diff options
Diffstat (limited to 'drivers/watchdog/da9052_wdt.c')
| -rw-r--r-- | drivers/watchdog/da9052_wdt.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c new file mode 100644 index 0000000..3f75129 --- /dev/null +++ b/drivers/watchdog/da9052_wdt.c @@ -0,0 +1,251 @@ +/* + * System monitoring driver for DA9052 PMICs. + * + * Copyright(c) 2012 Dialog Semiconductor Ltd. + * + * Author: Anthony Olech <Anthony.Olech@diasemi.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/uaccess.h> +#include <linux/platform_device.h> +#include <linux/time.h> +#include <linux/watchdog.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/delay.h> + +#include <linux/mfd/da9052/reg.h> +#include <linux/mfd/da9052/da9052.h> + +#define DA9052_DEF_TIMEOUT 4 +#define DA9052_TWDMIN 256 + +struct da9052_wdt_data { + struct watchdog_device wdt; + struct da9052 *da9052; + struct kref kref; + unsigned long jpast; +}; + +static const struct { + u8 reg_val; + int time; /* Seconds */ +} da9052_wdt_maps[] = { + { 1, 2 }, + { 2, 4 }, + { 3, 8 }, + { 4, 16 }, + { 5, 32 }, + { 5, 33 }, /* Actual time 32.768s so included both 32s and 33s */ + { 6, 65 }, + { 6, 66 }, /* Actual time 65.536s so include both, 65s and 66s */ + { 7, 131 }, +}; + + +static void da9052_wdt_release_resources(struct kref *r) +{ + struct da9052_wdt_data *driver_data = + container_of(r, struct da9052_wdt_data, kref); + + kfree(driver_data); +} + +static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + struct da9052 *da9052 = driver_data->da9052; + int ret, i; + + /* + * Disable the Watchdog timer before setting + * new time out. + */ + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + DA9052_CONTROLD_TWDSCALE, 0); + if (ret < 0) { + dev_err(da9052->dev, "Failed to disable watchdog bit, %d\n", + ret); + return ret; + } + if (timeout) { + /* + * To change the timeout, da9052 needs to + * be disabled for at least 150 us. + */ + udelay(150); + + /* Set the desired timeout */ + for (i = 0; i < ARRAY_SIZE(da9052_wdt_maps); i++) + if (da9052_wdt_maps[i].time == timeout) + break; + + if (i == ARRAY_SIZE(da9052_wdt_maps)) + ret = -EINVAL; + else + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + DA9052_CONTROLD_TWDSCALE, + da9052_wdt_maps[i].reg_val); + if (ret < 0) { + dev_err(da9052->dev, + "Failed to update timescale bit, %d\n", ret); + return ret; + } + + wdt_dev->timeout = timeout; + driver_data->jpast = jiffies; + } + + return 0; +} + +static void da9052_wdt_ref(struct watchdog_device *wdt_dev) +{ + struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + + kref_get(&driver_data->kref); +} + +static void da9052_wdt_unref(struct watchdog_device *wdt_dev) +{ + struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + + kref_put(&driver_data->kref, da9052_wdt_release_resources); +} + +static int da9052_wdt_start(struct watchdog_device *wdt_dev) +{ + return da9052_wdt_set_timeout(wdt_dev, wdt_dev->timeout); +} + +static int da9052_wdt_stop(struct watchdog_device *wdt_dev) +{ + return da9052_wdt_set_timeout(wdt_dev, 0); +} + +static int da9052_wdt_ping(struct watchdog_device *wdt_dev) +{ + struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + struct da9052 *da9052 = driver_data->da9052; + unsigned long msec, jnow = jiffies; + int ret; + + /* + * We have a minimum time for watchdog window called TWDMIN. A write + * to the watchdog before this elapsed time should cause an error. + */ + msec = (jnow - driver_data->jpast) * 1000/HZ; + if (msec < DA9052_TWDMIN) + mdelay(msec); + + /* Reset the watchdog timer */ + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + DA9052_CONTROLD_WATCHDOG, 1 << 7); + if (ret < 0) + goto err_strobe; + + /* + * FIXME: Reset the watchdog core, in general PMIC + * is supposed to do this + */ + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + DA9052_CONTROLD_WATCHDOG, 0 << 7); +err_strobe: + return ret; +} + +static struct watchdog_info da9052_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = "DA9052 Watchdog", +}; + +static const struct watchdog_ops da9052_wdt_ops = { + .owner = THIS_MODULE, + .start = da9052_wdt_start, + .stop = da9052_wdt_stop, + .ping = da9052_wdt_ping, + .set_timeout = da9052_wdt_set_timeout, + .ref = da9052_wdt_ref, + .unref = da9052_wdt_unref, +}; + + +static int __devinit da9052_wdt_probe(struct platform_device *pdev) +{ + struct da9052 *da9052 = dev_get_drvdata(pdev->dev.parent); + struct da9052_wdt_data *driver_data; + struct watchdog_device *da9052_wdt; + int ret; + + driver_data = devm_kzalloc(&pdev->dev, sizeof(*driver_data), + GFP_KERNEL); + if (!driver_data) { + dev_err(da9052->dev, "Unable to alloacate watchdog device\n"); + ret = -ENOMEM; + goto err; + } + driver_data->da9052 = da9052; + + da9052_wdt = &driver_data->wdt; + + da9052_wdt->timeout = DA9052_DEF_TIMEOUT; + da9052_wdt->info = &da9052_wdt_info; + da9052_wdt->ops = &da9052_wdt_ops; + watchdog_set_drvdata(da9052_wdt, driver_data); + + kref_init(&driver_data->kref); + + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + DA9052_CONTROLD_TWDSCALE, 0); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to disable watchdog bits, %d\n", + ret); + goto err; + } + + ret = watchdog_register_device(&driver_data->wdt); + if (ret != 0) { + dev_err(da9052->dev, "watchdog_register_device() failed: %d\n", + ret); + goto err; + } + + dev_set_drvdata(&pdev->dev, driver_data); +err: + return ret; +} + +static int __devexit da9052_wdt_remove(struct platform_device *pdev) +{ + struct da9052_wdt_data *driver_data = dev_get_drvdata(&pdev->dev); + + watchdog_unregister_device(&driver_data->wdt); + kref_put(&driver_data->kref, da9052_wdt_release_resources); + + return 0; +} + +static struct platform_driver da9052_wdt_driver = { + .probe = da9052_wdt_probe, + .remove = __devexit_p(da9052_wdt_remove), + .driver = { + .name = "da9052-watchdog", + }, +}; + +module_platform_driver(da9052_wdt_driver); + +MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>"); +MODULE_DESCRIPTION("DA9052 SM Device Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:da9052-watchdog"); |