From 0e3db173e2b9fd3b82246516e72c17763eb5f98d Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Fri, 2 Mar 2012 13:05:46 -0700 Subject: pinctrl: add usecount to pins for muxing Multiple mapping table entries could reference the same pin, and hence "own" it. This would be unusual now that pinctrl_get() represents a single state for a client device, but in the future when it represents all known states for a device, this is quite likely. Implement reference counting for pin ownership to handle this. Signed-off-by: Stephen Warren Acked-by: Dong Aisheng Signed-off-by: Linus Walleij --- drivers/pinctrl/pinmux.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'drivers/pinctrl/pinmux.c') diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index f0fb98d252e8..56ca42e6a6ec 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -83,11 +83,16 @@ static int pin_request(struct pinctrl_dev *pctldev, goto out; } - if (desc->owner && strcmp(desc->owner, owner)) { + if (desc->usecount && strcmp(desc->owner, owner)) { dev_err(pctldev->dev, "pin already requested\n"); goto out; } + + desc->usecount++; + if (desc->usecount > 1) + return 0; + desc->owner = owner; /* Let each pin increase references to this module */ @@ -111,12 +116,18 @@ static int pin_request(struct pinctrl_dev *pctldev, else status = 0; - if (status) + if (status) { dev_err(pctldev->dev, "->request on device %s failed for pin %d\n", pctldev->desc->name, pin); + module_put(pctldev->owner); + } + out_free_pin: - if (status) - desc->owner = NULL; + if (status) { + desc->usecount--; + if (!desc->usecount) + desc->owner = NULL; + } out: if (status) dev_err(pctldev->dev, "pin-%d (%s) status %d\n", @@ -150,6 +161,10 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, return NULL; } + desc->usecount--; + if (desc->usecount) + return NULL; + /* * If there is no kind of request function for the pin we just assume * we got it by default and proceed. -- cgit v1.2.3