The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 29c2c6aa32405dfee4a29911a51ba133edcedb0f Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Date: Mon, 14 Oct 2019 12:51:04 +0300
Subject: [PATCH] pinctrl: intel: Avoid potential glitches if pin is in GPIO
mode
When consumer requests a pin, in order to be on the safest side,
we switch it first to GPIO mode followed by immediate transition
to the input state. Due to posted writes it's luckily to be a single
I/O transaction.
However, if firmware or boot loader already configures the pin
to the GPIO mode, user expects no glitches for the requested pin.
We may check if the pin is pre-configured and leave it as is
till the actual consumer toggles its state to avoid glitches.
Fixes: 7981c0015af2 ("pinctrl: intel: Add Intel Sunrisepoint pin controller and GPIO support")
Depends-on: f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip")
Cc: stable@xxxxxxxxxxxxxxx
Cc: fei.yang@xxxxxxxxx
Reported-by: Oliver Barta <oliver.barta@xxxxxxxxx>
Reported-by: Malin Jonsson <malin.jonsson@xxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index bc013599a9a3..83981ad66a71 100644
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -52,6 +52,7 @@
#define PADCFG0_GPIROUTNMI BIT(17)
#define PADCFG0_PMODE_SHIFT 10
#define PADCFG0_PMODE_MASK GENMASK(13, 10)
+#define PADCFG0_PMODE_GPIO 0
#define PADCFG0_GPIORXDIS BIT(9)
#define PADCFG0_GPIOTXDIS BIT(8)
#define PADCFG0_GPIORXSTATE BIT(1)
@@ -332,7 +333,7 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
cfg1 = readl(intel_get_padcfg(pctrl, pin, PADCFG1));
mode = (cfg0 & PADCFG0_PMODE_MASK) >> PADCFG0_PMODE_SHIFT;
- if (!mode)
+ if (mode == PADCFG0_PMODE_GPIO)
seq_puts(s, "GPIO ");
else
seq_printf(s, "mode %d ", mode);
@@ -458,6 +459,11 @@ static void __intel_gpio_set_direction(void __iomem *padcfg0, bool input)
writel(value, padcfg0);
}
+static int intel_gpio_get_gpio_mode(void __iomem *padcfg0)
+{
+ return (readl(padcfg0) & PADCFG0_PMODE_MASK) >> PADCFG0_PMODE_SHIFT;
+}
+
static void intel_gpio_set_gpio_mode(void __iomem *padcfg0)
{
u32 value;
@@ -491,7 +497,20 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
}
padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
+
+ /*
+ * If pin is already configured in GPIO mode, we assume that
+ * firmware provides correct settings. In such case we avoid
+ * potential glitches on the pin. Otherwise, for the pin in
+ * alternative mode, consumer has to supply respective flags.
+ */
+ if (intel_gpio_get_gpio_mode(padcfg0) == PADCFG0_PMODE_GPIO) {
+ raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+ return 0;
+ }
+
intel_gpio_set_gpio_mode(padcfg0);
+
/* Disable TX buffer and enable RX (this will be input) */
__intel_gpio_set_direction(padcfg0, true);
