Re: [PATCH V5 1/5] clocksource: imx-sysctr: Add internal clock divider handle

From: Daniel Lezcano
Date: Tue Aug 06 2019 - 06:27:59 EST


On 06/08/2019 03:55, Anson Huang wrote:
> Gentle ping...

Coming back from vacation. It is in the pipe ... :)

>> From: Anson Huang <Anson.Huang@xxxxxxx>
>>
>> The system counter block guide states that the base clock is internally divided
>> by 3 before use, that means the clock input of system counter defined in DT
>> should be base clock which is normally from OSC, and then internally divided
>> by 3 before use.
>>
>> Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
>> ---
>> Changes since V4:
>> - to solve the clock driver probed after system counter driver issue,
>> now we can easily switch to
>> use fixed clock defined in DT and get its rate, then divided by 3 to
>> get real clock rate for
>> system counter driver, no need to add "clock-frequency" property in
>> DT.
>> ---
>> drivers/clocksource/timer-imx-sysctr.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/clocksource/timer-imx-sysctr.c
>> b/drivers/clocksource/timer-imx-sysctr.c
>> index fd7d680..b7c80a3 100644
>> --- a/drivers/clocksource/timer-imx-sysctr.c
>> +++ b/drivers/clocksource/timer-imx-sysctr.c
>> @@ -20,6 +20,8 @@
>> #define SYS_CTR_EN 0x1
>> #define SYS_CTR_IRQ_MASK 0x2
>>
>> +#define SYS_CTR_CLK_DIV 0x3
>> +
>> static void __iomem *sys_ctr_base;
>> static u32 cmpcr;
>>
>> @@ -134,6 +136,9 @@ static int __init sysctr_timer_init(struct device_node
>> *np)
>> if (ret)
>> return ret;
>>
>> + /* system counter clock is divided by 3 internally */
>> + to_sysctr.of_clk.rate /= SYS_CTR_CLK_DIV;
>> +
>> sys_ctr_base = timer_of_base(&to_sysctr);
>> cmpcr = readl(sys_ctr_base + CMPCR);
>> cmpcr &= ~SYS_CTR_EN;
>> --
>> 2.7.4
>


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