1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver 4 * 5 * Copyright (C) 2015 Xilinx, Inc. 6 * 7 */ 8 9 #include <linux/delay.h> 10 #include <linux/init.h> 11 #include <linux/io.h> 12 #include <linux/module.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/rtc.h> 16 17 /* RTC Registers */ 18 #define RTC_SET_TM_WR 0x00 19 #define RTC_SET_TM_RD 0x04 20 #define RTC_CALIB_WR 0x08 21 #define RTC_CALIB_RD 0x0C 22 #define RTC_CUR_TM 0x10 23 #define RTC_CUR_TICK 0x14 24 #define RTC_ALRM 0x18 25 #define RTC_INT_STS 0x20 26 #define RTC_INT_MASK 0x24 27 #define RTC_INT_EN 0x28 28 #define RTC_INT_DIS 0x2C 29 #define RTC_CTRL 0x40 30 31 #define RTC_FR_EN BIT(20) 32 #define RTC_FR_DATSHIFT 16 33 #define RTC_TICK_MASK 0xFFFF 34 #define RTC_INT_SEC BIT(0) 35 #define RTC_INT_ALRM BIT(1) 36 #define RTC_OSC_EN BIT(24) 37 #define RTC_BATT_EN BIT(31) 38 39 #define RTC_CALIB_DEF 0x198233 40 #define RTC_CALIB_MASK 0x1FFFFF 41 42 struct xlnx_rtc_dev { 43 struct rtc_device *rtc; 44 void __iomem *reg_base; 45 int alarm_irq; 46 int sec_irq; 47 unsigned int calibval; 48 }; 49 50 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) 51 { 52 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 53 unsigned long new_time; 54 55 /* 56 * The value written will be updated after 1 sec into the 57 * seconds read register, so we need to program time +1 sec 58 * to get the correct time on read. 59 */ 60 new_time = rtc_tm_to_time64(tm) + 1; 61 62 /* 63 * Writing into calibration register will clear the Tick Counter and 64 * force the next second to be signaled exactly in 1 second period 65 */ 66 xrtcdev->calibval &= RTC_CALIB_MASK; 67 writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); 68 69 writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR); 70 71 /* 72 * Clear the rtc interrupt status register after setting the 73 * time. During a read_time function, the code should read the 74 * RTC_INT_STATUS register and if bit 0 is still 0, it means 75 * that one second has not elapsed yet since RTC was set and 76 * the current time should be read from SET_TIME_READ register; 77 * otherwise, CURRENT_TIME register is read to report the time 78 */ 79 writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS); 80 81 return 0; 82 } 83 84 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm) 85 { 86 u32 status; 87 unsigned long read_time; 88 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 89 90 status = readl(xrtcdev->reg_base + RTC_INT_STS); 91 92 if (status & RTC_INT_SEC) { 93 /* 94 * RTC has updated the CURRENT_TIME with the time written into 95 * SET_TIME_WRITE register. 96 */ 97 read_time = readl(xrtcdev->reg_base + RTC_CUR_TM); 98 } else { 99 /* 100 * Time written in SET_TIME_WRITE has not yet updated into 101 * the seconds read register, so read the time from the 102 * SET_TIME_WRITE instead of CURRENT_TIME register. 103 * Since we add +1 sec while writing, we need to -1 sec while 104 * reading. 105 */ 106 read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1; 107 } 108 rtc_time64_to_tm(read_time, tm); 109 110 return 0; 111 } 112 113 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 114 { 115 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 116 117 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time); 118 alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM; 119 120 return 0; 121 } 122 123 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled) 124 { 125 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 126 127 if (enabled) 128 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN); 129 else 130 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); 131 132 return 0; 133 } 134 135 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 136 { 137 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 138 unsigned long alarm_time; 139 140 alarm_time = rtc_tm_to_time64(&alrm->time); 141 142 writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM)); 143 144 xlnx_rtc_alarm_irq_enable(dev, alrm->enabled); 145 146 return 0; 147 } 148 149 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev) 150 { 151 u32 rtc_ctrl; 152 153 /* Enable RTC switch to battery when VCC_PSAUX is not available */ 154 rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL); 155 rtc_ctrl |= RTC_BATT_EN; 156 writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL); 157 158 /* 159 * Based on crystal freq of 33.330 KHz 160 * set the seconds counter and enable, set fractions counter 161 * to default value suggested as per design spec 162 * to correct RTC delay in frequency over period of time. 163 */ 164 xrtcdev->calibval &= RTC_CALIB_MASK; 165 writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); 166 } 167 168 static const struct rtc_class_ops xlnx_rtc_ops = { 169 .set_time = xlnx_rtc_set_time, 170 .read_time = xlnx_rtc_read_time, 171 .read_alarm = xlnx_rtc_read_alarm, 172 .set_alarm = xlnx_rtc_set_alarm, 173 .alarm_irq_enable = xlnx_rtc_alarm_irq_enable, 174 }; 175 176 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) 177 { 178 struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id; 179 unsigned int status; 180 181 status = readl(xrtcdev->reg_base + RTC_INT_STS); 182 /* Check if interrupt asserted */ 183 if (!(status & (RTC_INT_SEC | RTC_INT_ALRM))) 184 return IRQ_NONE; 185 186 /* Clear RTC_INT_ALRM interrupt only */ 187 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS); 188 189 if (status & RTC_INT_ALRM) 190 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF); 191 192 return IRQ_HANDLED; 193 } 194 195 static int xlnx_rtc_probe(struct platform_device *pdev) 196 { 197 struct xlnx_rtc_dev *xrtcdev; 198 int ret; 199 200 xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL); 201 if (!xrtcdev) 202 return -ENOMEM; 203 204 platform_set_drvdata(pdev, xrtcdev); 205 206 xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev); 207 if (IS_ERR(xrtcdev->rtc)) 208 return PTR_ERR(xrtcdev->rtc); 209 210 xrtcdev->rtc->ops = &xlnx_rtc_ops; 211 xrtcdev->rtc->range_max = U32_MAX; 212 213 xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0); 214 if (IS_ERR(xrtcdev->reg_base)) 215 return PTR_ERR(xrtcdev->reg_base); 216 217 xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm"); 218 if (xrtcdev->alarm_irq < 0) 219 return xrtcdev->alarm_irq; 220 ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq, 221 xlnx_rtc_interrupt, 0, 222 dev_name(&pdev->dev), xrtcdev); 223 if (ret) { 224 dev_err(&pdev->dev, "request irq failed\n"); 225 return ret; 226 } 227 228 xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec"); 229 if (xrtcdev->sec_irq < 0) 230 return xrtcdev->sec_irq; 231 ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq, 232 xlnx_rtc_interrupt, 0, 233 dev_name(&pdev->dev), xrtcdev); 234 if (ret) { 235 dev_err(&pdev->dev, "request irq failed\n"); 236 return ret; 237 } 238 239 ret = of_property_read_u32(pdev->dev.of_node, "calibration", 240 &xrtcdev->calibval); 241 if (ret) 242 xrtcdev->calibval = RTC_CALIB_DEF; 243 244 xlnx_init_rtc(xrtcdev); 245 246 device_init_wakeup(&pdev->dev, 1); 247 248 return rtc_register_device(xrtcdev->rtc); 249 } 250 251 static int xlnx_rtc_remove(struct platform_device *pdev) 252 { 253 xlnx_rtc_alarm_irq_enable(&pdev->dev, 0); 254 device_init_wakeup(&pdev->dev, 0); 255 256 return 0; 257 } 258 259 static int __maybe_unused xlnx_rtc_suspend(struct device *dev) 260 { 261 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 262 263 if (device_may_wakeup(dev)) 264 enable_irq_wake(xrtcdev->alarm_irq); 265 else 266 xlnx_rtc_alarm_irq_enable(dev, 0); 267 268 return 0; 269 } 270 271 static int __maybe_unused xlnx_rtc_resume(struct device *dev) 272 { 273 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 274 275 if (device_may_wakeup(dev)) 276 disable_irq_wake(xrtcdev->alarm_irq); 277 else 278 xlnx_rtc_alarm_irq_enable(dev, 1); 279 280 return 0; 281 } 282 283 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume); 284 285 static const struct of_device_id xlnx_rtc_of_match[] = { 286 {.compatible = "xlnx,zynqmp-rtc" }, 287 { } 288 }; 289 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match); 290 291 static struct platform_driver xlnx_rtc_driver = { 292 .probe = xlnx_rtc_probe, 293 .remove = xlnx_rtc_remove, 294 .driver = { 295 .name = KBUILD_MODNAME, 296 .pm = &xlnx_rtc_pm_ops, 297 .of_match_table = xlnx_rtc_of_match, 298 }, 299 }; 300 301 module_platform_driver(xlnx_rtc_driver); 302 303 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver"); 304 MODULE_AUTHOR("Xilinx Inc."); 305 MODULE_LICENSE("GPL v2"); 306