linux-kernel - [PATCH 1/4] can: mcp251xfd: stop timestamp before sending chip to sleep

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Date: Wed, 17 Apr 2024 15:43:54 +0200
From: Gregor Herburger <gregor.herburger@...tq-group.com>
To: Marc Kleine-Budde <mkl@...gutronix.de>, 
 Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, 
 Thomas Kopp <thomas.kopp@...rochip.com>, 
 Vincent Mailhol <mailhol.vincent@...adoo.fr>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, 
 Conor Dooley <conor+dt@...nel.org>
Cc: linux-can@...r.kernel.org, netdev@...r.kernel.org, 
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, 
 linux@...tq-group.com, gregor.herburger@...tq-group.com, 
 alexander.stein@...tq-group.com
Subject: [PATCH 1/4] can: mcp251xfd: stop timestamp before sending chip to
 sleep

MCP2518FD exits Low-Power Mode (LPM) when CS is asserted. When chip
is send to sleep and the timestamp workqueue is not stopped chip is
waked by SPI transfer of mcp251xfd_timestamp_read.

So before sending chip to sleep stop timestamp otherwise the
mcp251xfd_timestamp_read callback would wake chip up.

Also there are error paths in mcp251xfd_chip_start where workqueue has
not been initialized but mcp251xfd_chip_stop is called. So check for
initialized func before canceling delayed_work.

Fixes: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN")
Signed-off-by: Gregor Herburger <gregor.herburger@...tq-group.com>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c      | 1 +
 drivers/net/can/spi/mcp251xfd/mcp251xfd-timestamp.c | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 1d9057dc44f2..eb699288c076 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -744,6 +744,7 @@ static void mcp251xfd_chip_stop(struct mcp251xfd_priv *priv,

 	mcp251xfd_chip_interrupts_disable(priv);
 	mcp251xfd_chip_rx_int_disable(priv);
+	mcp251xfd_timestamp_stop(priv);
 	mcp251xfd_chip_sleep(priv);
 }

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-timestamp.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-timestamp.c
index 712e09186987..537c31890838 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-timestamp.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-timestamp.c
@@ -67,5 +67,8 @@ void mcp251xfd_timestamp_init(struct mcp251xfd_priv *priv)

 void mcp251xfd_timestamp_stop(struct mcp251xfd_priv *priv)
 {
-	cancel_delayed_work_sync(&priv->timestamp);
+	struct work_struct *work = &priv->timestamp.work;
+
+	if (work->func)
+		cancel_delayed_work_sync(&priv->timestamp);
 }

-- 
2.34.1