Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753763AbbLJMaW (ORCPT ); Thu, 10 Dec 2015 07:30:22 -0500 Received: from mail-ob0-f172.google.com ([209.85.214.172]:36061 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753095AbbLJMaT (ORCPT ); Thu, 10 Dec 2015 07:30:19 -0500 MIME-Version: 1.0 In-Reply-To: <3399561.8ERHTtILhO@avalon> References: <1447958344-836-1-git-send-email-geert+renesas@glider.be> <1447958344-836-8-git-send-email-geert+renesas@glider.be> <3399561.8ERHTtILhO@avalon> Date: Thu, 10 Dec 2015 13:30:18 +0100 X-Google-Sender-Auth: 02JhjEZ_RAnCGY_ELLu1BCcb7WM Message-ID: Subject: Re: [PATCH 07/25] serial: sh-sci: Convert from clk_get() to devm_clk_get() From: Geert Uytterhoeven To: Laurent Pinchart Cc: Geert Uytterhoeven , Greg Kroah-Hartman , Simon Horman , Magnus Damm , Yoshinori Sato , "linux-serial@vger.kernel.org" , Linux-sh list , "linux-kernel@vger.kernel.org" , Linux PM list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2911 Lines: 76 Hi Laurent, On Thu, Nov 19, 2015 at 9:38 PM, Laurent Pinchart wrote: > On Thursday 19 November 2015 19:38:46 Geert Uytterhoeven wrote: >> Transfer clock cleanup handling to the core device management code. >> >> Signed-off-by: Geert Uytterhoeven >> --- >> drivers/tty/serial/sh-sci.c | 8 +++----- >> 1 file changed, 3 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c >> index cba51da604253db6..9442961a198378c7 100644 >> --- a/drivers/tty/serial/sh-sci.c >> +++ b/drivers/tty/serial/sh-sci.c >> @@ -2216,7 +2216,7 @@ static struct uart_ops sci_uart_ops = { >> static int sci_init_clocks(struct sci_port *sci_port, struct device *dev) >> { >> /* Get the SCI functional clock. It's called "fck" on ARM. */ >> - sci_port->fclk = clk_get(dev, "fck"); >> + sci_port->fclk = devm_clk_get(dev, "fck"); > > Have you tested what happens if you unbind the device from the driver while > userspace has the serial port open ? Yes I have. And I didn't notice any user-visible behavioral differences. There is a small ordering difference, though: with clk_get() and clk_put(), the explicit clk_put() is done before removing the device from its PM Domain (which involces another call to clk_put() on the module clock): device_release_driver __device_release_driver platform_drv_remove sci_remove sci_cleanup_single __clk_put genpd_dev_pm_detach pm_genpd_remove_device pm_clk_destroy __pm_clk_remove __clk_put When using devm_clk_get(), the managed cleanup is done after the device has been removed from its PM Domain: device_release_driver __device_release_driver platform_drv_remove genpd_dev_pm_detach pm_genpd_remove_device pm_clk_destroy __pm_clk_remove __clk_put release_nodes __clk_put This shouldn't make a difference, and applies to all other drivers using devm_*(), and devices that are part of a PM Domain. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/