FAILED: patch "[PATCH] counter: stm32-timer-cnt: fix ceiling miss-alignment with" failed to apply to 5.4-stable tree

PATCH [email protected] 2 participants 3 messages Mar 22, 2021 – Apr 10, 2021

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Stable branch Arm STM32 Counter STM32 timer/lptimer drivers

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[email protected]

author maintainer

2021-03-22 09:13 UTC #0 lore raw

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b14d72ac731753708a7c1a6b3657b9312b6f0042 Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <[email protected]>
Date: Wed, 3 Mar 2021 18:49:49 +0100
Subject: [PATCH] counter: stm32-timer-cnt: fix ceiling miss-alignment with
reload register

Ceiling value may be miss-aligned with what's actually configured into the ARR register. This is seen after probe as currently the ARR value is zero, whereas ceiling value is set to the maximum. So:
- reading ceiling reports zero
- in case the counter gets enabled without any prior configuration, it won't count.
- in case the function gets set by the user 1st, (priv->ceiling) is used.

Fix it by getting rid of the cached "priv->ceiling" variable. Rather use the ARR register value directly by using regmap read or write when needed. There should be no drawback on performance as priv->ceiling isn't used in performance critical path.
There's also no point in writing ARR while setting function (sms), so it can be safely removed.

Fixes ad29937e206f ("counter: Add STM32 Timer quadrature encoder")

Signed-off-by Fabrice Gasnier <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

Cc <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Jonathan Cameron <[email protected]>

drivers/counter/stm32-timer-cnt.c +3 -8

index 2295be3f309a..75bc401fdd18 100644
@@ -31,7 +31,6 @@ struct stm32_timer_cnt {
 	struct counter_device counter;
 	struct regmap *regmap;
 	struct clk *clk;
-	u32 ceiling;
 	u32 max_arr;
 	bool enabled;
 	struct stm32_timer_regs bak;

@@ -75,8 +74,10 @@ static int stm32_count_write(struct counter_device *counter,
 			     const unsigned long val)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
+	u32 ceiling;
 
-	if (val > priv->ceiling)
+	regmap_read(priv->regmap, TIM_ARR, &ceiling);
+	if (val > ceiling)
 		return -EINVAL;
 
 	return regmap_write(priv->regmap, TIM_CNT, val);

@@ -138,10 +139,6 @@ static int stm32_count_function_set(struct counter_device *counter,
 
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 
-	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
-	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
-	regmap_write(priv->regmap, TIM_ARR, priv->ceiling);
-
 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 
 	/* Make sure that registers are updated */

@@ -199,7 +196,6 @@ static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 	regmap_write(priv->regmap, TIM_ARR, ceiling);
 
-	priv->ceiling = ceiling;
 	return len;
 }

@@ -374,7 +370,6 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev)
 
 	priv->regmap = ddata->regmap;
 	priv->clk = ddata->clk;
-	priv->ceiling = ddata->max_arr;
 	priv->max_arr = ddata->max_arr;
 
 	priv->counter.name = dev_name(dev);

Sudip Mukherjee

Acked-by William Breathitt Gray

2021-04-06 16:14 UTC #1 lore raw

Hi Greg,

Quoted 5 lines · On Mon, Mar 22, 2021 at 10:12:18AM +0100, [email protected] wrote:

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Here is the bakport.

--
Regards
Sudip

From 90f7d51d99c6ebe7e5eb925da018653846eb05bd Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <[email protected]>
Date: Wed, 3 Mar 2021 18:49:49 +0100
Subject: [PATCH] counter: stm32-timer-cnt: fix ceiling miss-alignment with
reload register

commit b14d72ac731753708a7c1a6b3657b9312b6f0042 upstream

Fixes ad29937e206f ("counter: Add STM32 Timer quadrature encoder")

Signed-off-by Fabrice Gasnier <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

Cc <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Jonathan Cameron <[email protected]>

[sudip: adjuct context]

Signed-off-by Sudip Mukherjee <[email protected]>

---
 drivers/counter/stm32-timer-cnt.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

drivers/counter/stm32-timer-cnt.c +3 -9

index 75e08a98d09b..889ea7a6ed63 100644
@@ -24,7 +24,6 @@ struct stm32_timer_cnt {
 	struct counter_device counter;
 	struct regmap *regmap;
 	struct clk *clk;
-	u32 ceiling;
 	u32 max_arr;
 };

@@ -67,14 +66,15 @@ static int stm32_count_write(struct counter_device *counter,
 			     struct counter_count_write_value *val)
 {
 	struct stm32_timer_cnt *const priv = counter->priv;
-	u32 cnt;
+	u32 cnt, ceiling;
 	int err;
 
 	err = counter_count_write_value_get(&cnt, COUNTER_COUNT_POSITION, val);
 	if (err)
 		return err;
 
-	if (cnt > priv->ceiling)
+	regmap_read(priv->regmap, TIM_ARR, &ceiling);
+	if (cnt > ceiling)
 		return -EINVAL;
 
 	return regmap_write(priv->regmap, TIM_CNT, cnt);

@@ -136,10 +136,6 @@ static int stm32_count_function_set(struct counter_device *counter,
 
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 
-	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
-	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
-	regmap_write(priv->regmap, TIM_ARR, priv->ceiling);
-
 	regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 
 	/* Make sure that registers are updated */

@@ -197,7 +193,6 @@ static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
 	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 	regmap_write(priv->regmap, TIM_ARR, ceiling);
 
-	priv->ceiling = ceiling;
 	return len;
 }

@@ -369,7 +364,6 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev)
 
 	priv->regmap = ddata->regmap;
 	priv->clk = ddata->clk;
-	priv->ceiling = ddata->max_arr;
 	priv->max_arr = ddata->max_arr;
 
 	priv->counter.name = dev_name(dev);

Signature · 1 line

2.30.2

Greg KH

author maintainer

2021-04-10 11:38 UTC #2 lore raw

Quoted 10 lines · Sudip Mukherjee

Hi Greg,
Quoted 5 lines · On Mon, Mar 22, 2021 at 10:12:18AM +0100, [email protected] wrote:
The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
Here is the bakport.

Now queued up, thanks.

greg k-h