[PATCH v2 4/5] clk: scpi: register scpi-cpufreq once and clear on failure

[Xixin Liu]

scpi_clocks_probe() walks clock children and, for each DVFS provider, calls
platform_device_register_simple("scpi-cpufreq", -1, ...). Two related bugs:

1) Registration uses id = -1 and the fixed name "scpi-cpufreq". A second
   registration of the same name returns -EEXIST and overwrites the first
   good cpufreq_dev with ERR_PTR(-EEXIST). When cpufreq_dev is already
   set, continue so only the first successful registration remains.

2) On IS_ERR, cpufreq_dev still held the ERR_PTR; remove() would then
   call platform_device_unregister() on it (oops). Clear cpufreq_dev to
   NULL after the failure warn so remove() skips it.

Fixes: 9490f01e2471 ("clk: scpi: add support for cpufreq virtual device")
Fixes: 67bcc2c5f1da ("clk: scpi: don't add cpufreq device if the scpi dvfs node is disabled")
Signed-off-by: Xixin Liu <liuxixin at kylinos.cn>
---
 drivers/clk/clk-scpi.c | 6 +++++-
 
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-scpi.c b/drivers/clk/clk-scpi.c
index 3c33a9e3c690..e1891351c221 100644
--- a/drivers/clk/clk-scpi.c
+++ b/drivers/clk/clk-scpi.c
@@ -284,10 +284,14 @@ static int scpi_clocks_probe(struct platform_device *pdev)
 		if (match->data != &scpi_dvfs_ops)
 			continue;
 		/* Add the virtual cpufreq device if it's DVFS clock provider */
+		if (cpufreq_dev)
+			continue;
 		cpufreq_dev = platform_device_register_simple("scpi-cpufreq",
 							      -1, NULL, 0);
-		if (IS_ERR(cpufreq_dev))
+		if (IS_ERR(cpufreq_dev)) {
 			pr_warn("unable to register cpufreq device");
+			cpufreq_dev = NULL;
+		}
 	}
 	return 0;
 }
-- 
2.53.0