[PATCH] clk: divider: fix incorrect usage of container_of

[Jerome Brunet <jbrunet@baylibre.com>]

divider_recalc_rate() is an helper function used by clock divider of
different types, so the structure containing the 'hw' pointer is not
always a 'struct clk_divider'

At the following line:
> div = _get_div(table, val, flags, divider->width);

in several cases, the value of 'divider->width' is garbage as the actual
structure behind this memory is not a 'struct clk_divider'

Fortunately, this width value is used by _get_val() only when
CLK_DIVIDER_MAX_AT_ZERO flag is set. This has never been the case so
far when the structure is not a 'struct clk_divider'. This is probably
why we did not notice this bug before

Fixes: afe76c8fd030 ("clk: allow a clk divider with max divisor when zero")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
Hi Stephen, Mike,

In addition to clock, this patch also touch the rtc and drm directories.
As it is changing the API of the helper function, I have this fix in a
single commit to avoid breaking bisect.

Please let me know if you prefer to do differently.

Cheers
Jerome

drivers/clk/clk-divider.c                  | 7 +++----
 drivers/clk/hisilicon/clkdivider-hi6220.c  | 2 +-
 drivers/clk/nxp/clk-lpc32xx.c              | 2 +-
 drivers/clk/qcom/clk-regmap-divider.c      | 2 +-
 drivers/clk/sunxi-ng/ccu_div.c             | 2 +-
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c | 2 +-
 drivers/rtc/rtc-ac100.c                    | 6 ++++--
 include/linux/clk-provider.h               | 2 +-
 8 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 4ed516cb7276..b49942b9fe50 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -118,12 +118,11 @@ static unsigned int _get_val(const struct clk_div_table *table,
 unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
 				  unsigned int val,
 				  const struct clk_div_table *table,
-				  unsigned long flags)
+				  unsigned long flags, unsigned long width)
 {
-	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int div;
 
-	div = _get_div(table, val, flags, divider->width);
+	div = _get_div(table, val, flags, width);
 	if (!div) {
 		WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
 			"%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
@@ -145,7 +144,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 	val &= div_mask(divider->width);
 
 	return divider_recalc_rate(hw, parent_rate, val, divider->table,
-				   divider->flags);
+				   divider->flags, divider->width);
 }
 
 static bool _is_valid_table_div(const struct clk_div_table *table,
diff --git a/drivers/clk/hisilicon/clkdivider-hi6220.c b/drivers/clk/hisilicon/clkdivider-hi6220.c
index a1c1f684ad58..9f46cf9dcc65 100644
--- a/drivers/clk/hisilicon/clkdivider-hi6220.c
+++ b/drivers/clk/hisilicon/clkdivider-hi6220.c
@@ -56,7 +56,7 @@ static unsigned long hi6220_clkdiv_recalc_rate(struct clk_hw *hw,
 	val &= div_mask(dclk->width);
 
 	return divider_recalc_rate(hw, parent_rate, val, dclk->table,
-				   CLK_DIVIDER_ROUND_CLOSEST);
+				   CLK_DIVIDER_ROUND_CLOSEST, dclk->width);
 }
 
 static long hi6220_clkdiv_round_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/drivers/clk/nxp/clk-lpc32xx.c b/drivers/clk/nxp/clk-lpc32xx.c
index b669a5c10fee..f5d815f577e0 100644
--- a/drivers/clk/nxp/clk-lpc32xx.c
+++ b/drivers/clk/nxp/clk-lpc32xx.c
@@ -956,7 +956,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 	val &= div_mask(divider->width);
 
 	return divider_recalc_rate(hw, parent_rate, val, divider->table,
-				   divider->flags);
+				   divider->flags, divider->width);
 }
 
 static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/drivers/clk/qcom/clk-regmap-divider.c b/drivers/clk/qcom/clk-regmap-divider.c
index 53484912301e..928fcc16ee27 100644
--- a/drivers/clk/qcom/clk-regmap-divider.c
+++ b/drivers/clk/qcom/clk-regmap-divider.c
@@ -59,7 +59,7 @@ static unsigned long div_recalc_rate(struct clk_hw *hw,
 	div &= BIT(divider->width) - 1;
 
 	return divider_recalc_rate(hw, parent_rate, div, NULL,
-				   CLK_DIVIDER_ROUND_CLOSEST);
+				   CLK_DIVIDER_ROUND_CLOSEST, divider->width);
 }
 
 const struct clk_ops clk_regmap_div_ops = {
diff --git a/drivers/clk/sunxi-ng/ccu_div.c b/drivers/clk/sunxi-ng/ccu_div.c
index baa3cf96507b..302a18efd39f 100644
--- a/drivers/clk/sunxi-ng/ccu_div.c
+++ b/drivers/clk/sunxi-ng/ccu_div.c
@@ -71,7 +71,7 @@ static unsigned long ccu_div_recalc_rate(struct clk_hw *hw,
 						  parent_rate);
 
 	val = divider_recalc_rate(hw, parent_rate, val, cd->div.table,
-				  cd->div.flags);
+				  cd->div.flags, cd->div.width);
 
 	if (cd->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		val /= cd->fixed_post_div;
diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
index fe15aa64086f..71fe60e5f01f 100644
--- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
+++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_14nm.c
@@ -698,7 +698,7 @@ static unsigned long dsi_pll_14nm_postdiv_recalc_rate(struct clk_hw *hw,
 	val &= div_mask(width);
 
 	return divider_recalc_rate(hw, parent_rate, val, NULL,
-				   postdiv->flags);
+				   postdiv->flags, width);
 }
 
 static long dsi_pll_14nm_postdiv_round_rate(struct clk_hw *hw,
diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c
index 9e336184491c..0282ccc6181c 100644
--- a/drivers/rtc/rtc-ac100.c
+++ b/drivers/rtc/rtc-ac100.c
@@ -137,13 +137,15 @@ static unsigned long ac100_clkout_recalc_rate(struct clk_hw *hw,
 		div = (reg >> AC100_CLKOUT_PRE_DIV_SHIFT) &
 			((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1);
 		prate = divider_recalc_rate(hw, prate, div,
-					    ac100_clkout_prediv, 0);
+					    ac100_clkout_prediv, 0,
+					    AC100_CLKOUT_PRE_DIV_WIDTH);
 	}
 
 	div = (reg >> AC100_CLKOUT_DIV_SHIFT) &
 		(BIT(AC100_CLKOUT_DIV_WIDTH) - 1);
 	return divider_recalc_rate(hw, prate, div, NULL,
-				   CLK_DIVIDER_POWER_OF_TWO);
+				   CLK_DIVIDER_POWER_OF_TWO,
+				   AC100_CLKOUT_DIV_WIDTH);
 }
 
 static long ac100_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 73ac87f34df9..4c4001086447 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -412,7 +412,7 @@ extern const struct clk_ops clk_divider_ro_ops;
 
 unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
 		unsigned int val, const struct clk_div_table *table,
-		unsigned long flags);
+		unsigned long flags, unsigned long width);
 long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
 			       unsigned long rate, unsigned long *prate,
 			       const struct clk_div_table *table,
-- 
2.14.3