diff options
Diffstat (limited to 'drivers/rtc/rtc-twl.c')
| -rw-r--r-- | drivers/rtc/rtc-twl.c | 540 |
1 files changed, 540 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c new file mode 100644 index 00000000000..93565be12fa --- /dev/null +++ b/drivers/rtc/rtc-twl.c @@ -0,0 +1,540 @@ +/* + * rtc-twl4030.c -- TWL4030 Real Time Clock interface + * + * Copyright (C) 2007 MontaVista Software, Inc + * Author: Alexandre Rusev <source@mvista.com> + * + * Based on original TI driver twl4030-rtc.c + * Copyright (C) 2006 Texas Instruments, Inc. + * + * Based on rtc-omap.c + * Copyright (C) 2003 MontaVista Software, Inc. + * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com> + * Copyright (C) 2006 David Brownell + * + * 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/kernel.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/rtc.h> +#include <linux/bcd.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> + +#include <linux/i2c/twl.h> + + +/* + * RTC block register offsets (use TWL_MODULE_RTC) + */ +#define REG_SECONDS_REG 0x00 +#define REG_MINUTES_REG 0x01 +#define REG_HOURS_REG 0x02 +#define REG_DAYS_REG 0x03 +#define REG_MONTHS_REG 0x04 +#define REG_YEARS_REG 0x05 +#define REG_WEEKS_REG 0x06 + +#define REG_ALARM_SECONDS_REG 0x07 +#define REG_ALARM_MINUTES_REG 0x08 +#define REG_ALARM_HOURS_REG 0x09 +#define REG_ALARM_DAYS_REG 0x0A +#define REG_ALARM_MONTHS_REG 0x0B +#define REG_ALARM_YEARS_REG 0x0C + +#define REG_RTC_CTRL_REG 0x0D +#define REG_RTC_STATUS_REG 0x0E +#define REG_RTC_INTERRUPTS_REG 0x0F + +#define REG_RTC_COMP_LSB_REG 0x10 +#define REG_RTC_COMP_MSB_REG 0x11 + +/* RTC_CTRL_REG bitfields */ +#define BIT_RTC_CTRL_REG_STOP_RTC_M 0x01 +#define BIT_RTC_CTRL_REG_ROUND_30S_M 0x02 +#define BIT_RTC_CTRL_REG_AUTO_COMP_M 0x04 +#define BIT_RTC_CTRL_REG_MODE_12_24_M 0x08 +#define BIT_RTC_CTRL_REG_TEST_MODE_M 0x10 +#define BIT_RTC_CTRL_REG_SET_32_COUNTER_M 0x20 +#define BIT_RTC_CTRL_REG_GET_TIME_M 0x40 + +/* RTC_STATUS_REG bitfields */ +#define BIT_RTC_STATUS_REG_RUN_M 0x02 +#define BIT_RTC_STATUS_REG_1S_EVENT_M 0x04 +#define BIT_RTC_STATUS_REG_1M_EVENT_M 0x08 +#define BIT_RTC_STATUS_REG_1H_EVENT_M 0x10 +#define BIT_RTC_STATUS_REG_1D_EVENT_M 0x20 +#define BIT_RTC_STATUS_REG_ALARM_M 0x40 +#define BIT_RTC_STATUS_REG_POWER_UP_M 0x80 + +/* RTC_INTERRUPTS_REG bitfields */ +#define BIT_RTC_INTERRUPTS_REG_EVERY_M 0x03 +#define BIT_RTC_INTERRUPTS_REG_IT_TIMER_M 0x04 +#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M 0x08 + + +/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */ +#define ALL_TIME_REGS 6 + +/*----------------------------------------------------------------------*/ + +/* + * Supports 1 byte read from TWL4030 RTC register. + */ +static int twl4030_rtc_read_u8(u8 *data, u8 reg) +{ + int ret; + + ret = twl4030_i2c_read_u8(TWL4030_MODULE_RTC, data, reg); + if (ret < 0) + pr_err("twl4030_rtc: Could not read TWL4030" + "register %X - error %d\n", reg, ret); + return ret; +} + +/* + * Supports 1 byte write to TWL4030 RTC registers. + */ +static int twl4030_rtc_write_u8(u8 data, u8 reg) +{ + int ret; + + ret = twl4030_i2c_write_u8(TWL4030_MODULE_RTC, data, reg); + if (ret < 0) + pr_err("twl4030_rtc: Could not write TWL4030" + "register %X - error %d\n", reg, ret); + return ret; +} + +/* + * Cache the value for timer/alarm interrupts register; this is + * only changed by callers holding rtc ops lock (or resume). + */ +static unsigned char rtc_irq_bits; + +/* + * Enable 1/second update and/or alarm interrupts. + */ +static int set_rtc_irq_bit(unsigned char bit) +{ + unsigned char val; + int ret; + + val = rtc_irq_bits | bit; + val &= ~BIT_RTC_INTERRUPTS_REG_EVERY_M; + ret = twl4030_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG); + if (ret == 0) + rtc_irq_bits = val; + + return ret; +} + +/* + * Disable update and/or alarm interrupts. + */ +static int mask_rtc_irq_bit(unsigned char bit) +{ + unsigned char val; + int ret; + + val = rtc_irq_bits & ~bit; + ret = twl4030_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG); + if (ret == 0) + rtc_irq_bits = val; + + return ret; +} + +static int twl4030_rtc_alarm_irq_enable(struct device *dev, unsigned enabled) +{ + int ret; + + if (enabled) + ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + else + ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + + return ret; +} + +static int twl4030_rtc_update_irq_enable(struct device *dev, unsigned enabled) +{ + int ret; + + if (enabled) + ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + else + ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + + return ret; +} + +/* + * Gets current TWL4030 RTC time and date parameters. + * + * The RTC's time/alarm representation is not what gmtime(3) requires + * Linux to use: + * + * - Months are 1..12 vs Linux 0-11 + * - Years are 0..99 vs Linux 1900..N (we assume 21st century) + */ +static int twl4030_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[ALL_TIME_REGS + 1]; + int ret; + u8 save_control; + + ret = twl4030_rtc_read_u8(&save_control, REG_RTC_CTRL_REG); + if (ret < 0) + return ret; + + save_control |= BIT_RTC_CTRL_REG_GET_TIME_M; + + ret = twl4030_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + if (ret < 0) + return ret; + + ret = twl4030_i2c_read(TWL4030_MODULE_RTC, rtc_data, + REG_SECONDS_REG, ALL_TIME_REGS); + + if (ret < 0) { + dev_err(dev, "rtc_read_time error %d\n", ret); + return ret; + } + + tm->tm_sec = bcd2bin(rtc_data[0]); + tm->tm_min = bcd2bin(rtc_data[1]); + tm->tm_hour = bcd2bin(rtc_data[2]); + tm->tm_mday = bcd2bin(rtc_data[3]); + tm->tm_mon = bcd2bin(rtc_data[4]) - 1; + tm->tm_year = bcd2bin(rtc_data[5]) + 100; + + return ret; +} + +static int twl4030_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char save_control; + unsigned char rtc_data[ALL_TIME_REGS + 1]; + int ret; + + rtc_data[1] = bin2bcd(tm->tm_sec); + rtc_data[2] = bin2bcd(tm->tm_min); + rtc_data[3] = bin2bcd(tm->tm_hour); + rtc_data[4] = bin2bcd(tm->tm_mday); + rtc_data[5] = bin2bcd(tm->tm_mon + 1); + rtc_data[6] = bin2bcd(tm->tm_year - 100); + + /* Stop RTC while updating the TC registers */ + ret = twl4030_rtc_read_u8(&save_control, REG_RTC_CTRL_REG); + if (ret < 0) + goto out; + + save_control &= ~BIT_RTC_CTRL_REG_STOP_RTC_M; + twl4030_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + if (ret < 0) + goto out; + + /* update all the time registers in one shot */ + ret = twl4030_i2c_write(TWL4030_MODULE_RTC, rtc_data, + REG_SECONDS_REG, ALL_TIME_REGS); + if (ret < 0) { + dev_err(dev, "rtc_set_time error %d\n", ret); + goto out; + } + + /* Start back RTC */ + save_control |= BIT_RTC_CTRL_REG_STOP_RTC_M; + ret = twl4030_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + +out: + return ret; +} + +/* + * Gets current TWL4030 RTC alarm time. + */ +static int twl4030_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char rtc_data[ALL_TIME_REGS + 1]; + int ret; + + ret = twl4030_i2c_read(TWL4030_MODULE_RTC, rtc_data, + REG_ALARM_SECONDS_REG, ALL_TIME_REGS); + if (ret < 0) { + dev_err(dev, "rtc_read_alarm error %d\n", ret); + return ret; + } + + /* some of these fields may be wildcard/"match all" */ + alm->time.tm_sec = bcd2bin(rtc_data[0]); + alm->time.tm_min = bcd2bin(rtc_data[1]); + alm->time.tm_hour = bcd2bin(rtc_data[2]); + alm->time.tm_mday = bcd2bin(rtc_data[3]); + alm->time.tm_mon = bcd2bin(rtc_data[4]) - 1; + alm->time.tm_year = bcd2bin(rtc_data[5]) + 100; + + /* report cached alarm enable state */ + if (rtc_irq_bits & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) + alm->enabled = 1; + + return ret; +} + +static int twl4030_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[ALL_TIME_REGS + 1]; + int ret; + + ret = twl4030_rtc_alarm_irq_enable(dev, 0); + if (ret) + goto out; + + alarm_data[1] = bin2bcd(alm->time.tm_sec); + alarm_data[2] = bin2bcd(alm->time.tm_min); + alarm_data[3] = bin2bcd(alm->time.tm_hour); + alarm_data[4] = bin2bcd(alm->time.tm_mday); + alarm_data[5] = bin2bcd(alm->time.tm_mon + 1); + alarm_data[6] = bin2bcd(alm->time.tm_year - 100); + + /* update all the alarm registers in one shot */ + ret = twl4030_i2c_write(TWL4030_MODULE_RTC, alarm_data, + REG_ALARM_SECONDS_REG, ALL_TIME_REGS); + if (ret) { + dev_err(dev, "rtc_set_alarm error %d\n", ret); + goto out; + } + + if (alm->enabled) + ret = twl4030_rtc_alarm_irq_enable(dev, 1); +out: + return ret; +} + +static irqreturn_t twl4030_rtc_interrupt(int irq, void *rtc) +{ + unsigned long events = 0; + int ret = IRQ_NONE; + int res; + u8 rd_reg; + +#ifdef CONFIG_LOCKDEP + /* WORKAROUND for lockdep forcing IRQF_DISABLED on us, which + * we don't want and can't tolerate. Although it might be + * friendlier not to borrow this thread context... + */ + local_irq_enable(); +#endif + + res = twl4030_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG); + if (res) + goto out; + /* + * Figure out source of interrupt: ALARM or TIMER in RTC_STATUS_REG. + * only one (ALARM or RTC) interrupt source may be enabled + * at time, we also could check our results + * by reading RTS_INTERRUPTS_REGISTER[IT_TIMER,IT_ALARM] + */ + if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M) + events |= RTC_IRQF | RTC_AF; + else + events |= RTC_IRQF | RTC_UF; + + res = twl4030_rtc_write_u8(rd_reg | BIT_RTC_STATUS_REG_ALARM_M, + REG_RTC_STATUS_REG); + if (res) + goto out; + + /* Clear on Read enabled. RTC_IT bit of TWL4030_INT_PWR_ISR1 + * needs 2 reads to clear the interrupt. One read is done in + * do_twl4030_pwrirq(). Doing the second read, to clear + * the bit. + * + * FIXME the reason PWR_ISR1 needs an extra read is that + * RTC_IF retriggered until we cleared REG_ALARM_M above. + * But re-reading like this is a bad hack; by doing so we + * risk wrongly clearing status for some other IRQ (losing + * the interrupt). Be smarter about handling RTC_UF ... + */ + res = twl4030_i2c_read_u8(TWL4030_MODULE_INT, + &rd_reg, TWL4030_INT_PWR_ISR1); + if (res) + goto out; + + /* Notify RTC core on event */ + rtc_update_irq(rtc, 1, events); + + ret = IRQ_HANDLED; +out: + return ret; +} + +static struct rtc_class_ops twl4030_rtc_ops = { + .read_time = twl4030_rtc_read_time, + .set_time = twl4030_rtc_set_time, + .read_alarm = twl4030_rtc_read_alarm, + .set_alarm = twl4030_rtc_set_alarm, + .alarm_irq_enable = twl4030_rtc_alarm_irq_enable, + .update_irq_enable = twl4030_rtc_update_irq_enable, +}; + +/*----------------------------------------------------------------------*/ + +static int __devinit twl4030_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + int ret = 0; + int irq = platform_get_irq(pdev, 0); + u8 rd_reg; + + if (irq <= 0) + return -EINVAL; + + rtc = rtc_device_register(pdev->name, + &pdev->dev, &twl4030_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + ret = PTR_ERR(rtc); + dev_err(&pdev->dev, "can't register RTC device, err %ld\n", + PTR_ERR(rtc)); + goto out0; + + } + + platform_set_drvdata(pdev, rtc); + + ret = twl4030_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG); + if (ret < 0) + goto out1; + + if (rd_reg & BIT_RTC_STATUS_REG_POWER_UP_M) + dev_warn(&pdev->dev, "Power up reset detected.\n"); + + if (rd_reg & BIT_RTC_STATUS_REG_ALARM_M) + dev_warn(&pdev->dev, "Pending Alarm interrupt detected.\n"); + + /* Clear RTC Power up reset and pending alarm interrupts */ + ret = twl4030_rtc_write_u8(rd_reg, REG_RTC_STATUS_REG); + if (ret < 0) + goto out1; + + ret = request_irq(irq, twl4030_rtc_interrupt, + IRQF_TRIGGER_RISING, + dev_name(&rtc->dev), rtc); + if (ret < 0) { + dev_err(&pdev->dev, "IRQ is not free.\n"); + goto out1; + } + + /* Check RTC module status, Enable if it is off */ + ret = twl4030_rtc_read_u8(&rd_reg, REG_RTC_CTRL_REG); + if (ret < 0) + goto out2; + + if (!(rd_reg & BIT_RTC_CTRL_REG_STOP_RTC_M)) { + dev_info(&pdev->dev, "Enabling TWL4030-RTC.\n"); + rd_reg = BIT_RTC_CTRL_REG_STOP_RTC_M; + ret = twl4030_rtc_write_u8(rd_reg, REG_RTC_CTRL_REG); + if (ret < 0) + goto out2; + } + + /* init cached IRQ enable bits */ + ret = twl4030_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG); + if (ret < 0) + goto out2; + + return ret; + +out2: + free_irq(irq, rtc); +out1: + rtc_device_unregister(rtc); +out0: + return ret; +} + +/* + * Disable all TWL4030 RTC module interrupts. + * Sets status flag to free. + */ +static int __devexit twl4030_rtc_remove(struct platform_device *pdev) +{ + /* leave rtc running, but disable irqs */ + struct rtc_device *rtc = platform_get_drvdata(pdev); + int irq = platform_get_irq(pdev, 0); + + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + + free_irq(irq, rtc); + + rtc_device_unregister(rtc); + platform_set_drvdata(pdev, NULL); + return 0; +} + +static void twl4030_rtc_shutdown(struct platform_device *pdev) +{ + /* mask timer interrupts, but leave alarm interrupts on to enable + power-on when alarm is triggered */ + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); +} + +#ifdef CONFIG_PM + +static unsigned char irqstat; + +static int twl4030_rtc_suspend(struct platform_device *pdev, pm_message_t state) +{ + irqstat = rtc_irq_bits; + + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + return 0; +} + +static int twl4030_rtc_resume(struct platform_device *pdev) +{ + set_rtc_irq_bit(irqstat); + return 0; +} + +#else +#define twl4030_rtc_suspend NULL +#define twl4030_rtc_resume NULL +#endif + +MODULE_ALIAS("platform:twl4030_rtc"); + +static struct platform_driver twl4030rtc_driver = { + .probe = twl4030_rtc_probe, + .remove = __devexit_p(twl4030_rtc_remove), + .shutdown = twl4030_rtc_shutdown, + .suspend = twl4030_rtc_suspend, + .resume = twl4030_rtc_resume, + .driver = { + .owner = THIS_MODULE, + .name = "twl4030_rtc", + }, +}; + +static int __init twl4030_rtc_init(void) +{ + return platform_driver_register(&twl4030rtc_driver); +} +module_init(twl4030_rtc_init); + +static void __exit twl4030_rtc_exit(void) +{ + platform_driver_unregister(&twl4030rtc_driver); +} +module_exit(twl4030_rtc_exit); + +MODULE_AUTHOR("Texas Instruments, MontaVista Software"); +MODULE_LICENSE("GPL"); |