[PATCH] clk: meson clk-phase: fix division by zero in meson_clk_degrees_to_val()

[Zicheng Qu]

In the meson_clk_phase_set_phase() function, the variable phase->ph.width
is of type u8, with a range of 0 to 255. When calling
meson_clk_degrees_to_val with width as an argument, if width > 8,
phase_step(width) will return 0. Lead to a division by zero error in
DIV_ROUND_CLOSEST(). The same issue exists in the
meson_clk_triphase_set_phase() and meson_sclk_ws_inv_set_phase().

Fixes: 7b70689b07c1 ("clk: meson: add sclk-ws driver")
Cc: <stable at vger.kernel.org>
Signed-off-by: Zicheng Qu <quzicheng at huawei.com>
---
 drivers/clk/meson/clk-phase.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/clk/meson/clk-phase.c b/drivers/clk/meson/clk-phase.c
index c1526fbfb6c4..b88d59b7a90d 100644
--- a/drivers/clk/meson/clk-phase.c
+++ b/drivers/clk/meson/clk-phase.c
@@ -51,6 +51,9 @@ static int meson_clk_phase_set_phase(struct clk_hw *hw, int degrees)
 	struct meson_clk_phase_data *phase = meson_clk_phase_data(clk);
 	unsigned int val;
 
+	if (phase->ph.width > 8)
+		return -EINVAL;
+
 	val = meson_clk_degrees_to_val(degrees, phase->ph.width);
 	meson_parm_write(clk->map, &phase->ph, val);
 
@@ -110,6 +113,9 @@ static int meson_clk_triphase_set_phase(struct clk_hw *hw, int degrees)
 	struct meson_clk_triphase_data *tph = meson_clk_triphase_data(clk);
 	unsigned int val;
 
+	if (tph->ph0.width > 8)
+		return -EINVAL;
+
 	val = meson_clk_degrees_to_val(degrees, tph->ph0.width);
 	meson_parm_write(clk->map, &tph->ph0, val);
 	meson_parm_write(clk->map, &tph->ph1, val);
@@ -167,6 +173,9 @@ static int meson_sclk_ws_inv_set_phase(struct clk_hw *hw, int degrees)
 	struct meson_sclk_ws_inv_data *tph = meson_sclk_ws_inv_data(clk);
 	unsigned int val;
 
+	if (tph->ph.width > 8)
+		return -EINVAL;
+
 	val = meson_clk_degrees_to_val(degrees, tph->ph.width);
 	meson_parm_write(clk->map, &tph->ph, val);
 	meson_parm_write(clk->map, &tph->ws, val ? 0 : 1);
-- 
2.34.1