Received-SPF: pass (google.com: domain of linux-kernel+bounces-84903-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
From: =?utf-8?q?Th=C3=A9o_Lebrun?= <theo.lebrun@bootlin.com>
Date: Wed, 28 Feb 2024 12:28:24 +0100
Subject: [PATCH v2 26/30] Documentation: gpio: mention
 generic_handle_irq_safe()
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
Message-Id: <20240228-mbly-gpio-v2-26-3ba757474006@bootlin.com>
References: <20240228-mbly-gpio-v2-0-3ba757474006@bootlin.com>
In-Reply-To: <20240228-mbly-gpio-v2-0-3ba757474006@bootlin.com>
To: Linus Walleij <linus.walleij@linaro.org>, 
 Bartosz Golaszewski <brgl@bgdev.pl>, Rob Herring <robh+dt@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Conor Dooley <conor+dt@kernel.org>, Philipp Zabel <p.zabel@pengutronix.de>, 
 Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, 
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
 linux-mips@vger.kernel.org, Gregory CLEMENT <gregory.clement@bootlin.com>, 
 Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>, 
 Thomas Petazzoni <thomas.petazzoni@bootlin.com>, 
 Tawfik Bayouk <tawfik.bayouk@mobileye.com>, 
 =?utf-8?q?Th=C3=A9o_Lebrun?= <theo.lebrun@bootlin.com>, 
 Stephen Warren <swarren@wwwdotorg.org>, Jonathan Corbet <corbet@lwn.net>, 
 linux-doc@vger.kernel.org

generic_handle_irq() must be called from a no-IRQ context. Documentation
advices on using a fake raw lock to call generic_handle_irq() from any
context.

Since 509853f9e1e7 ("genirq: Provide generic_handle_irq_safe()"), a
better alternative is available.

To: Stephen Warren <swarren@wwwdotorg.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 Documentation/driver-api/gpio/driver.rst | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst
index bf6319cc531b..550d167a82ed 100644
--- a/Documentation/driver-api/gpio/driver.rst
+++ b/Documentation/driver-api/gpio/driver.rst
@@ -339,15 +339,8 @@ Cascaded GPIO irqchips usually fall in one of three categories:
 
   The generic_handle_irq() is expected to be called with IRQ disabled,
   so the IRQ core will complain if it is called from an IRQ handler which is
-  forced to a thread. The "fake?" raw lock can be used to work around this
-  problem::
-
-    raw_spinlock_t wa_lock;
-    static irqreturn_t omap_gpio_irq_handler(int irq, void *gpiobank)
-        unsigned long wa_lock_flags;
-        raw_spin_lock_irqsave(&bank->wa_lock, wa_lock_flags);
-        generic_handle_irq(irq_find_mapping(bank->chip.irq.domain, bit));
-        raw_spin_unlock_irqrestore(&bank->wa_lock, wa_lock_flags);
+  forced to a thread. generic_handle_irq_safe() can be used to work around
+  this problem; it can safely be called from any context.
 
 - GENERIC CHAINED GPIO IRQCHIPS: these are the same as "CHAINED GPIO irqchips",
   but chained IRQ handlers are not used. Instead GPIO IRQs dispatching is

-- 
2.44.0