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

From: Aswath Govindraju
Date: Tue Jun 07 2022 - 02:09:07 EST


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>
#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;
+
+ 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