--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ */
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <rtc.h>
+#include <asm/io.h>
+#include <linux/iopoll.h>
+
+#define STM32_RTC_TR 0x00
+#define STM32_RTC_DR 0x04
+#define STM32_RTC_ISR 0x0C
+#define STM32_RTC_PRER 0x10
+#define STM32_RTC_CR 0x18
+#define STM32_RTC_WPR 0x24
+
+/* STM32_RTC_TR bit fields */
+#define STM32_RTC_SEC_SHIFT 0
+#define STM32_RTC_SEC GENMASK(6, 0)
+#define STM32_RTC_MIN_SHIFT 8
+#define STM32_RTC_MIN GENMASK(14, 8)
+#define STM32_RTC_HOUR_SHIFT 16
+#define STM32_RTC_HOUR GENMASK(21, 16)
+
+/* STM32_RTC_DR bit fields */
+#define STM32_RTC_DATE_SHIFT 0
+#define STM32_RTC_DATE GENMASK(5, 0)
+#define STM32_RTC_MONTH_SHIFT 8
+#define STM32_RTC_MONTH GENMASK(12, 8)
+#define STM32_RTC_WDAY_SHIFT 13
+#define STM32_RTC_WDAY GENMASK(15, 13)
+#define STM32_RTC_YEAR_SHIFT 16
+#define STM32_RTC_YEAR GENMASK(23, 16)
+
+/* STM32_RTC_CR bit fields */
+#define STM32_RTC_CR_FMT BIT(6)
+
+/* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */
+#define STM32_RTC_ISR_INITS BIT(4)
+#define STM32_RTC_ISR_RSF BIT(5)
+#define STM32_RTC_ISR_INITF BIT(6)
+#define STM32_RTC_ISR_INIT BIT(7)
+
+/* STM32_RTC_PRER bit fields */
+#define STM32_RTC_PRER_PRED_S_SHIFT 0
+#define STM32_RTC_PRER_PRED_S GENMASK(14, 0)
+#define STM32_RTC_PRER_PRED_A_SHIFT 16
+#define STM32_RTC_PRER_PRED_A GENMASK(22, 16)
+
+/* STM32_RTC_WPR key constants */
+#define RTC_WPR_1ST_KEY 0xCA
+#define RTC_WPR_2ND_KEY 0x53
+#define RTC_WPR_WRONG_KEY 0xFF
+
+struct stm32_rtc_priv {
+ fdt_addr_t base;
+};
+
+static int stm32_rtc_get(struct udevice *dev, struct rtc_time *tm)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ u32 tr, dr;
+
+ tr = readl(priv->base + STM32_RTC_TR);
+ dr = readl(priv->base + STM32_RTC_DR);
+
+ tm->tm_sec = bcd2bin((tr & STM32_RTC_SEC) >> STM32_RTC_SEC_SHIFT);
+ tm->tm_min = bcd2bin((tr & STM32_RTC_MIN) >> STM32_RTC_MIN_SHIFT);
+ tm->tm_hour = bcd2bin((tr & STM32_RTC_HOUR) >> STM32_RTC_HOUR_SHIFT);
+
+ tm->tm_mday = bcd2bin((dr & STM32_RTC_DATE) >> STM32_RTC_DATE_SHIFT);
+ tm->tm_mon = bcd2bin((dr & STM32_RTC_MONTH) >> STM32_RTC_MONTH_SHIFT);
+ tm->tm_year = bcd2bin((dr & STM32_RTC_YEAR) >> STM32_RTC_YEAR_SHIFT);
+ tm->tm_wday = bcd2bin((dr & STM32_RTC_WDAY) >> STM32_RTC_WDAY_SHIFT);
+ tm->tm_yday = 0;
+ tm->tm_isdst = 0;
+
+ dev_dbg(dev, "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
+ tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+ return 0;
+}
+
+static void stm32_rtc_unlock(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+
+ writel(RTC_WPR_1ST_KEY, priv->base + STM32_RTC_WPR);
+ writel(RTC_WPR_2ND_KEY, priv->base + STM32_RTC_WPR);
+}
+
+static void stm32_rtc_lock(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+
+ writel(RTC_WPR_WRONG_KEY, priv->base + STM32_RTC_WPR);
+}
+
+static int stm32_rtc_enter_init_mode(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ u32 isr = readl(priv->base + STM32_RTC_ISR);
+
+ if (!(isr & STM32_RTC_ISR_INITF)) {
+ isr |= STM32_RTC_ISR_INIT;
+ writel(isr, priv->base + STM32_RTC_ISR);
+
+ return readl_poll_timeout(priv->base + STM32_RTC_ISR,
+ isr,
+ (isr & STM32_RTC_ISR_INITF),
+ 100000);
+ }
+
+ return 0;
+}
+
+static int stm32_rtc_wait_sync(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ u32 isr = readl(priv->base + STM32_RTC_ISR);
+
+ isr &= ~STM32_RTC_ISR_RSF;
+ writel(isr, priv->base + STM32_RTC_ISR);
+
+ /*
+ * Wait for RSF to be set to ensure the calendar registers are
+ * synchronised, it takes around 2 rtc_ck clock cycles
+ */
+ return readl_poll_timeout(priv->base + STM32_RTC_ISR,
+ isr, (isr & STM32_RTC_ISR_RSF),
+ 100000);
+}
+
+static void stm32_rtc_exit_init_mode(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ u32 isr = readl(priv->base + STM32_RTC_ISR);
+
+ isr &= ~STM32_RTC_ISR_INIT;
+ writel(isr, priv->base + STM32_RTC_ISR);
+}
+
+static int stm32_rtc_set_time(struct udevice *dev, u32 time, u32 date)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ stm32_rtc_unlock(dev);
+
+ ret = stm32_rtc_enter_init_mode(dev);
+ if (ret)
+ goto lock;
+
+ writel(time, priv->base + STM32_RTC_TR);
+ writel(date, priv->base + STM32_RTC_DR);
+
+ stm32_rtc_exit_init_mode(dev);
+
+ ret = stm32_rtc_wait_sync(dev);
+
+lock:
+ stm32_rtc_lock(dev);
+ return ret;
+}
+
+static int stm32_rtc_set(struct udevice *dev, const struct rtc_time *tm)
+{
+ u32 t, d;
+
+ dev_dbg(dev, "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
+ tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+ /* Time in BCD format */
+ t = (bin2bcd(tm->tm_sec) << STM32_RTC_SEC_SHIFT) & STM32_RTC_SEC;
+ t |= (bin2bcd(tm->tm_min) << STM32_RTC_MIN_SHIFT) & STM32_RTC_MIN;
+ t |= (bin2bcd(tm->tm_hour) << STM32_RTC_HOUR_SHIFT) & STM32_RTC_HOUR;
+
+ /* Date in BCD format */
+ d = (bin2bcd(tm->tm_mday) << STM32_RTC_DATE_SHIFT) & STM32_RTC_DATE;
+ d |= (bin2bcd(tm->tm_mon) << STM32_RTC_MONTH_SHIFT) & STM32_RTC_MONTH;
+ d |= (bin2bcd(tm->tm_year) << STM32_RTC_YEAR_SHIFT) & STM32_RTC_YEAR;
+ d |= (bin2bcd(tm->tm_wday) << STM32_RTC_WDAY_SHIFT) & STM32_RTC_WDAY;
+
+ return stm32_rtc_set_time(dev, t, d);
+}
+
+static int stm32_rtc_reset(struct udevice *dev)
+{
+ dev_dbg(dev, "Reset DATE\n");
+
+ return stm32_rtc_set_time(dev, 0, 0);
+}
+
+static int stm32_rtc_init(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
+ unsigned int rate;
+ struct clk clk;
+ int ret;
+ u32 isr = readl(priv->base + STM32_RTC_ISR);
+
+ if (isr & STM32_RTC_ISR_INITS)
+ return 0;
+
+ ret = clk_get_by_index(dev, 1, &clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(&clk);
+ if (ret) {
+ clk_free(&clk);
+ return ret;
+ }
+
+ rate = clk_get_rate(&clk);
+
+ /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
+ pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
+ pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
+
+ for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
+ pred_s = (rate / (pred_a + 1)) - 1;
+
+ if (((pred_s + 1) * (pred_a + 1)) == rate)
+ break;
+ }
+
+ /*
+ * Can't find a 1Hz, so give priority to RTC power consumption
+ * by choosing the higher possible value for prediv_a
+ */
+ if (pred_s > pred_s_max || pred_a > pred_a_max) {
+ pred_a = pred_a_max;
+ pred_s = (rate / (pred_a + 1)) - 1;
+ }
+
+ stm32_rtc_unlock(dev);
+
+ ret = stm32_rtc_enter_init_mode(dev);
+ if (ret) {
+ dev_err(dev,
+ "Can't enter in init mode. Prescaler config failed.\n");
+ goto unlock;
+ }
+
+ prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
+ prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
+ writel(prer, priv->base + STM32_RTC_PRER);
+
+ /* Force 24h time format */
+ cr = readl(priv->base + STM32_RTC_CR);
+ cr &= ~STM32_RTC_CR_FMT;
+ writel(cr, priv->base + STM32_RTC_CR);
+
+ stm32_rtc_exit_init_mode(dev);
+
+ ret = stm32_rtc_wait_sync(dev);
+
+unlock:
+ stm32_rtc_lock(dev);
+
+ if (ret) {
+ clk_disable(&clk);
+ clk_free(&clk);
+ }
+
+ return ret;
+}
+
+static int stm32_rtc_probe(struct udevice *dev)
+{
+ struct stm32_rtc_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ int ret;
+
+ priv->base = dev_read_addr(dev);
+ if (priv->base == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(&clk);
+ if (ret) {
+ clk_free(&clk);
+ return ret;
+ }
+
+ ret = stm32_rtc_init(dev);
+
+ if (ret) {
+ clk_disable(&clk);
+ clk_free(&clk);
+ }
+
+ return ret;
+}
+
+static const struct rtc_ops stm32_rtc_ops = {
+ .get = stm32_rtc_get,
+ .set = stm32_rtc_set,
+ .reset = stm32_rtc_reset,
+};
+
+static const struct udevice_id stm32_rtc_ids[] = {
+ { .compatible = "st,stm32mp1-rtc" },
+ { }
+};
+
+U_BOOT_DRIVER(rtc_stm32) = {
+ .name = "rtc-stm32",
+ .id = UCLASS_RTC,
+ .probe = stm32_rtc_probe,
+ .of_match = stm32_rtc_ids,
+ .ops = &stm32_rtc_ops,
+ .priv_auto_alloc_size = sizeof(struct stm32_rtc_priv),
+};
projects / oweals / u-boot.git / commitdiff