From f65e727464d7c0090f05548e8f323779eaa97eda Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Fri, 14 Aug 2020 13:07:30 +0200 Subject: [PATCH] rtc: rtc-rs5c313: Fix late hardware init rs5c313_rtc_init() calls platform_driver_register(), and initializes the hardware. This is wrong because of two reasons: 1. As soon as the driver has been registered, the device may be probed. If devm_rtc_device_register() is called before hardware initialization, reading the current time will fail: rs5c313 rs5c313: rs5c313_rtc_read_time: timeout error rs5c313 rs5c313: registered as rtc0 rs5c313 rs5c313: rs5c313_rtc_read_time: timeout error rs5c313 rs5c313: hctosys: unable to read the hardware clock 2. If the platform device does not exist, the driver will still write to a hardware device that may not be present. Fix this by moving the hardware initialization sequence to the driver's .probe() method. Signed-off-by: Geert Uytterhoeven Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20200814110731.29029-3-geert+renesas@glider.be --- drivers/rtc/rtc-rs5c313.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/rtc/rtc-rs5c313.c b/drivers/rtc/rtc-rs5c313.c index 00b5ef753935ec..af72e428b21817 100644 --- a/drivers/rtc/rtc-rs5c313.c +++ b/drivers/rtc/rtc-rs5c313.c @@ -366,8 +366,13 @@ static const struct rtc_class_ops rs5c313_rtc_ops = { static int rs5c313_rtc_probe(struct platform_device *pdev) { - struct rtc_device *rtc = devm_rtc_device_register(&pdev->dev, "rs5c313", - &rs5c313_rtc_ops, THIS_MODULE); + struct rtc_device *rtc; + + rs5c313_init_port(); + rs5c313_check_xstp_bit(); + + rtc = devm_rtc_device_register(&pdev->dev, "rs5c313", &rs5c313_rtc_ops, + THIS_MODULE); return PTR_ERR_OR_ZERO(rtc); } @@ -381,16 +386,7 @@ static struct platform_driver rs5c313_rtc_platform_driver = { static int __init rs5c313_rtc_init(void) { - int err; - - err = platform_driver_register(&rs5c313_rtc_platform_driver); - if (err) - return err; - - rs5c313_init_port(); - rs5c313_check_xstp_bit(); - - return 0; + return platform_driver_register(&rs5c313_rtc_platform_driver); } static void __exit rs5c313_rtc_exit(void)