diff options
Diffstat (limited to 'kernel/drivers/rtc/rtc-twl.c')
| -rw-r--r-- | kernel/drivers/rtc/rtc-twl.c | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/kernel/drivers/rtc/rtc-twl.c b/kernel/drivers/rtc/rtc-twl.c new file mode 100644 index 000000000..2dc787dc0 --- /dev/null +++ b/kernel/drivers/rtc/rtc-twl.c @@ -0,0 +1,621 @@ +/* + * rtc-twl.c -- TWL 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/of.h> + +#include <linux/i2c/twl.h> + + +/* + * RTC block register offsets (use TWL_MODULE_RTC) + */ +enum { + REG_SECONDS_REG = 0, + REG_MINUTES_REG, + REG_HOURS_REG, + REG_DAYS_REG, + REG_MONTHS_REG, + REG_YEARS_REG, + REG_WEEKS_REG, + + REG_ALARM_SECONDS_REG, + REG_ALARM_MINUTES_REG, + REG_ALARM_HOURS_REG, + REG_ALARM_DAYS_REG, + REG_ALARM_MONTHS_REG, + REG_ALARM_YEARS_REG, + + REG_RTC_CTRL_REG, + REG_RTC_STATUS_REG, + REG_RTC_INTERRUPTS_REG, + + REG_RTC_COMP_LSB_REG, + REG_RTC_COMP_MSB_REG, +}; +static const u8 twl4030_rtc_reg_map[] = { + [REG_SECONDS_REG] = 0x00, + [REG_MINUTES_REG] = 0x01, + [REG_HOURS_REG] = 0x02, + [REG_DAYS_REG] = 0x03, + [REG_MONTHS_REG] = 0x04, + [REG_YEARS_REG] = 0x05, + [REG_WEEKS_REG] = 0x06, + + [REG_ALARM_SECONDS_REG] = 0x07, + [REG_ALARM_MINUTES_REG] = 0x08, + [REG_ALARM_HOURS_REG] = 0x09, + [REG_ALARM_DAYS_REG] = 0x0A, + [REG_ALARM_MONTHS_REG] = 0x0B, + [REG_ALARM_YEARS_REG] = 0x0C, + + [REG_RTC_CTRL_REG] = 0x0D, + [REG_RTC_STATUS_REG] = 0x0E, + [REG_RTC_INTERRUPTS_REG] = 0x0F, + + [REG_RTC_COMP_LSB_REG] = 0x10, + [REG_RTC_COMP_MSB_REG] = 0x11, +}; +static const u8 twl6030_rtc_reg_map[] = { + [REG_SECONDS_REG] = 0x00, + [REG_MINUTES_REG] = 0x01, + [REG_HOURS_REG] = 0x02, + [REG_DAYS_REG] = 0x03, + [REG_MONTHS_REG] = 0x04, + [REG_YEARS_REG] = 0x05, + [REG_WEEKS_REG] = 0x06, + + [REG_ALARM_SECONDS_REG] = 0x08, + [REG_ALARM_MINUTES_REG] = 0x09, + [REG_ALARM_HOURS_REG] = 0x0A, + [REG_ALARM_DAYS_REG] = 0x0B, + [REG_ALARM_MONTHS_REG] = 0x0C, + [REG_ALARM_YEARS_REG] = 0x0D, + + [REG_RTC_CTRL_REG] = 0x10, + [REG_RTC_STATUS_REG] = 0x11, + [REG_RTC_INTERRUPTS_REG] = 0x12, + + [REG_RTC_COMP_LSB_REG] = 0x13, + [REG_RTC_COMP_MSB_REG] = 0x14, +}; + +/* 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 +#define BIT_RTC_CTRL_REG_RTC_V_OPT 0x80 + +/* 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 + +/*----------------------------------------------------------------------*/ +static u8 *rtc_reg_map; + +/* + * Supports 1 byte read from TWL RTC register. + */ +static int twl_rtc_read_u8(u8 *data, u8 reg) +{ + int ret; + + ret = twl_i2c_read_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg])); + if (ret < 0) + pr_err("Could not read TWL register %X - error %d\n", reg, ret); + return ret; +} + +/* + * Supports 1 byte write to TWL RTC registers. + */ +static int twl_rtc_write_u8(u8 data, u8 reg) +{ + int ret; + + ret = twl_i2c_write_u8(TWL_MODULE_RTC, data, (rtc_reg_map[reg])); + if (ret < 0) + pr_err("Could not write TWL 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; + + /* if the bit is set, return from here */ + if (rtc_irq_bits & bit) + return 0; + + val = rtc_irq_bits | bit; + val &= ~BIT_RTC_INTERRUPTS_REG_EVERY_M; + ret = twl_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; + + /* if the bit is clear, return from here */ + if (!(rtc_irq_bits & bit)) + return 0; + + val = rtc_irq_bits & ~bit; + ret = twl_rtc_write_u8(val, REG_RTC_INTERRUPTS_REG); + if (ret == 0) + rtc_irq_bits = val; + + return ret; +} + +static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled) +{ + struct platform_device *pdev = to_platform_device(dev); + int irq = platform_get_irq(pdev, 0); + static bool twl_rtc_wake_enabled; + int ret; + + if (enabled) { + ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) { + enable_irq_wake(irq); + twl_rtc_wake_enabled = true; + } + } else { + ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + if (twl_rtc_wake_enabled) { + disable_irq_wake(irq); + twl_rtc_wake_enabled = false; + } + } + + return ret; +} + +/* + * Gets current TWL 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 twl_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[ALL_TIME_REGS]; + int ret; + u8 save_control; + u8 rtc_control; + + ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG); + if (ret < 0) { + dev_err(dev, "%s: reading CTRL_REG, error %d\n", __func__, ret); + return ret; + } + /* for twl6030/32 make sure BIT_RTC_CTRL_REG_GET_TIME_M is clear */ + if (twl_class_is_6030()) { + if (save_control & BIT_RTC_CTRL_REG_GET_TIME_M) { + save_control &= ~BIT_RTC_CTRL_REG_GET_TIME_M; + ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + if (ret < 0) { + dev_err(dev, "%s clr GET_TIME, error %d\n", + __func__, ret); + return ret; + } + } + } + + /* Copy RTC counting registers to static registers or latches */ + rtc_control = save_control | BIT_RTC_CTRL_REG_GET_TIME_M; + + /* for twl6030/32 enable read access to static shadowed registers */ + if (twl_class_is_6030()) + rtc_control |= BIT_RTC_CTRL_REG_RTC_V_OPT; + + ret = twl_rtc_write_u8(rtc_control, REG_RTC_CTRL_REG); + if (ret < 0) { + dev_err(dev, "%s: writing CTRL_REG, error %d\n", __func__, ret); + return ret; + } + + ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data, + (rtc_reg_map[REG_SECONDS_REG]), ALL_TIME_REGS); + + if (ret < 0) { + dev_err(dev, "%s: reading data, error %d\n", __func__, ret); + return ret; + } + + /* for twl6030 restore original state of rtc control register */ + if (twl_class_is_6030()) { + ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + if (ret < 0) { + dev_err(dev, "%s: restore CTRL_REG, error %d\n", + __func__, 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 twl_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char save_control; + unsigned char rtc_data[ALL_TIME_REGS]; + int ret; + + rtc_data[0] = bin2bcd(tm->tm_sec); + rtc_data[1] = bin2bcd(tm->tm_min); + rtc_data[2] = bin2bcd(tm->tm_hour); + rtc_data[3] = bin2bcd(tm->tm_mday); + rtc_data[4] = bin2bcd(tm->tm_mon + 1); + rtc_data[5] = bin2bcd(tm->tm_year - 100); + + /* Stop RTC while updating the TC registers */ + ret = twl_rtc_read_u8(&save_control, REG_RTC_CTRL_REG); + if (ret < 0) + goto out; + + save_control &= ~BIT_RTC_CTRL_REG_STOP_RTC_M; + ret = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + if (ret < 0) + goto out; + + /* update all the time registers in one shot */ + ret = twl_i2c_write(TWL_MODULE_RTC, rtc_data, + (rtc_reg_map[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 = twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG); + +out: + return ret; +} + +/* + * Gets current TWL RTC alarm time. + */ +static int twl_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char rtc_data[ALL_TIME_REGS]; + int ret; + + ret = twl_i2c_read(TWL_MODULE_RTC, rtc_data, + (rtc_reg_map[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 twl_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[ALL_TIME_REGS]; + int ret; + + ret = twl_rtc_alarm_irq_enable(dev, 0); + if (ret) + goto out; + + alarm_data[0] = bin2bcd(alm->time.tm_sec); + alarm_data[1] = bin2bcd(alm->time.tm_min); + alarm_data[2] = bin2bcd(alm->time.tm_hour); + alarm_data[3] = bin2bcd(alm->time.tm_mday); + alarm_data[4] = bin2bcd(alm->time.tm_mon + 1); + alarm_data[5] = bin2bcd(alm->time.tm_year - 100); + + /* update all the alarm registers in one shot */ + ret = twl_i2c_write(TWL_MODULE_RTC, alarm_data, + (rtc_reg_map[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 = twl_rtc_alarm_irq_enable(dev, 1); +out: + return ret; +} + +static irqreturn_t twl_rtc_interrupt(int irq, void *rtc) +{ + unsigned long events; + int ret = IRQ_NONE; + int res; + u8 rd_reg; + + res = twl_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_PF; + + res = twl_rtc_write_u8(BIT_RTC_STATUS_REG_ALARM_M, + REG_RTC_STATUS_REG); + if (res) + goto out; + + if (twl_class_is_4030()) { + /* 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_twl_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 = twl_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 twl_rtc_ops = { + .read_time = twl_rtc_read_time, + .set_time = twl_rtc_set_time, + .read_alarm = twl_rtc_read_alarm, + .set_alarm = twl_rtc_set_alarm, + .alarm_irq_enable = twl_rtc_alarm_irq_enable, +}; + +/*----------------------------------------------------------------------*/ + +static int twl_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + int ret = -EINVAL; + int irq = platform_get_irq(pdev, 0); + u8 rd_reg; + + if (irq <= 0) + return ret; + + /* Initialize the register map */ + if (twl_class_is_4030()) + rtc_reg_map = (u8 *)twl4030_rtc_reg_map; + else + rtc_reg_map = (u8 *)twl6030_rtc_reg_map; + + ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG); + if (ret < 0) + return ret; + + 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 = twl_rtc_write_u8(rd_reg, REG_RTC_STATUS_REG); + if (ret < 0) + return ret; + + if (twl_class_is_6030()) { + twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK, + REG_INT_MSK_LINE_A); + twl6030_interrupt_unmask(TWL6030_RTC_INT_MASK, + REG_INT_MSK_STS_A); + } + + dev_info(&pdev->dev, "Enabling TWL-RTC\n"); + ret = twl_rtc_write_u8(BIT_RTC_CTRL_REG_STOP_RTC_M, REG_RTC_CTRL_REG); + if (ret < 0) + return ret; + + /* ensure interrupts are disabled, bootloaders can be strange */ + ret = twl_rtc_write_u8(0, REG_RTC_INTERRUPTS_REG); + if (ret < 0) + dev_warn(&pdev->dev, "unable to disable interrupt\n"); + + /* init cached IRQ enable bits */ + ret = twl_rtc_read_u8(&rtc_irq_bits, REG_RTC_INTERRUPTS_REG); + if (ret < 0) + return ret; + + device_init_wakeup(&pdev->dev, 1); + + rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &twl_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) { + dev_err(&pdev->dev, "can't register RTC device, err %ld\n", + PTR_ERR(rtc)); + return PTR_ERR(rtc); + } + + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, + twl_rtc_interrupt, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + dev_name(&rtc->dev), rtc); + if (ret < 0) { + dev_err(&pdev->dev, "IRQ is not free.\n"); + return ret; + } + + platform_set_drvdata(pdev, rtc); + return 0; +} + +/* + * Disable all TWL RTC module interrupts. + * Sets status flag to free. + */ +static int twl_rtc_remove(struct platform_device *pdev) +{ + /* leave rtc running, but disable irqs */ + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M); + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + if (twl_class_is_6030()) { + twl6030_interrupt_mask(TWL6030_RTC_INT_MASK, + REG_INT_MSK_LINE_A); + twl6030_interrupt_mask(TWL6030_RTC_INT_MASK, + REG_INT_MSK_STS_A); + } + + return 0; +} + +static void twl_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_SLEEP +static unsigned char irqstat; + +static int twl_rtc_suspend(struct device *dev) +{ + irqstat = rtc_irq_bits; + + mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_TIMER_M); + return 0; +} + +static int twl_rtc_resume(struct device *dev) +{ + set_rtc_irq_bit(irqstat); + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(twl_rtc_pm_ops, twl_rtc_suspend, twl_rtc_resume); + +#ifdef CONFIG_OF +static const struct of_device_id twl_rtc_of_match[] = { + {.compatible = "ti,twl4030-rtc", }, + { }, +}; +MODULE_DEVICE_TABLE(of, twl_rtc_of_match); +#endif + +MODULE_ALIAS("platform:twl_rtc"); + +static struct platform_driver twl4030rtc_driver = { + .probe = twl_rtc_probe, + .remove = twl_rtc_remove, + .shutdown = twl_rtc_shutdown, + .driver = { + .name = "twl_rtc", + .pm = &twl_rtc_pm_ops, + .of_match_table = of_match_ptr(twl_rtc_of_match), + }, +}; + +module_platform_driver(twl4030rtc_driver); + +MODULE_AUTHOR("Texas Instruments, MontaVista Software"); +MODULE_LICENSE("GPL"); |