On Mon, Jun 21, 2021 at 3:14 PM Michal Simek [off-list ref] wrote:

From: Arnd Bergmann <arnd@arndb.de>

When the firmware code is disabled, the incomplete error handling
in the clk driver causes compile-time warnings:

drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
  147 |         rate =  parent_rate * fbdiv;
      |                 ~~~~~~~~~~~~^~~~~~~
In function 'zynqmp_pll_get_mode',
    inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
   61 |         return ret_payload[1];
      |                ~~~~~~~~~~~^~~
drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
   53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
      |             ^~~~~~~~~~~
drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
   57 |         return val;
      |                ^~~

As it was apparently intentional to support this for compile testing
purposes, change the code to have just enough error handling for the
compiler to not notice the remaining bugs.

Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Simek <redacted>
---

Changes in v2:
Based on discussion here
Link: https://lore.kernel.org/r/20210421134844.3297838-1-arnd@kernel.org (local)
I have updated error return value which I got from clock core based on
error cases.

zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
clk_core_get_parent_by_index() where num_parents is incorrect index.

Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.

zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
default rate. But maybe -1ul which was used by Arnd is also good option.

Looks good to me. You changed more than I did now, so it might be better
to change my authorship to Co-developed-by, probably not worth respinning
for that.

       Arnd

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