xx_gpt_irq_setup(gpt, ofdev->dev.of_node); + + mutex_lock(&mpc52xx_gpt_list_mutex); + list_add(&gpt->list, &mpc52xx_gpt_list); + mutex_unlock(&mpc52xx_gpt_list_mutex); + + /* check if this device could be a watchdog */ + if (of_property_read_bool(ofdev->dev.of_node, "fsl,has-wdt") || + of_property_read_bool(ofdev->dev.of_node, "has-wdt")) { + const u32 *on_boot_wdt; + + gpt->wdt_mode = MPC52xx_GPT_CAN_WDT; + on_boot_wdt = of_get_property(ofdev->dev.of_node, + "fsl,wdt-on-boot", NULL); + if (on_boot_wdt) { + dev_info(gpt->dev, "used as watchdog\n"); + gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; + } else + dev_info(gpt->dev, "can function as watchdog\n"); + mpc52xx_gpt_wdt_setup(gpt, on_boot_wdt); + } + + return 0; +} + +static const struct of_device_id mpc52xx_gpt_match[] = { + { .compatible = "fsl,mpc5200-gpt", }, + + /* Depreciated compatible values; don't use for new dts files */ + { .compatible = "fsl,mpc5200-gpt-gpio", }, + { .compatible = "mpc5200-gpt", }, + {} +}; + +static struct platform_driver mpc52xx_gpt_driver = { + .driver = { + .name = "mpc52xx-gpt", + .suppress_bind_attrs = true, + .of_match_table = mpc52xx_gpt_match, + }, + .probe = mpc52xx_gpt_probe, +}; + +static int __init mpc52xx_gpt_init(void) +{ + return platform_driver_register(&mpc52xx_gpt_driver); +} + +/* Make sure GPIOs and IRQs get set up before anyone tries to use them */ +subsys_initcall(mpc52xx_gpt_init); +device_initcall(mpc52xx_gpt_wdt_init); 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