linux-kernel - Re: [PATCH v4 8/9] clocksource: atmel-st: use syscon/regmap

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Message-ID: <20150306084727.GH3989@piout.net>
Date:	Fri, 6 Mar 2015 09:47:27 +0100
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:	Nicolas Ferre <nicolas.ferre@...el.com>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Lee Jones <lee.jones@...aro.org>,
	Wim Van Sebroeck <wim@...ana.be>,
	Guenter Roeck <linux@...ck-us.net>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-watchdog@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v4 8/9] clocksource: atmel-st: use syscon/regmap

On 06/03/2015 at 09:43:02 +0100, Daniel Lezcano wrote :
> On 03/05/2015 04:49 PM, Alexandre Belloni wrote:
> >The register range from the system timer is also used by the watchdog driver.
> >Use a regmap to handle concurrent accesses.
> >
> >Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
> >Acked-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
> >---
> >  drivers/clocksource/timer-atmel-st.c | 99 ++++++++++++++----------------------
> >  1 file changed, 37 insertions(+), 62 deletions(-)
> >
> >diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c
> >index 7d062ab32674..c4a52e32675e 100644
> >--- a/drivers/clocksource/timer-atmel-st.c
> >+++ b/drivers/clocksource/timer-atmel-st.c
> >@@ -24,19 +24,19 @@
> >  #include <linux/irq.h>
> >  #include <linux/clockchips.h>
> >  #include <linux/export.h>
> >-#include <linux/of.h>
> >-#include <linux/of_address.h>
> >+#include <linux/mfd/syscon.h>
> >+#include <linux/mfd/syscon/atmel-st.h>
> >  #include <linux/of_irq.h>
> >+#include <linux/regmap.h>
> >
> >  #include <asm/mach/time.h>
> >
> >-#include <mach/at91_st.h>
> >-#include <mach/hardware.h>
> >-
> >  static unsigned long last_crtr;
> >  static u32 irqmask;
> >  static struct clock_event_device clkevt;
> >+static struct regmap *regmap_st;
> >
> >+#define AT91_SLOW_CLOCK		32768
> >  #define RM9200_TIMER_LATCH	((AT91_SLOW_CLOCK + HZ/2) / HZ)
> >
> >  /*
> >@@ -46,11 +46,11 @@ static struct clock_event_device clkevt;
> >   */
> >  static inline unsigned long read_CRTR(void)
> >  {
> >-	unsigned long x1, x2;
> >+	unsigned int x1, x2;
> >
> >-	x1 = at91_st_read(AT91_ST_CRTR);
> >+	regmap_read(regmap_st, AT91_ST_CRTR, &x1);
> >  	do {
> >-		x2 = at91_st_read(AT91_ST_CRTR);
> >+		regmap_read(regmap_st, AT91_ST_CRTR, &x2);
> >  		if (x1 == x2)
> >  			break;
> >  		x1 = x2;
> >@@ -63,7 +63,10 @@ static inline unsigned long read_CRTR(void)
> >   */
> >  static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
> >  {
> >-	u32	sr = at91_st_read(AT91_ST_SR) & irqmask;
> >+	u32 sr;
> >+
> >+	regmap_read(regmap_st, AT91_ST_SR, &sr);
> >+	sr &= irqmask;
> >
> >  	/*
> >  	 * irqs should be disabled here, but as the irq is shared they are only
> >@@ -96,7 +99,7 @@ static struct irqaction at91rm9200_timer_irq = {
> >  	.name		= "at91_tick",
> >  	.flags		= IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
> >  	.handler	= at91rm9200_timer_interrupt,
> >-	.irq		= NR_IRQS_LEGACY + AT91_ID_SYS,
> >+	.irq		= 0,
> 
> Is this change related to regmap ?
> 

It is related to the removing of hardware.h. I can do that in a separate
patch if you prefer.

> By the way, perhaps take the opportunity to replace setup_irq by request_irq
> (and check the return value) ?
> 

I tried and it fails, I didn't investigate yet.

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