| Message ID | 1344146488-9496-2-git-send-email-shawn.guo@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Aug 5, 2012 at 8:01 AM, Shawn Guo <shawn.guo@linaro.org> wrote: > Currently, unlike the non-DT probe where the gpio base is specified > with pdev->id, the DT probe uses the base dynamically allocated by > gpio core, which uses a completely different numbering scheme. This > causes two issues to user space applications which access sysfs entry > /sys/class/gpio/gpioN. Applied. Thanks, Linus Walleij
On Sun, Aug 05, 2012 at 02:01:26PM +0800, Shawn Guo wrote: > Currently, unlike the non-DT probe where the gpio base is specified > with pdev->id, the DT probe uses the base dynamically allocated by > gpio core, which uses a completely different numbering scheme. This > causes two issues to user space applications which access sysfs entry > /sys/class/gpio/gpioN. > > * It breaks the compatibility with user space applications between > non-DT and DT kernels. > > * It's not intuitive and sometimes hard for users to map the Linux > gpio number to the actual hardware pin. > > Use alias to identify the gpio port/bank, and then the gpio base > can be specified with port id to solve above issues. If alias is not > defined in device tree, the base number dynamically allocated by gpio > core will be used. > > Signed-off-by: Shawn Guo <shawn.guo@linaro.org> I applied patches 1, 2 and 4 to my imx35 dt tree and they work like a charm. Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> for these three. Thanks Uwe
diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c index 76e8cda..80f44bb 100644 --- a/drivers/gpio/gpio-mxc.c +++ b/drivers/gpio/gpio-mxc.c @@ -465,7 +465,8 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev) goto out_iounmap; port->bgc.gc.to_irq = mxc_gpio_to_irq; - port->bgc.gc.base = pdev->id * 32; + port->bgc.gc.base = (pdev->id < 0) ? of_alias_get_id(np, "gpio") * 32 : + pdev->id * 32; err = gpiochip_add(&port->bgc.gc); if (err)
Currently, unlike the non-DT probe where the gpio base is specified with pdev->id, the DT probe uses the base dynamically allocated by gpio core, which uses a completely different numbering scheme. This causes two issues to user space applications which access sysfs entry /sys/class/gpio/gpioN. * It breaks the compatibility with user space applications between non-DT and DT kernels. * It's not intuitive and sometimes hard for users to map the Linux gpio number to the actual hardware pin. Use alias to identify the gpio port/bank, and then the gpio base can be specified with port id to solve above issues. If alias is not defined in device tree, the base number dynamically allocated by gpio core will be used. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> --- drivers/gpio/gpio-mxc.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)