Re: [PATCH] gpio: davinci: Add support for system suspend/resume PM

[Aswath Govindraju <a-govindraju@xxxxxx>]

Hi Bart,

On 09/06/22 20:05, Bartosz Golaszewski wrote:
> On Tue, Jun 7, 2022 at 8:08 AM Aswath Govindraju <a-govindraju@xxxxxx> wrote:
>>
>> From: Devarsh Thakkar <devarsht@xxxxxx>
>>
>> Add support for system suspend/resume PM hooks, save the
>> register context of all the required gpio registers on suspend
>> and restore the context on resume.
>>
>> Signed-off-by: Devarsh Thakkar <devarsht@xxxxxx>
>> Signed-off-by: Aswath Govindraju <a-govindraju@xxxxxx>
>> ---
>>  drivers/gpio/gpio-davinci.c | 84 +++++++++++++++++++++++++++++++++++++
>>  1 file changed, 84 insertions(+)
>>
>> diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
>> index f960587f86a3..aca352337c46 100644
>> --- a/drivers/gpio/gpio-davinci.c
>> +++ b/drivers/gpio/gpio-davinci.c
>> @@ -23,6 +23,7 @@
>>  #include <linux/irqchip/chained_irq.h>
>>  #include <linux/spinlock.h>
>>
>> +#include <linux/pm_runtime.h>
> 
> The below can stay here but please move the pm_runtime include
> together with the other linux includes.
> 

moved this in the respin.

>>  #include <asm-generic/gpio.h>
>>
>>  #define MAX_REGS_BANKS 5
>> @@ -62,6 +63,8 @@ struct davinci_gpio_controller {
>>         void __iomem            *regs[MAX_REGS_BANKS];
>>         int                     gpio_unbanked;
>>         int                     irqs[MAX_INT_PER_BANK];
>> +       struct davinci_gpio_regs context[MAX_REGS_BANKS];
>> +       u32                     binten_context;
>>  };
>>
>>  static inline u32 __gpio_mask(unsigned gpio)
>> @@ -622,6 +625,86 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
>>         return 0;
>>  }
>>
>> +static void davinci_gpio_save_context(struct davinci_gpio_controller *chips,
>> +                                     u32 nbank)
>> +{
>> +       struct davinci_gpio_regs __iomem *g = NULL;
>> +       struct davinci_gpio_regs *context = NULL;
>> +       u32 bank = 0;
>> +       void __iomem *base = NULL;
> 
> Only initialize variables that need it, please.
> 

Removed the intializations in the respin.


Thank you for reviewing the patch. I have posted a respin v2,

https://patchwork.ozlabs.org/project/linux-gpio/patch/20220610054622.21281-1-a-govindraju@xxxxxx/

Regards,
Aswath

>> +
>> +       base = chips->regs[0] - offset_array[0];
>> +       chips->binten_context = readl_relaxed(base + BINTEN);
>> +
>> +       for (bank = 0; bank < nbank; bank++) {
>> +               g = chips->regs[bank];
>> +               context = &chips->context[bank];
>> +               context->dir = readl_relaxed(&g->dir);
>> +               context->set_data = readl_relaxed(&g->set_data);
>> +               context->set_rising = readl_relaxed(&g->set_rising);
>> +               context->set_falling = readl_relaxed(&g->set_falling);
>> +       }
>> +
>> +       /* Clear Bank interrupt enable bit */
>> +       writel_relaxed(0, base + BINTEN);
>> +
>> +       /* Clear all interrupt status registers */
>> +       writel_relaxed(0xFFFFFFFF, &g->intstat);
>> +}
>> +
>> +static void davinci_gpio_restore_context(struct davinci_gpio_controller *chips,
>> +                                        u32 nbank)
>> +{
>> +       struct davinci_gpio_regs __iomem *g = NULL;
>> +       struct davinci_gpio_regs *context = NULL;
>> +       u32 bank = 0;
>> +       void __iomem *base = NULL;
>> +
>> +       base = chips->regs[0] - offset_array[0];
>> +
>> +       if (readl_relaxed(base + BINTEN) != chips->binten_context)
>> +               writel_relaxed(chips->binten_context, base + BINTEN);
>> +
>> +       for (bank = 0; bank < nbank; bank++) {
>> +               g = chips->regs[bank];
>> +               context = &chips->context[bank];
>> +               if (readl_relaxed(&g->dir) != context->dir)
>> +                       writel_relaxed(context->dir, &g->dir);
>> +               if (readl_relaxed(&g->set_data) != context->set_data)
>> +                       writel_relaxed(context->set_data, &g->set_data);
>> +               if (readl_relaxed(&g->set_rising) != context->set_rising)
>> +                       writel_relaxed(context->set_rising, &g->set_rising);
>> +               if (readl_relaxed(&g->set_falling) != context->set_falling)
>> +                       writel_relaxed(context->set_falling, &g->set_falling);
>> +       }
>> +}
>> +
>> +static int __maybe_unused davinci_gpio_suspend(struct device *dev)
>> +{
>> +       struct davinci_gpio_controller *chips = dev_get_drvdata(dev);
>> +       struct davinci_gpio_platform_data *pdata = dev_get_platdata(dev);
>> +       u32 nbank = DIV_ROUND_UP(pdata->ngpio, 32);
>> +
>> +       davinci_gpio_save_context(chips, nbank);
>> +
>> +       return 0;
>> +}
>> +
>> +static int __maybe_unused davinci_gpio_resume(struct device *dev)
>> +{
>> +       struct davinci_gpio_controller *chips = dev_get_drvdata(dev);
>> +       struct davinci_gpio_platform_data *pdata = dev_get_platdata(dev);
>> +       u32 nbank = DIV_ROUND_UP(pdata->ngpio, 32);
>> +
>> +       davinci_gpio_restore_context(chips, nbank);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct dev_pm_ops davinci_gpio_dev_pm_ops = {
>> +       SET_SYSTEM_SLEEP_PM_OPS(davinci_gpio_suspend, davinci_gpio_resume)
>> +};
>> +
>>  static const struct of_device_id davinci_gpio_ids[] = {
>>         { .compatible = "ti,keystone-gpio", keystone_gpio_get_irq_chip},
>>         { .compatible = "ti,am654-gpio", keystone_gpio_get_irq_chip},
>> @@ -634,6 +717,7 @@ static struct platform_driver davinci_gpio_driver = {
>>         .probe          = davinci_gpio_probe,
>>         .driver         = {
>>                 .name           = "davinci_gpio",
>> +               .pm = &davinci_gpio_dev_pm_ops,
>>                 .of_match_table = of_match_ptr(davinci_gpio_ids),
>>         },
>>  };
>> --
>> 2.17.1
>>
> 
> Bart