1 /* 2 * RTC driver for NXP LPC178x/18xx/43xx Real-Time Clock (RTC) 3 * 4 * Copyright (C) 2011 NXP Semiconductors 5 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 */ 13 14 #include <linux/clk.h> 15 #include <linux/io.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 #include <linux/of_device.h> 20 #include <linux/platform_device.h> 21 #include <linux/rtc.h> 22 23 /* LPC24xx RTC register offsets and bits */ 24 #define LPC24XX_ILR 0x00 25 #define LPC24XX_RTCCIF BIT(0) 26 #define LPC24XX_RTCALF BIT(1) 27 #define LPC24XX_CTC 0x04 28 #define LPC24XX_CCR 0x08 29 #define LPC24XX_CLKEN BIT(0) 30 #define LPC178X_CCALEN BIT(4) 31 #define LPC24XX_CIIR 0x0c 32 #define LPC24XX_AMR 0x10 33 #define LPC24XX_ALARM_DISABLE 0xff 34 #define LPC24XX_CTIME0 0x14 35 #define LPC24XX_CTIME1 0x18 36 #define LPC24XX_CTIME2 0x1c 37 #define LPC24XX_SEC 0x20 38 #define LPC24XX_MIN 0x24 39 #define LPC24XX_HOUR 0x28 40 #define LPC24XX_DOM 0x2c 41 #define LPC24XX_DOW 0x30 42 #define LPC24XX_DOY 0x34 43 #define LPC24XX_MONTH 0x38 44 #define LPC24XX_YEAR 0x3c 45 #define LPC24XX_ALSEC 0x60 46 #define LPC24XX_ALMIN 0x64 47 #define LPC24XX_ALHOUR 0x68 48 #define LPC24XX_ALDOM 0x6c 49 #define LPC24XX_ALDOW 0x70 50 #define LPC24XX_ALDOY 0x74 51 #define LPC24XX_ALMON 0x78 52 #define LPC24XX_ALYEAR 0x7c 53 54 /* Macros to read fields in consolidated time (CT) registers */ 55 #define CT0_SECS(x) (((x) >> 0) & 0x3f) 56 #define CT0_MINS(x) (((x) >> 8) & 0x3f) 57 #define CT0_HOURS(x) (((x) >> 16) & 0x1f) 58 #define CT0_DOW(x) (((x) >> 24) & 0x07) 59 #define CT1_DOM(x) (((x) >> 0) & 0x1f) 60 #define CT1_MONTH(x) (((x) >> 8) & 0x0f) 61 #define CT1_YEAR(x) (((x) >> 16) & 0xfff) 62 #define CT2_DOY(x) (((x) >> 0) & 0xfff) 63 64 #define rtc_readl(dev, reg) readl((dev)->rtc_base + (reg)) 65 #define rtc_writel(dev, reg, val) writel((val), (dev)->rtc_base + (reg)) 66 67 struct lpc24xx_rtc { 68 void __iomem *rtc_base; 69 struct rtc_device *rtc; 70 struct clk *clk_rtc; 71 struct clk *clk_reg; 72 }; 73 74 static int lpc24xx_rtc_set_time(struct device *dev, struct rtc_time *tm) 75 { 76 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 77 78 /* Disable RTC during update */ 79 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); 80 81 rtc_writel(rtc, LPC24XX_SEC, tm->tm_sec); 82 rtc_writel(rtc, LPC24XX_MIN, tm->tm_min); 83 rtc_writel(rtc, LPC24XX_HOUR, tm->tm_hour); 84 rtc_writel(rtc, LPC24XX_DOW, tm->tm_wday); 85 rtc_writel(rtc, LPC24XX_DOM, tm->tm_mday); 86 rtc_writel(rtc, LPC24XX_DOY, tm->tm_yday); 87 rtc_writel(rtc, LPC24XX_MONTH, tm->tm_mon); 88 rtc_writel(rtc, LPC24XX_YEAR, tm->tm_year); 89 90 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); 91 92 return 0; 93 } 94 95 static int lpc24xx_rtc_read_time(struct device *dev, struct rtc_time *tm) 96 { 97 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 98 u32 ct0, ct1, ct2; 99 100 ct0 = rtc_readl(rtc, LPC24XX_CTIME0); 101 ct1 = rtc_readl(rtc, LPC24XX_CTIME1); 102 ct2 = rtc_readl(rtc, LPC24XX_CTIME2); 103 104 tm->tm_sec = CT0_SECS(ct0); 105 tm->tm_min = CT0_MINS(ct0); 106 tm->tm_hour = CT0_HOURS(ct0); 107 tm->tm_wday = CT0_DOW(ct0); 108 tm->tm_mon = CT1_MONTH(ct1); 109 tm->tm_mday = CT1_DOM(ct1); 110 tm->tm_year = CT1_YEAR(ct1); 111 tm->tm_yday = CT2_DOY(ct2); 112 113 return rtc_valid_tm(tm); 114 } 115 116 static int lpc24xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 117 { 118 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 119 struct rtc_time *tm = &wkalrm->time; 120 121 tm->tm_sec = rtc_readl(rtc, LPC24XX_ALSEC); 122 tm->tm_min = rtc_readl(rtc, LPC24XX_ALMIN); 123 tm->tm_hour = rtc_readl(rtc, LPC24XX_ALHOUR); 124 tm->tm_mday = rtc_readl(rtc, LPC24XX_ALDOM); 125 tm->tm_wday = rtc_readl(rtc, LPC24XX_ALDOW); 126 tm->tm_yday = rtc_readl(rtc, LPC24XX_ALDOY); 127 tm->tm_mon = rtc_readl(rtc, LPC24XX_ALMON); 128 tm->tm_year = rtc_readl(rtc, LPC24XX_ALYEAR); 129 130 wkalrm->enabled = rtc_readl(rtc, LPC24XX_AMR) == 0; 131 wkalrm->pending = !!(rtc_readl(rtc, LPC24XX_ILR) & LPC24XX_RTCCIF); 132 133 return rtc_valid_tm(&wkalrm->time); 134 } 135 136 static int lpc24xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 137 { 138 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 139 struct rtc_time *tm = &wkalrm->time; 140 141 /* Disable alarm irq during update */ 142 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 143 144 rtc_writel(rtc, LPC24XX_ALSEC, tm->tm_sec); 145 rtc_writel(rtc, LPC24XX_ALMIN, tm->tm_min); 146 rtc_writel(rtc, LPC24XX_ALHOUR, tm->tm_hour); 147 rtc_writel(rtc, LPC24XX_ALDOM, tm->tm_mday); 148 rtc_writel(rtc, LPC24XX_ALDOW, tm->tm_wday); 149 rtc_writel(rtc, LPC24XX_ALDOY, tm->tm_yday); 150 rtc_writel(rtc, LPC24XX_ALMON, tm->tm_mon); 151 rtc_writel(rtc, LPC24XX_ALYEAR, tm->tm_year); 152 153 if (wkalrm->enabled) 154 rtc_writel(rtc, LPC24XX_AMR, 0); 155 156 return 0; 157 } 158 159 static int lpc24xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) 160 { 161 struct lpc24xx_rtc *rtc = dev_get_drvdata(dev); 162 163 if (enable) 164 rtc_writel(rtc, LPC24XX_AMR, 0); 165 else 166 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 167 168 return 0; 169 } 170 171 static irqreturn_t lpc24xx_rtc_interrupt(int irq, void *data) 172 { 173 unsigned long events = RTC_IRQF; 174 struct lpc24xx_rtc *rtc = data; 175 u32 rtc_iir; 176 177 /* Check interrupt cause */ 178 rtc_iir = rtc_readl(rtc, LPC24XX_ILR); 179 if (rtc_iir & LPC24XX_RTCALF) { 180 events |= RTC_AF; 181 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 182 } 183 184 /* Clear interrupt status and report event */ 185 rtc_writel(rtc, LPC24XX_ILR, rtc_iir); 186 rtc_update_irq(rtc->rtc, 1, events); 187 188 return IRQ_HANDLED; 189 } 190 191 static const struct rtc_class_ops lpc24xx_rtc_ops = { 192 .read_time = lpc24xx_rtc_read_time, 193 .set_time = lpc24xx_rtc_set_time, 194 .read_alarm = lpc24xx_rtc_read_alarm, 195 .set_alarm = lpc24xx_rtc_set_alarm, 196 .alarm_irq_enable = lpc24xx_rtc_alarm_irq_enable, 197 }; 198 199 static int lpc24xx_rtc_probe(struct platform_device *pdev) 200 { 201 struct lpc24xx_rtc *rtc; 202 struct resource *res; 203 int irq, ret; 204 205 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); 206 if (!rtc) 207 return -ENOMEM; 208 209 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 210 rtc->rtc_base = devm_ioremap_resource(&pdev->dev, res); 211 if (IS_ERR(rtc->rtc_base)) 212 return PTR_ERR(rtc->rtc_base); 213 214 irq = platform_get_irq(pdev, 0); 215 if (irq < 0) { 216 dev_warn(&pdev->dev, "can't get interrupt resource\n"); 217 return irq; 218 } 219 220 rtc->clk_rtc = devm_clk_get(&pdev->dev, "rtc"); 221 if (IS_ERR(rtc->clk_rtc)) { 222 dev_err(&pdev->dev, "error getting rtc clock\n"); 223 return PTR_ERR(rtc->clk_rtc); 224 } 225 226 rtc->clk_reg = devm_clk_get(&pdev->dev, "reg"); 227 if (IS_ERR(rtc->clk_reg)) { 228 dev_err(&pdev->dev, "error getting reg clock\n"); 229 return PTR_ERR(rtc->clk_reg); 230 } 231 232 ret = clk_prepare_enable(rtc->clk_rtc); 233 if (ret) { 234 dev_err(&pdev->dev, "unable to enable rtc clock\n"); 235 return ret; 236 } 237 238 ret = clk_prepare_enable(rtc->clk_reg); 239 if (ret) { 240 dev_err(&pdev->dev, "unable to enable reg clock\n"); 241 goto disable_rtc_clk; 242 } 243 244 platform_set_drvdata(pdev, rtc); 245 246 /* Clear any pending interrupts */ 247 rtc_writel(rtc, LPC24XX_ILR, LPC24XX_RTCCIF | LPC24XX_RTCALF); 248 249 /* Enable RTC count */ 250 rtc_writel(rtc, LPC24XX_CCR, LPC24XX_CLKEN | LPC178X_CCALEN); 251 252 ret = devm_request_irq(&pdev->dev, irq, lpc24xx_rtc_interrupt, 0, 253 pdev->name, rtc); 254 if (ret < 0) { 255 dev_warn(&pdev->dev, "can't request interrupt\n"); 256 goto disable_clks; 257 } 258 259 rtc->rtc = devm_rtc_device_register(&pdev->dev, "lpc24xx-rtc", 260 &lpc24xx_rtc_ops, THIS_MODULE); 261 if (IS_ERR(rtc->rtc)) { 262 dev_err(&pdev->dev, "can't register rtc device\n"); 263 ret = PTR_ERR(rtc->rtc); 264 goto disable_clks; 265 } 266 267 return 0; 268 269 disable_clks: 270 clk_disable_unprepare(rtc->clk_reg); 271 disable_rtc_clk: 272 clk_disable_unprepare(rtc->clk_rtc); 273 return ret; 274 } 275 276 static int lpc24xx_rtc_remove(struct platform_device *pdev) 277 { 278 struct lpc24xx_rtc *rtc = platform_get_drvdata(pdev); 279 280 /* Ensure all interrupt sources are masked */ 281 rtc_writel(rtc, LPC24XX_AMR, LPC24XX_ALARM_DISABLE); 282 rtc_writel(rtc, LPC24XX_CIIR, 0); 283 284 rtc_writel(rtc, LPC24XX_CCR, LPC178X_CCALEN); 285 286 clk_disable_unprepare(rtc->clk_rtc); 287 clk_disable_unprepare(rtc->clk_reg); 288 289 return 0; 290 } 291 292 static const struct of_device_id lpc24xx_rtc_match[] = { 293 { .compatible = "nxp,lpc1788-rtc" }, 294 { } 295 }; 296 MODULE_DEVICE_TABLE(of, lpc24xx_rtc_match); 297 298 static struct platform_driver lpc24xx_rtc_driver = { 299 .probe = lpc24xx_rtc_probe, 300 .remove = lpc24xx_rtc_remove, 301 .driver = { 302 .name = "lpc24xx-rtc", 303 .of_match_table = lpc24xx_rtc_match, 304 }, 305 }; 306 module_platform_driver(lpc24xx_rtc_driver); 307 308 MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com>"); 309 MODULE_DESCRIPTION("RTC driver for the LPC178x/18xx/408x/43xx SoCs"); 310 MODULE_LICENSE("GPL"); 311