clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate

.determine_rate is meant to replace .round_rate in CCF in the future.
Switch over to .determine_rate now that clk_divider_ops has gained
support for that.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Abel Vesa <abel.vesa@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20210702225145.2643303-3-martin.blumenstingl@googlemail.com
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>

clk: imx: Rename the imx_clk_divider_gate to imply it's clk_hw based

Renaming the imx_clk_divider_gate register function to imx_clk_hw_divider_gate
to be more obvious it is clk_hw based.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

clk: imx: clk-divider-gate: drop redundant initialization

There is no need to initialize flags as 0.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

clk: imx: clk-divider-gate: fix a typo in comment

Fix a typo in comment: resue -> reuse.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

clk: core: replace clk_{readl,writel} with {readl,writel}

Now that clk_{readl,writel} is just an alias for {readl,writel}, we can
switch all users of clk_* to use the accessors directly and remove the
helpers.

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
[sboyd@kernel.org: Also convert renesas file so that this can be
compile independently]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: imx: add gatable clock divider support

For dividers with zero indicating clock is disabled, instead of giving a
warning each time like "clkx: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not
set" in exist code, we'd like to introduce enable/disable function for it.
e.g.
000b - Clock disabled
001b - Divide by 1
010b - Divide by 2
...

Set rate when the clk is disabled will cache the rate request and only
when the clk is enabled will the driver actually program the hardware to
have the requested divider value. Similarly, when the clk is disabled we'll
write a 0 there, but when the clk is enabled we'll restore whatever rate
(divider) was chosen last.

It does mean that recalc rate will be sort of odd, because when the clk is
off it will return 0, and when the clk is on it will return the right rate.
So to make things work, we'll need to return the cached rate in recalc rate
when the clk is off and read the hardware when the clk is on.

NOTE for the default off divider, the recalc rate will still return 0 as
there's still no proper preset rate. Enable such divider will give user
a reminder error message.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
[sboyd@kernel.org: Include clk.h for sparse warnings]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>