1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC) 4 * 5 * Copyright (C) 2011 NXP Semiconductors 6 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/io.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/of.h> 14 #include <linux/of_device.h> 15 #include <linux/platform_device.h> 16 #include <linux/rtc.h> 17 18 /* LPC24xx RTC register offsets and bits */ 19 #define LPC24XX_ILR 0x00 20 #define LPC24XX_RTCCIF BIT(0) 21 #define LPC24XX_RTCALF BIT(1) 22 #define LPC24XX_CTC 0x04 23 #define LPC24XX_CCR 0x08 24 #define LPC24XX_CLKEN BIT(0) 25 #define LPC178X_CCALEN BIT(4) 26 #define LPC24XX_CIIR 0x0c 27 #define LPC24XX_AMR 0x10 28 #define LPC24XX_ALARM_DISABLE 0xff 29 #define LPC24XX_CTIME0 0x14 30 #define LPC24XX_CTIME1 0x18 31 #define LPC24XX_CTIME2 0x1c 32 #define LPC24XX_SEC 0x20 33 #define LPC24XX_MIN 0x24 34 #define LPC24XX_HOUR 0x28 35 #define LPC24XX_DOM 0x2c 36 #define LPC24XX_DOW 0x30 37 #define LPC24XX_DOY 0x34 38 #define LPC24XX_MONTH 0x38 39 #define LPC24XX_YEAR 0x3c 40 #define LPC24XX_ALSEC 0x60 41 #define LPC24XX_ALMIN 0x64 42 #define LPC24XX_ALHOUR 0x68 43 #define LPC24XX_ALDOM 0x6c 44 #define LPC24XX_ALDOW 0x70 45 #define LPC24XX_ALDOY 0x74 46 #define LPC24XX_ALMON 0x78 47 #define LPC24XX_ALYEAR 0x7c 48 49 /* Macros to read fields in consolidated time (CT) registers */ 50 #define CT0_SECS(x) (((x) >> 0) & 0x3f) 51 #define CT0_MINS(x) (((x) >> 8) & 0x3f) 52 #define CT0_HOURS(x) (((x) >> 16) & 0x1f) 53 #define CT0_DOW(x) (((x) >> 24) & 0x07) 54 #define CT1_DOM(x) (((x) >> 0) & 0x1f) 55 #define CT1_MONTH(x) (((x) >> 8) & 0x0f) 56 #define CT1_YEAR(x) (((x) >> 16) & 0xfff) 57 #define CT2_DOY(x) (((x) >> 0) & 0xfff) 58 59 #define rtc_readl(dev, reg) readl((dev)->rtc_base + (reg)) 60 #define rtc_writel(dev, reg, val) writel((val), (dev)->rtc_base + (reg)) 61 62 struct lpc24xx_rtc { 63 void __iomem *rtc_base; 64 struct rtc_device *rtc; 65 struct clk *clk_rtc; 66 struct clk *clk_reg; 67 }; 68 69 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm) 70 { 71 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 72 73 /* Disable RTC during update */ 74 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); 75 76 rtc_writel(rtc, LPC24XX_SEC, tm->tm_sec); 77 rtc_writel(rtc, LPC24XX_MIN, tm->tm_min); 78 rtc_writel(rtc, LPC24XX_HOUR, tm->tm_hour); 79 rtc_writel(rtc, LPC24XX_DOW, tm->tm_wday); 80 rtc_writel(rtc, LPC24XX_DOM, tm->tm_mday); 81 rtc_writel(rtc, LPC24XX_DOY, tm->tm_yday); 82 rtc_writel(rtc, LPC24XX_MONTH, tm->tm_mon); 83 rtc_writel(rtc, LPC24XX_YEAR, tm->tm_year); 84 85 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); 86 87 return 0; 88 } 89 90 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm) 91 { 92 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 93 u32 ct0, ct1, ct2; 94 95 ct0 = rtc_readl(rtc, LPC24XX_CTIME0); 96 ct1 = rtc_readl(rtc, LPC24XX_CTIME1); 97 ct2 = rtc_readl(rtc, LPC24XX_CTIME2); 98 99 tm->tm_sec = CT0_SECS(ct0); 100 tm->tm_min = CT0_MINS(ct0); 101 tm->tm_hour = CT0_HOURS(ct0); 102 tm->tm_wday = CT0_DOW(ct0); 103 tm->tm_mon = CT1_MONTH(ct1); 104 tm->tm_mday = CT1_DOM(ct1); 105 tm->tm_year = CT1_YEAR(ct1); 106 tm->tm_yday = CT2_DOY(ct2); 107 108 return 0; 109 } 110 111 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 112 { 113 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 114 struct rtc_time *tm = &wkalrm->time; 115 116 tm->tm_sec = rtc_readl(rtc, LPC24XX_ALSEC); 117 tm->tm_min = rtc_readl(rtc, LPC24XX_ALMIN); 118 tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR); 119 tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM); 120 tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW); 121 tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY); 122 tm->tm_mon = rtc_readl(rtc, LPC24XX_ALMON); 123 tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR); 124 125 wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0; 126 wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF); 127 128 return rtc_valid_tm(&wkalrm->time); 129 } 130 131 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 132 { 133 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 134 struct rtc_time *tm = &wkalrm->time; 135 136 /* Disable alarm irq during update */ 137 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 138 139 rtc_writel(rtc, LPC24XX_ALSEC, tm->tm_sec); 140 rtc_writel(rtc, LPC24XX_ALMIN, tm->tm_min); 141 rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour); 142 rtc_writel(rtc, LPC24XX_ALDOM, tm->tm_mday); 143 rtc_writel(rtc, LPC24XX_ALDOW, tm->tm_wday); 144 rtc_writel(rtc, LPC24XX_ALDOY, tm->tm_yday); 145 rtc_writel(rtc, LPC24XX_ALMON, tm->tm_mon); 146 rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year); 147 148 if (wkalrm->enabled) 149 rtc_writel(rtc, LPC24XX_AMR, 0); 150 151 return 0; 152 } 153 154 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) 155 { 156 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 157 158 if (enable) 159 rtc_writel(rtc, LPC24XX_AMR, 0); 160 else 161 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 162 163 return 0; 164 } 165 166 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data) 167 { 168 unsigned long events = RTC_IRQF; 169 struct lpc24xx_rtc *rtc = data; 170 u32 rtc_iir; 171 172 /* Check interrupt cause */ 173 rtc_iir = rtc_readl(rtc, LPC24XX_ILR); 174 if (rtc_iir & LPC24XX_RTCALF) { 175 events |= RTC_AF; 176 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 177 } 178 179 /* Clear interrupt status and report event */ 180 rtc_writel(rtc, LPC24XX_ILR, rtc_iir); 181 rtc_update_irq(rtc->rtc, 1, events); 182 183 return IRQ_HANDLED; 184 } 185 186 static const struct rtc_class_ops lpc24xx_rtc_ops = { 187 .read_time = lpc24xx_rtc_read_time, 188 .set_time = lpc24xx_rtc_set_time, 189 .read_alarm = lpc24xx_rtc_read_alarm, 190 .set_alarm = lpc24xx_rtc_set_alarm, 191 .alarm_irq_enable = lpc24xx_rtc_alarm_irq_enable, 192 }; 193 194 static int lpc24xx_rtc_probe(struct platform_device *pdev) 195 { 196 struct lpc24xx_rtc *rtc; 197 int irq, ret; 198 199 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); 200 if (!rtc) 201 return -ENOMEM; 202 203 rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0); 204 if (IS_ERR(rtc->rtc_base)) 205 return PTR_ERR(rtc->rtc_base); 206 207 irq = platform_get_irq(pdev, 0); 208 if (irq < 0) 209 return irq; 210 211 rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc"); 212 if (IS_ERR(rtc->clk_rtc)) { 213 dev_err(&pdev->dev, "error getting rtc clock\n"); 214 return PTR_ERR(rtc->clk_rtc); 215 } 216 217 rtc->clk_reg = devm_clk_get(&pdev->dev, "reg"); 218 if (IS_ERR(rtc->clk_reg)) { 219 dev_err(&pdev->dev, "error getting reg clock\n"); 220 return PTR_ERR(rtc->clk_reg); 221 } 222 223 ret = clk_prepare_enable(rtc->clk_rtc); 224 if (ret) { 225 dev_err(&pdev->dev, "unable to enable rtc clock\n"); 226 return ret; 227 } 228 229 ret = clk_prepare_enable(rtc->clk_reg); 230 if (ret) { 231 dev_err(&pdev->dev, "unable to enable reg clock\n"); 232 goto disable_rtc_clk; 233 } 234 235 platform_set_drvdata(pdev, rtc); 236 237 /* Clear any pending interrupts */ 238 rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF); 239 240 /* Enable RTC count */ 241 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); 242 243 ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0, 244 pdev->name, rtc); 245 if (ret < 0) { 246 dev_warn(&pdev->dev, "can't request interrupt\n"); 247 goto disable_clks; 248 } 249 250 rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc", 251 &lpc24xx_rtc_ops, THIS_MODULE); 252 if (IS_ERR(rtc->rtc)) { 253 dev_err(&pdev->dev, "can't register rtc device\n"); 254 ret = PTR_ERR(rtc->rtc); 255 goto disable_clks; 256 } 257 258 return 0; 259 260 disable_clks: 261 clk_disable_unprepare(rtc->clk_reg); 262 disable_rtc_clk: 263 clk_disable_unprepare(rtc->clk_rtc); 264 return ret; 265 } 266 267 static void lpc24xx_rtc_remove(struct platform_device *pdev) 268 { 269 struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev); 270 271 /* Ensure all interrupt sources are masked */ 272 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 273 rtc_writel(rtc, LPC24XX_CIIR, 0); 274 275 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); 276 277 clk_disable_unprepare(rtc->clk_rtc); 278 clk_disable_unprepare(rtc->clk_reg); 279 } 280 281 static const struct of_device_id lpc24xx_rtc_match[] = { 282 { .compatible = "nxp,lpc1788-rtc" }, 283 { } 284 }; 285 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match); 286 287 static struct platform_driver lpc24xx_rtc_driver = { 288 .probe = lpc24xx_rtc_probe, 289 .remove_new = lpc24xx_rtc_remove, 290 .driver = { 291 .name = "lpc24xx-rtc", 292 .of_match_table = lpc24xx_rtc_match, 293 }, 294 }; 295 module_platform_driver(lpc24xx_rtc_driver); 296 297 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>"); 298 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs"); 299 MODULE_LICENSE("GPL"); 300