kernel/drivers/clk/tegra/clk-periph-gate.c, branch linux-6.9.y

clk: tegra: Don't deassert reset on enabling clocks

2021-05-31T13:16:46Z

The Tegra clock driver contains legacy code which deasserts hardware reset when peripheral clocks are enabled. This behaviour comes from a pre-CCF era of the Tegra drivers. This is unacceptable for modern kernel drivers which use generic CCF and reset-control APIs because it breaks assumptions of the drivers about clk/reset sequences and about reset-propagation delays. Hence remove the awkward legacy behaviour from the clk driver. In particular PMC driver assumes that hardware blocks remains in reset while power domain is turning on, but the clk driver deasserts the reset before power clamp is removed, hence breaking the driver's assumption. Signed-off-by: Dmitry Osipenko Signed-off-by: Thierry Reding

clk: tegra: Fix refcounting of gate clocks

2021-05-31T13:16:24Z

The refcounting of the gate clocks has a bug causing the enable_refcnt to underflow when unused clocks are disabled. This happens because clk provider erroneously bumps the refcount if clock is enabled at a boot time, which it shouldn't be doing, and it does this only for the gate clocks, while peripheral clocks are using the same gate ops and the peripheral clocks are missing the initial bump. Hence the refcount of the peripheral clocks is 0 when unused clocks are disabled and then the counter is decremented further by the gate ops, causing the integer underflow. Fix this problem by removing the erroneous bump and by implementing the disable_unused() callback, which disables the unused gates properly. The visible effect of the bug is such that the unused clocks are never gated if a loaded kernel module grabs the unused clocks and starts to use them. In practice this shouldn't cause any real problems for the drivers and boards supported by the kernel today. Acked-by: Thierry Reding Signed-off-by: Dmitry Osipenko Signed-off-by: Thierry Reding

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201

2019-05-30T18:29:52Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 228 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Steve Winslow Reviewed-by: Richard Fontana Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171438.107155473@linutronix.de Signed-off-by: Greg Kroah-Hartman

clk: tegra: Fix disable unused for clocks sharing enable bit

2017-03-20T13:13:52Z

In case 2 clocks share an enable bit and one of them is enabled by a driver and the other one is not, CCF will think it's enabled because it will only look at the HW state. Therefore it will disable the clock and thus also disable the other clock which was enabled. Solve this by reading the initial state of the enable bit and incrementing the refcount if it's set. Signed-off-by: Peter De Schrijver Signed-off-by: Thierry Reding

clk: tegra: Constify peripheral clock registers

2016-04-28T10:41:45Z

The peripheral clock registers are defined in static tables. These tables never need to be modified at runtime, so they can reside in read-only memory. Signed-off-by: Thierry Reding

clk: tegra: Properly include clk.h

2015-07-20T18:11:17Z

Clock provider drivers generally shouldn't include clk.h because it's the consumer API. Only include clk.h in files that are using it. Also add in a clkdev.h include that was missing in a file using clkdev APIs. Cc: Peter De Schrijver Cc: Thierry Reding Signed-off-by: Stephen Boyd

ARM: tegra: Move includes to include/soc/tegra

2014-07-17T11:26:47Z

In order to not clutter the include/linux directory with SoC specific headers, move the Tegra-specific headers out into a separate directory. Signed-off-by: Thierry Reding

clk: tegra: remove legacy reset APIs

2013-12-11T23:45:07Z

Now that no code uses the custom Tegra module reset API, we can remove its implementation. Signed-off-by: Stephen Warren Reviewed-by: Thierry Reding Acked-By: Peter De Schrijver

clk: tegra: simplify periph clock data

2013-11-26T16:45:40Z

This patch determines the register bank for clock enable/disable and reset based on the clock ID instead of hardcoding it in the tables describing the clocks. This results in less data to be maintained in the tables, making the code easier to understand. The full benefit of the change will be realized once also other clocktypes will be table based. Signed-off-by: Peter De Schrijver

clk: tegra: Workaround for Tegra114 MSENC problem

2013-04-04T22:10:59Z

Workaround a hardware bug in MSENC during clock enable. Signed-off-by: Peter De Schrijver Acked-by: Mike Turquette Signed-off-by: Stephen Warren