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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sean Nyekjaer <sean@geanix.com>, Mark Brown <broonie@kernel.org>,
	Sasha Levin <sashal@kernel.org>,
	alain.volmat@foss.st.com, mcoquelin.stm32@gmail.com,
	alexandre.torgue@foss.st.com, linux-spi@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.15 08/27] spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run
Date: Fri, 18 Nov 2022 21:13:33 -0500	[thread overview]
Message-ID: <20221119021352.1774592-8-sashal@kernel.org> (raw)
In-Reply-To: <20221119021352.1774592-1-sashal@kernel.org>

From: Sean Nyekjaer <sean@geanix.com>

[ Upstream commit 62aa1a344b0904549f6de7af958e8a1136fd5228 ]

When this driver is used with a driver that uses preallocated spi_transfer
structs. The speed_hz is halved by every run. This results in:

spi_stm32 44004000.spi: SPI transfer setup failed
ads7846 spi0.0: SPI transfer failed: -22

Example when running with DIV_ROUND_UP():
- First run; speed_hz = 1000000, spi->clk_rate 125000000
  div 125 -> mbrdiv = 7, cur_speed = 976562
- Second run; speed_hz = 976562
  div 128,00007 (roundup to 129) -> mbrdiv = 8, cur_speed = 488281
- Third run; speed_hz = 488281
  div 256,000131072067109 (roundup to 257) and then -EINVAL is returned.

Use DIV_ROUND_CLOSEST to allow to round down and allow us to keep the
set speed.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Link: https://lore.kernel.org/r/20221103080043.3033414-1-sean@geanix.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-stm32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 9bd3fd1652f7..fdb5f36d77ef 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -434,7 +434,7 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz,
 	u32 div, mbrdiv;
 
 	/* Ensure spi->clk_rate is even */
-	div = DIV_ROUND_UP(spi->clk_rate & ~0x1, speed_hz);
+	div = DIV_ROUND_CLOSEST(spi->clk_rate & ~0x1, speed_hz);
 
 	/*
 	 * SPI framework set xfer->speed_hz to master->max_speed_hz if
-- 
2.35.1


WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sean Nyekjaer <sean@geanix.com>, Mark Brown <broonie@kernel.org>,
	Sasha Levin <sashal@kernel.org>,
	alain.volmat@foss.st.com, mcoquelin.stm32@gmail.com,
	alexandre.torgue@foss.st.com, linux-spi@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.15 08/27] spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run
Date: Fri, 18 Nov 2022 21:13:33 -0500	[thread overview]
Message-ID: <20221119021352.1774592-8-sashal@kernel.org> (raw)
In-Reply-To: <20221119021352.1774592-1-sashal@kernel.org>

From: Sean Nyekjaer <sean@geanix.com>

[ Upstream commit 62aa1a344b0904549f6de7af958e8a1136fd5228 ]

When this driver is used with a driver that uses preallocated spi_transfer
structs. The speed_hz is halved by every run. This results in:

spi_stm32 44004000.spi: SPI transfer setup failed
ads7846 spi0.0: SPI transfer failed: -22

Example when running with DIV_ROUND_UP():
- First run; speed_hz = 1000000, spi->clk_rate 125000000
  div 125 -> mbrdiv = 7, cur_speed = 976562
- Second run; speed_hz = 976562
  div 128,00007 (roundup to 129) -> mbrdiv = 8, cur_speed = 488281
- Third run; speed_hz = 488281
  div 256,000131072067109 (roundup to 257) and then -EINVAL is returned.

Use DIV_ROUND_CLOSEST to allow to round down and allow us to keep the
set speed.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Link: https://lore.kernel.org/r/20221103080043.3033414-1-sean@geanix.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-stm32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 9bd3fd1652f7..fdb5f36d77ef 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -434,7 +434,7 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz,
 	u32 div, mbrdiv;
 
 	/* Ensure spi->clk_rate is even */
-	div = DIV_ROUND_UP(spi->clk_rate & ~0x1, speed_hz);
+	div = DIV_ROUND_CLOSEST(spi->clk_rate & ~0x1, speed_hz);
 
 	/*
 	 * SPI framework set xfer->speed_hz to master->max_speed_hz if
-- 
2.35.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-11-19  2:21 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-19  2:13 [PATCH AUTOSEL 5.15 01/27] wifi: mac80211: fix memory free error when registering wiphy fail Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 02/27] wifi: mac80211_hwsim: fix debugfs attribute ps with rc table support Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 03/27] riscv: dts: sifive unleashed: Add PWM controlled LEDs Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 04/27] audit: fix undefined behavior in bit shift for AUDIT_BIT Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 05/27] wifi: airo: do not assign -1 to unsigned char Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 06/27] wifi: mac80211: Fix ack frame idr leak when mesh has no route Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 07/27] wifi: ath11k: Fix QCN9074 firmware boot on x86 Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` Sasha Levin [this message]
2022-11-19  2:13   ` [PATCH AUTOSEL 5.15 08/27] spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 09/27] clocksource/drivers/hyperv: add data structure for reference TSC MSR Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 10/27] x86/hyperv: fix invalid writes to MSRs during root partition kexec Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 11/27] selftests/bpf: Add verifier test for release_reference() Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 12/27] Revert "net: macsec: report real_dev features when HW offloading is enabled" Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 13/27] ACPI: video: Add backlight=native DMI quirk for Dell G15 5515 Sasha Levin
2022-11-19 13:20   ` Daniel Dadap
2022-11-24 16:53     ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 14/27] platform/x86: ideapad-laptop: Disable touchpad_switch Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 15/27] platform/x86: touchscreen_dmi: Add info for the RCA Cambio W101 v2 2-in-1 Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 16/27] platform/x86/intel/pmt: Sapphire Rapids PMT errata fix Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 17/27] platform/x86/intel/hid: Add some ACPI device IDs Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 18/27] scsi: ibmvfc: Avoid path failures during live migration Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 19/27] scsi: scsi_debug: Make the READ CAPACITY response compliant with ZBC Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 20/27] drm: panel-orientation-quirks: Add quirk for Acer Switch V 10 (SW5-017) Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 21/27] block, bfq: fix null pointer dereference in bfq_bio_bfqg() Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 22/27] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 23/27] nvmet: fix memory leak in nvmet_subsys_attr_model_store_locked Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 24/27] Revert "drm/amdgpu: Revert "drm/amdgpu: getting fan speed pwm for vega10 properly"" Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2023-01-03 12:38   ` Yury Zhuravlev
2023-01-03 12:38     ` Yury Zhuravlev
2023-01-08  3:56     ` Yury Zhuravlev
2023-01-08  3:56       ` Yury Zhuravlev
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 25/27] ALSA: usb-audio: add quirk to fix Hamedal C20 disconnect issue Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 26/27] RISC-V: vdso: Do not add missing symbols to version section in linker script Sasha Levin
2022-11-19  2:13   ` Sasha Levin
2022-11-19  2:13 ` [PATCH AUTOSEL 5.15 27/27] MIPS: pic32: treat port as signed integer Sasha Levin

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