linux-toradex.git/drivers/clk/clk.c, branch v3.13.9

clk: of: helper for determining number of parent clocks

2013-10-08T06:13:33+00:00

Walks the "clocks" array of parent clock phandles and returns the
number.

Signed-off-by: Mike Turquette

clk: Correct lookup logic in clk_fetch_parent_index()

2013-10-02T01:40:17+00:00

This function is supposed to iterate over all parents of given child
clock to find the index of given parent clock in its parent list,
using parent cache if possible and falling back to string compare
otherwise. However currently the logic falls back to string compare in
every iteration in which clock cache entry does not match given parent,
due to wrong check conditions.

This patch corrects the logic to continue the loop if parent cache entry
is present and does not match requested parent clock. In addition,
redundant checks for parent cache array presence are removed, because it
is always allocated in the beginning of the function.

Signed-off-by: Tomasz Figa 
Signed-off-by: Mike Turquette

clk: Use kcalloc() to allocate arrays

2013-10-02T01:40:16+00:00

Instead of calculating sizes of arrays manually, kcalloc() can be used
to allocate arrays of elements with defined size. This is just a cleanup
patch without any functional changes.

Signed-off-by: Tomasz Figa 
Signed-off-by: Mike Turquette

clk: Add error handling to clk_fetch_parent_index()

2013-10-02T01:40:16+00:00

There are at least two different error cases that can happen in
clk_fetch_parent_index() function:
 - allocation failure,
 - parent clock lookup failure,
however it returns only an u8, which is supposed to contain parent clock
index.

This patch modified the function to return full int instead allowing
positive clock indices and negative error codes to be returned. All
users of this function are adjusted as well to handle the return value
correctly.

Signed-off-by: Tomasz Figa 
Signed-off-by: Mike Turquette

clk: only call get_parent if there is one

2013-09-09T21:10:10+00:00

In __clk_init(), after a clock is mostly initialized, a scan is done
of the orphan clocks to see if the clock being registered is the
parent of any of them.

This code assumes that any clock that provides a get_parent method
actually has at least one parent, and that's not a valid assumption.

As a result, an orphan clock with no parent can return *something*
as the parent index, and that value is blindly used to dereference
the orphan's parent_names[] array (which will be ZERO_SIZE_PTR or
NULL).

Fix this by ensuring get_parent is only called for orphans with at
least one parent.

Signed-off-by: Alex Elder 
Signed-off-by: Mike Turquette

clk: Move symbol export to proper location

2013-09-03T20:41:29+00:00

The __clk_get_flags() symbol is exported immediately following the
clk_unprepare_unused_subtree() function. This is unusual, since a symbol
export typically follows body of the function that it exports.

Signed-off-by: Thierry Reding 
Signed-off-by: Mike Turquette

clk: fix new_parent dereference before null check

2013-08-30T19:52:01+00:00

Commit 71472c0 (clk: add support for clock reparent on set_rate) added a
dereference of the new_parent pointer in clk_reparent(), but as detected
by smatch clk_reparent() later checks whether new_parent is NULL.

The dereference was in order to clear the new parent's new_child pointer
to avoid duplicate POST_RATE_CHANGE notifications, so clearly isn't
necessary if the new parent is NULL, so move it inside the "if
(new_parent)" block.

Reported-by: Dan Carpenter 
Signed-off-by: James Hogan 
Signed-off-by: Mike Turquette

clk: get matching entry under lock in of_clk_init()

2013-08-27T23:05:39+00:00

Currently of_clk_init() finds a matching device node while holding
the device tree spinlock.  When a matching device node is found, the
lock is dropped and then re-acquired in order to get a reference
to the matching device id structure.

Acquiring the spinlock twice is unnecessary (and it opens a
vulnerable window that could conceivably lead to errors).

There already exists an interface for both finding and taking a
reference to a device id under lock, so use it.

Signed-off-by: Alex Elder 
Reviewed-by: Christian Daudt 
Reviewed-by: Markus Mayer 
Reviewed-by: Matt Porter 
Signed-off-by: Mike Turquette

clk: handle NULL struct clk gracefully

2013-08-22T06:58:09+00:00

At some point changes to clk_set_rate and clk_set_parent introduced a
bug whereby NULL struct clk pointers were treated as an error. This is
in violation of the API in include/linux/clk.h. Reintroduce graceful
handling of NULL clk's by bailing from clk_set_rate and clk_set_parent
with return codes of zero.

Signed-off-by: Mike Turquette

clk: clk-mux: implement remuxing on set_rate

2013-08-19T19:27:18+00:00

Implement clk-mux remuxing if the CLK_SET_RATE_NO_REPARENT flag isn't
set. This implements determine_rate for clk-mux to propagate to each
parent and to choose the best one (like clk-divider this chooses the
parent which provides the fastest rate <= the requested rate).

The determine_rate op is implemented as a core helper function so that
it can be easily used by more complex clocks which incorporate muxes.

Signed-off-by: James Hogan 
Reviewed-by: Stephen Boyd 
Cc: Mike Turquette 
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette