[PATCH V2 15/16] serial: 8250_bcm2835aux: add PM suspend/resume support

[Stefan Wahren]

Am 14.08.24 um 14:18 schrieb Ulf Hansson:
> On Sun, 28 Jul 2024 at 15:07, Stefan Wahren <wahrenst at gmx.net> wrote:
>> This adds suspend/resume support for the 8250_bcm2835aux
>> driver to provide power management support on attached
>> devices.
>>
>> Signed-off-by: Stefan Wahren <wahrenst at gmx.net>
>> ---
>>   drivers/tty/serial/8250/8250_bcm2835aux.c | 37 +++++++++++++++++++++++
>>   1 file changed, 37 insertions(+)
>>
>> diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
>> index 121a5ce86050..36e2bb34d82b 100644
>> --- a/drivers/tty/serial/8250/8250_bcm2835aux.c
>> +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
>> @@ -13,6 +13,7 @@
>>    */
>>
>>   #include <linux/clk.h>
>> +#include <linux/console.h>
>>   #include <linux/io.h>
>>   #include <linux/module.h>
>>   #include <linux/of.h>
>> @@ -213,11 +214,47 @@ static const struct acpi_device_id bcm2835aux_serial_acpi_match[] = {
>>   };
>>   MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match);
>>
>> +static int bcm2835aux_suspend(struct device *dev)
>> +{
>> +       struct bcm2835aux_data *data = dev_get_drvdata(dev);
>> +       struct uart_8250_port *up = serial8250_get_port(data->line);
>> +
>> +       serial8250_suspend_port(data->line);
>> +
>> +       if (device_may_wakeup(dev))
>> +               return 0;
>> +
>> +       if (uart_console(&up->port) && !console_suspend_enabled)
>> +               return 0;
>> +
>> +       clk_disable_unprepare(data->clk);
>> +       return 0;
>> +}
>> +
>> +static int bcm2835aux_resume(struct device *dev)
>> +{
>> +       struct bcm2835aux_data *data = dev_get_drvdata(dev);
>> +       int ret;
>> +
>> +       ret = clk_prepare_enable(data->clk);
> Doesn't this create clk prepare/enable - unprepare/disable imbalance
> problem when the uart is configured for system wakeup?
Thanks, i will send a follow-up

Regards
>
>> +       if (ret)
>> +               return ret;
>> +
>> +       serial8250_resume_port(data->line);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct dev_pm_ops bcm2835aux_dev_pm_ops = {
>> +       SYSTEM_SLEEP_PM_OPS(bcm2835aux_suspend, bcm2835aux_resume)
>> +};
>> +
>>   static struct platform_driver bcm2835aux_serial_driver = {
>>          .driver = {
>>                  .name = "bcm2835-aux-uart",
>>                  .of_match_table = bcm2835aux_serial_match,
>>                  .acpi_match_table = bcm2835aux_serial_acpi_match,
>> +               .pm = pm_ptr(&bcm2835aux_dev_pm_ops),
>>          },
>>          .probe  = bcm2835aux_serial_probe,
>>          .remove_new = bcm2835aux_serial_remove,
>> --
>> 2.34.1
>>
> Kind regards
> Uffe
>