linux-kernel - [PATCH v2] mtd: spi-nor: hisi-sfc: Remove excessive clk_disable

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Message-Id: <20210709144529.31379-1-novikov@ispras.ru>
Date:   Fri,  9 Jul 2021 17:45:29 +0300
From:   Evgeny Novikov <novikov@...ras.ru>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>
Cc:     Evgeny Novikov <novikov@...ras.ru>,
        Michael Walle <michael@...le.cc>,
        Pratyush Yadav <p.yadav@...com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Lee Jones <lee.jones@...aro.org>,
        Pan Bian <bianpan2016@....com>, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org, ldv-project@...uxtesting.org
Subject: [PATCH v2] mtd: spi-nor: hisi-sfc: Remove excessive clk_disable_unprepare()

hisi_spi_nor_probe() invokes clk_disable_unprepare() on all paths after
successful call of clk_prepare_enable(). Besides, the clock is enabled by
hispi_spi_nor_prep() and disabled by hispi_spi_nor_unprep(). So at remove
time it is not possible to have the clock enabled. The patch removes
excessive clk_disable_unprepare() from hisi_spi_nor_remove().

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: e523f11141bd ("mtd: spi-nor: add hisilicon spi-nor flash controller driver")
Signed-off-by: Evgeny Novikov <novikov@...ras.ru>
Reviewed-by: Pratyush Yadav <p.yadav@...com>
---
v2: Fix notes from Pratyush Yadav:
    - Describe better why clock disabling is not necessary at remove time.
    - Add tag Fixes.
---
 drivers/mtd/spi-nor/controllers/hisi-sfc.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/controllers/hisi-sfc.c b/drivers/mtd/spi-nor/controllers/hisi-sfc.c
index 47fbf1d1e557..516e50269478 100644
--- a/drivers/mtd/spi-nor/controllers/hisi-sfc.c
+++ b/drivers/mtd/spi-nor/controllers/hisi-sfc.c
@@ -477,7 +477,6 @@ static int hisi_spi_nor_remove(struct platform_device *pdev)
 
 	hisi_spi_nor_unregister_all(host);
 	mutex_destroy(&host->lock);
-	clk_disable_unprepare(host->clk);
 	return 0;
 }
 
-- 
2.26.2