Re: [PATCH v5 2/4] clocksource: stm32: only use 32 bits timers

From: Benjamin Gaignard
Date: Wed Oct 18 2017 - 08:25:24 EST


2017-10-18 10:21 GMT+02:00 Julien Thierry <julien.thierry@xxxxxxx>:
>
>
> On 18/10/17 08:43, Benjamin Gaignard wrote:
>>
>> 16 bits hardware are not enough accure to be used.
>> Do no allow them to be probed by tested max counter value.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
>> ---
>> drivers/clocksource/timer-stm32.c | 23 +++++++++--------------
>> 1 file changed, 9 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/clocksource/timer-stm32.c
>> b/drivers/clocksource/timer-stm32.c
>> index abff21c..f7e4eec 100644
>> --- a/drivers/clocksource/timer-stm32.c
>> +++ b/drivers/clocksource/timer-stm32.c
>> @@ -81,9 +81,9 @@ static irqreturn_t stm32_clock_event_handler(int irq,
>> void *dev_id)
>> static int __init stm32_clockevent_init(struct device_node *node)
>> {
>> struct reset_control *rstc;
>> - unsigned long max_delta;
>> - int ret, bits, prescaler = 1;
>> + unsigned long max_arr;
>> struct timer_of *to;
>> + int ret;
>> to = kzalloc(sizeof(*to), GFP_KERNEL);
>> if (!to)
>> @@ -113,26 +113,21 @@ static int __init stm32_clockevent_init(struct
>> device_node *node)
>> /* Detect whether the timer is 16 or 32 bits */
>> writel_relaxed(~0U, timer_of_base(to) + TIM_ARR);
>> - max_delta = readl_relaxed(timer_of_base(to) + TIM_ARR);
>> - if (max_delta == ~0U) {
>> - prescaler = 1;
>> - bits = 32;
>> - } else {
>> - prescaler = 1024;
>> - bits = 16;
>> + max_arr = readl_relaxed(timer_of_base(to) + TIM_ARR);
>> + if (max_arr != ~0U) {
>> + pr_err("32 bits timer is needed\n");
>> + return -EINVAL;
>
>
> Same as with previous patch, I think "to" should get freed.

Yes I could solve that in the first patch

>
> Also, why is there no function to undo what timer_of_init did? Shouldn't we
> be able to free the irqs and unmap the timer io base here?

timer-of doesn't provide deinit function since I will have to do a new version
I will add it.

Benjamin
>
> Cheers,
>
> --
> Julien Thierry