Messages in this thread | | | Date | Thu, 10 Dec 2015 13:30:18 +0100 | Subject | Re: [PATCH 07/25] serial: sh-sci: Convert from clk_get() to devm_clk_get() | From | Geert Uytterhoeven <> |
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Hi Laurent,
On Thu, Nov 19, 2015 at 9:38 PM, Laurent Pinchart <laurent.pinchart@ideasonboard.com> 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 <geert+renesas@glider.be> >> --- >> 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
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