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

Daniel Lezcano
2015-03-09T11:14:03Z

On 03/06/2015 09:47 AM, Alexandre Belloni wrote:
> 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@free-electrons.com>
>>> Acked-by: Boris Brezillon <boris.brezillon@free-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.

Yeah, because it is not obvious to see a connection between the removal
of hardware.h and the syscon/regmap changes.

I would suggest you create a patch to replace setup_irq with
register_irq so that will remove this structure and the irq
initialization to zero.

>> 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.

It shouldn't be a big deal, register_irq is more or less a wrapper to
setup_irq.

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