diff options
Diffstat (limited to 'drivers/rtc/rtc-digicolor.c')
| -rw-r--r-- | drivers/rtc/rtc-digicolor.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-digicolor.c b/drivers/rtc/rtc-digicolor.c new file mode 100644 index 000000000000..8d05596a6765 --- /dev/null +++ b/drivers/rtc/rtc-digicolor.c @@ -0,0 +1,227 @@ +/* + * Real Time Clock driver for Conexant Digicolor + * + * Copyright (C) 2015 Paradox Innovation Ltd. + * + * Author: Baruch Siach <baruch@tkos.co.il> + * + * 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/io.h> +#include <linux/iopoll.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/of.h> + +#define DC_RTC_CONTROL 0x0 +#define DC_RTC_TIME 0x8 +#define DC_RTC_REFERENCE 0xc +#define DC_RTC_ALARM 0x10 +#define DC_RTC_INTFLAG_CLEAR 0x14 +#define DC_RTC_INTENABLE 0x16 + +#define DC_RTC_CMD_MASK 0xf +#define DC_RTC_GO_BUSY BIT(7) + +#define CMD_NOP 0 +#define CMD_RESET 1 +#define CMD_WRITE 3 +#define CMD_READ 4 + +#define CMD_DELAY_US (10*1000) +#define CMD_TIMEOUT_US (500*CMD_DELAY_US) + +struct dc_rtc { + struct rtc_device *rtc_dev; + void __iomem *regs; +}; + +static int dc_rtc_cmds(struct dc_rtc *rtc, const u8 *cmds, int len) +{ + u8 val; + int i, ret; + + for (i = 0; i < len; i++) { + writeb_relaxed((cmds[i] & DC_RTC_CMD_MASK) | DC_RTC_GO_BUSY, + rtc->regs + DC_RTC_CONTROL); + ret = readb_relaxed_poll_timeout( + rtc->regs + DC_RTC_CONTROL, val, + !(val & DC_RTC_GO_BUSY), CMD_DELAY_US, CMD_TIMEOUT_US); + if (ret < 0) + return ret; + } + + return 0; +} + +static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val) +{ + static const u8 read_cmds[] = {CMD_READ, CMD_NOP}; + u32 reference, time1, time2; + int ret; + + ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds)); + if (ret < 0) + return ret; + + reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); + time1 = readl_relaxed(rtc->regs + DC_RTC_TIME); + /* Read twice to ensure consistency */ + while (1) { + time2 = readl_relaxed(rtc->regs + DC_RTC_TIME); + if (time1 == time2) + break; + time1 = time2; + } + + *val = reference + time1; + return 0; +} + +static int dc_rtc_write(struct dc_rtc *rtc, u32 val) +{ + static const u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP}; + + writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE); + return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds)); +} + +static int dc_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct dc_rtc *rtc = dev_get_drvdata(dev); + unsigned long now; + int ret; + + ret = dc_rtc_read(rtc, &now); + if (ret < 0) + return ret; + rtc_time64_to_tm(now, tm); + + return 0; +} + +static int dc_rtc_set_mmss(struct device *dev, unsigned long secs) +{ + struct dc_rtc *rtc = dev_get_drvdata(dev); + + return dc_rtc_write(rtc, secs); +} + +static int dc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct dc_rtc *rtc = dev_get_drvdata(dev); + u32 alarm_reg, reference; + unsigned long now; + int ret; + + alarm_reg = readl_relaxed(rtc->regs + DC_RTC_ALARM); + reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); + rtc_time64_to_tm(reference + alarm_reg, &alarm->time); + + ret = dc_rtc_read(rtc, &now); + if (ret < 0) + return ret; + + alarm->pending = alarm_reg + reference > now; + alarm->enabled = readl_relaxed(rtc->regs + DC_RTC_INTENABLE); + + return 0; +} + +static int dc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct dc_rtc *rtc = dev_get_drvdata(dev); + time64_t alarm_time; + u32 reference; + + alarm_time = rtc_tm_to_time64(&alarm->time); + + reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE); + writel_relaxed(alarm_time - reference, rtc->regs + DC_RTC_ALARM); + + writeb_relaxed(!!alarm->enabled, rtc->regs + DC_RTC_INTENABLE); + + return 0; +} + +static int dc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct dc_rtc *rtc = dev_get_drvdata(dev); + + writeb_relaxed(!!enabled, rtc->regs + DC_RTC_INTENABLE); + + return 0; +} + +static struct rtc_class_ops dc_rtc_ops = { + .read_time = dc_rtc_read_time, + .set_mmss = dc_rtc_set_mmss, + .read_alarm = dc_rtc_read_alarm, + .set_alarm = dc_rtc_set_alarm, + .alarm_irq_enable = dc_rtc_alarm_irq_enable, +}; + +static irqreturn_t dc_rtc_irq(int irq, void *dev_id) +{ + struct dc_rtc *rtc = dev_id; + + writeb_relaxed(1, rtc->regs + DC_RTC_INTFLAG_CLEAR); + rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF); + + return IRQ_HANDLED; +} + +static int __init dc_rtc_probe(struct platform_device *pdev) +{ + struct resource *res; + struct dc_rtc *rtc; + int irq, ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rtc->regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rtc->regs)) + return PTR_ERR(rtc->regs); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + ret = devm_request_irq(&pdev->dev, irq, dc_rtc_irq, 0, pdev->name, rtc); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, rtc); + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, + &dc_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + + return 0; +} + +static const struct of_device_id dc_dt_ids[] = { + { .compatible = "cnxt,cx92755-rtc" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, dc_dt_ids); + +static struct platform_driver dc_rtc_driver = { + .driver = { + .name = "digicolor_rtc", + .of_match_table = of_match_ptr(dc_dt_ids), + }, +}; +module_platform_driver_probe(dc_rtc_driver, dc_rtc_probe); + +MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); +MODULE_DESCRIPTION("Conexant Digicolor Realtime Clock Driver (RTC)"); +MODULE_LICENSE("GPL"); |