hwrng: omap3-rom - Call clk_disable_unprepare() on exit only if not idled

BugLink: https://bugs.launchpad.net/bugs/1858462

[ Upstream commit eaecce12 ]

When unloading omap3-rom-rng, we'll get the following:

WARNING: CPU: 0 PID: 100 at drivers/clk/clk.c:948 clk_core_disable

This is because the clock may be already disabled by omap3_rom_rng_idle().
Let's fix the issue by checking for rng_idle on exit.

Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Adam Ford <aford173@gmail.com>
Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Fixes: 1c6b7c21 ("hwrng: OMAP3 ROM Random Number Generator support")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/char/hw_random/omap3-rom-rng.c

@@ -119,7 +119,8 @@ static int omap3_rom_rng_probe(struct platform_device *pdev)
 static int omap3_rom_rng_remove(struct platform_device *pdev)
 {
 	hwrng_unregister(&omap3_rom_rng_ops);
-	clk_disable_unprepare(rng_clk);
+	if (!rng_idle)
+		clk_disable_unprepare(rng_clk);
 	return 0;
 }