--- /dev/null
+commit f94ffbc2c2a4128c4412bb483d0807722dfb682b
+Author: Russell King <rmk+kernel@armlinux.org.uk>
+Date: Fri Sep 29 11:23:31 2017 +0100
+
+ rtc: armada38x: add support for trimming the RTC
+
+ Add support for trimming the RTC using the offset mechanism. This RTC
+ supports two modes: low update mode and high update mode. Low update
+ mode has finer precision than high update mode, so we use the low mode
+ where possible.
+
+ Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
+ Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
+
+--- a/drivers/rtc/rtc-armada38x.c
++++ b/drivers/rtc/rtc-armada38x.c
+@@ -28,6 +28,8 @@
+ #define RTC_IRQ_AL_EN BIT(0)
+ #define RTC_IRQ_FREQ_EN BIT(1)
+ #define RTC_IRQ_FREQ_1HZ BIT(2)
++#define RTC_CCR 0x18
++#define RTC_CCR_MODE BIT(15)
+
+ #define RTC_TIME 0xC
+ #define RTC_ALARM1 0x10
+@@ -343,18 +345,117 @@ static irqreturn_t armada38x_rtc_alarm_i
+ return IRQ_HANDLED;
+ }
+
++/*
++ * The information given in the Armada 388 functional spec is complex.
++ * They give two different formulas for calculating the offset value,
++ * but when considering "Offset" as an 8-bit signed integer, they both
++ * reduce down to (we shall rename "Offset" as "val" here):
++ *
++ * val = (f_ideal / f_measured - 1) / resolution where f_ideal = 32768
++ *
++ * Converting to time, f = 1/t:
++ * val = (t_measured / t_ideal - 1) / resolution where t_ideal = 1/32768
++ *
++ * => t_measured / t_ideal = val * resolution + 1
++ *
++ * "offset" in the RTC interface is defined as:
++ * t = t0 * (1 + offset * 1e-9)
++ * where t is the desired period, t0 is the measured period with a zero
++ * offset, which is t_measured above. With t0 = t_measured and t = t_ideal,
++ * offset = (t_ideal / t_measured - 1) / 1e-9
++ *
++ * => t_ideal / t_measured = offset * 1e-9 + 1
++ *
++ * so:
++ *
++ * offset * 1e-9 + 1 = 1 / (val * resolution + 1)
++ *
++ * We want "resolution" to be an integer, so resolution = R * 1e-9, giving
++ * offset = 1e18 / (val * R + 1e9) - 1e9
++ * val = (1e18 / (offset + 1e9) - 1e9) / R
++ * with a common transformation:
++ * f(x) = 1e18 / (x + 1e9) - 1e9
++ * offset = f(val * R)
++ * val = f(offset) / R
++ *
++ * Armada 38x supports two modes, fine mode (954ppb) and coarse mode (3815ppb).
++ */
++static long armada38x_ppb_convert(long ppb)
++{
++ long div = ppb + 1000000000L;
++
++ return div_s64(1000000000000000000LL + div / 2, div) - 1000000000L;
++}
++
++static int armada38x_rtc_read_offset(struct device *dev, long *offset)
++{
++ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
++ unsigned long ccr, flags;
++ long ppb_cor;
++
++ spin_lock_irqsave(&rtc->lock, flags);
++ ccr = rtc->data->read_rtc_reg(rtc, RTC_CCR);
++ spin_unlock_irqrestore(&rtc->lock, flags);
++
++ ppb_cor = (ccr & RTC_CCR_MODE ? 3815 : 954) * (s8)ccr;
++ /* ppb_cor + 1000000000L can never be zero */
++ *offset = armada38x_ppb_convert(ppb_cor);
++
++ return 0;
++}
++
++static int armada38x_rtc_set_offset(struct device *dev, long offset)
++{
++ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
++ unsigned long ccr = 0;
++ long ppb_cor, off;
++
++ /*
++ * The maximum ppb_cor is -128 * 3815 .. 127 * 3815, but we
++ * need to clamp the input. This equates to -484270 .. 488558.
++ * Not only is this to stop out of range "off" but also to
++ * avoid the division by zero in armada38x_ppb_convert().
++ */
++ offset = clamp(offset, -484270L, 488558L);
++
++ ppb_cor = armada38x_ppb_convert(offset);
++
++ /*
++ * Use low update mode where possible, which gives a better
++ * resolution of correction.
++ */
++ off = DIV_ROUND_CLOSEST(ppb_cor, 954);
++ if (off > 127 || off < -128) {
++ ccr = RTC_CCR_MODE;
++ off = DIV_ROUND_CLOSEST(ppb_cor, 3815);
++ }
++
++ /*
++ * Armada 388 requires a bit pattern in bits 14..8 depending on
++ * the sign bit: { 0, ~S, S, S, S, S, S }
++ */
++ ccr |= (off & 0x3fff) ^ 0x2000;
++ rtc_delayed_write(ccr, rtc, RTC_CCR);
++
++ return 0;
++}
++
+ static const struct rtc_class_ops armada38x_rtc_ops = {
+ .read_time = armada38x_rtc_read_time,
+ .set_time = armada38x_rtc_set_time,
+ .read_alarm = armada38x_rtc_read_alarm,
+ .set_alarm = armada38x_rtc_set_alarm,
+ .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
++ .read_offset = armada38x_rtc_read_offset,
++ .set_offset = armada38x_rtc_set_offset,
+ };
+
+ static const struct rtc_class_ops armada38x_rtc_ops_noirq = {
+ .read_time = armada38x_rtc_read_time,
+ .set_time = armada38x_rtc_set_time,
+ .read_alarm = armada38x_rtc_read_alarm,
++ .read_offset = armada38x_rtc_read_offset,
++ .set_offset = armada38x_rtc_set_offset,
+ };
+
+ static const struct armada38x_rtc_data armada38x_data = {
+++ /dev/null
-commit f94ffbc2c2a4128c4412bb483d0807722dfb682b
-Author: Russell King <rmk+kernel@armlinux.org.uk>
-Date: Fri Sep 29 11:23:31 2017 +0100
-
- rtc: armada38x: add support for trimming the RTC
-
- Add support for trimming the RTC using the offset mechanism. This RTC
- supports two modes: low update mode and high update mode. Low update
- mode has finer precision than high update mode, so we use the low mode
- where possible.
-
- Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
- Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
-
---- a/drivers/rtc/rtc-armada38x.c
-+++ b/drivers/rtc/rtc-armada38x.c
-@@ -28,6 +28,8 @@
- #define RTC_IRQ_AL_EN BIT(0)
- #define RTC_IRQ_FREQ_EN BIT(1)
- #define RTC_IRQ_FREQ_1HZ BIT(2)
-+#define RTC_CCR 0x18
-+#define RTC_CCR_MODE BIT(15)
-
- #define RTC_TIME 0xC
- #define RTC_ALARM1 0x10
-@@ -343,18 +345,117 @@ static irqreturn_t armada38x_rtc_alarm_i
- return IRQ_HANDLED;
- }
-
-+/*
-+ * The information given in the Armada 388 functional spec is complex.
-+ * They give two different formulas for calculating the offset value,
-+ * but when considering "Offset" as an 8-bit signed integer, they both
-+ * reduce down to (we shall rename "Offset" as "val" here):
-+ *
-+ * val = (f_ideal / f_measured - 1) / resolution where f_ideal = 32768
-+ *
-+ * Converting to time, f = 1/t:
-+ * val = (t_measured / t_ideal - 1) / resolution where t_ideal = 1/32768
-+ *
-+ * => t_measured / t_ideal = val * resolution + 1
-+ *
-+ * "offset" in the RTC interface is defined as:
-+ * t = t0 * (1 + offset * 1e-9)
-+ * where t is the desired period, t0 is the measured period with a zero
-+ * offset, which is t_measured above. With t0 = t_measured and t = t_ideal,
-+ * offset = (t_ideal / t_measured - 1) / 1e-9
-+ *
-+ * => t_ideal / t_measured = offset * 1e-9 + 1
-+ *
-+ * so:
-+ *
-+ * offset * 1e-9 + 1 = 1 / (val * resolution + 1)
-+ *
-+ * We want "resolution" to be an integer, so resolution = R * 1e-9, giving
-+ * offset = 1e18 / (val * R + 1e9) - 1e9
-+ * val = (1e18 / (offset + 1e9) - 1e9) / R
-+ * with a common transformation:
-+ * f(x) = 1e18 / (x + 1e9) - 1e9
-+ * offset = f(val * R)
-+ * val = f(offset) / R
-+ *
-+ * Armada 38x supports two modes, fine mode (954ppb) and coarse mode (3815ppb).
-+ */
-+static long armada38x_ppb_convert(long ppb)
-+{
-+ long div = ppb + 1000000000L;
-+
-+ return div_s64(1000000000000000000LL + div / 2, div) - 1000000000L;
-+}
-+
-+static int armada38x_rtc_read_offset(struct device *dev, long *offset)
-+{
-+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
-+ unsigned long ccr, flags;
-+ long ppb_cor;
-+
-+ spin_lock_irqsave(&rtc->lock, flags);
-+ ccr = rtc->data->read_rtc_reg(rtc, RTC_CCR);
-+ spin_unlock_irqrestore(&rtc->lock, flags);
-+
-+ ppb_cor = (ccr & RTC_CCR_MODE ? 3815 : 954) * (s8)ccr;
-+ /* ppb_cor + 1000000000L can never be zero */
-+ *offset = armada38x_ppb_convert(ppb_cor);
-+
-+ return 0;
-+}
-+
-+static int armada38x_rtc_set_offset(struct device *dev, long offset)
-+{
-+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
-+ unsigned long ccr = 0;
-+ long ppb_cor, off;
-+
-+ /*
-+ * The maximum ppb_cor is -128 * 3815 .. 127 * 3815, but we
-+ * need to clamp the input. This equates to -484270 .. 488558.
-+ * Not only is this to stop out of range "off" but also to
-+ * avoid the division by zero in armada38x_ppb_convert().
-+ */
-+ offset = clamp(offset, -484270L, 488558L);
-+
-+ ppb_cor = armada38x_ppb_convert(offset);
-+
-+ /*
-+ * Use low update mode where possible, which gives a better
-+ * resolution of correction.
-+ */
-+ off = DIV_ROUND_CLOSEST(ppb_cor, 954);
-+ if (off > 127 || off < -128) {
-+ ccr = RTC_CCR_MODE;
-+ off = DIV_ROUND_CLOSEST(ppb_cor, 3815);
-+ }
-+
-+ /*
-+ * Armada 388 requires a bit pattern in bits 14..8 depending on
-+ * the sign bit: { 0, ~S, S, S, S, S, S }
-+ */
-+ ccr |= (off & 0x3fff) ^ 0x2000;
-+ rtc_delayed_write(ccr, rtc, RTC_CCR);
-+
-+ return 0;
-+}
-+
- static const struct rtc_class_ops armada38x_rtc_ops = {
- .read_time = armada38x_rtc_read_time,
- .set_time = armada38x_rtc_set_time,
- .read_alarm = armada38x_rtc_read_alarm,
- .set_alarm = armada38x_rtc_set_alarm,
- .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
-+ .read_offset = armada38x_rtc_read_offset,
-+ .set_offset = armada38x_rtc_set_offset,
- };
-
- static const struct rtc_class_ops armada38x_rtc_ops_noirq = {
- .read_time = armada38x_rtc_read_time,
- .set_time = armada38x_rtc_set_time,
- .read_alarm = armada38x_rtc_read_alarm,
-+ .read_offset = armada38x_rtc_read_offset,
-+ .set_offset = armada38x_rtc_set_offset,
- };
-
- static const struct armada38x_rtc_data armada38x_data = {
--- /dev/null
+From 1a990fefb641398fb580a0ea0be99b0ff27cbb9b Mon Sep 17 00:00:00 2001
+From: Baruch Siach <baruch@tkos.co.il>
+Date: Thu, 21 Jun 2018 20:40:23 +0300
+Subject: [PATCH] rtc: armada38x: reset after rtc power loss
+
+When the RTC block looses power it needs a reset sequence to make it
+usable again. Otherwise, writes to the time register have no effect.
+
+This reset sequence combines information from the mvebu_rtc driver in
+the Marvell provided U-Boot, and the SolidRun provided U-Boot repo.
+
+Tested on the Armada 388 based SolidRun Clearfog Base.
+
+Signed-off-by: Baruch Siach <baruch@tkos.co.il>
+Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
+Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
+---
+ drivers/rtc/rtc-armada38x.c | 23 +++++++++++++++++++++++
+ 1 file changed, 23 insertions(+)
+
+diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c
+index 1e4978c..bde53c8c 100644
+--- a/drivers/rtc/rtc-armada38x.c
++++ b/drivers/rtc/rtc-armada38x.c
+@@ -30,6 +30,8 @@
+ #define RTC_IRQ_FREQ_1HZ BIT(2)
+ #define RTC_CCR 0x18
+ #define RTC_CCR_MODE BIT(15)
++#define RTC_CONF_TEST 0x1C
++#define RTC_NOMINAL_TIMING BIT(13)
+
+ #define RTC_TIME 0xC
+ #define RTC_ALARM1 0x10
+@@ -75,6 +77,7 @@ struct armada38x_rtc {
+ void __iomem *regs_soc;
+ spinlock_t lock;
+ int irq;
++ bool initialized;
+ struct value_to_freq *val_to_freq;
+ struct armada38x_rtc_data *data;
+ };
+@@ -226,6 +229,23 @@ static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
+ return 0;
+ }
+
++static void armada38x_rtc_reset(struct armada38x_rtc *rtc)
++{
++ u32 reg;
++
++ reg = rtc->data->read_rtc_reg(rtc, RTC_CONF_TEST);
++ /* If bits [7:0] are non-zero, assume RTC was uninitialized */
++ if (reg & 0xff) {
++ rtc_delayed_write(0, rtc, RTC_CONF_TEST);
++ msleep(500); /* Oscillator startup time */
++ rtc_delayed_write(0, rtc, RTC_TIME);
++ rtc_delayed_write(SOC_RTC_ALARM1 | SOC_RTC_ALARM2, rtc,
++ RTC_STATUS);
++ rtc_delayed_write(RTC_NOMINAL_TIMING, rtc, RTC_CCR);
++ }
++ rtc->initialized = true;
++}
++
+ static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+ {
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+@@ -237,6 +257,9 @@ static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+ if (ret)
+ goto out;
+
++ if (!rtc->initialized)
++ armada38x_rtc_reset(rtc);
++
+ spin_lock_irqsave(&rtc->lock, flags);
+ rtc_delayed_write(time, rtc, RTC_TIME);
+ spin_unlock_irqrestore(&rtc->lock, flags);
+--
+2.7.4
+
+++ /dev/null
-Some boards like the Turris Omnia have an RTC chip that does not get
-initialized. Initializing the RTC at the driver level helps get rid of
-bootloader hacks that write special register values.
-
---- a/drivers/rtc/rtc-armada38x.c
-+++ b/drivers/rtc/rtc-armada38x.c
-@@ -30,6 +30,9 @@
- #define RTC_IRQ_FREQ_1HZ BIT(2)
- #define RTC_CCR 0x18
- #define RTC_CCR_MODE BIT(15)
-+#define RTC_CCR_NORMAL_PPB 0x2000
-+#define RTC_TEST_CONF 0x1c
-+#define RTC_TEST_CONF_MASK 0xff
-
- #define RTC_TIME 0xC
- #define RTC_ALARM1 0x10
-@@ -91,6 +94,7 @@ struct armada38x_rtc_data {
- void (*clear_isr)(struct armada38x_rtc *rtc);
- void (*unmask_interrupt)(struct armada38x_rtc *rtc);
- u32 alarm;
-+ void (*init_rtc)(struct armada38x_rtc *rtc);
- };
-
- /*
-@@ -202,6 +206,23 @@ static void armada38x_unmask_interrupt(s
- writel(val | SOC_RTC_ALARM1_MASK, rtc->regs_soc + SOC_RTC_INTERRUPT);
- }
-
-+static void armada38x_rtc_init(struct armada38x_rtc *rtc)
-+{
-+ u32 reg;
-+
-+ /* Test RTC test configuration register bits [7:0] */
-+ reg = readl(rtc->regs + RTC_TEST_CONF);
-+ /* If bits [7:0] are non-zero, assume RTC was uninitialized */
-+ if (reg & RTC_TEST_CONF_MASK) {
-+ rtc_delayed_write(0, rtc, RTC_TEST_CONF);
-+ rtc_delayed_write(0, rtc, RTC_TIME);
-+ rtc_delayed_write((RTC_STATUS_ALARM1 | RTC_STATUS_ALARM2),
-+ rtc, RTC_STATUS);
-+ rtc_delayed_write(RTC_CCR_NORMAL_PPB, rtc, RTC_CCR);
-+ }
-+ return;
-+}
-+
- static void armada8k_clear_isr(struct armada38x_rtc *rtc)
- {
- writel(RTC_8K_ALARM2, rtc->regs_soc + RTC_8K_ISR);
-@@ -464,6 +485,7 @@ static const struct armada38x_rtc_data a
- .clear_isr = armada38x_clear_isr,
- .unmask_interrupt = armada38x_unmask_interrupt,
- .alarm = ALARM1,
-+ .init_rtc = armada38x_rtc_init,
- };
-
- static const struct armada38x_rtc_data armada8k_data = {
-@@ -558,6 +580,17 @@ static __init int armada38x_rtc_probe(st
- dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
- return ret;
- }
-+
-+ /*
-+ * Try to detect if RTC is in uninitialized state.
-+ * It is not definitive to know if the RTC is in an uninialized state or not,
-+ * but the following call will read some bits in the RTC unit and guess if
-+ * if it's in that state, and accordingly set it to sane default values.
-+ */
-+ if (rtc->data->init_rtc) {
-+ rtc->data->init_rtc(rtc);
-+ }
-+
- return 0;
- }
-
projects / openwrt / openwrt.git / commitdiff