diff options
Diffstat (limited to 'drivers/rtc/rtc-pm8xxx.c')
| -rw-r--r-- | drivers/rtc/rtc-pm8xxx.c | 550 |
1 files changed, 550 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c new file mode 100644 index 00000000000..d420e9d877e --- /dev/null +++ b/drivers/rtc/rtc-pm8xxx.c @@ -0,0 +1,550 @@ +/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/rtc.h> +#include <linux/pm.h> +#include <linux/slab.h> +#include <linux/spinlock.h> + +#include <linux/mfd/pm8xxx/core.h> +#include <linux/mfd/pm8xxx/rtc.h> + + +/* RTC Register offsets from RTC CTRL REG */ +#define PM8XXX_ALARM_CTRL_OFFSET 0x01 +#define PM8XXX_RTC_WRITE_OFFSET 0x02 +#define PM8XXX_RTC_READ_OFFSET 0x06 +#define PM8XXX_ALARM_RW_OFFSET 0x0A + +/* RTC_CTRL register bit fields */ +#define PM8xxx_RTC_ENABLE BIT(7) +#define PM8xxx_RTC_ALARM_ENABLE BIT(1) +#define PM8xxx_RTC_ALARM_CLEAR BIT(0) + +#define NUM_8_BIT_RTC_REGS 0x4 + +/** + * struct pm8xxx_rtc - rtc driver internal structure + * @rtc: rtc device for this driver. + * @rtc_alarm_irq: rtc alarm irq number. + * @rtc_base: address of rtc control register. + * @rtc_read_base: base address of read registers. + * @rtc_write_base: base address of write registers. + * @alarm_rw_base: base address of alarm registers. + * @ctrl_reg: rtc control register. + * @rtc_dev: device structure. + * @ctrl_reg_lock: spinlock protecting access to ctrl_reg. + */ +struct pm8xxx_rtc { + struct rtc_device *rtc; + int rtc_alarm_irq; + int rtc_base; + int rtc_read_base; + int rtc_write_base; + int alarm_rw_base; + u8 ctrl_reg; + struct device *rtc_dev; + spinlock_t ctrl_reg_lock; +}; + +/* + * The RTC registers need to be read/written one byte at a time. This is a + * hardware limitation. + */ +static int pm8xxx_read_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val, + int base, int count) +{ + int i, rc; + struct device *parent = rtc_dd->rtc_dev->parent; + + for (i = 0; i < count; i++) { + rc = pm8xxx_readb(parent, base + i, &rtc_val[i]); + if (rc < 0) { + dev_err(rtc_dd->rtc_dev, "PMIC read failed\n"); + return rc; + } + } + + return 0; +} + +static int pm8xxx_write_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val, + int base, int count) +{ + int i, rc; + struct device *parent = rtc_dd->rtc_dev->parent; + + for (i = 0; i < count; i++) { + rc = pm8xxx_writeb(parent, base + i, rtc_val[i]); + if (rc < 0) { + dev_err(rtc_dd->rtc_dev, "PMIC write failed\n"); + return rc; + } + } + + return 0; +} + +/* + * Steps to write the RTC registers. + * 1. Disable alarm if enabled. + * 2. Write 0x00 to LSB. + * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0]. + * 4. Enable alarm if disabled in step 1. + */ +static int pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + int rc, i; + unsigned long secs, irq_flags; + u8 value[NUM_8_BIT_RTC_REGS], reg = 0, alarm_enabled = 0, ctrl_reg; + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + rtc_tm_to_time(tm, &secs); + + for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) { + value[i] = secs & 0xFF; + secs >>= 8; + } + + dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs); + + spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags); + ctrl_reg = rtc_dd->ctrl_reg; + + if (ctrl_reg & PM8xxx_RTC_ALARM_ENABLE) { + alarm_enabled = 1; + ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE; + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, + 1); + if (rc < 0) { + dev_err(dev, "Write to RTC control register " + "failed\n"); + goto rtc_rw_fail; + } + rtc_dd->ctrl_reg = ctrl_reg; + } else + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + + /* Write 0 to Byte[0] */ + reg = 0; + rc = pm8xxx_write_wrapper(rtc_dd, ®, rtc_dd->rtc_write_base, 1); + if (rc < 0) { + dev_err(dev, "Write to RTC write data register failed\n"); + goto rtc_rw_fail; + } + + /* Write Byte[1], Byte[2], Byte[3] */ + rc = pm8xxx_write_wrapper(rtc_dd, value + 1, + rtc_dd->rtc_write_base + 1, 3); + if (rc < 0) { + dev_err(dev, "Write to RTC write data register failed\n"); + goto rtc_rw_fail; + } + + /* Write Byte[0] */ + rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->rtc_write_base, 1); + if (rc < 0) { + dev_err(dev, "Write to RTC write data register failed\n"); + goto rtc_rw_fail; + } + + if (alarm_enabled) { + ctrl_reg |= PM8xxx_RTC_ALARM_ENABLE; + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, + 1); + if (rc < 0) { + dev_err(dev, "Write to RTC control register " + "failed\n"); + goto rtc_rw_fail; + } + rtc_dd->ctrl_reg = ctrl_reg; + } + +rtc_rw_fail: + if (alarm_enabled) + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + + return rc; +} + +static int pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + int rc; + u8 value[NUM_8_BIT_RTC_REGS], reg; + unsigned long secs; + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->rtc_read_base, + NUM_8_BIT_RTC_REGS); + if (rc < 0) { + dev_err(dev, "RTC read data register failed\n"); + return rc; + } + + /* + * Read the LSB again and check if there has been a carry over. + * If there is, redo the read operation. + */ + rc = pm8xxx_read_wrapper(rtc_dd, ®, rtc_dd->rtc_read_base, 1); + if (rc < 0) { + dev_err(dev, "RTC read data register failed\n"); + return rc; + } + + if (unlikely(reg < value[0])) { + rc = pm8xxx_read_wrapper(rtc_dd, value, + rtc_dd->rtc_read_base, NUM_8_BIT_RTC_REGS); + if (rc < 0) { + dev_err(dev, "RTC read data register failed\n"); + return rc; + } + } + + secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24); + + rtc_time_to_tm(secs, tm); + + rc = rtc_valid_tm(tm); + if (rc < 0) { + dev_err(dev, "Invalid time read from RTC\n"); + return rc; + } + + dev_dbg(dev, "secs = %lu, h:m:s == %d:%d:%d, d/m/y = %d/%d/%d\n", + secs, tm->tm_hour, tm->tm_min, tm->tm_sec, + tm->tm_mday, tm->tm_mon, tm->tm_year); + + return 0; +} + +static int pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + int rc, i; + u8 value[NUM_8_BIT_RTC_REGS], ctrl_reg; + unsigned long secs, irq_flags; + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + rtc_tm_to_time(&alarm->time, &secs); + + for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) { + value[i] = secs & 0xFF; + secs >>= 8; + } + + spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags); + + rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base, + NUM_8_BIT_RTC_REGS); + if (rc < 0) { + dev_err(dev, "Write to RTC ALARM register failed\n"); + goto rtc_rw_fail; + } + + ctrl_reg = rtc_dd->ctrl_reg; + ctrl_reg = alarm->enabled ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) : + (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE); + + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1); + if (rc < 0) { + dev_err(dev, "Write to RTC control register failed\n"); + goto rtc_rw_fail; + } + + rtc_dd->ctrl_reg = ctrl_reg; + + dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n", + alarm->time.tm_hour, alarm->time.tm_min, + alarm->time.tm_sec, alarm->time.tm_mday, + alarm->time.tm_mon, alarm->time.tm_year); +rtc_rw_fail: + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + return rc; +} + +static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + int rc; + u8 value[NUM_8_BIT_RTC_REGS]; + unsigned long secs; + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base, + NUM_8_BIT_RTC_REGS); + if (rc < 0) { + dev_err(dev, "RTC alarm time read failed\n"); + return rc; + } + + secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24); + + rtc_time_to_tm(secs, &alarm->time); + + rc = rtc_valid_tm(&alarm->time); + if (rc < 0) { + dev_err(dev, "Invalid alarm time read from RTC\n"); + return rc; + } + + dev_dbg(dev, "Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n", + alarm->time.tm_hour, alarm->time.tm_min, + alarm->time.tm_sec, alarm->time.tm_mday, + alarm->time.tm_mon, alarm->time.tm_year); + + return 0; +} + +static int pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) +{ + int rc; + unsigned long irq_flags; + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + u8 ctrl_reg; + + spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags); + ctrl_reg = rtc_dd->ctrl_reg; + ctrl_reg = (enable) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) : + (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE); + + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1); + if (rc < 0) { + dev_err(dev, "Write to RTC control register failed\n"); + goto rtc_rw_fail; + } + + rtc_dd->ctrl_reg = ctrl_reg; + +rtc_rw_fail: + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + return rc; +} + +static struct rtc_class_ops pm8xxx_rtc_ops = { + .read_time = pm8xxx_rtc_read_time, + .set_alarm = pm8xxx_rtc_set_alarm, + .read_alarm = pm8xxx_rtc_read_alarm, + .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable, +}; + +static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id) +{ + struct pm8xxx_rtc *rtc_dd = dev_id; + u8 ctrl_reg; + int rc; + unsigned long irq_flags; + + rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF); + + spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags); + + /* Clear the alarm enable bit */ + ctrl_reg = rtc_dd->ctrl_reg; + ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE; + + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1); + if (rc < 0) { + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + dev_err(rtc_dd->rtc_dev, "Write to RTC control register " + "failed\n"); + goto rtc_alarm_handled; + } + + rtc_dd->ctrl_reg = ctrl_reg; + spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags); + + /* Clear RTC alarm register */ + rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base + + PM8XXX_ALARM_CTRL_OFFSET, 1); + if (rc < 0) { + dev_err(rtc_dd->rtc_dev, "RTC Alarm control register read " + "failed\n"); + goto rtc_alarm_handled; + } + + ctrl_reg &= ~PM8xxx_RTC_ALARM_CLEAR; + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base + + PM8XXX_ALARM_CTRL_OFFSET, 1); + if (rc < 0) + dev_err(rtc_dd->rtc_dev, "Write to RTC Alarm control register" + " failed\n"); + +rtc_alarm_handled: + return IRQ_HANDLED; +} + +static int __devinit pm8xxx_rtc_probe(struct platform_device *pdev) +{ + int rc; + u8 ctrl_reg; + bool rtc_write_enable = false; + struct pm8xxx_rtc *rtc_dd; + struct resource *rtc_resource; + const struct pm8xxx_rtc_platform_data *pdata = + dev_get_platdata(&pdev->dev); + + if (pdata != NULL) + rtc_write_enable = pdata->rtc_write_enable; + + rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL); + if (rtc_dd == NULL) { + dev_err(&pdev->dev, "Unable to allocate memory!\n"); + return -ENOMEM; + } + + /* Initialise spinlock to protect RTC control register */ + spin_lock_init(&rtc_dd->ctrl_reg_lock); + + rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0); + if (rtc_dd->rtc_alarm_irq < 0) { + dev_err(&pdev->dev, "Alarm IRQ resource absent!\n"); + rc = -ENXIO; + goto fail_rtc_enable; + } + + rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO, + "pmic_rtc_base"); + if (!(rtc_resource && rtc_resource->start)) { + dev_err(&pdev->dev, "RTC IO resource absent!\n"); + rc = -ENXIO; + goto fail_rtc_enable; + } + + rtc_dd->rtc_base = rtc_resource->start; + + /* Setup RTC register addresses */ + rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET; + rtc_dd->rtc_read_base = rtc_dd->rtc_base + PM8XXX_RTC_READ_OFFSET; + rtc_dd->alarm_rw_base = rtc_dd->rtc_base + PM8XXX_ALARM_RW_OFFSET; + + rtc_dd->rtc_dev = &pdev->dev; + + /* Check if the RTC is on, else turn it on */ + rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1); + if (rc < 0) { + dev_err(&pdev->dev, "RTC control register read failed!\n"); + goto fail_rtc_enable; + } + + if (!(ctrl_reg & PM8xxx_RTC_ENABLE)) { + ctrl_reg |= PM8xxx_RTC_ENABLE; + rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, + 1); + if (rc < 0) { + dev_err(&pdev->dev, "Write to RTC control register " + "failed\n"); + goto fail_rtc_enable; + } + } + + rtc_dd->ctrl_reg = ctrl_reg; + if (rtc_write_enable == true) + pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time; + + platform_set_drvdata(pdev, rtc_dd); + + /* Register the RTC device */ + rtc_dd->rtc = rtc_device_register("pm8xxx_rtc", &pdev->dev, + &pm8xxx_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc_dd->rtc)) { + dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n", + __func__, PTR_ERR(rtc_dd->rtc)); + rc = PTR_ERR(rtc_dd->rtc); + goto fail_rtc_enable; + } + + /* Request the alarm IRQ */ + rc = request_any_context_irq(rtc_dd->rtc_alarm_irq, + pm8xxx_alarm_trigger, IRQF_TRIGGER_RISING, + "pm8xxx_rtc_alarm", rtc_dd); + if (rc < 0) { + dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc); + goto fail_req_irq; + } + + device_init_wakeup(&pdev->dev, 1); + + dev_dbg(&pdev->dev, "Probe success !!\n"); + + return 0; + +fail_req_irq: + rtc_device_unregister(rtc_dd->rtc); +fail_rtc_enable: + platform_set_drvdata(pdev, NULL); + kfree(rtc_dd); + return rc; +} + +static int __devexit pm8xxx_rtc_remove(struct platform_device *pdev) +{ + struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev); + + device_init_wakeup(&pdev->dev, 0); + free_irq(rtc_dd->rtc_alarm_irq, rtc_dd); + rtc_device_unregister(rtc_dd->rtc); + platform_set_drvdata(pdev, NULL); + kfree(rtc_dd); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int pm8xxx_rtc_resume(struct device *dev) +{ + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(rtc_dd->rtc_alarm_irq); + + return 0; +} + +static int pm8xxx_rtc_suspend(struct device *dev) +{ + struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(rtc_dd->rtc_alarm_irq); + + return 0; +} +#endif + +SIMPLE_DEV_PM_OPS(pm8xxx_rtc_pm_ops, pm8xxx_rtc_suspend, pm8xxx_rtc_resume); + +static struct platform_driver pm8xxx_rtc_driver = { + .probe = pm8xxx_rtc_probe, + .remove = __devexit_p(pm8xxx_rtc_remove), + .driver = { + .name = PM8XXX_RTC_DEV_NAME, + .owner = THIS_MODULE, + .pm = &pm8xxx_rtc_pm_ops, + }, +}; + +static int __init pm8xxx_rtc_init(void) +{ + return platform_driver_register(&pm8xxx_rtc_driver); +} +module_init(pm8xxx_rtc_init); + +static void __exit pm8xxx_rtc_exit(void) +{ + platform_driver_unregister(&pm8xxx_rtc_driver); +} +module_exit(pm8xxx_rtc_exit); + +MODULE_ALIAS("platform:rtc-pm8xxx"); +MODULE_DESCRIPTION("PMIC8xxx RTC driver"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>"); 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