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| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2019-10-14 11:51:04 +0200 |
|---|---|---|
| committer | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2019-10-30 15:05:18 +0100 |
| commit | 4973ddc8426405ebe71c48bd3d5e20d83877c076 (patch) | |
| tree | f0795a27fa7e09d003d48e1541a306c36f54a0df /drivers/pinctrl | |
| parent | Linux 5.4-rc5 (diff) | |
| download | linux-4973ddc8426405ebe71c48bd3d5e20d83877c076.tar.xz linux-4973ddc8426405ebe71c48bd3d5e20d83877c076.zip | |
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@vger.kernel.org
Cc: fei.yang@intel.com
Reported-by: Oliver Barta <oliver.barta@aptiv.com>
Reported-by: Malin Jonsson <malin.jonsson@ericsson.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Diffstat (limited to 'drivers/pinctrl')
| -rw-r--r-- | drivers/pinctrl/intel/pinctrl-intel.c | 21 |
1 files changed, 20 insertions, 1 deletions
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); |