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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-07-01 13:55:39 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-07-01 13:55:39 +0200
commit19ed3bb5587b30ace275cb604fb2b9c60dc49de0 (patch)
treee44bf7a63c6df69dacd4ee4501a97618daa5c013 /drivers/pwm/pwm-stm32.c
parent783100f6ea0ae74a4ff3d616d4bce3b54badf347 (diff)
parent22a40d14b572deb80c0648557f4bd502d7e83826 (diff)
Merge 6.10-rc6 into char-misc-next
We need the char/misc/iio fixes in here as well to build on top of. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pwm/pwm-stm32.c')
-rw-r--r--drivers/pwm/pwm-stm32.c23
1 files changed, 16 insertions, 7 deletions
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index a2f231d13a9f..8bae3fd2b330 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -321,22 +321,30 @@ static int stm32_pwm_config(struct stm32_pwm *priv, unsigned int ch,
* First we need to find the minimal value for prescaler such that
*
* period_ns * clkrate
- * ------------------------------
+ * ------------------------------ < max_arr + 1
* NSEC_PER_SEC * (prescaler + 1)
*
- * isn't bigger than max_arr.
+ * This equation is equivalent to
+ *
+ * period_ns * clkrate
+ * ---------------------------- < prescaler + 1
+ * NSEC_PER_SEC * (max_arr + 1)
+ *
+ * Using integer division and knowing that the right hand side is
+ * integer, this is further equivalent to
+ *
+ * (period_ns * clkrate) // (NSEC_PER_SEC * (max_arr + 1)) ≤ prescaler
*/
prescaler = mul_u64_u64_div_u64(period_ns, clk_get_rate(priv->clk),
- (u64)NSEC_PER_SEC * priv->max_arr);
- if (prescaler > 0)
- prescaler -= 1;
-
+ (u64)NSEC_PER_SEC * ((u64)priv->max_arr + 1));
if (prescaler > MAX_TIM_PSC)
return -EINVAL;
prd = mul_u64_u64_div_u64(period_ns, clk_get_rate(priv->clk),
(u64)NSEC_PER_SEC * (prescaler + 1));
+ if (!prd)
+ return -EINVAL;
/*
* All channels share the same prescaler and counter so when two
@@ -673,7 +681,8 @@ static int stm32_pwm_probe(struct platform_device *pdev)
* .apply() won't overflow.
*/
if (clk_get_rate(priv->clk) > 1000000000)
- return dev_err_probe(dev, -EINVAL, "Failed to lock clock\n");
+ return dev_err_probe(dev, -EINVAL, "Clock freq too high (%lu)\n",
+ clk_get_rate(priv->clk));
chip->ops = &stm32pwm_ops;