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