From 7e6086d9e54a159a6257c02bb7fc5805c614aad2 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Sun, 5 Aug 2012 14:01:26 +0800 Subject: [PATCH] gpio/mxc: specify gpio base for device tree probe MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Tested-by: Uwe Kleine-König Signed-off-by: Linus Walleij --- drivers/gpio/gpio-mxc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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) -- 2.7.4