From: Martin Fuzzey martin.fuzzey@flowbird.group
commit 950ac33dbe6ff656a623d862022f0762ec061ba7 upstream.
The STM32MP1 RTC may have 2 clocks, the pclk and the rtc_ck.
If clk_prepare_enable() fails for the second clock (rtc_ck) we must only call clk_disable_unprepare() for the first clock (pclk) but currently we call it on both leading to a WARN:
[ 15.629568] WARNING: CPU: 0 PID: 146 at drivers/clk/clk.c:958 clk_core_disable+0xb0/0xc8 [ 15.637620] ck_rtc already disabled [ 15.663322] CPU: 0 PID: 146 Comm: systemd-udevd Not tainted 5.4.77-pknbsp-svn5759-atag-v5.4.77-204-gea4235203137-dirty #2413 [ 15.674510] Hardware name: STM32 (Device Tree Support) [ 15.679658] [<c0111148>] (unwind_backtrace) from [<c010c0b8>] (show_stack+0x10/0x14) [ 15.687371] [<c010c0b8>] (show_stack) from [<c0ab3d28>] (dump_stack+0xc0/0xe0) [ 15.694574] [<c0ab3d28>] (dump_stack) from [<c012360c>] (__warn+0xc8/0xf0) [ 15.701428] [<c012360c>] (__warn) from [<c0123694>] (warn_slowpath_fmt+0x60/0x94) [ 15.708894] [<c0123694>] (warn_slowpath_fmt) from [<c053b518>] (clk_core_disable+0xb0/0xc8) [ 15.717230] [<c053b518>] (clk_core_disable) from [<c053c190>] (clk_core_disable_lock+0x18/0x24) [ 15.725924] [<c053c190>] (clk_core_disable_lock) from [<bf0adc44>] (stm32_rtc_probe+0x124/0x5e4 [rtc_stm32]) [ 15.735739] [<bf0adc44>] (stm32_rtc_probe [rtc_stm32]) from [<c05f7d4c>] (platform_drv_probe+0x48/0x98) [ 15.745095] [<c05f7d4c>] (platform_drv_probe) from [<c05f5cec>] (really_probe+0x1f0/0x458) [ 15.753338] [<c05f5cec>] (really_probe) from [<c05f61c4>] (driver_probe_device+0x70/0x1c4) [ 15.761584] [<c05f61c4>] (driver_probe_device) from [<c05f6580>] (device_driver_attach+0x58/0x60) [ 15.770439] [<c05f6580>] (device_driver_attach) from [<c05f6654>] (__driver_attach+0xcc/0x170) [ 15.779032] [<c05f6654>] (__driver_attach) from [<c05f40d8>] (bus_for_each_dev+0x58/0x7c) [ 15.787191] [<c05f40d8>] (bus_for_each_dev) from [<c05f4ffc>] (bus_add_driver+0xdc/0x1f8) [ 15.795352] [<c05f4ffc>] (bus_add_driver) from [<c05f6ed8>] (driver_register+0x7c/0x110) [ 15.803425] [<c05f6ed8>] (driver_register) from [<c01027bc>] (do_one_initcall+0x70/0x1b8) [ 15.811588] [<c01027bc>] (do_one_initcall) from [<c01a1094>] (do_init_module+0x58/0x1f8) [ 15.819660] [<c01a1094>] (do_init_module) from [<c01a0074>] (load_module+0x1e58/0x23c8) [ 15.827646] [<c01a0074>] (load_module) from [<c01a0860>] (sys_finit_module+0xa0/0xd4) [ 15.835459] [<c01a0860>] (sys_finit_module) from [<c01011e0>] (__sys_trace_return+0x0/0x20)
Signed-off-by: Martin Fuzzey martin.fuzzey@flowbird.group Fixes: 4e64350f42e2 ("rtc: add STM32 RTC driver") Cc: stable@vger.kernel.org Reviewed-by: Nobuhiro Iwamatsu iwamatsu@nigauri.org Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Link: https://lore.kernel.org/r/1623087421-19722-1-git-send-email-martin.fuzzey@fl... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/rtc/rtc-stm32.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -754,7 +754,7 @@ static int stm32_rtc_probe(struct platfo
ret = clk_prepare_enable(rtc->rtc_ck); if (ret) - goto err; + goto err_no_rtc_ck;
if (rtc->data->need_dbp) regmap_update_bits(rtc->dbp, rtc->dbp_reg, @@ -830,10 +830,12 @@ static int stm32_rtc_probe(struct platfo }
return 0; + err: + clk_disable_unprepare(rtc->rtc_ck); +err_no_rtc_ck: if (rtc->data->has_pclk) clk_disable_unprepare(rtc->pclk); - clk_disable_unprepare(rtc->rtc_ck);
if (rtc->data->need_dbp) regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);