diff options
Diffstat (limited to 'drivers/rtc/rtc-fsl-ftm-alarm.c')
| -rw-r--r-- | drivers/rtc/rtc-fsl-ftm-alarm.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-fsl-ftm-alarm.c b/drivers/rtc/rtc-fsl-ftm-alarm.c new file mode 100644 index 000000000000..8df2075af9a2 --- /dev/null +++ b/drivers/rtc/rtc-fsl-ftm-alarm.c @@ -0,0 +1,337 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Freescale FlexTimer Module (FTM) alarm device driver. + * + * Copyright 2014 Freescale Semiconductor, Inc. + * Copyright 2019 NXP + * + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/module.h> +#include <linux/fsl/ftm.h> +#include <linux/rtc.h> +#include <linux/time.h> + +#define FTM_SC_CLK(c) ((c) << FTM_SC_CLK_MASK_SHIFT) + +/* + * Select Fixed frequency clock (32KHz) as clock source + * of FlexTimer Module + */ +#define FTM_SC_CLKS_FIXED_FREQ 0x02 +#define FIXED_FREQ_CLK 32000 + +/* Select 128 (2^7) as divider factor */ +#define MAX_FREQ_DIV (1 << FTM_SC_PS_MASK) + +/* Maximum counter value in FlexTimer's CNT registers */ +#define MAX_COUNT_VAL 0xffff + +struct ftm_rtc { + struct rtc_device *rtc_dev; + void __iomem *base; + bool big_endian; + u32 alarm_freq; +}; + +static inline u32 rtc_readl(struct ftm_rtc *dev, u32 reg) +{ + if (dev->big_endian) + return ioread32be(dev->base + reg); + else + return ioread32(dev->base + reg); +} + +static inline void rtc_writel(struct ftm_rtc *dev, u32 reg, u32 val) +{ + if (dev->big_endian) + iowrite32be(val, dev->base + reg); + else + iowrite32(val, dev->base + reg); +} + +static inline void ftm_counter_enable(struct ftm_rtc *rtc) +{ + u32 val; + + /* select and enable counter clock source */ + val = rtc_readl(rtc, FTM_SC); + val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); + val |= (FTM_SC_PS_MASK | FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ)); + rtc_writel(rtc, FTM_SC, val); +} + +static inline void ftm_counter_disable(struct ftm_rtc *rtc) +{ + u32 val; + + /* disable counter clock source */ + val = rtc_readl(rtc, FTM_SC); + val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK); + rtc_writel(rtc, FTM_SC, val); +} + +static inline void ftm_irq_acknowledge(struct ftm_rtc *rtc) +{ + unsigned int timeout = 100; + + /* + *Fix errata A-007728 for flextimer + * If the FTM counter reaches the FTM_MOD value between + * the reading of the TOF bit and the writing of 0 to + * the TOF bit, the process of clearing the TOF bit + * does not work as expected when FTMx_CONF[NUMTOF] != 0 + * and the current TOF count is less than FTMx_CONF[NUMTOF]. + * If the above condition is met, the TOF bit remains set. + * If the TOF interrupt is enabled (FTMx_SC[TOIE] = 1),the + * TOF interrupt also remains asserted. + * + * Above is the errata discription + * + * In one word: software clearing TOF bit not works when + * FTMx_CONF[NUMTOF] was seted as nonzero and FTM counter + * reaches the FTM_MOD value. + * + * The workaround is clearing TOF bit until it works + * (FTM counter doesn't always reache the FTM_MOD anyway), + * which may cost some cycles. + */ + while ((FTM_SC_TOF & rtc_readl(rtc, FTM_SC)) && timeout--) + rtc_writel(rtc, FTM_SC, rtc_readl(rtc, FTM_SC) & (~FTM_SC_TOF)); +} + +static inline void ftm_irq_enable(struct ftm_rtc *rtc) +{ + u32 val; + + val = rtc_readl(rtc, FTM_SC); + val |= FTM_SC_TOIE; + rtc_writel(rtc, FTM_SC, val); +} + +static inline void ftm_irq_disable(struct ftm_rtc *rtc) +{ + u32 val; + + val = rtc_readl(rtc, FTM_SC); + val &= ~FTM_SC_TOIE; + rtc_writel(rtc, FTM_SC, val); +} + +static inline void ftm_reset_counter(struct ftm_rtc *rtc) +{ + /* + * The CNT register contains the FTM counter value. + * Reset clears the CNT register. Writing any value to COUNT + * updates the counter with its initial value, CNTIN. + */ + rtc_writel(rtc, FTM_CNT, 0x00); +} + +static void ftm_clean_alarm(struct ftm_rtc *rtc) +{ + ftm_counter_disable(rtc); + + rtc_writel(rtc, FTM_CNTIN, 0x00); + rtc_writel(rtc, FTM_MOD, ~0U); + + ftm_reset_counter(rtc); +} + +static irqreturn_t ftm_rtc_alarm_interrupt(int irq, void *dev) +{ + struct ftm_rtc *rtc = dev; + + ftm_irq_acknowledge(rtc); + ftm_irq_disable(rtc); + ftm_clean_alarm(rtc); + + return IRQ_HANDLED; +} + +static int ftm_rtc_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct ftm_rtc *rtc = dev_get_drvdata(dev); + + if (enabled) + ftm_irq_enable(rtc); + else + ftm_irq_disable(rtc); + + return 0; +} + +/* + * Note: + * The function is not really getting time from the RTC + * since FlexTimer is not a RTC device, but we need to + * get time to setup alarm, so we are using system time + * for now. + */ +static int ftm_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct timespec64 ts64; + + ktime_get_real_ts64(&ts64); + rtc_time_to_tm(ts64.tv_sec, tm); + + return 0; +} + +static int ftm_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + return 0; +} + +/* + * 1. Select fixed frequency clock (32KHz) as clock source; + * 2. Select 128 (2^7) as divider factor; + * So clock is 250 Hz (32KHz/128). + * + * 3. FlexTimer's CNT register is a 32bit register, + * but the register's 16 bit as counter value,it's other 16 bit + * is reserved.So minimum counter value is 0x0,maximum counter + * value is 0xffff. + * So max alarm value is 262 (65536 / 250) seconds + */ +static int ftm_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + struct rtc_time tm; + unsigned long now, alm_time, cycle; + struct ftm_rtc *rtc = dev_get_drvdata(dev); + + ftm_rtc_read_time(dev, &tm); + rtc_tm_to_time(&tm, &now); + rtc_tm_to_time(&alm->time, &alm_time); + + ftm_clean_alarm(rtc); + cycle = (alm_time - now) * rtc->alarm_freq; + if (cycle > MAX_COUNT_VAL) { + pr_err("Out of alarm range {0~262} seconds.\n"); + return -ERANGE; + } + + ftm_irq_disable(rtc); + + /* + * The counter increments until the value of MOD is reached, + * at which point the counter is reloaded with the value of CNTIN. + * The TOF (the overflow flag) bit is set when the FTM counter + * changes from MOD to CNTIN. So we should using the cycle - 1. + */ + rtc_writel(rtc, FTM_MOD, cycle - 1); + + ftm_counter_enable(rtc); + ftm_irq_enable(rtc); + + return 0; + +} + +static const struct rtc_class_ops ftm_rtc_ops = { + .read_time = ftm_rtc_read_time, + .read_alarm = ftm_rtc_read_alarm, + .set_alarm = ftm_rtc_set_alarm, + .alarm_irq_enable = ftm_rtc_alarm_irq_enable, +}; + +static int ftm_rtc_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct resource *r; + int irq; + int ret; + struct ftm_rtc *rtc; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (unlikely(!rtc)) { + dev_err(&pdev->dev, "cannot alloc memory for rtc\n"); + return -ENOMEM; + } + + platform_set_drvdata(pdev, rtc); + + rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!r) { + dev_err(&pdev->dev, "cannot get resource for rtc\n"); + return -ENODEV; + } + + rtc->base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(rtc->base)) { + dev_err(&pdev->dev, "cannot ioremap resource for rtc\n"); + return PTR_ERR(rtc->base); + } + + irq = irq_of_parse_and_map(np, 0); + if (irq <= 0) { + dev_err(&pdev->dev, "unable to get IRQ from DT, %d\n", irq); + return -EINVAL; + } + + ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt, + IRQF_NO_SUSPEND, dev_name(&pdev->dev), rtc); + if (ret < 0) { + dev_err(&pdev->dev, "failed to request irq\n"); + return ret; + } + + rtc->big_endian = of_property_read_bool(np, "big-endian"); + rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV; + rtc->rtc_dev->ops = &ftm_rtc_ops; + + device_init_wakeup(&pdev->dev, true); + + ret = rtc_register_device(rtc->rtc_dev); + if (ret) { + dev_err(&pdev->dev, "can't register rtc device\n"); + return ret; + } + + return 0; +} + +static const struct of_device_id ftm_rtc_match[] = { + { .compatible = "fsl,ls1012a-ftm-alarm", }, + { .compatible = "fsl,ls1021a-ftm-alarm", }, + { .compatible = "fsl,ls1028a-ftm-alarm", }, + { .compatible = "fsl,ls1043a-ftm-alarm", }, + { .compatible = "fsl,ls1046a-ftm-alarm", }, + { .compatible = "fsl,ls1088a-ftm-alarm", }, + { .compatible = "fsl,ls208xa-ftm-alarm", }, + { .compatible = "fsl,lx2160a-ftm-alarm", }, + { }, +}; + +static struct platform_driver ftm_rtc_driver = { + .probe = ftm_rtc_probe, + .driver = { + .name = "ftm-alarm", + .of_match_table = ftm_rtc_match, + }, +}; + +static int __init ftm_alarm_init(void) +{ + return platform_driver_register(&ftm_rtc_driver); +} + +device_initcall(ftm_alarm_init); + +MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver"); +MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>"); +MODULE_LICENSE("GPL"); |