diff options
Diffstat (limited to 'drivers/rtc/rtc-ab3100.c')
| -rw-r--r-- | drivers/rtc/rtc-ab3100.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ab3100.c b/drivers/rtc/rtc-ab3100.c new file mode 100644 index 000000000..2ed6def90 --- /dev/null +++ b/drivers/rtc/rtc-ab3100.c @@ -0,0 +1,254 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007-2009 ST-Ericsson AB + * RTC clock driver for the AB3100 Analog Baseband Chip + * Author: Linus Walleij <linus.walleij@stericsson.com> + */ +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/mfd/abx500.h> + +/* Clock rate in Hz */ +#define AB3100_RTC_CLOCK_RATE 32768 + +/* + * The AB3100 RTC registers. These are the same for + * AB3000 and AB3100. + * Control register: + * Bit 0: RTC Monitor cleared=0, active=1, if you set it + * to 1 it remains active until RTC power is lost. + * Bit 1: 32 kHz Oscillator, 0 = on, 1 = bypass + * Bit 2: Alarm on, 0 = off, 1 = on + * Bit 3: 32 kHz buffer disabling, 0 = enabled, 1 = disabled + */ +#define AB3100_RTC 0x53 +/* default setting, buffer disabled, alarm on */ +#define RTC_SETTING 0x30 +/* Alarm when AL0-AL3 == TI0-TI3 */ +#define AB3100_AL0 0x56 +#define AB3100_AL1 0x57 +#define AB3100_AL2 0x58 +#define AB3100_AL3 0x59 +/* This 48-bit register that counts up at 32768 Hz */ +#define AB3100_TI0 0x5a +#define AB3100_TI1 0x5b +#define AB3100_TI2 0x5c +#define AB3100_TI3 0x5d +#define AB3100_TI4 0x5e +#define AB3100_TI5 0x5f + +/* + * RTC clock functions and device struct declaration + */ +static int ab3100_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + u8 regs[] = {AB3100_TI0, AB3100_TI1, AB3100_TI2, + AB3100_TI3, AB3100_TI4, AB3100_TI5}; + unsigned char buf[6]; + u64 hw_counter = rtc_tm_to_time64(tm) * AB3100_RTC_CLOCK_RATE * 2; + int err = 0; + int i; + + buf[0] = (hw_counter) & 0xFF; + buf[1] = (hw_counter >> 8) & 0xFF; + buf[2] = (hw_counter >> 16) & 0xFF; + buf[3] = (hw_counter >> 24) & 0xFF; + buf[4] = (hw_counter >> 32) & 0xFF; + buf[5] = (hw_counter >> 40) & 0xFF; + + for (i = 0; i < 6; i++) { + err = abx500_set_register_interruptible(dev, 0, + regs[i], buf[i]); + if (err) + return err; + } + + /* Set the flag to mark that the clock is now set */ + return abx500_mask_and_set_register_interruptible(dev, 0, + AB3100_RTC, + 0x01, 0x01); + +} + +static int ab3100_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + time64_t time; + u8 rtcval; + int err; + + err = abx500_get_register_interruptible(dev, 0, + AB3100_RTC, &rtcval); + if (err) + return err; + + if (!(rtcval & 0x01)) { + dev_info(dev, "clock not set (lost power)"); + return -EINVAL; + } else { + u64 hw_counter; + u8 buf[6]; + + /* Read out time registers */ + err = abx500_get_register_page_interruptible(dev, 0, + AB3100_TI0, + buf, 6); + if (err != 0) + return err; + + hw_counter = ((u64) buf[5] << 40) | ((u64) buf[4] << 32) | + ((u64) buf[3] << 24) | ((u64) buf[2] << 16) | + ((u64) buf[1] << 8) | (u64) buf[0]; + time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2); + } + + rtc_time64_to_tm(time, tm); + + return 0; +} + +static int ab3100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + time64_t time; + u64 hw_counter; + u8 buf[6]; + u8 rtcval; + int err; + + /* Figure out if alarm is enabled or not */ + err = abx500_get_register_interruptible(dev, 0, + AB3100_RTC, &rtcval); + if (err) + return err; + if (rtcval & 0x04) + alarm->enabled = 1; + else + alarm->enabled = 0; + /* No idea how this could be represented */ + alarm->pending = 0; + /* Read out alarm registers, only 4 bytes */ + err = abx500_get_register_page_interruptible(dev, 0, + AB3100_AL0, buf, 4); + if (err) + return err; + hw_counter = ((u64) buf[3] << 40) | ((u64) buf[2] << 32) | + ((u64) buf[1] << 24) | ((u64) buf[0] << 16); + time = hw_counter / (u64) (AB3100_RTC_CLOCK_RATE * 2); + + rtc_time64_to_tm(time, &alarm->time); + + return rtc_valid_tm(&alarm->time); +} + +static int ab3100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + u8 regs[] = {AB3100_AL0, AB3100_AL1, AB3100_AL2, AB3100_AL3}; + unsigned char buf[4]; + time64_t secs; + u64 hw_counter; + int err; + int i; + + secs = rtc_tm_to_time64(&alarm->time); + hw_counter = secs * AB3100_RTC_CLOCK_RATE * 2; + buf[0] = (hw_counter >> 16) & 0xFF; + buf[1] = (hw_counter >> 24) & 0xFF; + buf[2] = (hw_counter >> 32) & 0xFF; + buf[3] = (hw_counter >> 40) & 0xFF; + + /* Set the alarm */ + for (i = 0; i < 4; i++) { + err = abx500_set_register_interruptible(dev, 0, + regs[i], buf[i]); + if (err) + return err; + } + /* Then enable the alarm */ + return abx500_mask_and_set_register_interruptible(dev, 0, + AB3100_RTC, (1 << 2), + alarm->enabled << 2); +} + +static int ab3100_rtc_irq_enable(struct device *dev, unsigned int enabled) +{ + /* + * It's not possible to enable/disable the alarm IRQ for this RTC. + * It does not actually trigger any IRQ: instead its only function is + * to power up the system, if it wasn't on. This will manifest as + * a "power up cause" in the AB3100 power driver (battery charging etc) + * and need to be handled there instead. + */ + if (enabled) + return abx500_mask_and_set_register_interruptible(dev, 0, + AB3100_RTC, (1 << 2), + 1 << 2); + else + return abx500_mask_and_set_register_interruptible(dev, 0, + AB3100_RTC, (1 << 2), + 0); +} + +static const struct rtc_class_ops ab3100_rtc_ops = { + .read_time = ab3100_rtc_read_time, + .set_time = ab3100_rtc_set_time, + .read_alarm = ab3100_rtc_read_alarm, + .set_alarm = ab3100_rtc_set_alarm, + .alarm_irq_enable = ab3100_rtc_irq_enable, +}; + +static int __init ab3100_rtc_probe(struct platform_device *pdev) +{ + int err; + u8 regval; + struct rtc_device *rtc; + + /* The first RTC register needs special treatment */ + err = abx500_get_register_interruptible(&pdev->dev, 0, + AB3100_RTC, ®val); + if (err) { + dev_err(&pdev->dev, "unable to read RTC register\n"); + return -ENODEV; + } + + if ((regval & 0xFE) != RTC_SETTING) { + dev_warn(&pdev->dev, "not default value in RTC reg 0x%x\n", + regval); + } + + if ((regval & 1) == 0) { + /* + * Set bit to detect power loss. + * This bit remains until RTC power is lost. + */ + regval = 1 | RTC_SETTING; + err = abx500_set_register_interruptible(&pdev->dev, 0, + AB3100_RTC, regval); + /* Ignore any error on this write */ + } + + rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + rtc->ops = &ab3100_rtc_ops; + /* 48bit counter at (AB3100_RTC_CLOCK_RATE * 2) */ + rtc->range_max = U32_MAX; + + platform_set_drvdata(pdev, rtc); + + return rtc_register_device(rtc); +} + +static struct platform_driver ab3100_rtc_driver = { + .driver = { + .name = "ab3100-rtc", + }, +}; + +module_platform_driver_probe(ab3100_rtc_driver, ab3100_rtc_probe); + +MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); +MODULE_DESCRIPTION("AB3100 RTC Driver"); +MODULE_LICENSE("GPL"); |