Merge branch 'linux-5.7' of git://github.com/skeggsb/linux into drm-fixes

[linux-2.6-microblaze.git] / include / linux / ptp_clock_kernel.h

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index c64a1ef..121a7ed 100644 (file)
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -223,6 +223,12 @@ extern s32 scaled_ppm_to_ppb(long ppm);
 /**
  * ptp_find_pin() - obtain the pin index of a given auxiliary function
  *
+ * The caller must hold ptp_clock::pincfg_mux.  Drivers do not have
+ * access to that mutex as ptp_clock is an opaque type.  However, the
+ * core code acquires the mutex before invoking the driver's
+ * ptp_clock_info::enable() callback, and so drivers may call this
+ * function from that context.
+ *
  * @ptp:    The clock obtained from ptp_clock_register().
  * @func:   One of the ptp_pin_function enumerated values.
  * @chan:   The particular functional channel to find.
@@ -233,6 +239,19 @@ extern s32 scaled_ppm_to_ppb(long ppm);
 int ptp_find_pin(struct ptp_clock *ptp,
                 enum ptp_pin_function func, unsigned int chan);
 
+/**
+ * ptp_find_pin_unlocked() - wrapper for ptp_find_pin()
+ *
+ * This function acquires the ptp_clock::pincfg_mux mutex before
+ * invoking ptp_find_pin().  Instead of using this function, drivers
+ * should most likely call ptp_find_pin() directly from their
+ * ptp_clock_info::enable() method.
+ *
+ */
+
+int ptp_find_pin_unlocked(struct ptp_clock *ptp,
+                         enum ptp_pin_function func, unsigned int chan);
+
 /**
  * ptp_schedule_worker() - schedule ptp auxiliary work
  *