RTC fixes for 5.5

- cmos: revert AltCentury support on AMD/Hygon
  - mt6397: fix alarm register overwrite
  - sun6i: ensure clock is working on R40
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Merge tag 'rtc-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC fixes from Alexandre Belloni:
 "A few fixes for this cycle. The CMOS AltCentury support broke a few
  platforms with a recent BIOS so I reverted it. The mt6397 fix is not
  that critical but good to have. And finally, the sun6i fix repairs
  WiFi and BT on a few platforms.

  Summary:

   - cmos: revert AltCentury support on AMD/Hygon

   - mt6397: fix alarm register overwrite

   - sun6i: ensure clock is working on R40"

* tag 'rtc-5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  rtc: cmos: Revert "rtc: Fix the AltCentury value on AMD/Hygon platform"
  rtc: mt6397: fix alarm register overwrite
  rtc: sun6i: Add support for RTC clocks on R40

drivers/rtc/rtc-mc146818-lib.c

@@ -172,20 +172,7 @@ int mc146818_set_time(struct rtc_time *time)
 	save_control = CMOS_READ(RTC_CONTROL);
 	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
-
-#ifdef CONFIG_X86
-	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
-	     boot_cpu_data.x86 == 0x17) ||
-	     boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
-		CMOS_WRITE((save_freq_select & (~RTC_DIV_RESET2)),
-			RTC_FREQ_SELECT);
-		save_freq_select &= ~RTC_DIV_RESET2;
-	} else
-		CMOS_WRITE((save_freq_select | RTC_DIV_RESET2),
-			RTC_FREQ_SELECT);
-#else
-	CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT);
-#endif
+	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 
 #ifdef CONFIG_MACH_DECSTATION
 	CMOS_WRITE(real_yrs, RTC_DEC_YEAR);

drivers/rtc/rtc-mt6397.c

@@ -47,7 +47,7 @@ static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
 		irqen = irqsta & ~RTC_IRQ_EN_AL;
 		mutex_lock(&rtc->lock);
 		if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
-				 irqen) < 0)
+				 irqen) == 0)
 			mtk_rtc_write_trigger(rtc);
 		mutex_unlock(&rtc->lock);
 
@@ -169,12 +169,12 @@ static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
 	mutex_unlock(&rtc->lock);
 
-	tm->tm_sec = data[RTC_OFFSET_SEC];
-	tm->tm_min = data[RTC_OFFSET_MIN];
-	tm->tm_hour = data[RTC_OFFSET_HOUR];
-	tm->tm_mday = data[RTC_OFFSET_DOM];
-	tm->tm_mon = data[RTC_OFFSET_MTH];
-	tm->tm_year = data[RTC_OFFSET_YEAR];
+	tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK;
+	tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK;
+	tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK;
+	tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK;
+	tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK;
+	tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK;
 
 	tm->tm_year += RTC_MIN_YEAR_OFFSET;
 	tm->tm_mon--;
@@ -195,14 +195,25 @@ static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
 	tm->tm_mon++;
 
-	data[RTC_OFFSET_SEC] = tm->tm_sec;
-	data[RTC_OFFSET_MIN] = tm->tm_min;
-	data[RTC_OFFSET_HOUR] = tm->tm_hour;
-	data[RTC_OFFSET_DOM] = tm->tm_mday;
-	data[RTC_OFFSET_MTH] = tm->tm_mon;
-	data[RTC_OFFSET_YEAR] = tm->tm_year;
-
 	mutex_lock(&rtc->lock);
+	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
+			       data, RTC_OFFSET_COUNT);
+	if (ret < 0)
+		goto exit;
+
+	data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) |
+				(tm->tm_sec & RTC_AL_SEC_MASK));
+	data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) |
+				(tm->tm_min & RTC_AL_MIN_MASK));
+	data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) |
+				(tm->tm_hour & RTC_AL_HOU_MASK));
+	data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) |
+				(tm->tm_mday & RTC_AL_DOM_MASK));
+	data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) |
+				(tm->tm_mon & RTC_AL_MTH_MASK));
+	data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) |
+				(tm->tm_year & RTC_AL_YEA_MASK));
+
 	if (alm->enabled) {
 		ret = regmap_bulk_write(rtc->regmap,
 					rtc->addr_base + RTC_AL_SEC,

drivers/rtc/rtc-sun6i.c

@@ -379,6 +379,22 @@ static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
 CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
 		      sun50i_h6_rtc_clk_init);
 
+/*
+ * The R40 user manual is self-conflicting on whether the prescaler is
+ * fixed or configurable. The clock diagram shows it as fixed, but there
+ * is also a configurable divider in the RTC block.
+ */
+static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
+	.rc_osc_rate = 16000000,
+	.fixed_prescaler = 512,
+};
+static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
+		      sun8i_r40_rtc_clk_init);
+
 static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
 	.rc_osc_rate = 32000,
 	.has_out_clk = 1,

include/linux/mfd/mt6397/rtc.h

@@ -46,6 +46,14 @@
 
 #define RTC_AL_SEC             0x0018
 
+#define RTC_AL_SEC_MASK        0x003f
+#define RTC_AL_MIN_MASK        0x003f
+#define RTC_AL_HOU_MASK        0x001f
+#define RTC_AL_DOM_MASK        0x001f
+#define RTC_AL_DOW_MASK        0x0007
+#define RTC_AL_MTH_MASK        0x000f
+#define RTC_AL_YEA_MASK        0x007f
+
 #define RTC_PDN2               0x002e
 #define RTC_PDN2_PWRON_ALARM   BIT(4)