S805 RTC driver

Add support for the AMLogic meson8b/meson6 RTC block.

Signed-off-by Ben Dooks <[email protected]>

---

drivers/rtc/rtc-meson.c new file +12 -0

+
+/* registers accessed from cpu bus */
+#define RTC_REG(x)	((x) * 4)	/* rtc registers 0-4 */
+
+#define LINE_SDI	(1 << 2)
+#define LINE_SEN	(1 << 1)
+#define LINE_SCLK	(1 << 0)
+
+#define RTCREG0_START_SER	BIT(17)
+#define RTCREG0_WAIT_SER	BIT(22)
+
+#define RTCREG1_READY	BIT(1)

drivers/rtc/rtc-meson.c new file +23 -0

+
+struct meson_rtc {
+	struct rtc_device	*rtc;	/* rtc device we created */
+	struct device		*dev;	/* device we bound from */
+	struct reset_control	*reset;	/* reset source */
+	struct mutex		lock;	/* rtc lock */
+	void __iomem		*regs;	/* rtc register access */
+};
+
+static void meson_rtc_setline(struct meson_rtc *rtc, unsigned bit, unsigned to)
+{
+	u32 reg0;
+
+	reg0 = readl(rtc->regs + RTC_REG(0));
+	if (to)
+		reg0 |= bit;
+	else
+		reg0 &= ~bit;
+	writel(reg0, rtc->regs + RTC_REG(0));
+	
+}
+
+static void meson_rtc_sclk_pulse(struct meson_rtc *rtc)

drivers/rtc/rtc-meson.c new file +13 -0

+	meson_rtc_sclk_pulse(rtc);
+}
+
+static void meson_rtc_send_bits(struct meson_rtc *rtc, u32 data, unsigned nr)
+{
+	u32 bit = 1 << (nr - 1);
+	
+	while (bit) {
+		meson_rtc_send_bit(rtc, data & bit);
+		bit >>= 1;
+	}
+}
+

drivers/rtc/rtc-meson.c new file +34 -0

+}
+
+static u32 meson_rtc_get_data(struct meson_rtc *rtc)
+{
+	u32 val = 0;
+	int bit;
+
+	for (bit = 0; bit < RTC_DATA_BITS; bit++) {
+		meson_rtc_sclk_pulse(rtc);
+		val <<= 1;
+		val |= meson_rtc_read_sdo(rtc);
+	}
+
+	return val;
+}
+
+static int meson_rtc_wait_bus(struct meson_rtc *rtc, unsigned timeout_ms)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms);
+	u32 val;
+
+	val = readl(rtc->regs + RTC_REG(0));
+	val &= ~(LINE_SDI | LINE_SEN | LINE_SCLK);
+	writel(val, rtc->regs + RTC_REG(0));
+
+	while (time_before(jiffies, timeout)) {
+		val = readl(rtc->regs + RTC_REG(1));
+		if (val & RTCREG1_READY)
+			return 1;
+
+		dev_info(rtc->dev, "%s: reg1=%08x\n", __func__, val);
+		msleep(10);
+	}
+

drivers/rtc/rtc-meson.c new file +51 -0

+
+		dev_warn(rtc->dev, "failed to get bus, re-setting\n");
+
+		retries--;
+		ret = reset_control_reset(rtc->reset);
+		if (ret)
+			return ret;
+	}
+
+	dev_err(rtc->dev, "%s: bus is not ready\n", __func__);
+	return -ETIMEDOUT;
+}
+
+static int meson_rtc_read(struct meson_rtc *rtc, unsigned int reg, u32 *data)
+{
+	int ret;
+
+	ret = meson_rtc_get_bus(rtc);
+	if (ret)
+		return ret;
+
+	meson_rtc_setline(rtc, LINE_SEN, 1);
+	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);
+	meson_rtc_setline(rtc, LINE_SEN, 0);
+	meson_rtc_set_dir(rtc, 0);
+	*data = meson_rtc_get_data(rtc);
+
+	return 0;
+}
+
+static int meson_rtc_write(struct meson_rtc *rtc, unsigned int reg, u32 data)
+{
+	int ret;
+
+	ret = meson_rtc_get_bus(rtc);
+	if (ret)
+		return ret;
+
+	meson_rtc_setline(rtc, LINE_SEN, 1);
+	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);
+	meson_rtc_setline(rtc, LINE_SEN, 0);
+	meson_rtc_set_dir(rtc, 1);
+	meson_rtc_send_bits(rtc, data, RTC_DATA_BITS);
+
+	return 0;
+}
+
+static int meson_rtc_gettime(struct device *dev, struct rtc_time *tm)
+{
+	struct meson_rtc *rtc = dev_get_drvdata(dev);
+	int ret;

drivers/rtc/rtc-meson.c new file +40 -0

+	
+	mutex_unlock(&rtc->lock);
+	return 0;
+}
+
+static int meson_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+	struct meson_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long time;
+	int ret;
+	
+	mutex_lock(&rtc->lock);
+
+	rtc_tm_to_time(tm, &time);
+	ret = meson_rtc_write(rtc, RTC_COUNTER, time);
+	
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static const struct rtc_class_ops meson_rtc_ops = {
+	.read_time	= meson_rtc_gettime,
+	.set_time	= meson_rtc_settime,
+};
+
+static int meson_rtc_wait_serialiser(struct meson_rtc *rtc)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(100);
+
+	while (time_before(jiffies, timeout)) {
+		if (!(readl(rtc->regs + RTC_REG(0)) & RTCREG0_WAIT_SER))
+			return 0;
+		msleep(10);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int meson_rtc_write_static(struct meson_rtc *rtc, u32 data)
+{

drivers/rtc/rtc-meson.c new file +68 -0

+	return 0;
+}
+
+static int meson_rtc_probe(struct platform_device *pdev)
+{
+	struct meson_rtc *rtc;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	u32 tm;
+	int ret;
+	
+	rtc = devm_kzalloc(dev, sizeof(struct meson_rtc), GFP_KERNEL);
+	if (!rtc) {
+		dev_err(dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->regs = devm_ioremap_resource(dev, res);
+	rtc->dev = dev;
+
+	if (IS_ERR(rtc->regs))
+		return PTR_ERR(rtc->regs);
+	
+	mutex_init(&rtc->lock);
+	platform_set_drvdata(pdev, rtc);
+
+	ret = meson_rtc_write_static(rtc,
+				     MESON_STATIC_BIAS_CUR | MESON_STATIC_VOLTAGE);
+	if (ret) {
+		dev_err(dev, "failed to set static values\n");
+		return ret;
+	}
+
+	rtc->reset = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(rtc->reset))
+		dev_warn(dev, "no reset available, rtc may not work\n");
+
+	/* check if we can read RTC counter, if not then the RTC is probably
+	 * not functional. If it isn't probably best to not bind */
+	ret = meson_rtc_read(rtc, RTC_COUNTER, &tm);
+	if (ret) {
+		dev_err(dev, "cannot read RTC counter, RTC not functional\n");
+		return ret;
+	}
+
+	rtc->rtc = devm_rtc_device_register(dev, "meson",
+					    &meson_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc)) {
+		dev_err(dev, "cannot attach rtc\n");
+		return PTR_ERR(rtc->rtc);
+	}
+
+	dev_info(dev, "device registered\n");
+	return 0;
+}
+
+static const struct of_device_id meson_rtc_dt_match[] = {
+	{ .compatible = "amlogic,meson6-rtc", },
+	{ .compatible = "amlogic,meson8-rtc", },
+	{ .compatible = "amlogic,meson8b-rtc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, meson_rtc_dt_match);
+
+static struct platform_driver meson_rtc_driver = {
+	.probe		= meson_rtc_probe,
+	.driver		= {

Hi Ben,

Quoted 4 lines · Ben Dooks

Add support for the AMLogic meson8b/meson6 RTC block.

Signed-off-by Ben Dooks <[email protected]>

---

[...]

Quoted 16 lines

drivers/rtc/rtc-meson.c new file +16 -0

+
+/* registers accessed from cpu bus */
+#define RTC_REG(x)	((x) * 4)	/* rtc registers 0-4 */
+
+#define LINE_SDI	(1 << 2)
+#define LINE_SEN	(1 << 1)
+#define LINE_SCLK	(1 << 0)
+
+#define RTCREG0_START_SER	BIT(17)
+#define RTCREG0_WAIT_SER	BIT(22)
+
+#define RTCREG1_READY	BIT(1)
+
+/* rtc registers accessed via rtc-serial inteface */
+#define RTC_COUNTER		(0)
+#define RTC_SEC_ADJ		(2)

drivers/rtc/rtc-meson.c line 41

Quoted 6 lines

drivers/rtc/rtc-meson.c new file +6 -0

+
+#define RTC_ADDR_BITS		(3)	/* number of address bits to send */
+#define RTC_DATA_BITS		(32)	/* number of data bits to tx/rx */
+
+#define MESON_STATIC_BIAS_CUR	(0x5 << 1)
+#define MESON_STATIC_VOLTAGE	(0x3 << 11)

Cleanup indentation here.

Quoted 27 lines

drivers/rtc/rtc-meson.c new file +27 -0

+
+struct meson_rtc {
+	struct rtc_device	*rtc;	/* rtc device we created */
+	struct device		*dev;	/* device we bound from */
+	struct reset_control	*reset;	/* reset source */
+	struct mutex		lock;	/* rtc lock */
+	void __iomem		*regs;	/* rtc register access */
+};
+
+static void meson_rtc_setline(struct meson_rtc *rtc, unsigned bit, unsigned to)
+{
+	u32 reg0;
+
+	reg0 = readl(rtc->regs + RTC_REG(0));
+	if (to)
+		reg0 |= bit;
+	else
+		reg0 &= ~bit;
+	writel(reg0, rtc->regs + RTC_REG(0));
+	
+}
+
+static void meson_rtc_sclk_pulse(struct meson_rtc *rtc)
+{
+	udelay(5);
+	meson_rtc_setline(rtc, LINE_SCLK, 0);
+	udelay(5);

drivers/rtc/rtc-meson.c line 74

Quoted 6 lines

drivers/rtc/rtc-meson.c new file +6 -0

+	meson_rtc_setline(rtc, LINE_SCLK, 1);
+}
+
+static void meson_rtc_send_bit(struct meson_rtc *rtc, unsigned bit)
+{
+	meson_rtc_setline(rtc, LINE_SDI, bit ? 1 : 0);

You can use !!bit here also

Quoted 17 lines

drivers/rtc/rtc-meson.c new file +17 -0

+	meson_rtc_sclk_pulse(rtc);
+}
+
+static void meson_rtc_send_bits(struct meson_rtc *rtc, u32 data, unsigned nr)
+{
+	u32 bit = 1 << (nr - 1);
+	
+	while (bit) {
+		meson_rtc_send_bit(rtc, data & bit);
+		bit >>= 1;
+	}
+}
+
+static void meson_rtc_set_dir(struct meson_rtc *rtc, u32 mode)
+{
+	meson_rtc_setline(rtc, LINE_SDI, 0);
+	meson_rtc_send_bit(rtc, mode);

drivers/rtc/rtc-meson.c line 97

Quoted 6 lines

drivers/rtc/rtc-meson.c new file +6 -0

+	meson_rtc_setline(rtc, LINE_SDI, 0);
+}
+
+static u32 meson_rtc_read_sdo(struct meson_rtc *rtc)
+{
+	return readl(rtc->regs + RTC_REG(1)) & (1 << 0);

Drop the << 0 here, or replace by BIT(0)

Quoted 38 lines

drivers/rtc/rtc-meson.c new file +38 -0

+}
+
+static u32 meson_rtc_get_data(struct meson_rtc *rtc)
+{
+	u32 val = 0;
+	int bit;
+
+	for (bit = 0; bit < RTC_DATA_BITS; bit++) {
+		meson_rtc_sclk_pulse(rtc);
+		val <<= 1;
+		val |= meson_rtc_read_sdo(rtc);
+	}
+
+	return val;
+}
+
+static int meson_rtc_wait_bus(struct meson_rtc *rtc, unsigned timeout_ms)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(timeout_ms);
+	u32 val;
+
+	val = readl(rtc->regs + RTC_REG(0));
+	val &= ~(LINE_SDI | LINE_SEN | LINE_SCLK);
+	writel(val, rtc->regs + RTC_REG(0));
+
+	while (time_before(jiffies, timeout)) {
+		val = readl(rtc->regs + RTC_REG(1));
+		if (val & RTCREG1_READY)
+			return 1;
+
+		dev_info(rtc->dev, "%s: reg1=%08x\n", __func__, val);
+		msleep(10);
+	}
+
+	return 0;
+}
+
+static int meson_rtc_get_bus(struct meson_rtc *rtc)

drivers/rtc/rtc-meson.c line 141

Quoted 6 lines

drivers/rtc/rtc-meson.c new file +6 -0

+{
+	int ret, retries = 3;
+
+	while (retries) {
+		if (meson_rtc_wait_bus(rtc, 300))
+			return 0;

Put the timeout time in a define 300 to be easily changed.

Quoted 55 lines

drivers/rtc/rtc-meson.c new file +55 -0

+
+		dev_warn(rtc->dev, "failed to get bus, re-setting\n");
+
+		retries--;
+		ret = reset_control_reset(rtc->reset);
+		if (ret)
+			return ret;
+	}
+
+	dev_err(rtc->dev, "%s: bus is not ready\n", __func__);
+	return -ETIMEDOUT;
+}
+
+static int meson_rtc_read(struct meson_rtc *rtc, unsigned int reg, u32 *data)
+{
+	int ret;
+
+	ret = meson_rtc_get_bus(rtc);
+	if (ret)
+		return ret;
+
+	meson_rtc_setline(rtc, LINE_SEN, 1);
+	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);
+	meson_rtc_setline(rtc, LINE_SEN, 0);
+	meson_rtc_set_dir(rtc, 0);
+	*data = meson_rtc_get_data(rtc);
+
+	return 0;
+}
+
+static int meson_rtc_write(struct meson_rtc *rtc, unsigned int reg, u32 data)
+{
+	int ret;
+
+	ret = meson_rtc_get_bus(rtc);
+	if (ret)
+		return ret;
+
+	meson_rtc_setline(rtc, LINE_SEN, 1);
+	meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS);
+	meson_rtc_setline(rtc, LINE_SEN, 0);
+	meson_rtc_set_dir(rtc, 1);
+	meson_rtc_send_bits(rtc, data, RTC_DATA_BITS);
+
+	return 0;
+}
+
+static int meson_rtc_gettime(struct device *dev, struct rtc_time *tm)
+{
+	struct meson_rtc *rtc = dev_get_drvdata(dev);
+	int ret;
+	u32 time;
+
+	mutex_lock(&rtc->lock);
+

drivers/rtc/rtc-meson.c line 202

Quoted 6 lines

drivers/rtc/rtc-meson.c new file +6 -0

+	ret = meson_rtc_read(rtc, RTC_COUNTER, &time);
+	if (ret)
+		return ret;
+
+	rtc_time_to_tm(time, tm);
+	dev_info(dev, "read time %lu\n", (unsigned long)time);

Replace by a dev_dbg here.

Quoted 40 lines

drivers/rtc/rtc-meson.c new file +40 -0

+	
+	mutex_unlock(&rtc->lock);
+	return 0;
+}
+
+static int meson_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+	struct meson_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long time;
+	int ret;
+	
+	mutex_lock(&rtc->lock);
+
+	rtc_tm_to_time(tm, &time);
+	ret = meson_rtc_write(rtc, RTC_COUNTER, time);
+	
+	mutex_unlock(&rtc->lock);
+	return ret;
+}
+
+static const struct rtc_class_ops meson_rtc_ops = {
+	.read_time	= meson_rtc_gettime,
+	.set_time	= meson_rtc_settime,
+};
+
+static int meson_rtc_wait_serialiser(struct meson_rtc *rtc)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(100);
+
+	while (time_before(jiffies, timeout)) {
+		if (!(readl(rtc->regs + RTC_REG(0)) & RTCREG0_WAIT_SER))
+			return 0;
+		msleep(10);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int meson_rtc_write_static(struct meson_rtc *rtc, u32 data)
+{

drivers/rtc/rtc-meson.c line 252

Quoted 10 lines

drivers/rtc/rtc-meson.c new file +10 -0

+	u32 tmp;
+
+	mutex_lock(&rtc->lock);
+
+	writel(data >> 8, rtc->regs + RTC_REG(4));
+
+	tmp = readl(rtc->regs + RTC_REG(0));
+	tmp &= ~(0xff << 24);
+	tmp |= (data << 24);
+	tmp |= RTCREG0_START_SER;

Add a define for the shifts here.

drivers/rtc/rtc-meson.c line 261

Quoted 9 lines

drivers/rtc/rtc-meson.c new file +9 -0

+
+	writel(tmp, rtc->regs + RTC_REG(0));
+
+	if (meson_rtc_wait_serialiser(rtc))
+		return -ETIMEDOUT;
+
+	dev_info(rtc->dev, "rtc_reg0 = %08x\n", readl(rtc->regs + RTC_REG(0)));
+	mutex_unlock(&rtc->lock);
+

dev_dbg instead here.

Quoted 74 lines

drivers/rtc/rtc-meson.c new file +74 -0

+	return 0;
+}
+
+static int meson_rtc_probe(struct platform_device *pdev)
+{
+	struct meson_rtc *rtc;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	u32 tm;
+	int ret;
+	
+	rtc = devm_kzalloc(dev, sizeof(struct meson_rtc), GFP_KERNEL);
+	if (!rtc) {
+		dev_err(dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->regs = devm_ioremap_resource(dev, res);
+	rtc->dev = dev;
+
+	if (IS_ERR(rtc->regs))
+		return PTR_ERR(rtc->regs);
+	
+	mutex_init(&rtc->lock);
+	platform_set_drvdata(pdev, rtc);
+
+	ret = meson_rtc_write_static(rtc,
+				     MESON_STATIC_BIAS_CUR | MESON_STATIC_VOLTAGE);
+	if (ret) {
+		dev_err(dev, "failed to set static values\n");
+		return ret;
+	}
+
+	rtc->reset = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(rtc->reset))
+		dev_warn(dev, "no reset available, rtc may not work\n");
+
+	/* check if we can read RTC counter, if not then the RTC is probably
+	 * not functional. If it isn't probably best to not bind */
+	ret = meson_rtc_read(rtc, RTC_COUNTER, &tm);
+	if (ret) {
+		dev_err(dev, "cannot read RTC counter, RTC not functional\n");
+		return ret;
+	}
+
+	rtc->rtc = devm_rtc_device_register(dev, "meson",
+					    &meson_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc->rtc)) {
+		dev_err(dev, "cannot attach rtc\n");
+		return PTR_ERR(rtc->rtc);
+	}
+
+	dev_info(dev, "device registered\n");
+	return 0;
+}
+
+static const struct of_device_id meson_rtc_dt_match[] = {
+	{ .compatible = "amlogic,meson6-rtc", },
+	{ .compatible = "amlogic,meson8-rtc", },
+	{ .compatible = "amlogic,meson8b-rtc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, meson_rtc_dt_match);
+
+static struct platform_driver meson_rtc_driver = {
+	.probe		= meson_rtc_probe,
+	.driver		= {
+		.name	= "meson-rtc",
+		.of_match_table	= of_match_ptr(meson_rtc_dt_match),
+	},
+};
+module_platform_driver(meson_rtc_driver);
+

drivers/rtc/rtc-meson.c line 339

Quoted 5 lines

drivers/rtc/rtc-meson.c new file +4 -0

+MODULE_DESCRIPTION("AMLogic MESON RTC Driver");
+MODULE_AUTHOR("Ben Dooks <[email protected]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:meson-rtc");

Neil

Add support for the AMLogic meson8b/meson6 RTC block.

Signed-off-by Ben Dooks <[email protected]>

---
 drivers/rtc/Kconfig     |  10 ++
 drivers/rtc/Makefile    |   1 +
 drivers/rtc/rtc-meson.c | 339 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 350 insertions(+)
 create mode 100644 drivers/rtc/rtc-meson.c

drivers/rtc/Kconfig +0 -0

index 9f8b59d..a90634f5 100644

This has been sitting in my tree for a while, so I thought it would be a good idea to try and get it moving along and possibly submittied soon.

I've not been able to fully test this as I don't have an S805 MMC driver to allow me to boot to a userland on my ODroid-C1 board.

This has been sitting in my tree for a while, so I thought it would be a good idea to try and get it moving along and possibly submittied soon.

I've not been able to fully test this as I don't have an S805 MMC driver to allow me to boot to a userland on my ODroid-C1 board.

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Quoted 7 lines · Ben Dooks

This has been sitting in my tree for a while, so I thought it would be a good idea to try and get it moving along and possibly submittied soon.

I've not been able to fully test this as I don't have an S805 MMC driver to allow me to boot to a userland on my ODroid-C1 board.

You could generate a dummy buildroot initramfs loaded in the Image with the RTC tools.

Quoted 7 lines · Ben Dooks

This has been sitting in my tree for a while, so I thought it would be a good idea to try and get it moving along and possibly submittied soon.

I've not been able to fully test this as I don't have an S805 MMC driver to allow me to boot to a userland on my ODroid-C1 board.

You could generate a dummy buildroot initramfs loaded in the Image with the RTC tools.