On i.MX8QM, HDMI LPCG clocks operation needs SCU clock "hdmi_ipg_clk"
to be ON. While during noirq suspend phase, "hdmi_ipg_clk" is disabled
by HDMI IRQ STEER driver, so SError will be triggered when accessing
the HDMI LPCG registers.
Skip all HDMI LPCG clocks save/restore to avoid SError during
system suspend/resume, it will NOT introduce additional power consumption
as their parent clock is disabled when suspend.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20241027-imx-clk-v1-v3-5-89152574d1d7@nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Back-to-back LPCG writes can be ignored by the LPCG register due to
a HW bug. The writes need to be separated by at least 4 cycles of
the gated clock. See https://www.nxp.com.cn/docs/en/errata/IMX8_1N94W.pdf
The workaround is implemented as follows:
1. For clocks running greater than or equal to 24MHz, a read
followed by the write will provide sufficient delay.
2. For clocks running below 24MHz, add a delay of 4 clock cylces
after the write to the LPCG register.
Fixes: 2f77296d3d ("clk: imx: add lpcg clock support")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Link: https://lore.kernel.org/r/20241027-imx-clk-v1-v3-1-89152574d1d7@nxp.com
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
When register failed, clk will be freed, it will generate dangling pointer
problem in later reference. it should return directly.
Signed-off-by: Jian Dong <dongjian@yulong.com>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
LPCG clock state may be lost when it's power domain is completely
off during system suspend/resume and we need save and restore the
state properly.
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Used to support runtime pm.
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
One LPCG controller supports up to 8 clock outputs while each of them
is fixed to 4 bits. It supports only gating function with fixed bits.
So we can use the clk-indices to fetch the corresponding clock idx from
device tree. With this way, we can write a generic LPCG clock drivers.
This patch add that support to parse clocks from device tree.
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Michael Turquette <mturquette@baylibre.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
It is better to explicitly include the required header file rather
then get it through some recursive include.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
The Low-Power Clock Gate (LPCG) modules contain a local programming
model to control the clock gates for the peripherals. An LPCG module
is used to locally gate the clocks for the associated peripheral.
And they're bedind the SCU clock.
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
