linux-kernel - [PATCH v3 25/31] clk: mediatek: pll: Implement error handling in register API

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Date:   Tue,  8 Feb 2022 20:40:28 +0800
From:   Chen-Yu Tsai <wenst@...omium.org>
To:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     Chen-Yu Tsai <wenst@...omium.org>,
        Chun-Jie Chen <chun-jie.chen@...iatek.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Miles Chen <miles.chen@...iatek.com>,
        linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 25/31] clk: mediatek: pll: Implement error handling in register API

The pll clk type registration function does not stop or return errors
if any clk failed to be registered, nor does it implement an error
handling path. This may result in a partially working device if any
step failed.

Make the register function return proper error codes, and bail out if
errors occur. Proper cleanup, i.e. unregister any clks that were
successfully registered, and unmap the I/O space, is done in the new
error path.

Signed-off-by: Chen-Yu Tsai <wenst@...omium.org>
Reviewed-by: Miles Chen <miles.chen@...iatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/clk/mediatek/clk-pll.c | 23 +++++++++++++++++++----
 drivers/clk/mediatek/clk-pll.h |  6 +++---
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
index 8439d37e354d..817a80293bfc 100644
--- a/drivers/clk/mediatek/clk-pll.c
+++ b/drivers/clk/mediatek/clk-pll.c
@@ -377,8 +377,9 @@ static void mtk_clk_unregister_pll(struct clk *clk)
 	kfree(pll);
 }
 
-void mtk_clk_register_plls(struct device_node *node,
-		const struct mtk_pll_data *plls, int num_plls, struct clk_onecell_data *clk_data)
+int mtk_clk_register_plls(struct device_node *node,
+			  const struct mtk_pll_data *plls, int num_plls,
+			  struct clk_onecell_data *clk_data)
 {
 	void __iomem *base;
 	int i;
@@ -387,7 +388,7 @@ void mtk_clk_register_plls(struct device_node *node,
 	base = of_iomap(node, 0);
 	if (!base) {
 		pr_err("%s(): ioremap failed\n", __func__);
-		return;
+		return -EINVAL;
 	}
 
 	for (i = 0; i < num_plls; i++) {
@@ -397,11 +398,25 @@ void mtk_clk_register_plls(struct device_node *node,
 
 		if (IS_ERR(clk)) {
 			pr_err("Failed to register clk %s: %pe\n", pll->name, clk);
-			continue;
+			goto err;
 		}
 
 		clk_data->clks[pll->id] = clk;
 	}
+
+	return 0;
+
+err:
+	while (--i >= 0) {
+		const struct mtk_pll_data *pll = &plls[i];
+
+		mtk_clk_unregister_pll(clk_data->clks[pll->id]);
+		clk_data->clks[pll->id] = ERR_PTR(-ENOENT);
+	}
+
+	iounmap(base);
+
+	return PTR_ERR(clk);
 }
 EXPORT_SYMBOL_GPL(mtk_clk_register_plls);
 
diff --git a/drivers/clk/mediatek/clk-pll.h b/drivers/clk/mediatek/clk-pll.h
index a889b1e472e7..bf06e44caef9 100644
--- a/drivers/clk/mediatek/clk-pll.h
+++ b/drivers/clk/mediatek/clk-pll.h
@@ -48,9 +48,9 @@ struct mtk_pll_data {
 	u8 pll_en_bit; /* Assume 0, indicates BIT(0) by default */
 };
 
-void mtk_clk_register_plls(struct device_node *node,
-			   const struct mtk_pll_data *plls, int num_plls,
-			   struct clk_onecell_data *clk_data);
+int mtk_clk_register_plls(struct device_node *node,
+			  const struct mtk_pll_data *plls, int num_plls,
+			  struct clk_onecell_data *clk_data);
 void mtk_clk_unregister_plls(const struct mtk_pll_data *plls, int num_plls,
 			     struct clk_onecell_data *clk_data);
 
-- 
2.35.0.263.gb82422642f-goog