linux-kernel - Re: [PATCH v2 1/3] clk: samsung: introduce nMUX for MUX clks that can reparented

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Date: Thu, 28 Mar 2024 11:14:19 +0000
From: Tudor Ambarus <tudor.ambarus@...aro.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
 peter.griffin@...aro.org
Cc: alim.akhtar@...sung.com, linux-arm-kernel@...ts.infradead.org,
 linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
 andre.draszik@...aro.org, willmcvicker@...gle.com, kernel-team@...roid.com,
 s.nawrocki@...sung.com, cw00.choi@...sung.com, mturquette@...libre.com,
 sboyd@...nel.org, semen.protsenko@...aro.org, linux-clk@...r.kernel.org,
 jaewon02.kim@...sung.com
Subject: Re: [PATCH v2 1/3] clk: samsung: introduce nMUX for MUX clks that can
 reparented



On 3/28/24 09:56, Krzysztof Kozlowski wrote:
> On 26/03/2024 18:28, Tudor Ambarus wrote:
>> All samsung MUX clocks that are defined with MUX() set the
>> CLK_SET_RATE_NO_REPARENT flag in __MUX(), which prevents MUXes to be
>> reparented during clk_set_rate().
>>
>> Introduce nMUX() for MUX clocks that can be reparented. One user of
>> nMUX() will be GS101. GS101 defines MUX clocks that are dedicated for
>> each instance of an IP (see MUX USI). The reparenting of these MUX clocks
>> will not affect other instances of the same IP or different IPs
>> altogether.
>>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@...aro.org>
>> ---
>>  drivers/clk/samsung/clk.h | 20 ++++++++++++++++++++
>>  1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/clk/samsung/clk.h b/drivers/clk/samsung/clk.h
>> index a70bd7cce39f..01f58b7686db 100644
>> --- a/drivers/clk/samsung/clk.h
>> +++ b/drivers/clk/samsung/clk.h
>> @@ -146,6 +146,26 @@ struct samsung_mux_clock {
>>  #define MUX_F(_id, cname, pnames, o, s, w, f, mf)		\
>>  	__MUX(_id, cname, pnames, o, s, w, f, mf)
>>  
>> +/* Used by MUX clocks where reparenting is allowed. */
> 
> ...where reparenting on clock rate change is allowed
> 
> Because otherwise this suggest muxes cannot change :)

Ok.
> 
> No need to resend just for this, I can fix it while applying. Still
> waiting for some review, till EOD.
> 

Andre' suggested I can avoid defining __nMUX() by removing the
CLK_SET_RATE_NO_REPARENT flag from __MUX() and instead add the flag in
the MUX() and MUX_F() definitions. Something like this:


diff --git a/drivers/clk/samsung/clk.h b/drivers/clk/samsung/clk.h
index a70bd7cce39f..fb06caa71f0a 100644
--- a/drivers/clk/samsung/clk.h
+++ b/drivers/clk/samsung/clk.h
@@ -133,7 +133,7 @@ struct samsung_mux_clock {
                .name           = cname,                        \
                .parent_names   = pnames,                       \
                .num_parents    = ARRAY_SIZE(pnames),           \
-               .flags          = (f) | CLK_SET_RATE_NO_REPARENT, \
+               .flags          = f,                            \
                .offset         = o,                            \
                .shift          = s,                            \
                .width          = w,                            \
@@ -141,9 +141,16 @@ struct samsung_mux_clock {
        }

 #define MUX(_id, cname, pnames, o, s, w)                       \
-       __MUX(_id, cname, pnames, o, s, w, 0, 0)
+       __MUX(_id, cname, pnames, o, s, w, CLK_SET_RATE_NO_REPARENT, 0)

 #define MUX_F(_id, cname, pnames, o, s, w, f, mf)              \
+       __MUX(_id, cname, pnames, o, s, w, (f) |
CLK_SET_RATE_NO_REPARENT, mf)
+
+/* Used by MUX clocks where reparenting on clock rate change is allowed. */
+#define nMUX(_id, cname, pnames, o, s, w)                      \
+       __MUX(_id, cname, pnames, o, s, w, 0, 0)
+
+#define nMUX_F(_id, cname, pnames, o, s, w, f, mf)             \
        __MUX(_id, cname, pnames, o, s, w, f, mf)

I find the suggestion fine. Will submit v3 in a min, addressing all the
comments.

Thanks,
ta