[PATCH v2 1/2] dt-bindings: clocksource: Add Spreadtrum SC9860 timer

[PATCH v2 1/2] dt-bindings: clocksource: Add Spreadtrum SC9860 timer

[Baolin Wang]

This patch adds documentation of device tree bindings for the timers
found on Spreadtrum SC9860 platform.

Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
Changes since v1:
 - Add acked tag from Rob.
---
 .../bindings/timer/spreadtrum,sprd-timer.txt       |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/spreadtrum,sprd-timer.txt

diff --git a/Documentation/devicetree/bindings/timer/spreadtrum,sprd-timer.txt b/Documentation/devicetree/bindings/timer/spreadtrum,sprd-timer.txt
new file mode 100644
index 0000000..f9d5eb9
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/spreadtrum,sprd-timer.txt
@@ -0,0 +1,20 @@
+Spreadtrum timers
+
+The Spreadtrum SC9860 platform provides 3 general-purpose timers.
+These timers can support 32bit or 64bit counter, as well as supporting
+period mode or one-shot mode, and they are can be wakeup source
+during deep sleep.
+
+Required properties:
+- compatible: should be "sprd,sc9860-timer" for SC9860 platform.
+- reg: The register address of the timer device.
+- interrupts: Should contain the interrupt for the timer device.
+- clock-frequency: The frequency of the clock that drives the counter, in Hz.
+
+Example:
+	timer@40050000 {
+		compatible = "sprd,sc9860-timer";
+		reg = <0 0x40050000 0 0x20>;
+		interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>;
+		clock-frequency = <32768>;
+	};
-- 
1.7.9.5

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[PATCH v2 2/2] clocksource: sprd: Add timer driver for Spreadtrum SC9860 platform

[Baolin Wang]

The Spreadtrum SC9860 platform will use the architected timers as local
clock events, but we also need a broadcast timer device to wakeup the
cpus when the cpus are in sleep mode.

Thus this patch registers the timer0 to be a broadcast timer supporting
periodic and oneshot events.

Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
---
Changes since v1:
 - Change to 32bit counter to avoid build warning.
---
 drivers/clocksource/Kconfig      |    8 ++
 drivers/clocksource/Makefile     |    1 +
 drivers/clocksource/sprd-timer.c |  211 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 220 insertions(+)
 create mode 100644 drivers/clocksource/sprd-timer.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index c729a88..48c8702 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -441,6 +441,14 @@ config MTK_TIMER
 	help
 	  Support for Mediatek timer driver.
 
+config SPRD_TIMER
+	bool "Spreadtrum timer driver"
+	depends on GENERIC_CLOCKEVENTS
+	depends on ARCH_SPRD || COMPILE_TEST
+	select TIMER_OF
+	help
+	  Enables the support for the Spreadtrum timer driver.
+
 config SYS_SUPPORTS_SH_MTU2
         bool
 
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 72711f1..62bf264 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_CLKSRC_TI_32K)	+= timer-ti-32k.o
 obj-$(CONFIG_CLKSRC_NPS)	+= timer-nps.o
 obj-$(CONFIG_OXNAS_RPS_TIMER)	+= timer-oxnas-rps.o
 obj-$(CONFIG_OWL_TIMER)		+= owl-timer.o
+obj-$(CONFIG_SPRD_TIMER)	+= sprd-timer.o
 
 obj-$(CONFIG_ARC_TIMERS)		+= arc_timer.o
 obj-$(CONFIG_ARM_ARCH_TIMER)		+= arm_arch_timer.o
diff --git a/drivers/clocksource/sprd-timer.c b/drivers/clocksource/sprd-timer.c
new file mode 100644
index 0000000..e90f948
--- /dev/null
+++ b/drivers/clocksource/sprd-timer.c
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2017 Spreadtrum Communications Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define TIMER_NAME		"sprd_timer"
+
+#define TIMER_LOAD_LO		0x0
+#define TIMER_LOAD_HI		0x4
+#define TIMER_VALUE_LO		0x8
+#define TIMER_VALUE_HI		0xc
+
+#define TIMER_CTL		0x10
+#define TIMER_CTL_PERIOD_MODE	BIT(0)
+#define TIMER_CTL_ENABLE	BIT(1)
+#define TIMER_CTL_64BIT_WIDTH	BIT(16)
+
+#define TIMER_INT		0x14
+#define TIMER_INT_EN		BIT(0)
+#define TIMER_INT_RAW_STS	BIT(1)
+#define TIMER_INT_MASK_STS	BIT(2)
+#define TIMER_INT_CLR		BIT(3)
+
+#define TIMER_VALUE_SHDW_LO	0x18
+#define TIMER_VALUE_SHDW_HI	0x1c
+
+#define TIMER_VALUE_LO_MASK	GENMASK(31, 0)
+
+struct sprd_timer_device {
+	struct clock_event_device ce;
+	void __iomem *base;
+	u32 freq;
+	int irq;
+};
+
+static inline struct sprd_timer_device *
+to_sprd_timer(struct clock_event_device *c)
+{
+	return container_of(c, struct sprd_timer_device, ce);
+}
+
+static void sprd_timer_enable(struct sprd_timer_device *timer, u32 flag)
+{
+	u32 val = readl_relaxed(timer->base + TIMER_CTL);
+
+	val |= TIMER_CTL_ENABLE;
+	if (flag & TIMER_CTL_64BIT_WIDTH)
+		val |= TIMER_CTL_64BIT_WIDTH;
+	else
+		val &= ~TIMER_CTL_64BIT_WIDTH;
+
+	if (flag & TIMER_CTL_PERIOD_MODE)
+		val |= TIMER_CTL_PERIOD_MODE;
+	else
+		val &= ~TIMER_CTL_PERIOD_MODE;
+
+	writel_relaxed(val, timer->base + TIMER_CTL);
+}
+
+static void sprd_timer_disable(struct sprd_timer_device *timer)
+{
+	u32 val = readl_relaxed(timer->base + TIMER_CTL);
+
+	val &= ~TIMER_CTL_ENABLE;
+	writel_relaxed(val, timer->base + TIMER_CTL);
+}
+
+static void sprd_timer_update_counter(struct sprd_timer_device *timer,
+				      unsigned long cycles)
+{
+	writel_relaxed(cycles & TIMER_VALUE_LO_MASK,
+		       timer->base + TIMER_LOAD_LO);
+	writel_relaxed(0, timer->base + TIMER_LOAD_HI);
+}
+
+static void sprd_timer_enable_interrupt(struct sprd_timer_device *timer)
+{
+	writel_relaxed(TIMER_INT_EN, timer->base + TIMER_INT);
+}
+
+static void sprd_timer_clear_interrupt(struct sprd_timer_device *timer)
+{
+	u32 val = readl_relaxed(timer->base + TIMER_INT);
+
+	val |= TIMER_INT_CLR;
+	writel_relaxed(val, timer->base + TIMER_INT);
+}
+
+static int sprd_timer_set_next_event(unsigned long cycles,
+				     struct clock_event_device *ce)
+{
+	struct sprd_timer_device *timer = to_sprd_timer(ce);
+
+	sprd_timer_disable(timer);
+	sprd_timer_update_counter(timer, cycles);
+	sprd_timer_enable(timer, 0);
+
+	return 0;
+}
+
+static int sprd_timer_set_periodic(struct clock_event_device *ce)
+{
+	struct sprd_timer_device *timer = to_sprd_timer(ce);
+	unsigned long cycles = DIV_ROUND_UP(timer->freq, HZ);
+
+	sprd_timer_disable(timer);
+	sprd_timer_update_counter(timer, cycles);
+	sprd_timer_enable(timer, TIMER_CTL_PERIOD_MODE);
+
+	return 0;
+}
+
+static int sprd_timer_shutdown(struct clock_event_device *ce)
+{
+	struct sprd_timer_device *timer = to_sprd_timer(ce);
+
+	sprd_timer_disable(timer);
+	return 0;
+}
+
+static irqreturn_t sprd_timer_interrupt(int irq, void *dev_id)
+{
+	struct sprd_timer_device *timer = dev_id;
+
+	sprd_timer_clear_interrupt(timer);
+
+	if (clockevent_state_oneshot(&timer->ce))
+		sprd_timer_disable(timer);
+
+	timer->ce.event_handler(&timer->ce);
+	return IRQ_HANDLED;
+}
+
+static void __init sprd_timer_clkevt_init(struct sprd_timer_device *timer)
+{
+	timer->ce.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
+				CLOCK_EVT_FEAT_ONESHOT;
+	timer->ce.set_next_event = sprd_timer_set_next_event;
+	timer->ce.set_state_periodic = sprd_timer_set_periodic;
+	timer->ce.set_state_shutdown = sprd_timer_shutdown;
+	timer->ce.name = TIMER_NAME;
+	timer->ce.rating = 300;
+	timer->ce.irq = timer->irq;
+	timer->ce.cpumask = cpu_possible_mask;
+
+	sprd_timer_enable_interrupt(timer);
+	clockevents_config_and_register(&timer->ce, timer->freq, 1, UINT_MAX);
+}
+
+static int __init sprd_timer_init(struct device_node *np)
+{
+	struct sprd_timer_device *timer;
+	int ret;
+
+	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
+	if (!timer)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(np, "clock-frequency", &timer->freq);
+	if (ret) {
+		pr_err("failed to get clock frequency\n");
+		goto err_freq;
+	}
+
+	timer->base = of_iomap(np, 0);
+	if (!timer->base) {
+		pr_err("%s: unable to map resource\n", np->name);
+		ret = -ENXIO;
+		goto err_freq;
+	}
+
+	timer->irq = irq_of_parse_and_map(np, 0);
+	if (timer->irq < 0) {
+		pr_crit("%s: unable to parse timer irq\n", np->name);
+		ret = timer->irq;
+		goto err_map_irq;
+	}
+
+	ret = request_irq(timer->irq, sprd_timer_interrupt, IRQF_TIMER,
+			  TIMER_NAME, timer);
+	if (ret) {
+		pr_err("failed to setup irq %d\n", timer->irq);
+		goto err_request_irq;
+	}
+
+	sprd_timer_clkevt_init(timer);
+
+	return 0;
+
+err_request_irq:
+	irq_dispose_mapping(timer->irq);
+err_map_irq:
+	iounmap(timer->base);
+err_freq:
+	kfree(timer);
+
+	return ret;
+}
+
+TIMER_OF_DECLARE(sc9860_timer, "sprd,sc9860-timer", sprd_timer_init);
-- 
1.7.9.5

Re: [PATCH v2 2/2] clocksource: sprd: Add timer driver for Spreadtrum SC9860 platform

[Daniel Lezcano]

On 28/11/2017 03:45, Baolin Wang wrote:
> The Spreadtrum SC9860 platform will use the architected timers as local
> clock events, but we also need a broadcast timer device to wakeup the
> cpus when the cpus are in sleep mode.
> 
> Thus this patch registers the timer0 to be a broadcast timer supporting
> periodic and oneshot events.

This changelog is inadequate. It is pointless to explain why you submit
this driver.

It would be much more interesting to describe the timer internals.

> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---
> Changes since v1:
>  - Change to 32bit counter to avoid build warning.
> ---
>  drivers/clocksource/Kconfig      |    8 ++
>  drivers/clocksource/Makefile     |    1 +
>  drivers/clocksource/sprd-timer.c |  211 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 220 insertions(+)
>  create mode 100644 drivers/clocksource/sprd-timer.c

Even if it is not a general rule, can you rename this driver to
timer-sprd.c ? I would like little by little to converge all the timer
names to this pattern.

> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index c729a88..48c8702 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -441,6 +441,14 @@ config MTK_TIMER
>  	help
>  	  Support for Mediatek timer driver.
>  
> +config SPRD_TIMER
> +	bool "Spreadtrum timer driver"
> +	depends on GENERIC_CLOCKEVENTS

Remove GENERIC_CLOCKEVENTS because of:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/drivers/clocksource/Kconfig#n2

> +	depends on ARCH_SPRD || COMPILE_TEST

Remove the dependency on ARCH_SPRD, the arch's Kconfig must select
SPRD_TIMER.

Move the COMPILE_TEST as the other drivers.

	bool "Spreadtrum timer driver" if COMPILE_TEST

> +	select TIMER_O> +	help
> +	  Enables the support for the Spreadtrum timer driver.
> +
>  config SYS_SUPPORTS_SH_MTU2
>          bool
>  
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index 72711f1..62bf264 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_CLKSRC_TI_32K)	+= timer-ti-32k.o
>  obj-$(CONFIG_CLKSRC_NPS)	+= timer-nps.o
>  obj-$(CONFIG_OXNAS_RPS_TIMER)	+= timer-oxnas-rps.o
>  obj-$(CONFIG_OWL_TIMER)		+= owl-timer.o
> +obj-$(CONFIG_SPRD_TIMER)	+= sprd-timer.o
>  
>  obj-$(CONFIG_ARC_TIMERS)		+= arc_timer.o
>  obj-$(CONFIG_ARM_ARCH_TIMER)		+= arm_arch_timer.o
> diff --git a/drivers/clocksource/sprd-timer.c b/drivers/clocksource/sprd-timer.c
> new file mode 100644
> index 0000000..e90f948
> --- /dev/null
> +++ b/drivers/clocksource/sprd-timer.c
> @@ -0,0 +1,211 @@
> +/*
> + * Copyright (C) 2017 Spreadtrum Communications Inc.
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + */

Please fix the above with proper format (one example in timer-of.c).

> +#include <linux/clocksource.h>
> +#include <linux/clockchips.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/sched_clock.h>

Are you sure you need sched_clock and clocksource ?

> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>

These headers won't be needed anymore when using the timer-of API (see
the init function comment below).

> +#define TIMER_NAME		"sprd_timer"
> +
> +#define TIMER_LOAD_LO		0x0
> +#define TIMER_LOAD_HI		0x4
> +#define TIMER_VALUE_LO		0x8
> +#define TIMER_VALUE_HI		0xc
> +
> +#define TIMER_CTL		0x10
> +#define TIMER_CTL_PERIOD_MODE	BIT(0)
> +#define TIMER_CTL_ENABLE	BIT(1)
> +#define TIMER_CTL_64BIT_WIDTH	BIT(16)
> +
> +#define TIMER_INT		0x14
> +#define TIMER_INT_EN		BIT(0)
> +#define TIMER_INT_RAW_STS	BIT(1)
> +#define TIMER_INT_MASK_STS	BIT(2)
> +#define TIMER_INT_CLR		BIT(3)
> +
> +#define TIMER_VALUE_SHDW_LO	0x18
> +#define TIMER_VALUE_SHDW_HI	0x1c
> +
> +#define TIMER_VALUE_LO_MASK	GENMASK(31, 0)
> +
> +struct sprd_timer_device {
> +	struct clock_event_device ce;
> +	void __iomem *base;
> +	u32 freq;
> +	int irq;
> +};
> +
> +static inline struct sprd_timer_device *
> +to_sprd_timer(struct clock_event_device *c)
> +{
> +	return container_of(c, struct sprd_timer_device, ce);
> +}
> +
> +static void sprd_timer_enable(struct sprd_timer_device *timer, u32 flag)
> +{
> +	u32 val = readl_relaxed(timer->base + TIMER_CTL);
> +
> +	val |= TIMER_CTL_ENABLE;
> +	if (flag & TIMER_CTL_64BIT_WIDTH)
> +		val |= TIMER_CTL_64BIT_WIDTH;
> +	else
> +		val &= ~TIMER_CTL_64BIT_WIDTH;
> +
> +	if (flag & TIMER_CTL_PERIOD_MODE)
> +		val |= TIMER_CTL_PERIOD_MODE;
> +	else
> +		val &= ~TIMER_CTL_PERIOD_MODE;
> +
> +	writel_relaxed(val, timer->base + TIMER_CTL);
> +}
> +
> +static void sprd_timer_disable(struct sprd_timer_device *timer)
> +{
> +	u32 val = readl_relaxed(timer->base + TIMER_CTL);
> +
> +	val &= ~TIMER_CTL_ENABLE;
> +	writel_relaxed(val, timer->base + TIMER_CTL);
> +}
> +
> +static void sprd_timer_update_counter(struct sprd_timer_device *timer,
> +				      unsigned long cycles)
> +{
> +	writel_relaxed(cycles & TIMER_VALUE_LO_MASK,
> +		       timer->base + TIMER_LOAD_LO);
> +	writel_relaxed(0, timer->base + TIMER_LOAD_HI);
> +}
> +
> +static void sprd_timer_enable_interrupt(struct sprd_timer_device *timer)
> +{
> +	writel_relaxed(TIMER_INT_EN, timer->base + TIMER_INT);
> +}
> +
> +static void sprd_timer_clear_interrupt(struct sprd_timer_device *timer)
> +{
> +	u32 val = readl_relaxed(timer->base + TIMER_INT);
> +
> +	val |= TIMER_INT_CLR;
> +	writel_relaxed(val, timer->base + TIMER_INT);
> +}
> +
> +static int sprd_timer_set_next_event(unsigned long cycles,
> +				     struct clock_event_device *ce)
> +{
> +	struct sprd_timer_device *timer = to_sprd_timer(ce);
> +
> +	sprd_timer_disable(timer);
> +	sprd_timer_update_counter(timer, cycles);
> +	sprd_timer_enable(timer, 0);
> +
> +	return 0;
> +}
> +
> +static int sprd_timer_set_periodic(struct clock_event_device *ce)
> +{
> +	struct sprd_timer_device *timer = to_sprd_timer(ce);
> +	unsigned long cycles = DIV_ROUND_UP(timer->freq, HZ);
> +
> +	sprd_timer_disable(timer);
> +	sprd_timer_update_counter(timer, cycles);
> +	sprd_timer_enable(timer, TIMER_CTL_PERIOD_MODE);
> +
> +	return 0;
> +}
> +
> +static int sprd_timer_shutdown(struct clock_event_device *ce)
> +{
> +	struct sprd_timer_device *timer = to_sprd_timer(ce);
> +
> +	sprd_timer_disable(timer);
> +	return 0;
> +}
> +
> +static irqreturn_t sprd_timer_interrupt(int irq, void *dev_id)
> +{
> +	struct sprd_timer_device *timer = dev_id;
> +
> +	sprd_timer_clear_interrupt(timer);
> +
> +	if (clockevent_state_oneshot(&timer->ce))
> +		sprd_timer_disable(timer);
> +
> +	timer->ce.event_handler(&timer->ce);
> +	return IRQ_HANDLED;
> +}
> +
> +static void __init sprd_timer_clkevt_init(struct sprd_timer_device *timer)
> +{
> +	timer->ce.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
> +				CLOCK_EVT_FEAT_ONESHOT;
> +	timer->ce.set_next_event = sprd_timer_set_next_event;
> +	timer->ce.set_state_periodic = sprd_timer_set_periodic;
> +	timer->ce.set_state_shutdown = sprd_timer_shutdown;
> +	timer->ce.name = TIMER_NAME;
> +	timer->ce.rating = 300;
> +	timer->ce.irq = timer->irq;
> +	timer->ce.cpumask = cpu_possible_mask;
> +
> +	sprd_timer_enable_interrupt(timer);
> +	clockevents_config_and_register(&timer->ce, timer->freq, 1, UINT_MAX);
> +}
> +
> +static int __init sprd_timer_init(struct device_node *np)
> +{
> +	struct sprd_timer_device *timer;
> +	int ret;
> +
> +	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
> +	if (!timer)
> +		return -ENOMEM;
> +
> +	ret = of_property_read_u32(np, "clock-frequency", &timer->freq);
> +	if (ret) {
> +		pr_err("failed to get clock frequency\n");
> +		goto err_freq;
> +	}
> +
> +	timer->base = of_iomap(np, 0);
> +	if (!timer->base) {
> +		pr_err("%s: unable to map resource\n", np->name);
> +		ret = -ENXIO;
> +		goto err_freq;
> +	}
> +
> +	timer->irq = irq_of_parse_and_map(np, 0);
> +	if (timer->irq < 0) {
> +		pr_crit("%s: unable to parse timer irq\n", np->name);
> +		ret = timer->irq;
> +		goto err_map_irq;
> +	}
> +
> +	ret = request_irq(timer->irq, sprd_timer_interrupt, IRQF_TIMER,
> +			  TIMER_NAME, timer);
> +	if (ret) {
> +		pr_err("failed to setup irq %d\n", timer->irq);
> +		goto err_request_irq;
> +	}
> +	sprd_timer_clkevt_init(timer);

Please use the timer-of API, that will save you all these operations and
checks.

One example at:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/sun4i_timer.c#n143

And then use the function:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/sun4i_timer.c#n174


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Re: [PATCH v2 2/2] clocksource: sprd: Add timer driver for Spreadtrum SC9860 platform

[Baolin Wang]

Hi Daniel,

On 7 December 2017 at 18:44, Daniel Lezcano <daniel.lezcano-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> wrote:
> On 28/11/2017 03:45, Baolin Wang wrote:
>> The Spreadtrum SC9860 platform will use the architected timers as local
>> clock events, but we also need a broadcast timer device to wakeup the
>> cpus when the cpus are in sleep mode.
>>
>> Thus this patch registers the timer0 to be a broadcast timer supporting
>> periodic and oneshot events.
>
> This changelog is inadequate. It is pointless to explain why you submit
> this driver.
>
> It would be much more interesting to describe the timer internals.

Sure.

>
>> Signed-off-by: Baolin Wang <baolin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org>
>> ---
>> Changes since v1:
>>  - Change to 32bit counter to avoid build warning.
>> ---
>>  drivers/clocksource/Kconfig      |    8 ++
>>  drivers/clocksource/Makefile     |    1 +
>>  drivers/clocksource/sprd-timer.c |  211 ++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 220 insertions(+)
>>  create mode 100644 drivers/clocksource/sprd-timer.c
>
> Even if it is not a general rule, can you rename this driver to
> timer-sprd.c ? I would like little by little to converge all the timer
> names to this pattern.

OK.

>
>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>> index c729a88..48c8702 100644
>> --- a/drivers/clocksource/Kconfig
>> +++ b/drivers/clocksource/Kconfig
>> @@ -441,6 +441,14 @@ config MTK_TIMER
>>       help
>>         Support for Mediatek timer driver.
>>
>> +config SPRD_TIMER
>> +     bool "Spreadtrum timer driver"
>> +     depends on GENERIC_CLOCKEVENTS
>
> Remove GENERIC_CLOCKEVENTS because of:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/drivers/clocksource/Kconfig#n2

Yes, here GENERIC_CLOCKEVENTS is redundant.

>
>> +     depends on ARCH_SPRD || COMPILE_TEST
>
> Remove the dependency on ARCH_SPRD, the arch's Kconfig must select
> SPRD_TIMER.
>
> Move the COMPILE_TEST as the other drivers.

OK.

>
>         bool "Spreadtrum timer driver" if COMPILE_TEST
>
>> +     select TIMER_O> +       help
>> +       Enables the support for the Spreadtrum timer driver.
>> +
>>  config SYS_SUPPORTS_SH_MTU2
>>          bool
>>
>> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
>> index 72711f1..62bf264 100644
>> --- a/drivers/clocksource/Makefile
>> +++ b/drivers/clocksource/Makefile
>> @@ -54,6 +54,7 @@ obj-$(CONFIG_CLKSRC_TI_32K) += timer-ti-32k.o
>>  obj-$(CONFIG_CLKSRC_NPS)     += timer-nps.o
>>  obj-$(CONFIG_OXNAS_RPS_TIMER)        += timer-oxnas-rps.o
>>  obj-$(CONFIG_OWL_TIMER)              += owl-timer.o
>> +obj-$(CONFIG_SPRD_TIMER)     += sprd-timer.o
>>
>>  obj-$(CONFIG_ARC_TIMERS)             += arc_timer.o
>>  obj-$(CONFIG_ARM_ARCH_TIMER)         += arm_arch_timer.o
>> diff --git a/drivers/clocksource/sprd-timer.c b/drivers/clocksource/sprd-timer.c
>> new file mode 100644
>> index 0000000..e90f948
>> --- /dev/null
>> +++ b/drivers/clocksource/sprd-timer.c
>> @@ -0,0 +1,211 @@
>> +/*
>> + * Copyright (C) 2017 Spreadtrum Communications Inc.
>> + *
>> + * SPDX-License-Identifier: GPL-2.0
>> + */
>
> Please fix the above with proper format (one example in timer-of.c).

OK.

>
>> +#include <linux/clocksource.h>
>> +#include <linux/clockchips.h>
>> +#include <linux/init.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/sched_clock.h>
>
> Are you sure you need sched_clock and clocksource ?

Sorry, I forgot to remove them.

>
>> +#include <linux/slab.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>
> These headers won't be needed anymore when using the timer-of API (see
> the init function comment below).

OK.

>
>> +#define TIMER_NAME           "sprd_timer"
>> +
>> +#define TIMER_LOAD_LO                0x0
>> +#define TIMER_LOAD_HI                0x4
>> +#define TIMER_VALUE_LO               0x8
>> +#define TIMER_VALUE_HI               0xc
>> +
>> +#define TIMER_CTL            0x10
>> +#define TIMER_CTL_PERIOD_MODE        BIT(0)
>> +#define TIMER_CTL_ENABLE     BIT(1)
>> +#define TIMER_CTL_64BIT_WIDTH        BIT(16)
>> +
>> +#define TIMER_INT            0x14
>> +#define TIMER_INT_EN         BIT(0)
>> +#define TIMER_INT_RAW_STS    BIT(1)
>> +#define TIMER_INT_MASK_STS   BIT(2)
>> +#define TIMER_INT_CLR                BIT(3)
>> +
>> +#define TIMER_VALUE_SHDW_LO  0x18
>> +#define TIMER_VALUE_SHDW_HI  0x1c
>> +
>> +#define TIMER_VALUE_LO_MASK  GENMASK(31, 0)
>> +
>> +struct sprd_timer_device {
>> +     struct clock_event_device ce;
>> +     void __iomem *base;
>> +     u32 freq;
>> +     int irq;
>> +};
>> +
>> +static inline struct sprd_timer_device *
>> +to_sprd_timer(struct clock_event_device *c)
>> +{
>> +     return container_of(c, struct sprd_timer_device, ce);
>> +}
>> +
>> +static void sprd_timer_enable(struct sprd_timer_device *timer, u32 flag)
>> +{
>> +     u32 val = readl_relaxed(timer->base + TIMER_CTL);
>> +
>> +     val |= TIMER_CTL_ENABLE;
>> +     if (flag & TIMER_CTL_64BIT_WIDTH)
>> +             val |= TIMER_CTL_64BIT_WIDTH;
>> +     else
>> +             val &= ~TIMER_CTL_64BIT_WIDTH;
>> +
>> +     if (flag & TIMER_CTL_PERIOD_MODE)
>> +             val |= TIMER_CTL_PERIOD_MODE;
>> +     else
>> +             val &= ~TIMER_CTL_PERIOD_MODE;
>> +
>> +     writel_relaxed(val, timer->base + TIMER_CTL);
>> +}
>> +
>> +static void sprd_timer_disable(struct sprd_timer_device *timer)
>> +{
>> +     u32 val = readl_relaxed(timer->base + TIMER_CTL);
>> +
>> +     val &= ~TIMER_CTL_ENABLE;
>> +     writel_relaxed(val, timer->base + TIMER_CTL);
>> +}
>> +
>> +static void sprd_timer_update_counter(struct sprd_timer_device *timer,
>> +                                   unsigned long cycles)
>> +{
>> +     writel_relaxed(cycles & TIMER_VALUE_LO_MASK,
>> +                    timer->base + TIMER_LOAD_LO);
>> +     writel_relaxed(0, timer->base + TIMER_LOAD_HI);
>> +}
>> +
>> +static void sprd_timer_enable_interrupt(struct sprd_timer_device *timer)
>> +{
>> +     writel_relaxed(TIMER_INT_EN, timer->base + TIMER_INT);
>> +}
>> +
>> +static void sprd_timer_clear_interrupt(struct sprd_timer_device *timer)
>> +{
>> +     u32 val = readl_relaxed(timer->base + TIMER_INT);
>> +
>> +     val |= TIMER_INT_CLR;
>> +     writel_relaxed(val, timer->base + TIMER_INT);
>> +}
>> +
>> +static int sprd_timer_set_next_event(unsigned long cycles,
>> +                                  struct clock_event_device *ce)
>> +{
>> +     struct sprd_timer_device *timer = to_sprd_timer(ce);
>> +
>> +     sprd_timer_disable(timer);
>> +     sprd_timer_update_counter(timer, cycles);
>> +     sprd_timer_enable(timer, 0);
>> +
>> +     return 0;
>> +}
>> +
>> +static int sprd_timer_set_periodic(struct clock_event_device *ce)
>> +{
>> +     struct sprd_timer_device *timer = to_sprd_timer(ce);
>> +     unsigned long cycles = DIV_ROUND_UP(timer->freq, HZ);
>> +
>> +     sprd_timer_disable(timer);
>> +     sprd_timer_update_counter(timer, cycles);
>> +     sprd_timer_enable(timer, TIMER_CTL_PERIOD_MODE);
>> +
>> +     return 0;
>> +}
>> +
>> +static int sprd_timer_shutdown(struct clock_event_device *ce)
>> +{
>> +     struct sprd_timer_device *timer = to_sprd_timer(ce);
>> +
>> +     sprd_timer_disable(timer);
>> +     return 0;
>> +}
>> +
>> +static irqreturn_t sprd_timer_interrupt(int irq, void *dev_id)
>> +{
>> +     struct sprd_timer_device *timer = dev_id;
>> +
>> +     sprd_timer_clear_interrupt(timer);
>> +
>> +     if (clockevent_state_oneshot(&timer->ce))
>> +             sprd_timer_disable(timer);
>> +
>> +     timer->ce.event_handler(&timer->ce);
>> +     return IRQ_HANDLED;
>> +}
>> +
>> +static void __init sprd_timer_clkevt_init(struct sprd_timer_device *timer)
>> +{
>> +     timer->ce.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
>> +                             CLOCK_EVT_FEAT_ONESHOT;
>> +     timer->ce.set_next_event = sprd_timer_set_next_event;
>> +     timer->ce.set_state_periodic = sprd_timer_set_periodic;
>> +     timer->ce.set_state_shutdown = sprd_timer_shutdown;
>> +     timer->ce.name = TIMER_NAME;
>> +     timer->ce.rating = 300;
>> +     timer->ce.irq = timer->irq;
>> +     timer->ce.cpumask = cpu_possible_mask;
>> +
>> +     sprd_timer_enable_interrupt(timer);
>> +     clockevents_config_and_register(&timer->ce, timer->freq, 1, UINT_MAX);
>> +}
>> +
>> +static int __init sprd_timer_init(struct device_node *np)
>> +{
>> +     struct sprd_timer_device *timer;
>> +     int ret;
>> +
>> +     timer = kzalloc(sizeof(*timer), GFP_KERNEL);
>> +     if (!timer)
>> +             return -ENOMEM;
>> +
>> +     ret = of_property_read_u32(np, "clock-frequency", &timer->freq);
>> +     if (ret) {
>> +             pr_err("failed to get clock frequency\n");
>> +             goto err_freq;
>> +     }
>> +
>> +     timer->base = of_iomap(np, 0);
>> +     if (!timer->base) {
>> +             pr_err("%s: unable to map resource\n", np->name);
>> +             ret = -ENXIO;
>> +             goto err_freq;
>> +     }
>> +
>> +     timer->irq = irq_of_parse_and_map(np, 0);
>> +     if (timer->irq < 0) {
>> +             pr_crit("%s: unable to parse timer irq\n", np->name);
>> +             ret = timer->irq;
>> +             goto err_map_irq;
>> +     }
>> +
>> +     ret = request_irq(timer->irq, sprd_timer_interrupt, IRQF_TIMER,
>> +                       TIMER_NAME, timer);
>> +     if (ret) {
>> +             pr_err("failed to setup irq %d\n", timer->irq);
>> +             goto err_request_irq;
>> +     }
>> +     sprd_timer_clkevt_init(timer);
>
> Please use the timer-of API, that will save you all these operations and
> checks.
>
> One example at:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/sun4i_timer.c#n143
>
> And then use the function:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/sun4i_timer.c#n174
>

I missed timer-of APIs, and I will check it and use timer-of APIs.
Really appreciated for your useful comments.

-- 
Baolin.wang
Best Regards
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