[PATCH v2 0/6] rtc: at91sam9: add DT support

[PATCH v2 0/6] rtc: at91sam9: add DT support

[Boris BREZILLON]

Hello,

This patch series adds DT support to the atmel at91sam9 RTC driver.

It also removes any machine specific inclusions to prepare the migration
to multi platform kernel support, and retain the slow clock to prevent
the CCF from disabling it at the end of boot.

Best Regards,

Boris

Changes since v1:
 - remove non CCF specific case by adding the appropriate clk_lookup
   entries in arch/arm/mach-at91/<soc-name>.c files

Boris BREZILLON (6):
  rtc: at91sam9: remove references to mach specific headers
  rtc: at91sam9: use standard readl/writel functions instead of raw
    versions
  rtc: at91sam9: add DT support
  ARM: at91: add clk_lookup entry for RTT devices
  rtc: at91sam9: use clk API instead of relying on AT91_SLOW_CLOCK
  rtc: at91sam9: add DT bindings documentation

 .../devicetree/bindings/rtc/atmel,at91sam9-rtc.txt | 20 +++++++
 arch/arm/mach-at91/at91sam9260.c                   |  2 +
 arch/arm/mach-at91/at91sam9261.c                   |  2 +
 arch/arm/mach-at91/at91sam9263.c                   |  4 ++
 arch/arm/mach-at91/at91sam9g45.c                   |  2 +
 arch/arm/mach-at91/at91sam9rl.c                    |  2 +
 arch/arm/mach-at91/clock.c                         |  2 +-
 arch/arm/mach-at91/clock.h                         |  1 +
 drivers/rtc/rtc-at91sam9.c                         | 63 ++++++++++++++++++----
 9 files changed, 87 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt

-- 
1.9.1

[PATCH v2 1/6] rtc: at91sam9: remove references to mach specific headers

[Boris BREZILLON]

In order to support multi platform kernel drivers should not include
machine specific headers.
Copy RTT macros in the driver code and remove any machine specific
headers.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 drivers/rtc/rtc-at91sam9.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 5963743..51f0038 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -22,10 +22,6 @@
 #include <linux/platform_data/atmel.h>
 #include <linux/io.h>
 
-#include <mach/at91_rtt.h>
-#include <mach/cpu.h>
-#include <mach/hardware.h>
-
 /*
  * This driver uses two configurable hardware resources that live in the
  * AT91SAM9 backup power domain (intended to be powered at all times)
@@ -47,6 +43,24 @@
  * registers available, likewise usable for more than "RTC" support.
  */
 
+#define AT91_RTT_MR		0x00			/* Real-time Mode Register */
+#define AT91_RTT_RTPRES		(0xffff << 0)		/* Real-time Timer Prescaler Value */
+#define AT91_RTT_ALMIEN		(1 << 16)		/* Alarm Interrupt Enable */
+#define AT91_RTT_RTTINCIEN	(1 << 17)		/* Real Time Timer Increment Interrupt Enable */
+#define AT91_RTT_RTTRST		(1 << 18)		/* Real Time Timer Restart */
+
+#define AT91_RTT_AR		0x04			/* Real-time Alarm Register */
+#define AT91_RTT_ALMV		(0xffffffff)		/* Alarm Value */
+
+#define AT91_RTT_VR		0x08			/* Real-time Value Register */
+#define AT91_RTT_CRTV		(0xffffffff)		/* Current Real-time Value */
+
+#define AT91_RTT_SR		0x0c			/* Real-time Status Register */
+#define AT91_RTT_ALMS		(1 << 0)		/* Real-time Alarm Status */
+#define AT91_RTT_RTTINC		(1 << 1)		/* Real-time Timer Increment */
+
+#define AT91_SLOW_CLOCK		32768
+
 /*
  * We store ALARM_DISABLED in ALMV to record that no alarm is set.
  * It's also the reset value for that field.
-- 
1.9.1

[PATCH v2 2/6] rtc: at91sam9: use standard readl/writel functions instead of raw versions

[Boris BREZILLON]

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 drivers/rtc/rtc-at91sam9.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 51f0038..74a9ca0 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -77,14 +77,14 @@ struct sam9_rtc {
 };
 
 #define rtt_readl(rtc, field) \
-	__raw_readl((rtc)->rtt + AT91_RTT_ ## field)
+	readl((rtc)->rtt + AT91_RTT_ ## field)
 #define rtt_writel(rtc, field, val) \
-	__raw_writel((val), (rtc)->rtt + AT91_RTT_ ## field)
+	writel((val), (rtc)->rtt + AT91_RTT_ ## field)
 
 #define gpbr_readl(rtc) \
-	__raw_readl((rtc)->gpbr)
+	readl((rtc)->gpbr)
 #define gpbr_writel(rtc, val) \
-	__raw_writel((val), (rtc)->gpbr)
+	writel((val), (rtc)->gpbr)
 
 /*
  * Read current time and date in RTC
-- 
1.9.1

[PATCH v2 3/6] rtc: at91sam9: add DT support

[Boris BREZILLON]

Add of_match_table to the existing driver so that rtc nodes defined in at91
DTs can be attached to this driver.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 drivers/rtc/rtc-at91sam9.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 74a9ca0..57014b7 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -454,6 +454,14 @@ static int at91_rtc_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 
+#ifdef CONFIG_OF
+static const struct of_device_id at91_rtc_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-rtt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
+#endif
+
 static struct platform_driver at91_rtc_driver = {
 	.probe		= at91_rtc_probe,
 	.remove		= at91_rtc_remove,
@@ -462,6 +470,7 @@ static struct platform_driver at91_rtc_driver = {
 		.name	= "rtc-at91sam9",
 		.owner	= THIS_MODULE,
 		.pm	= &at91_rtc_pm_ops,
+		.of_match_table = of_match_ptr(at91_rtc_dt_ids),
 	},
 };
 
-- 
1.9.1

[PATCH v2 4/6] ARM: at91: add clk_lookup entry for RTT devices

[Boris BREZILLON]

First export the clk32k clk.
Then add clk_lookup entries for RTT devices so that rtc-at91sam9 driver
can retrieve and manipulate the slow clk.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 arch/arm/mach-at91/at91sam9260.c | 2 ++
 arch/arm/mach-at91/at91sam9261.c | 2 ++
 arch/arm/mach-at91/at91sam9263.c | 4 ++++
 arch/arm/mach-at91/at91sam9g45.c | 2 ++
 arch/arm/mach-at91/at91sam9rl.c  | 2 ++
 arch/arm/mach-at91/clock.c       | 2 +-
 arch/arm/mach-at91/clock.h       | 1 +
 7 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c
index 3477ba9..a853d4c 100644
--- a/arch/arm/mach-at91/at91sam9260.c
+++ b/arch/arm/mach-at91/at91sam9260.c
@@ -217,6 +217,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID("pclk", "fffbc000.ssc", &ssc_clk),
 	CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9260.0", &twi_clk),
 	CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g20.0", &twi_clk),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.0", &clk32k),
 	/* more usart lookup table for DT entries */
 	CLKDEV_CON_DEV_ID("usart", "fffff200.serial", &mck),
 	CLKDEV_CON_DEV_ID("usart", "fffb0000.serial", &usart0_clk),
@@ -237,6 +238,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID("mci_clk", "fffa8000.mmc", &mmc_clk),
 	CLKDEV_CON_DEV_ID("spi_clk", "fffc8000.spi", &spi0_clk),
 	CLKDEV_CON_DEV_ID("spi_clk", "fffcc000.spi", &spi1_clk),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd20.rtc", &clk32k),
 	/* fake hclk clock */
 	CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &ohci_clk),
 	CLKDEV_CON_ID("pioA", &pioA_clk),
diff --git a/arch/arm/mach-at91/at91sam9261.c b/arch/arm/mach-at91/at91sam9261.c
index fb164a5..3f5a299 100644
--- a/arch/arm/mach-at91/at91sam9261.c
+++ b/arch/arm/mach-at91/at91sam9261.c
@@ -192,6 +192,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_ID("pioA", &pioA_clk),
 	CLKDEV_CON_ID("pioB", &pioB_clk),
 	CLKDEV_CON_ID("pioC", &pioC_clk),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.0", &clk32k),
 	/* more lookup table for DT entries */
 	CLKDEV_CON_DEV_ID("usart", "fffff200.serial", &mck),
 	CLKDEV_CON_DEV_ID("usart", "fffb0000.serial", &usart0_clk),
@@ -209,6 +210,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID(NULL, "fffff400.gpio", &pioA_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffff600.gpio", &pioB_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffff800.gpio", &pioC_clk),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd20.rtc", &clk32k),
 };
 
 static struct clk_lookup usart_clocks_lookups[] = {
diff --git a/arch/arm/mach-at91/at91sam9263.c b/arch/arm/mach-at91/at91sam9263.c
index 810fa5f..bef5b96 100644
--- a/arch/arm/mach-at91/at91sam9263.c
+++ b/arch/arm/mach-at91/at91sam9263.c
@@ -201,6 +201,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID("t0_clk", "atmel_tcb.0", &tcb_clk),
 	CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9260.0", &twi_clk),
 	CLKDEV_CON_DEV_ID(NULL, "at91sam9rl-pwm", &pwm_clk),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.0", &clk32k),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.1", &clk32k),
 	/* fake hclk clock */
 	CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &ohci_clk),
 	CLKDEV_CON_ID("pioA", &pioA_clk),
@@ -227,6 +229,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID(NULL, "fffff800.gpio", &pioCDE_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffffa00.gpio", &pioCDE_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffb8000.pwm", &pwm_clk),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd20.rtc", &clk32k),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd50.rtc", &clk32k),
 };
 
 static struct clk_lookup usart_clocks_lookups[] = {
diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c
index 9d45496..69fdfcc 100644
--- a/arch/arm/mach-at91/at91sam9g45.c
+++ b/arch/arm/mach-at91/at91sam9g45.c
@@ -253,6 +253,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID(NULL, "atmel_tdes", &aestdessha_clk),
 	CLKDEV_CON_DEV_ID(NULL, "atmel_aes", &aestdessha_clk),
 	CLKDEV_CON_DEV_ID(NULL, "at91sam9rl-pwm", &pwm_clk),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.0", &clk32k),
 	/* more usart lookup table for DT entries */
 	CLKDEV_CON_DEV_ID("usart", "ffffee00.serial", &mck),
 	CLKDEV_CON_DEV_ID("usart", "fff8c000.serial", &usart0_clk),
@@ -279,6 +280,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID(NULL, "fffff600.gpio", &pioC_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffff800.gpio", &pioDE_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffffa00.gpio", &pioDE_clk),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd20.rtc", &clk32k),
 
 	CLKDEV_CON_ID("pioA", &pioA_clk),
 	CLKDEV_CON_ID("pioB", &pioB_clk),
diff --git a/arch/arm/mach-at91/at91sam9rl.c b/arch/arm/mach-at91/at91sam9rl.c
index 878d501..a82dc61 100644
--- a/arch/arm/mach-at91/at91sam9rl.c
+++ b/arch/arm/mach-at91/at91sam9rl.c
@@ -205,6 +205,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_ID("pioB", &pioB_clk),
 	CLKDEV_CON_ID("pioC", &pioC_clk),
 	CLKDEV_CON_ID("pioD", &pioD_clk),
+	CLKDEV_CON_DEV_ID(NULL, "rtc-at91sam9.0", &clk32k),
 	/* more lookup table for DT entries */
 	CLKDEV_CON_DEV_ID("usart", "fffff200.serial", &mck),
 	CLKDEV_CON_DEV_ID("usart", "fffb0000.serial", &usart0_clk),
@@ -223,6 +224,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID(NULL, "fffff600.gpio", &pioB_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffff800.gpio", &pioC_clk),
 	CLKDEV_CON_DEV_ID(NULL, "fffffa00.gpio", &pioD_clk),
+	CLKDEV_CON_DEV_ID(NULL, "fffffd20.rtc", &clk32k),
 	CLKDEV_CON_ID("adc_clk", &tsc_clk),
 };
 
diff --git a/arch/arm/mach-at91/clock.c b/arch/arm/mach-at91/clock.c
index 034529d..f5cfed75 100644
--- a/arch/arm/mach-at91/clock.c
+++ b/arch/arm/mach-at91/clock.c
@@ -115,7 +115,7 @@ static u32 at91_pllb_usb_init;
  * 48 MHz (unless no USB function clocks are needed).  The main clock and
  * both PLLs are turned off to run in "slow clock mode" (system suspend).
  */
-static struct clk clk32k = {
+struct clk clk32k = {
 	.name		= "clk32k",
 	.rate_hz	= AT91_SLOW_CLOCK,
 	.users		= 1,		/* always on */
diff --git a/arch/arm/mach-at91/clock.h b/arch/arm/mach-at91/clock.h
index a98a39b..6eb825a 100644
--- a/arch/arm/mach-at91/clock.h
+++ b/arch/arm/mach-at91/clock.h
@@ -34,6 +34,7 @@ struct clk {
 extern int __init clk_register(struct clk *clk);
 extern struct clk mck;
 extern struct clk utmi_clk;
+extern struct clk clk32k;
 
 #define CLKDEV_CON_ID(_id, _clk)			\
 	{						\
-- 
1.9.1

[PATCH v2 5/6] rtc: at91sam9: use clk API instead of relying on AT91_SLOW_CLOCK

[Boris BREZILLON]

The RTT block is using the slow clock which is accessible through the clk
API.
Use the clk API to retrieve, enable and get the slow clk rate instead of
the AT91_SLOW_CLOCK macro (which hardcodes the slow clk rate).
Doing this allows us to reference the clk thus preventing the CCF from
disabling it during the "disable unused" phase.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 drivers/rtc/rtc-at91sam9.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 57014b7..a6c498e 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -21,6 +21,7 @@
 #include <linux/slab.h>
 #include <linux/platform_data/atmel.h>
 #include <linux/io.h>
+#include <linux/clk.h>
 
 /*
  * This driver uses two configurable hardware resources that live in the
@@ -59,8 +60,6 @@
 #define AT91_RTT_ALMS		(1 << 0)		/* Real-time Alarm Status */
 #define AT91_RTT_RTTINC		(1 << 1)		/* Real-time Timer Increment */
 
-#define AT91_SLOW_CLOCK		32768
-
 /*
  * We store ALARM_DISABLED in ALMV to record that no alarm is set.
  * It's also the reset value for that field.
@@ -74,6 +73,7 @@ struct sam9_rtc {
 	u32			imr;
 	void __iomem		*gpbr;
 	int 			irq;
+	struct clk		*sclk;
 };
 
 #define rtt_readl(rtc, field) \
@@ -310,6 +310,7 @@ static int at91_rtc_probe(struct platform_device *pdev)
 	struct sam9_rtc	*rtc;
 	int		ret, irq;
 	u32		mr;
+	unsigned int	sclk_rate;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	r_gpbr = platform_get_resource(pdev, IORESOURCE_MEM, 1);
@@ -348,11 +349,27 @@ static int at91_rtc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	rtc->sclk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(rtc->sclk))
+		return PTR_ERR(rtc->sclk);
+
+	sclk_rate = clk_get_rate(rtc->sclk);
+	if (!sclk_rate || sclk_rate > AT91_RTT_RTTRST) {
+		dev_err(&pdev->dev, "Invalid slow clock rate");
+		return -EINVAL;
+	}
+
+	ret = clk_prepare_enable(rtc->sclk);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not enable slow clock");
+		return ret;
+	}
+
 	mr = rtt_readl(rtc, MR);
 
 	/* unless RTT is counting at 1 Hz, re-initialize it */
-	if ((mr & AT91_RTT_RTPRES) != AT91_SLOW_CLOCK) {
-		mr = AT91_RTT_RTTRST | (AT91_SLOW_CLOCK & AT91_RTT_RTPRES);
+	if ((mr & AT91_RTT_RTPRES) != sclk_rate) {
+		mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES);
 		gpbr_writel(rtc, 0);
 	}
 
@@ -397,6 +414,9 @@ static int at91_rtc_remove(struct platform_device *pdev)
 	/* disable all interrupts */
 	rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
 
+	if (!IS_ERR(rtc->sclk))
+		clk_disable_unprepare(rtc->sclk);
+
 	return 0;
 }
 
-- 
1.9.1

[PATCH v2 6/6] rtc: at91sam9: add DT bindings documentation

[Boris BREZILLON]

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
---
 .../devicetree/bindings/rtc/atmel,at91sam9-rtc.txt   | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt

diff --git a/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt b/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt
new file mode 100644
index 0000000..9ca455f
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/atmel,at91sam9-rtc.txt
@@ -0,0 +1,20 @@
+Atmel AT91SAM9260 Real Time Timer
+
+Required properties:
+- compatible: should be: "atmel,at91sam9260-rtt"
+- reg: should contain 2 memory regions
+  * the first one encodes the memory region of the RTT controller
+  * the second one encodes the GPBR (General Purpose Backup Resgisters)
+    memory region used to store the current time
+- interrupts: rtc alarm/event interrupt
+- clocks: should contain one clock pointing the the slow clk
+
+Example:
+
+rtc@fffffe00 {
+	compatible = "atmel,at91sam9260-rtt";
+	reg = <0xfffffd20 0x10
+	       0xfffffd50 0x4>;
+	interrupts = <1 4 7>;
+	clocks = <&clk32k>;
+};
-- 
1.9.1

Re: [PATCH v2 0/6] rtc: at91sam9: add DT support

[Alexandre Belloni]

On 09/09/2014 at 11:30:29 +0200, Boris Brezillon wrote :
> Hello,
> 
> This patch series adds DT support to the atmel at91sam9 RTC driver.
> 
> It also removes any machine specific inclusions to prepare the migration
> to multi platform kernel support, and retain the slow clock to prevent
> the CCF from disabling it at the end of boot.
> 

Whole series is:

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com