AM625: Unexpected GPIO behavior when resuming from the Deep Sleep mode.

Hello,

I don't think we have a solution for this item yet. I'll check internally.

Just to make sure, do these pins have an external resistor attached?

We've noticed in previous tests that pulling the internet, active state resistor high has helped on GPIOs that don't have an external resistor. This was done by setting the PADCONFIG Bit 16=0 & Bit 17=1. Try this change and let us know the results.

Best Regards,
Anshu

Hi Anshu Madwesh

Both pins GPMC0_CLK (P25) and USB0_DRVVBUS (C20) has an external 100k pull-down resistors and they can't be changed to pull-ups.

I turned on the internal pull up for the GPMC0_CLK (P25) pin by setting the PADCONFIG Bits as you suggested.

I still have a signal dropping to zero volts before resuming from Deep Sleep mode. But now it drops to zero for 500ns instead of 200ms.

But we should not have any voltage drops on this pin before exiting from the DeepSleep mode.

Hello,

Thank you for the update. Let me share these results internally and from there can try some ideas to debug this further.

Best Regards,

Anshu

Hello,

Can you try the following patch for the GPIO driver? The idea is to check the GPIO is restoring its value before the IO Isolation step.

diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
index 69f3d864f69d..fc25e3d5fc77 100644
--- a/drivers/gpio/gpio-davinci.c
+++ b/drivers/gpio/gpio-davinci.c
@@ -698,8 +698,13 @@ static int davinci_gpio_resume(struct device *dev)
        return 0;
 }
  
-DEFINE_SIMPLE_DEV_PM_OPS(davinci_gpio_dev_pm_ops, davinci_gpio_suspend,
-                        davinci_gpio_resume);
+//DEFINE_SIMPLE_DEV_PM_OPS(davinci_gpio_dev_pm_ops, davinci_gpio_suspend,
+//                      davinci_gpio_resume);
+
+static const struct dev_pm_ops davinci_gpio_dev_pm_ops = {
+        .suspend = davinci_gpio_suspend,
+        .resume_noirq = davinci_gpio_resume,
+};
  
 static const struct of_device_id davinci_gpio_ids[] = {
        { .compatible = "ti,keystone-gpio", keystone_gpio_get_irq_chip},

Best Regards,

Anshu

Hello,

Apologies for the confusion. Ignore the GPIO patch in the previous post. Please try the attached patch on ti_sci.c

drivers/firmware/ti_sci.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 7323f44bab7e..072cbe6d6aa2 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -3735,11 +3735,33 @@ static int ti_sci_suspend(struct device *dev)
 	return 0;
 }
 
+
+static	u32 gpio_dir[8], gpio_out[8];
+
 static int ti_sci_suspend_noirq(struct device *dev)
 {
 	struct ti_sci_info *info = dev_get_drvdata(dev);
 	int ret = 0;
 
+	void __iomem *gpio_chip_1, *gpio_chip_2; // We are saving gpio context...
+	gpio_chip_1 = ioremap(0x00600000, 0x100);
+	gpio_chip_2 = ioremap(0x00601000, 0x100);
+	for (int i = 0; i < 8; i++)
+	{
+		if(i<4) {
+			gpio_dir[i] = readl(gpio_chip_1 + 0x10 + i*0x28); // DIR 01 start
+			gpio_out[i] = readl(gpio_chip_1 + 0x14 + i*0x28);  // OUT_DATA01 start next starts after 0x28
+		}
+		else {
+			gpio_dir[i] = readl(gpio_chip_2 + 0x10 + (i-4)*0x28); // DIR 01 start
+			gpio_out[i] = readl(gpio_chip_2 + 0x14 + (i-4)*0x28);  // OUT_DATA01 start next starts after 0x28
+
+		}
+	}
+	
+	dev_info(dev, "%s: Saving gpio ctx dir = |%x| out = |%x|\n", __func__, 
+			 gpio_dir[0], gpio_out[0]);
+
 	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_ENABLE);
 	if (ret)
 		return ret;
@@ -3754,6 +3776,22 @@ static int ti_sci_resume(struct device *dev)
 	u32 source;
 	u64 time;
 	int ret = 0;
+	void __iomem *gpio_chip_1, *gpio_chip_2; // We are restoring gpio context...
+	gpio_chip_1 = ioremap(0x00600000, 0x100);
+	gpio_chip_2 = ioremap(0x00601000, 0x100);
+	for (int i = 0; i < 8; i++)
+	{
+		if (i < 4) {
+			writel(gpio_dir[i],gpio_chip_1 + 0x10 + i*0x28); // DIR 01 start
+			writel(gpio_out[i], gpio_chip_1 + 0x14 + i*0x28);  // OUT_DATA01 start next starts after 0x28
+		} else {
+			writel(gpio_dir[i],gpio_chip_2 + 0x10 + (i-4)*0x28); // DIR 01 start
+			writel(gpio_out[i], gpio_chip_2 + 0x14 + (i-4)*0x28);  // OUT_DATA01 start next starts after 0x28
+		}
+	}
+	
+	dev_info(dev, "%s: restoring gpio ctx dir = |%x| out = |%x|\n", __func__, 
+			 gpio_dir[0], gpio_out[0]);
 
 	ret = ti_sci_cmd_set_io_isolation(&info->handle, TISCI_MSG_VALUE_IO_DISABLE);
 	if (ret)

base-commit: 6de6e418c80edfbe08f4a5f851c721bd60c0123b
-- 
2.34.1

Best Regards,

Anshu