Re: [PATCH 6/9] arm: twr-k70f120m: clock source drivers for Kinetis SoC

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Hi Stephen,

Thanks for the valuable input - all of those points are now on my checklist for the work on the second iteration of this patchset.

On Tue, 23 Jun 2015, Stephen Boyd wrote:

On 06/23/2015 02:19 PM, Paul Osmialowski wrote:

diff --git a/drivers/clk/clk-kinetis.c b/drivers/clk/clk-kinetis.c
new file mode 100644
index 0000000..dea1054
--- /dev/null
+++ b/drivers/clk/clk-kinetis.c
@@ -0,0 +1,226 @@
+/*
+ * clk-kinetis.c - Clock driver for Kinetis K70 MCG
+ *
+ * Based on legacy pre-OF code by Alexander Potashev <aspotashev@xxxxxxxxxxx>
+ *
+ * Copyright (C) 2015 Paul Osmialowski <pawelo@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ */
+
+#include <linux/clk.h>

Is this using the consumer API? Please remove this include.

+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/err.h>
+#include <mach/kinetis.h>
+#include <mach/power.h>

It would be nice if we didn't need these mach includes so that this
driver can be easily build tested.

+
+#include <dt-bindings/clock/kinetis-mcg.h>
[..]
+}
+
+CLK_OF_DECLARE(kinetis_mcg, "fsl,kinetis-cmu", kinetis_mcg_init);

A clocksource isn't the same as a clk provider. Please split this patch
into two, one for the clk provider (drivers/clk) and one for the
clocksource driver (drivers/clocksource).

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 0f1c77e..1d2ecde 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -106,6 +106,11 @@ config CLKSRC_EFM32
 	  Support to use the timers of EFM32 SoCs as clock source and clock
 	  event device.

+config CLKSRC_KINETIS
+	bool "Clocksource for Kinetis SoCs"
+	depends on OF && ARM && ARCH_KINETIS

Doesn't ARCH_KINETIS imply ARM? Seems that we can drop the ARM
dependency here.

+	select CLKSRC_OF


diff --git a/drivers/clocksource/timer-kinetis.c b/drivers/clocksource/timer-kinetis.c
new file mode 100644
index 0000000..634f365
--- /dev/null
+++ b/drivers/clocksource/timer-kinetis.c
[..]
+
+/*
+ * Clock event device set mode function
+ */
+static void kinetis_clockevent_tmr_set_mode(
+	enum clock_event_mode mode, struct clock_event_device *clk)

s/clk/evt/ ?

+{
+	struct kinetis_clock_event_ddata *pit =
+		container_of(clk, struct kinetis_clock_event_ddata, evtdev);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		kinetis_pit_enable(pit->base, 1);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	default:
+		kinetis_pit_enable(pit->base, 0);
+	}
+}
+
+/*
+ * Configure the timer to generate an interrupt in the specified amount of ticks
+ */
+static int kinetis_clockevent_tmr_set_next_event(
+	unsigned long delta, struct clock_event_device *c)
+{
+	struct kinetis_clock_event_ddata *pit =
+		container_of(c, struct kinetis_clock_event_ddata, evtdev);
+	unsigned long flags;
+
+	raw_local_irq_save(flags);

What is this protecting against?

+	kinetis_pit_init(pit->base, delta);
+	kinetis_pit_enable(pit->base, 1);
+	raw_local_irq_restore(flags);
+
+	return 0;
+}
+
+static struct kinetis_clock_event_ddata
+		kinetis_clockevent_tmrs[KINETIS_PIT_CHANNELS] = {
+	{
+		.evtdev = {
+			.name		= "fsl,kinetis-pit-timer0",
+			.rating		= 200,
+			.features	=
+			    CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+			.set_mode	= kinetis_clockevent_tmr_set_mode,
+			.set_next_event	= kinetis_clockevent_tmr_set_next_event,
+		},
+	},
+	{
+		.evtdev = {
+			.name		= "fsl,kinetis-pit-timer1",
+		},
+	},
+	{
+		.evtdev = {
+			.name		= "fsl,kinetis-pit-timer2",
+		},
+	},
+	{
+		.evtdev = {
+			.name		= "fsl,kinetis-pit-timer3",
+		},
+	},
+};
+
+/*
+ * Timer IRQ handler
+ */
+static irqreturn_t kinetis_clockevent_tmr_irq_handler(int irq, void *dev_id)
+{
+	struct kinetis_clock_event_ddata *tmr = dev_id;
+
+	KINETIS_PIT_WR(tmr->base, tflg, KINETIS_PIT_TFLG_TIF_MSK);
+
+	tmr->evtdev.event_handler(&(tmr->evtdev));

Unnecessary parentheses, please remove them.

+
+	return IRQ_HANDLED;
+}
+
+/*
+ * System timer IRQ action
+ */
+static struct irqaction kinetis_clockevent_irqaction[KINETIS_PIT_CHANNELS] = {
+	{
+		.name = "Kinetis Kernel Time Tick (pit0)",
+		.flags = IRQF_TIMER | IRQF_IRQPOLL,
+		.dev_id = &kinetis_clockevent_tmrs[0],
+		.handler = kinetis_clockevent_tmr_irq_handler,
+	}, {
+		.name = "Kinetis Kernel Time Tick (pit1)",
+		.flags = IRQF_TIMER | IRQF_IRQPOLL,
+		.dev_id = &kinetis_clockevent_tmrs[1],
+		.handler = kinetis_clockevent_tmr_irq_handler,
+	}, {
+		.name = "Kinetis Kernel Time Tick (pit2)",
+		.flags = IRQF_TIMER | IRQF_IRQPOLL,
+		.dev_id = &kinetis_clockevent_tmrs[2],
+		.handler = kinetis_clockevent_tmr_irq_handler,
+	}, {
+		.name = "Kinetis Kernel Time Tick (pit3)",
+		.flags = IRQF_TIMER | IRQF_IRQPOLL,
+		.dev_id = &kinetis_clockevent_tmrs[3],
+		.handler = kinetis_clockevent_tmr_irq_handler,
+	},
+};

Any reason we can't just use request_irq() instead of having a set of
static irq actions?

+
+static void __init kinetis_clockevent_init(struct device_node *np)
+{
[..]
irq;
+	}
+
+	chan = of_alias_get_id(np, "pit");
+	if ((chan < 0) || (chan >= KINETIS_PIT_CHANNELS)) {

Unnecessary parentheses, please remove them.

--
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