linux-kernel - Re: [PATCH 1/2] iio: adc: stm32: Iterate through all ADCs in irq handler

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Message-ID: <955f3ed8-fad9-95fc-e036-8a8a6f99de50@foss.st.com>
Date:   Fri, 13 May 2022 15:05:46 +0200
From:   Fabrice Gasnier <fabrice.gasnier@...s.st.com>
To:     Yannick Brosseau <yannick.brosseau@...il.com>, <jic23@...nel.org>,
        <lars@...afoo.de>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...s.st.com>, <olivier.moysan@...s.st.com>
CC:     <paul@...pouillou.net>, <linux-iio@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] iio: adc: stm32: Iterate through all ADCs in irq
 handler

On 5/7/22 00:56, Yannick Brosseau wrote:
> The irq handler was only checking the mask for the first ADCs in the case of the
> F4 and H7 generation, since it was using the num_irq value. This patch add
> the number of ADC in the common register, which map to the number of entries of
> eoc_msk and ovr_msk in stm32_adc_common_regs.
> 
> Tested on a STM32F429NIH6
> 
> Signed-off-by: Yannick Brosseau <yannick.brosseau@...il.com>
> ---
>  drivers/iio/adc/stm32-adc-core.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 


Hi Yannick,

I confirm you've identified and analyzed here a regression. This is
something that I noticed also earlier (Olivier and I had some patches in
our downstream tree for that. Shame on me that I haven't sent them right
away).

So, I'm fine with your current patch. Please add a Fixes: tag as
suggested by Jonathan and Paul in the cover letter.
Fixes: 695e2f5c289b ("iio: adc: stm32-adc: fix a regression when using
dma and irq")

While you're at it, I suggest to also mention "fix" in the commit
tittle, to make it clear: e.g. it fixes a regression in irq handling on
stm32f4 and stm32h7.


> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
> index 142656232157..11c08c56acb0 100644
> --- a/drivers/iio/adc/stm32-adc-core.c
> +++ b/drivers/iio/adc/stm32-adc-core.c
> @@ -64,6 +64,7 @@ struct stm32_adc_priv;
>   * @max_clk_rate_hz: maximum analog clock rate (Hz, from datasheet)
>   * @has_syscfg: SYSCFG capability flags
>   * @num_irqs:	number of interrupt lines
> + * @num_adcs:   number of ADC instances in the common registers

Minor comment here, this rather is the 'maximum' number of ADC
instances. E.g. on stm32h7, there are two ADC blocks: ADC12 with 2 ADCs
and ADC3 with 1 ADC instantiated separately. So you could update the
comment and/or variable name.

Thanks & Best Regards,
Fabrice


>   */
>  struct stm32_adc_priv_cfg {
>  	const struct stm32_adc_common_regs *regs;
> @@ -71,6 +72,7 @@ struct stm32_adc_priv_cfg {
>  	u32 max_clk_rate_hz;
>  	unsigned int has_syscfg;
>  	unsigned int num_irqs;
> +	unsigned int num_adcs;
>  };
>  
>  /**
> @@ -352,7 +354,7 @@ static void stm32_adc_irq_handler(struct irq_desc *desc)
>  	 * before invoking the interrupt handler (e.g. call ISR only for
>  	 * IRQ-enabled ADCs).
>  	 */
> -	for (i = 0; i < priv->cfg->num_irqs; i++) {
> +	for (i = 0; i < priv->cfg->num_adcs; i++) {
>  		if ((status & priv->cfg->regs->eoc_msk[i] &&
>  		     stm32_adc_eoc_enabled(priv, i)) ||
>  		     (status & priv->cfg->regs->ovr_msk[i]))
> @@ -792,6 +794,7 @@ static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = {
>  	.clk_sel = stm32f4_adc_clk_sel,
>  	.max_clk_rate_hz = 36000000,
>  	.num_irqs = 1,
> +	.num_adcs = 3,
>  };
>  
>  static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
> @@ -800,6 +803,7 @@ static const struct stm32_adc_priv_cfg stm32h7_adc_priv_cfg = {
>  	.max_clk_rate_hz = 36000000,
>  	.has_syscfg = HAS_VBOOSTER,
>  	.num_irqs = 1,
> +	.num_adcs = 2,
>  };
>  
>  static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
> @@ -808,6 +812,7 @@ static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
>  	.max_clk_rate_hz = 40000000,
>  	.has_syscfg = HAS_VBOOSTER | HAS_ANASWVDD,
>  	.num_irqs = 2,
> +	.num_adcs = 2,
>  };
>  
>  static const struct of_device_id stm32_adc_of_match[] = {