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Date: Thu, 9 Jun 2022 16:35:14 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Aswath Govindraju <a-govindraju@...com>
Cc: Devarsh Thakkar <devarsht@...com>,
Vignesh Raghavendra <vigneshr@...com>,
Keerthy <j-keerthy@...com>,
Linus Walleij <linus.walleij@...aro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: davinci: Add support for system suspend/resume PM
On Tue, Jun 7, 2022 at 8:08 AM Aswath Govindraju <a-govindraju@...com> wrote:
>
> From: Devarsh Thakkar <devarsht@...com>
>
> 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@...com>
> Signed-off-by: Aswath Govindraju <a-govindraju@...com>
> ---
> 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.
> #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.
> +
> + 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
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