linux-kernel - [PATCH 5.9 129/255] pinctrl: intel: Set default bias in case no particular value given

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Date:   Tue, 17 Nov 2020 14:04:29 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jamie McClymont <jamie@...ius.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.9 129/255] pinctrl: intel: Set default bias in case no particular value given

From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

[ Upstream commit f3c75e7a9349d1d33eb53ddc1b31640994969f73 ]

When GPIO library asks pin control to set the bias, it doesn't pass
any value of it and argument is considered boolean (and this is true
for ACPI GpioIo() / GpioInt() resources, by the way). Thus, individual
drivers must behave well, when they got the resistance value of 1 Ohm,
i.e. transforming it to sane default.

In case of Intel pin control hardware the 5 kOhm sounds plausible
because on one hand it's a minimum of resistors present in all
hardware generations and at the same time it's high enough to minimize
leakage current (will be only 200 uA with the above choice).

Fixes: e57725eabf87 ("pinctrl: intel: Add support for hardware debouncer")
Reported-by: Jamie McClymont <jamie@...ius.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pinctrl/intel/pinctrl-intel.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index b738b28239bd4..31e7840bc5e25 100644
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -683,6 +683,10 @@ static int intel_config_set_pull(struct intel_pinctrl *pctrl, unsigned int pin,
 
 		value |= PADCFG1_TERM_UP;
 
+		/* Set default strength value in case none is given */
+		if (arg == 1)
+			arg = 5000;
+
 		switch (arg) {
 		case 20000:
 			value |= PADCFG1_TERM_20K << PADCFG1_TERM_SHIFT;
@@ -705,6 +709,10 @@ static int intel_config_set_pull(struct intel_pinctrl *pctrl, unsigned int pin,
 	case PIN_CONFIG_BIAS_PULL_DOWN:
 		value &= ~(PADCFG1_TERM_UP | PADCFG1_TERM_MASK);
 
+		/* Set default strength value in case none is given */
+		if (arg == 1)
+			arg = 5000;
+
 		switch (arg) {
 		case 20000:
 			value |= PADCFG1_TERM_20K << PADCFG1_TERM_SHIFT;
-- 
2.27.0