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* clk.txt: standardize document formatMauro Carvalho Chehab2017-07-141-83/+106
| | | | | | | | | | | | | | | | | Each text file under Documentation follows a different format. Some doesn't even have titles! Change its representation to follow the adopted standard, using ReST markups for it to be parseable by Sphinx: - Use section/title markups; - Use :Author: for authorship; - Mark literals and literal blocks; - Mark tables; - Use ReST notation for footnotes. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* Documentation: clk: update file names containing referenced structuresAndi Shyti2016-08-141-20/+22
| | | | | | | | | | | | | | | Commit 'b09d6d991' removes include/linux/clk-private.h and re-arranges the clock related structures contained in it in different files. The documentation has not been updated accordingly, thus it wasn't anymore consistent. Place the structures referenced by Documentation/clk.txt in the correct files and update their contents to the latest status. Signed-off-by: Andi Shyti <andi.shyti@samsung.com> [geert: Fix path to clk.c, whitespace, more clk_core, ...] Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* clk: change clk_ops' ->determine_rate() prototypeBoris Brezillon2015-07-271-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clock rates are stored in an unsigned long field, but ->determine_rate() (which returns a rounded rate from a requested one) returns a long value (errors are reported using negative error codes), which can lead to long overflow if the clock rate exceed 2Ghz. Change ->determine_rate() prototype to return 0 or an error code, and pass a pointer to a clk_rate_request structure containing the expected target rate and the rate constraints imposed by clk users. The clk_rate_request structure might be extended in the future to contain other kind of constraints like the rounding policy, the maximum clock inaccuracy or other things that are not yet supported by the CCF (power consumption constraints ?). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> CC: Jonathan Corbet <corbet@lwn.net> CC: Tony Lindgren <tony@atomide.com> CC: Ralf Baechle <ralf@linux-mips.org> CC: "Emilio López" <emilio@elopez.com.ar> CC: Maxime Ripard <maxime.ripard@free-electrons.com> Acked-by: Tero Kristo <t-kristo@ti.com> CC: Peter De Schrijver <pdeschrijver@nvidia.com> CC: Prashant Gaikwad <pgaikwad@nvidia.com> CC: Stephen Warren <swarren@wwwdotorg.org> CC: Thierry Reding <thierry.reding@gmail.com> CC: Alexandre Courbot <gnurou@gmail.com> CC: linux-doc@vger.kernel.org CC: linux-kernel@vger.kernel.org CC: linux-arm-kernel@lists.infradead.org CC: linux-omap@vger.kernel.org CC: linux-mips@linux-mips.org CC: linux-tegra@vger.kernel.org [sboyd@codeaurora.org: Fix parent dereference problem in __clk_determine_rate()] Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Tested-by: Romain Perier <romain.perier@gmail.com> Signed-off-by: Heiko Stuebner <heiko@sntech.de> [sboyd@codeaurora.org: Folded in fix from Heiko for fixed-rate clocks without parents or a rate determining op] Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
* clk: Update docs after removal of clk-private.hDaniel Thompson2015-05-131-25/+2
| | | | | | | | | | | | | | | Currently Documentation/clk.txt describes an obsolete techinique to statically define struct clk objects. This capability was removed by b09d6d991025("clk: remove clk-private.h") and is no longer supported. The documentation describing the feature should be removed. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michael Turquette <mturquette@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
* clk: Add rate constraints to clocksTomeu Vizoso2015-02-021-0/+2
| | | | | | | | | | | | | | | | Adds a way for clock consumers to set maximum and minimum rates. This can be used for thermal drivers to set minimum rates, or by misc. drivers to set maximum rates to assure a minimum performance level. Changes the signature of the determine_rate callback by adding the parameters min_rate and max_rate. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> [sboyd@codeaurora.org: set req_rate in __clk_init] Signed-off-by: Michael Turquette <mturquette@linaro.org> [mturquette@linaro.org: min/max rate for sun6i_ahb1_clk_determine_rate migrated clk-private.h changes to clk.c]
* clk: Change clk_ops->determine_rate to return a clk_hw as the best parentTomeu Vizoso2014-12-031-1/+1
| | | | | | | | This is in preparation for clock providers to not have to deal with struct clk. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Michael Turquette <mturquette@linaro.org>
* clk: Improve clk_ops documentationGeert Uytterhoeven2014-05-121-5/+11
| | | | | | | | | | | | | | | | | General: - Add parameter names to .round_rate() and .set_rate(). Documentation/clk.txt: - Add missing parameter for .set_rate(), - Add missing .debug_init(). include/linux/clk-provider.h: - Add parent rate documentation for .round_rate(), - Reorder documentation to match implementation order, - Add missing documentation for .init(). Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Mike Turquette <mturquette@linaro.org>
* Documentation: clk: Add locking documentationLaurent Pinchart2014-03-191-0/+34
| | | | | | | | Briefly document the common clock framework locking scheme from a clock driver point of view. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
* clk: Add set_rate_and_parent() opStephen Boyd2014-01-161-0/+3
| | | | | | | | | | | | | | | Some of Qualcomm's clocks can change their parent and rate at the same time with a single register write. Add support for this hardware to the common clock framework by adding a new set_rate_and_parent() op. When the clock framework determines that both the parent and the rate are going to change during clk_set_rate() it will call the .set_rate_and_parent() op if available and fall back to calling .set_parent() followed by .set_rate() otherwise. Reviewed-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
* clk: add clk accuracy retrieval supportBoris BREZILLON2013-12-221-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | The clock accuracy is expressed in ppb (parts per billion) and represents the possible clock drift. Say you have a clock (e.g. an oscillator) which provides a fixed clock of 20MHz with an accuracy of +- 20Hz. This accuracy expressed in ppb is 20Hz/20MHz = 1000 ppb (or 1 ppm). Clock users may need the clock accuracy information in order to choose the best clock (the one with the best accuracy) across several available clocks. This patch adds clk accuracy retrieval support for common clk framework by means of a new function called clk_get_accuracy. This function returns the given clock accuracy expressed in ppb. In order to get the clock accuracy, this implementation adds one callback called recalc_accuracy to the clk_ops structure. This callback is given the parent clock accuracy (if the clock is not a root clock) and should recalculate the given clock accuracy. This callback is optional and may be implemented if the clock is not a perfect clock (accuracy != 0 ppb). Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
* clk: add support for clock reparent on set_rateJames Hogan2013-08-191-20/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add core support to allow clock implementations to select the best parent clock when rounding a rate, e.g. the one which can provide the closest clock rate to that requested. This is by way of adding a new clock op, determine_rate(), which is like round_rate() but has an extra parameter to allow the clock implementation to optionally select a different parent clock. The core then takes care of reparenting the clock when setting the rate. The parent change takes place with the help of some new private data members. struct clk::new_parent specifies a clock's new parent (NULL indicates no change), and struct clk::new_child specifies a clock's new child (whose new_parent member points back to it). The purpose of these are to allow correct walking of the future tree for notifications prior to actually reparenting any clocks, specifically to skip child clocks who are being reparented to another clock (they will be notified via the new parent), and to include any new child clock. These pointers are set by clk_calc_subtree(), and the new_child pointer gets cleared when a child is actually reparented to avoid duplicate POST_RATE_CHANGE notifications. Each place where round_rate() is called, determine_rate() is checked first and called in preference. This restructures a few of the call sites to simplify the logic into if/else blocks. Signed-off-by: James Hogan <james.hogan@imgtec.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Mike Turquette <mturquette@linaro.org> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Mike Turquette <mturquette@linaro.org>
* doc: clk: Fix incorrect wordingSachin Kamat2013-06-101-1/+1
| | | | | | Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Acked-by: Rob Landley <rob@landley.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* clk: add clk_ignore_unused option to keep boot clocks onOlof Johansson2013-04-271-0/+11
| | | | | | | | | | | This is primarily useful when there's a driver that doesn't claim clocks properly, but the bootloader leaves them on. It's not expected to be used in normal cases, but for bringup and debug it's very useful to have the option to not gate unclaimed clocks that are still on. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Mike Turquette <mturquette@linaro.org> [mturquette@linaro.org: fixed up trivial merge issue]
* documentation: clk: fix couple of misspellingEduardo Valentin2013-03-211-2/+2
| | | | | | | Correcting misspelling inside the clk.txt. Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
* Documentation: common clk APIMike Turquette2012-03-161-0/+233
Provide documentation for the common clk structures and APIs. This code can be found in drivers/clk/ and include/linux/clk*.h. Signed-off-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Mike Turquette <mturquette@ti.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Cc: Russell King <linux@arm.linux.org.uk> Cc: Jeremy Kerr <jeremy.kerr@canonical.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnd Bergman <arnd.bergmann@linaro.org> Cc: Paul Walmsley <paul@pwsan.com> Cc: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Richard Zhao <richard.zhao@linaro.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: Magnus Damm <magnus.damm@gmail.com> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Linus Walleij <linus.walleij@stericsson.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Amit Kucheria <amit.kucheria@linaro.org> Cc: Deepak Saxena <dsaxena@linaro.org> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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