[PATCH] spi: meson-spicc: do not rely on busy flag in pow2 clk ops

[PATCH] spi: meson-spicc: do not rely on busy flag in pow2 clk ops

[Neil Armstrong]

Since [1], controller's busy flag isn't set anymore when the
__spi_transfer_message_noqueue() is used instead of the
__spi_pump_transfer_message() logic for spi_sync transfers.

Since the pow2 clock ops were limited to only be available when a
transfer is ongoing (between prepare_transfer_hardware and
unprepare_transfer_hardware callbacks), the only way to track this
down is to check for the controller cur_msg.

[1] ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")

Fixes: 09992025dacd ("spi: meson-spicc: add local pow2 clock ops to preserve rate between messages")
Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
Reported-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/spi/spi-meson-spicc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
index e4cb52e1fe26..6974a1c947aa 100644
--- a/drivers/spi/spi-meson-spicc.c
+++ b/drivers/spi/spi-meson-spicc.c
@@ -537,7 +537,7 @@ static unsigned long meson_spicc_pow2_recalc_rate(struct clk_hw *hw,
 	struct clk_divider *divider = to_clk_divider(hw);
 	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
 
-	if (!spicc->master->cur_msg || !spicc->master->busy)
+	if (!spicc->master->cur_msg)
 		return 0;
 
 	return clk_divider_ops.recalc_rate(hw, parent_rate);
@@ -549,7 +549,7 @@ static int meson_spicc_pow2_determine_rate(struct clk_hw *hw,
 	struct clk_divider *divider = to_clk_divider(hw);
 	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
 
-	if (!spicc->master->cur_msg || !spicc->master->busy)
+	if (!spicc->master->cur_msg)
 		return -EINVAL;
 
 	return clk_divider_ops.determine_rate(hw, req);
@@ -561,7 +561,7 @@ static int meson_spicc_pow2_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct clk_divider *divider = to_clk_divider(hw);
 	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
 
-	if (!spicc->master->cur_msg || !spicc->master->busy)
+	if (!spicc->master->cur_msg)
 		return -EINVAL;
 
 	return clk_divider_ops.set_rate(hw, rate, parent_rate);
-- 
2.25.1


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Re: [PATCH] spi: meson-spicc: do not rely on busy flag in pow2 clk ops

[Markus Schneider-Pargmann]

Hi Neil,

thanks for fixing.

On Thu, Sep 08, 2022 at 02:18:03PM +0200, Neil Armstrong wrote:
> Since [1], controller's busy flag isn't set anymore when the
> __spi_transfer_message_noqueue() is used instead of the
> __spi_pump_transfer_message() logic for spi_sync transfers.
> 
> Since the pow2 clock ops were limited to only be available when a
> transfer is ongoing (between prepare_transfer_hardware and
> unprepare_transfer_hardware callbacks), the only way to track this
> down is to check for the controller cur_msg.
> 
> [1] ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
> 
> Fixes: 09992025dacd ("spi: meson-spicc: add local pow2 clock ops to preserve rate between messages")
> Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync")
> Reported-by: Markus Schneider-Pargmann <msp@baylibre.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

Tested-by: Markus Schneider-Pargmann <msp@baylibre.com>

Best,
Markus

> ---
>  drivers/spi/spi-meson-spicc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
> index e4cb52e1fe26..6974a1c947aa 100644
> --- a/drivers/spi/spi-meson-spicc.c
> +++ b/drivers/spi/spi-meson-spicc.c
> @@ -537,7 +537,7 @@ static unsigned long meson_spicc_pow2_recalc_rate(struct clk_hw *hw,
>  	struct clk_divider *divider = to_clk_divider(hw);
>  	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
>  
> -	if (!spicc->master->cur_msg || !spicc->master->busy)
> +	if (!spicc->master->cur_msg)
>  		return 0;
>  
>  	return clk_divider_ops.recalc_rate(hw, parent_rate);
> @@ -549,7 +549,7 @@ static int meson_spicc_pow2_determine_rate(struct clk_hw *hw,
>  	struct clk_divider *divider = to_clk_divider(hw);
>  	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
>  
> -	if (!spicc->master->cur_msg || !spicc->master->busy)
> +	if (!spicc->master->cur_msg)
>  		return -EINVAL;
>  
>  	return clk_divider_ops.determine_rate(hw, req);
> @@ -561,7 +561,7 @@ static int meson_spicc_pow2_set_rate(struct clk_hw *hw, unsigned long rate,
>  	struct clk_divider *divider = to_clk_divider(hw);
>  	struct meson_spicc_device *spicc = pow2_clk_to_spicc(divider);
>  
> -	if (!spicc->master->cur_msg || !spicc->master->busy)
> +	if (!spicc->master->cur_msg)
>  		return -EINVAL;
>  
>  	return clk_divider_ops.set_rate(hw, rate, parent_rate);
> -- 
> 2.25.1
> 

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Re: [PATCH] spi: meson-spicc: do not rely on busy flag in pow2 clk ops

[Mark Brown]

On Thu, 8 Sep 2022 14:18:03 +0200, Neil Armstrong wrote:
> Since [1], controller's busy flag isn't set anymore when the
> __spi_transfer_message_noqueue() is used instead of the
> __spi_pump_transfer_message() logic for spi_sync transfers.
> 
> Since the pow2 clock ops were limited to only be available when a
> transfer is ongoing (between prepare_transfer_hardware and
> unprepare_transfer_hardware callbacks), the only way to track this
> down is to check for the controller cur_msg.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: meson-spicc: do not rely on busy flag in pow2 clk ops
      commit: 36acf80fc0c4b5ebe6fa010b524d442ee7f08fd3

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

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