> Hi, > > On 11/07/2019 22:37:48+0800, Biwen Li wrote: > > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index > > 9d997fa..5cccb07 100644 > > --- a/drivers/rtc/Makefile > > +++ b/drivers/rtc/Makefile > > @@ -79,6 +79,7 @@ obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += > rtc-hid-sensor-time.o > > obj-$(CONFIG_RTC_DRV_HYM8563) += rtc-hym8563.o > > obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o > > obj-$(CONFIG_RTC_DRV_IMX_SC) += rtc-imx-sc.o > > +obj-$(CONFIG_RTC_DRV_FSL_FTM_ALARM) += rtc-fsl-ftm-alarm.o > > This file is sorted alphabetically. I will correct it in v4. > > > obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o > > obj-$(CONFIG_RTC_DRV_ISL12026) += rtc-isl12026.o > > obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o > > diff --git a/drivers/rtc/rtc-fsl-ftm-alarm.c > > b/drivers/rtc/rtc-fsl-ftm-alarm.c new file mode 100644 index > > 0000000..4fd0d6b > > --- /dev/null > > +++ b/drivers/rtc/rtc-fsl-ftm-alarm.c > > @@ -0,0 +1,347 @@ > > +// 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; > > + unsigned long local_time; > > + > > + ktime_get_real_ts64(&ts64); > > + local_time = (unsigned long)(ts64.tv_sec - > > + (sys_tz.tz_minuteswest * 60)); > > The RTC time is in UTC time, you should not care about the timezone here. I will correct it in v4. > > > + > > + rtc_time_to_tm(local_time, 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 -EINVAL; > > Use -ERANGE here. I will correct it in v4. > > > + } > > + > > + 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)) { > > + pr_err("ftm: cannot alloc memery for rtc\n"); > > + return -ENOMEM; > > + } > > + > > + platform_set_drvdata(pdev, rtc); > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + if (!r) { > > + pr_err("ftm: cannot get resource for rtc\n"); > > + return -ENODEV; > > + } > > + > > + rtc->base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(rtc->base)) { > > + pr_err("ftm: cannot ioremap resource for rtc\n"); > > + return PTR_ERR(rtc->base); > > + } > > + > > + irq = irq_of_parse_and_map(np, 0); > > + if (irq <= 0) { > > + pr_err("ftm: unable to get IRQ from DT, %d\n", irq); > > + return -EINVAL; > > + } > > + > > + rtc->big_endian = of_property_read_bool(np, "big-endian"); > > + > > + ret = devm_request_irq(&pdev->dev, irq, ftm_rtc_alarm_interrupt, > > + IRQF_NO_SUSPEND, > dev_name(&pdev->dev), > > + rtc); > > There is a possible race condition here. As soon as devm_request_irq is called, > the interrupt handler may be called leading to a null pointer dereference > because rtc->rtc_dev is not yet allocated. Please use devm_rtc_allocate_device > and rtc_register_device to solve that. I will request irq after calling devm_rtc_device_register in v4. > > > + if (ret < 0) { > > + dev_err(&pdev->dev, "failed to request irq\n"); > > + return ret; > > + } > > + > > + rtc->alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV; > > + > > + ftm_clean_alarm(rtc); > > + > > Do you really need to remove the alarm here? Needn't,register's value of flextimer is 0 when reset.I will remove it in v4. > > > + device_init_wakeup(&pdev->dev, true); > > + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "ftm-alarm", > > + > &ftm_rtc_ops, > > + > THIS_MODULE); > > + if (IS_ERR(rtc->rtc_dev)) { > > + dev_err(&pdev->dev, "can't register rtc device\n"); > > + return PTR_ERR(rtc->rtc_dev); > > + } > > + return ret; > > +} > > + > > +static const struct of_device_id ftm_rtc_match[] = { > > + { .compatible = "fsl,ls1012a-ftm-alarm", }, > > + { .compatible = "fsl,ls1021a-ftm-alarm", }, > > + { .compatible = "fsl,ls1043a-ftm-alarm", }, > > + { .compatible = "fsl,ls1046a-ftm-alarm", }, > > + { .compatible = "fsl,ls1088a-ftm-alarm", }, > > + { .compatible = "fsl,ls208xa-ftm-alarm", }, > > + { .compatible = "fsl,ls1028a-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); > > +} > > + > > +/* > > + * Ensure that the driver is initialized after > > + * any real rtc driver > > + * - The flextimer is not a real rtc device, > > + * it don't have time and date registers of rtc. > > + * - The flextimer rtc alarm driver gets time from wall time, > > + * but the wall time is not ready.so the time from the driver is wrong. > > + * - If system regist it before any other real rtc device,it will > > + * be emulated as rtc0,date command will read wrong time for user. > > + */ > > +device_initcall_sync(ftm_alarm_init); > > No, please register that as a regular RTC driver and stop using RTC_HCTOSYS or > use the DT aliases to ensure it is not used as the primary RTC. I will register that as a regular RTC driver in v4. > > > + > > +MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver"); > > +MODULE_AUTHOR("Biwen Li <biwen.li@xxxxxxx>"); > MODULE_LICENSE("GPL"); > > -- > > 2.7.4 > > > > -- > Alexandre Belloni, Bootlin > Embedded Linux and Kernel engineering > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbootlin. > com&data=02%7C01%7Cbiwen.li%40nxp.com%7C4e834acfe10d4480c30 > 308d707d89428%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63 > 6986499109183286&sdata=fPH%2BL%2Bp7tQOk8HmGZjd%2Bjj8r0s%2 > Bix9lD%2B9HWLXpuk2M%3D&reserved=0