From 2f102a5efe84808768a57ac2a5f1884bd56d62d8 Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Sun, 18 Aug 2024 19:49:36 +0200 Subject: serial: 8250_bcm2835aux: Fix clock imbalance in PM resume During review Ulf Hansson discovered a clock imbalance in the recently introduced PM resume code. The driver should enable the clock only in case it has been disabled in suspend before. In order to make the conditions easier to read, refactor this into a separate function. Reported-by: Ulf Hansson Closes: https://lore.kernel.org/linux-arm-kernel/CAPDyKFoJh3j8xSeXZ9o031YZLTCDYVA+dgvURuwozjDpU_aauA@mail.gmail.com/ Fixes: 0e1d8780526f ("serial: 8250_bcm2835aux: add PM suspend/resume support") Signed-off-by: Stefan Wahren Link: https://lore.kernel.org/r/20240818174936.88372-1-wahrenst@gmx.net Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_bcm2835aux.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c index 829abef2564d..d7a0f271263a 100644 --- a/drivers/tty/serial/8250/8250_bcm2835aux.c +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c @@ -214,17 +214,27 @@ static const struct acpi_device_id bcm2835aux_serial_acpi_match[] = { }; MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match); -static int bcm2835aux_suspend(struct device *dev) +static bool bcm2835aux_can_disable_clock(struct device *dev) { struct bcm2835aux_data *data = dev_get_drvdata(dev); struct uart_8250_port *up = serial8250_get_port(data->line); - serial8250_suspend_port(data->line); - if (device_may_wakeup(dev)) - return 0; + return false; if (uart_console(&up->port) && !console_suspend_enabled) + return false; + + return true; +} + +static int bcm2835aux_suspend(struct device *dev) +{ + struct bcm2835aux_data *data = dev_get_drvdata(dev); + + serial8250_suspend_port(data->line); + + if (!bcm2835aux_can_disable_clock(dev)) return 0; clk_disable_unprepare(data->clk); @@ -236,9 +246,11 @@ static int bcm2835aux_resume(struct device *dev) struct bcm2835aux_data *data = dev_get_drvdata(dev); int ret; - ret = clk_prepare_enable(data->clk); - if (ret) - return ret; + if (bcm2835aux_can_disable_clock(dev)) { + ret = clk_prepare_enable(data->clk); + if (ret) + return ret; + } serial8250_resume_port(data->line); -- cgit