diff options
Diffstat (limited to 'drivers/rtc/rtc-zynqmp.c')
| -rw-r--r-- | drivers/rtc/rtc-zynqmp.c | 142 |
1 files changed, 117 insertions, 25 deletions
diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c index f440bb52be92..3baa2b481d9f 100644 --- a/drivers/rtc/rtc-zynqmp.c +++ b/drivers/rtc/rtc-zynqmp.c @@ -6,6 +6,7 @@ * */ +#include <linux/clk.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/io.h> @@ -36,17 +37,23 @@ #define RTC_OSC_EN BIT(24) #define RTC_BATT_EN BIT(31) -#define RTC_CALIB_DEF 0x198233 +#define RTC_CALIB_DEF 0x7FFF #define RTC_CALIB_MASK 0x1FFFFF #define RTC_ALRM_MASK BIT(1) #define RTC_MSEC 1000 +#define RTC_FR_MASK 0xF0000 +#define RTC_FR_MAX_TICKS 16 +#define RTC_PPB 1000000000LL +#define RTC_MIN_OFFSET -32768000 +#define RTC_MAX_OFFSET 32767000 struct xlnx_rtc_dev { struct rtc_device *rtc; void __iomem *reg_base; int alarm_irq; int sec_irq; - unsigned int calibval; + struct clk *rtc_clk; + unsigned int freq; }; static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) @@ -61,13 +68,6 @@ static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) */ new_time = rtc_tm_to_time64(tm) + 1; - /* - * Writing into calibration register will clear the Tick Counter and - * force the next second to be signaled exactly in 1 second period - */ - xrtcdev->calibval &= RTC_CALIB_MASK; - writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); - writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR); /* @@ -173,15 +173,76 @@ static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev) rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL); rtc_ctrl |= RTC_BATT_EN; writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL); +} - /* - * Based on crystal freq of 33.330 KHz - * set the seconds counter and enable, set fractions counter - * to default value suggested as per design spec - * to correct RTC delay in frequency over period of time. +static int xlnx_rtc_read_offset(struct device *dev, long *offset) +{ + struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); + unsigned long long rtc_ppb = RTC_PPB; + unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq); + unsigned int calibval; + long offset_val; + + calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD); + /* Offset with seconds ticks */ + offset_val = calibval & RTC_TICK_MASK; + offset_val = offset_val - RTC_CALIB_DEF; + offset_val = offset_val * tick_mult; + + /* Offset with fractional ticks */ + if (calibval & RTC_FR_EN) + offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT) + * (tick_mult / RTC_FR_MAX_TICKS); + *offset = offset_val; + + return 0; +} + +static int xlnx_rtc_set_offset(struct device *dev, long offset) +{ + struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); + unsigned long long rtc_ppb = RTC_PPB; + unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq); + unsigned char fract_tick = 0; + unsigned int calibval; + short int max_tick; + int fract_offset; + + if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET) + return -ERANGE; + + /* Number ticks for given offset */ + max_tick = div_s64_rem(offset, tick_mult, &fract_offset); + + /* Number fractional ticks for given offset */ + if (fract_offset) { + if (fract_offset < 0) { + fract_offset = fract_offset + tick_mult; + max_tick--; + } + if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) { + for (fract_tick = 1; fract_tick < 16; fract_tick++) { + if (fract_offset <= + (fract_tick * + (tick_mult / RTC_FR_MAX_TICKS))) + break; + } + } + } + + /* Zynqmp RTC uses second and fractional tick + * counters for compensation */ - xrtcdev->calibval &= RTC_CALIB_MASK; - writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); + calibval = max_tick + RTC_CALIB_DEF; + + if (fract_tick) + calibval |= RTC_FR_EN; + + calibval |= (fract_tick << RTC_FR_DATSHIFT); + + writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); + + return 0; } static const struct rtc_class_ops xlnx_rtc_ops = { @@ -190,6 +251,8 @@ static const struct rtc_class_ops xlnx_rtc_ops = { .read_alarm = xlnx_rtc_read_alarm, .set_alarm = xlnx_rtc_set_alarm, .alarm_irq_enable = xlnx_rtc_alarm_irq_enable, + .read_offset = xlnx_rtc_read_offset, + .set_offset = xlnx_rtc_set_offset, }; static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) @@ -214,6 +277,10 @@ static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) static int xlnx_rtc_probe(struct platform_device *pdev) { struct xlnx_rtc_dev *xrtcdev; + bool is_alarm_set = false; + u32 pending_alrm_irq; + u32 current_time; + u32 alarm_time; int ret; xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL); @@ -233,6 +300,17 @@ static int xlnx_rtc_probe(struct platform_device *pdev) if (IS_ERR(xrtcdev->reg_base)) return PTR_ERR(xrtcdev->reg_base); + /* Clear any pending alarm interrupts from previous kernel/boot */ + pending_alrm_irq = readl(xrtcdev->reg_base + RTC_INT_STS) & RTC_INT_ALRM; + if (pending_alrm_irq) + writel(pending_alrm_irq, xrtcdev->reg_base + RTC_INT_STS); + + /* Check if a valid alarm is already set from previous kernel/boot */ + alarm_time = readl(xrtcdev->reg_base + RTC_ALRM); + current_time = readl(xrtcdev->reg_base + RTC_CUR_TM); + if (alarm_time > current_time && alarm_time != 0) + is_alarm_set = true; + xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm"); if (xrtcdev->alarm_irq < 0) return xrtcdev->alarm_irq; @@ -255,24 +333,38 @@ static int xlnx_rtc_probe(struct platform_device *pdev) return ret; } - ret = of_property_read_u32(pdev->dev.of_node, "calibration", - &xrtcdev->calibval); - if (ret) - xrtcdev->calibval = RTC_CALIB_DEF; + /* Getting the rtc info */ + xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc"); + if (IS_ERR(xrtcdev->rtc_clk)) { + if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER) + dev_warn(&pdev->dev, "Device clock not found.\n"); + } + xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk); + if (!xrtcdev->freq) { + ret = of_property_read_u32(pdev->dev.of_node, "calibration", + &xrtcdev->freq); + if (ret) + xrtcdev->freq = RTC_CALIB_DEF; + } + ret = readl(xrtcdev->reg_base + RTC_CALIB_RD); + if (!ret) + writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR)); xlnx_init_rtc(xrtcdev); - device_init_wakeup(&pdev->dev, 1); + /* Re-enable alarm interrupt if a valid alarm was found */ + if (is_alarm_set) + writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN); + + device_init_wakeup(&pdev->dev, true); return devm_rtc_register_device(xrtcdev->rtc); } -static int xlnx_rtc_remove(struct platform_device *pdev) +static void xlnx_rtc_remove(struct platform_device *pdev) { xlnx_rtc_alarm_irq_enable(&pdev->dev, 0); - device_init_wakeup(&pdev->dev, 0); - - return 0; + device_init_wakeup(&pdev->dev, false); } static int __maybe_unused xlnx_rtc_suspend(struct device *dev) |