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