diff options
| author | Daniel Golle <daniel@makrotopia.org> | 2025-09-16 22:37:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-22 12:13:54 +0200 |
| commit | d518314a1fa4e980a227d1b2bda1badf433cb932 (patch) | |
| tree | e58294f52cafb6ee61990f981dfae9e66f1f0616 /drivers/tty | |
| parent | serial: 8250_dw: handle reset control deassert error (diff) | |
| download | linux-d518314a1fa4e980a227d1b2bda1badf433cb932.tar.gz linux-d518314a1fa4e980a227d1b2bda1badf433cb932.zip | |
serial: 8250_mtk: Enable baud clock and manage in runtime PM
Some MediaTek SoCs got a gated UART baud clock, which currently gets
disabled as the clk subsystem believes it would be unused. This results in
the uart freezing right after "clk: Disabling unused clocks" on those
platforms.
Request the baud clock to be prepared and enabled during probe, and to
restore run-time power management capabilities to what it was before commit
e32a83c70cf9 ("serial: 8250-mtk: modify mtk uart power and clock
management") disable and unprepare the baud clock when suspending the UART,
prepare and enable it again when resuming it.
Fixes: e32a83c70cf9 ("serial: 8250-mtk: modify mtk uart power and clock management")
Fixes: b6c7ff2693ddc ("serial: 8250_mtk: Simplify clock sequencing and runtime PM")
Cc: stable <stable@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/de5197ccc31e1dab0965cabcc11ca92e67246cf6.1758058441.git.daniel@makrotopia.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/8250/8250_mtk.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index b44de2ed7413..5875a7b9b4b1 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -435,6 +435,7 @@ static int __maybe_unused mtk8250_runtime_suspend(struct device *dev) while (serial_in(up, MTK_UART_DEBUG0)); + clk_disable_unprepare(data->uart_clk); clk_disable_unprepare(data->bus_clk); return 0; @@ -445,6 +446,7 @@ static int __maybe_unused mtk8250_runtime_resume(struct device *dev) struct mtk8250_data *data = dev_get_drvdata(dev); clk_prepare_enable(data->bus_clk); + clk_prepare_enable(data->uart_clk); return 0; } @@ -475,13 +477,13 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p, int dmacnt; #endif - data->uart_clk = devm_clk_get(&pdev->dev, "baud"); + data->uart_clk = devm_clk_get_enabled(&pdev->dev, "baud"); if (IS_ERR(data->uart_clk)) { /* * For compatibility with older device trees try unnamed * clk when no baud clk can be found. */ - data->uart_clk = devm_clk_get(&pdev->dev, NULL); + data->uart_clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(data->uart_clk)) { dev_warn(&pdev->dev, "Can't get uart clock\n"); return PTR_ERR(data->uart_clk); |