From: Radim Pavlik radim.pavlik@tbs-biometrics.com
stable inclusion from stable-5.10.51 commit b5f2982e06096ebeafe43edf47052e2ab7661279 bugzilla: 175263 https://gitee.com/openeuler/kernel/issues/I4DT6F
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 897120d41e7afd9da435cb00041a142aeeb53c07 ]
Checking value of MCP_INTF in mcp23s08_irq suggests that the handler may be called even when there is no interrupt pending.
But the actual interrupt could happened between reading MCP_INTF and MCP_GPIO. In this situation we got nothing from MCP_INTF, but the event gets acknowledged on the expander by reading MCP_GPIO. This leads to losing events.
Fix the problem by not reading any register until we see something in MCP_INTF.
The error was reproduced and fix tested on MCP23017.
Signed-off-by: Radim Pavlik radim.pavlik@tbs-biometrics.com Link: https://lore.kernel.org/r/AM7PR06MB6769E1183F68DEBB252F665ABA3E9@AM7PR06MB67... Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/pinctrl/pinctrl-mcp23s08.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pinctrl/pinctrl-mcp23s08.c b/drivers/pinctrl/pinctrl-mcp23s08.c index ce2d8014b7e0..799d596a1a4b 100644 --- a/drivers/pinctrl/pinctrl-mcp23s08.c +++ b/drivers/pinctrl/pinctrl-mcp23s08.c @@ -351,6 +351,11 @@ static irqreturn_t mcp23s08_irq(int irq, void *data) if (mcp_read(mcp, MCP_INTF, &intf)) goto unlock;
+ if (intf == 0) { + /* There is no interrupt pending */ + return IRQ_HANDLED; + } + if (mcp_read(mcp, MCP_INTCAP, &intcap)) goto unlock;
@@ -368,11 +373,6 @@ static irqreturn_t mcp23s08_irq(int irq, void *data) mcp->cached_gpio = gpio; mutex_unlock(&mcp->lock);
- if (intf == 0) { - /* There is no interrupt pending */ - return IRQ_HANDLED; - } - dev_dbg(mcp->chip.parent, "intcap 0x%04X intf 0x%04X gpio_orig 0x%04X gpio 0x%04X\n", intcap, intf, gpio_orig, gpio);