1 /* 2 * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver 3 * 4 * Copyright (C) 2015 Xilinx, Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License along with 16 * this program. If not, see <http://www.gnu.org/licenses/>. 17 * 18 */ 19 20 #include <linux/delay.h> 21 #include <linux/init.h> 22 #include <linux/io.h> 23 #include <linux/module.h> 24 #include <linux/of.h> 25 #include <linux/platform_device.h> 26 #include <linux/rtc.h> 27 28 /* RTC Registers */ 29 #define RTC_SET_TM_WR 0x00 30 #define RTC_SET_TM_RD 0x04 31 #define RTC_CALIB_WR 0x08 32 #define RTC_CALIB_RD 0x0C 33 #define RTC_CUR_TM 0x10 34 #define RTC_CUR_TICK 0x14 35 #define RTC_ALRM 0x18 36 #define RTC_INT_STS 0x20 37 #define RTC_INT_MASK 0x24 38 #define RTC_INT_EN 0x28 39 #define RTC_INT_DIS 0x2C 40 #define RTC_CTRL 0x40 41 42 #define RTC_FR_EN BIT(20) 43 #define RTC_FR_DATSHIFT 16 44 #define RTC_TICK_MASK 0xFFFF 45 #define RTC_INT_SEC BIT(0) 46 #define RTC_INT_ALRM BIT(1) 47 #define RTC_OSC_EN BIT(24) 48 #define RTC_BATT_EN BIT(31) 49 50 #define RTC_CALIB_DEF 0x198233 51 #define RTC_CALIB_MASK 0x1FFFFF 52 #define RTC_SEC_MAX_VAL 0xFFFFFFFF 53 54 struct xlnx_rtc_dev { 55 struct rtc_device *rtc; 56 void __iomem *reg_base; 57 int alarm_irq; 58 int sec_irq; 59 int calibval; 60 }; 61 62 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm) 63 { 64 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 65 unsigned long new_time; 66 67 /* 68 * The value written will be updated after 1 sec into the 69 * seconds read register, so we need to program time +1 sec 70 * to get the correct time on read. 71 */ 72 new_time = rtc_tm_to_time64(tm) + 1; 73 74 if (new_time > RTC_SEC_MAX_VAL) 75 return -EINVAL; 76 77 /* 78 * Writing into calibration register will clear the Tick Counter and 79 * force the next second to be signaled exactly in 1 second period 80 */ 81 xrtcdev->calibval &= RTC_CALIB_MASK; 82 writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); 83 84 writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR); 85 86 /* 87 * Clear the rtc interrupt status register after setting the 88 * time. During a read_time function, the code should read the 89 * RTC_INT_STATUS register and if bit 0 is still 0, it means 90 * that one second has not elapsed yet since RTC was set and 91 * the current time should be read from SET_TIME_READ register; 92 * otherwise, CURRENT_TIME register is read to report the time 93 */ 94 writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS); 95 96 return 0; 97 } 98 99 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm) 100 { 101 u32 status; 102 unsigned long read_time; 103 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 104 105 status = readl(xrtcdev->reg_base + RTC_INT_STS); 106 107 if (status & RTC_INT_SEC) { 108 /* 109 * RTC has updated the CURRENT_TIME with the time written into 110 * SET_TIME_WRITE register. 111 */ 112 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_CUR_TM), tm); 113 } else { 114 /* 115 * Time written in SET_TIME_WRITE has not yet updated into 116 * the seconds read register, so read the time from the 117 * SET_TIME_WRITE instead of CURRENT_TIME register. 118 * Since we add +1 sec while writing, we need to -1 sec while 119 * reading. 120 */ 121 read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1; 122 rtc_time64_to_tm(read_time, tm); 123 } 124 125 return 0; 126 } 127 128 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 129 { 130 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 131 132 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time); 133 alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM; 134 135 return 0; 136 } 137 138 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled) 139 { 140 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 141 142 if (enabled) 143 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN); 144 else 145 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS); 146 147 return 0; 148 } 149 150 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 151 { 152 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 153 unsigned long alarm_time; 154 155 alarm_time = rtc_tm_to_time64(&alrm->time); 156 157 if (alarm_time > RTC_SEC_MAX_VAL) 158 return -EINVAL; 159 160 writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM)); 161 162 xlnx_rtc_alarm_irq_enable(dev, alrm->enabled); 163 164 return 0; 165 } 166 167 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev) 168 { 169 u32 rtc_ctrl; 170 171 /* Enable RTC switch to battery when VCC_PSAUX is not available */ 172 rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL); 173 rtc_ctrl |= RTC_BATT_EN; 174 writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL); 175 176 /* 177 * Based on crystal freq of 33.330 KHz 178 * set the seconds counter and enable, set fractions counter 179 * to default value suggested as per design spec 180 * to correct RTC delay in frequency over period of time. 181 */ 182 xrtcdev->calibval &= RTC_CALIB_MASK; 183 writel(xrtcdev->calibval, (xrtcdev->reg_base + RTC_CALIB_WR)); 184 } 185 186 static const struct rtc_class_ops xlnx_rtc_ops = { 187 .set_time = xlnx_rtc_set_time, 188 .read_time = xlnx_rtc_read_time, 189 .read_alarm = xlnx_rtc_read_alarm, 190 .set_alarm = xlnx_rtc_set_alarm, 191 .alarm_irq_enable = xlnx_rtc_alarm_irq_enable, 192 }; 193 194 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id) 195 { 196 struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id; 197 unsigned int status; 198 199 status = readl(xrtcdev->reg_base + RTC_INT_STS); 200 /* Check if interrupt asserted */ 201 if (!(status & (RTC_INT_SEC | RTC_INT_ALRM))) 202 return IRQ_NONE; 203 204 /* Clear RTC_INT_ALRM interrupt only */ 205 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS); 206 207 if (status & RTC_INT_ALRM) 208 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF); 209 210 return IRQ_HANDLED; 211 } 212 213 static int xlnx_rtc_probe(struct platform_device *pdev) 214 { 215 struct xlnx_rtc_dev *xrtcdev; 216 struct resource *res; 217 int ret; 218 219 xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL); 220 if (!xrtcdev) 221 return -ENOMEM; 222 223 platform_set_drvdata(pdev, xrtcdev); 224 225 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 226 227 xrtcdev->reg_base = devm_ioremap_resource(&pdev->dev, res); 228 if (IS_ERR(xrtcdev->reg_base)) 229 return PTR_ERR(xrtcdev->reg_base); 230 231 xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm"); 232 if (xrtcdev->alarm_irq < 0) { 233 dev_err(&pdev->dev, "no irq resource\n"); 234 return xrtcdev->alarm_irq; 235 } 236 ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq, 237 xlnx_rtc_interrupt, 0, 238 dev_name(&pdev->dev), xrtcdev); 239 if (ret) { 240 dev_err(&pdev->dev, "request irq failed\n"); 241 return ret; 242 } 243 244 xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec"); 245 if (xrtcdev->sec_irq < 0) { 246 dev_err(&pdev->dev, "no irq resource\n"); 247 return xrtcdev->sec_irq; 248 } 249 ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq, 250 xlnx_rtc_interrupt, 0, 251 dev_name(&pdev->dev), xrtcdev); 252 if (ret) { 253 dev_err(&pdev->dev, "request irq failed\n"); 254 return ret; 255 } 256 257 ret = of_property_read_u32(pdev->dev.of_node, "calibration", 258 &xrtcdev->calibval); 259 if (ret) 260 xrtcdev->calibval = RTC_CALIB_DEF; 261 262 xlnx_init_rtc(xrtcdev); 263 264 device_init_wakeup(&pdev->dev, 1); 265 266 xrtcdev->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, 267 &xlnx_rtc_ops, THIS_MODULE); 268 return PTR_ERR_OR_ZERO(xrtcdev->rtc); 269 } 270 271 static int xlnx_rtc_remove(struct platform_device *pdev) 272 { 273 xlnx_rtc_alarm_irq_enable(&pdev->dev, 0); 274 device_init_wakeup(&pdev->dev, 0); 275 276 return 0; 277 } 278 279 static int __maybe_unused xlnx_rtc_suspend(struct device *dev) 280 { 281 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 282 283 if (device_may_wakeup(dev)) 284 enable_irq_wake(xrtcdev->alarm_irq); 285 else 286 xlnx_rtc_alarm_irq_enable(dev, 0); 287 288 return 0; 289 } 290 291 static int __maybe_unused xlnx_rtc_resume(struct device *dev) 292 { 293 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev); 294 295 if (device_may_wakeup(dev)) 296 disable_irq_wake(xrtcdev->alarm_irq); 297 else 298 xlnx_rtc_alarm_irq_enable(dev, 1); 299 300 return 0; 301 } 302 303 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume); 304 305 static const struct of_device_id xlnx_rtc_of_match[] = { 306 {.compatible = "xlnx,zynqmp-rtc" }, 307 { } 308 }; 309 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match); 310 311 static struct platform_driver xlnx_rtc_driver = { 312 .probe = xlnx_rtc_probe, 313 .remove = xlnx_rtc_remove, 314 .driver = { 315 .name = KBUILD_MODNAME, 316 .pm = &xlnx_rtc_pm_ops, 317 .of_match_table = xlnx_rtc_of_match, 318 }, 319 }; 320 321 module_platform_driver(xlnx_rtc_driver); 322 323 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver"); 324 MODULE_AUTHOR("Xilinx Inc."); 325 MODULE_LICENSE("GPL v2"); 326