LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Dave Gerlach <d-gerlach@ti.com>,
	Kevin Hilman <khilman@baylibre.com>,
	Tony Lindgren <tony@atomide.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 17/31] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218
Date: Tue, 24 Aug 2021 13:07:29 -0400	[thread overview]
Message-ID: <20210824170743.710957-18-sashal@kernel.org> (raw)
In-Reply-To: <20210824170743.710957-1-sashal@kernel.org>

From: Dave Gerlach <d-gerlach@ti.com>

[ Upstream commit 20a6b3fd8e2e2c063b25fbf2ee74d86b898e5087 ]

Based on the latest timing specifications for the TPS65218 from the data
sheet, http://www.ti.com/lit/ds/symlink/tps65218.pdf, document SLDS206
from November 2014, we must change the i2c bus speed to better fit within
the minimum high SCL time required for proper i2c transfer.

When running at 400khz, measurements show that SCL spends
0.8125 uS/1.666 uS high/low which violates the requirement for minimum
high period of SCL provided in datasheet Table 7.6 which is 1 uS.
Switching to 100khz gives us 5 uS/5 uS high/low which both fall above
the minimum given values for 100 khz, 4.0 uS/4.7 uS high/low.

Without this patch occasionally a voltage set operation from the kernel
will appear to have worked but the actual voltage reflected on the PMIC
will not have updated, causing problems especially with cpufreq that may
update to a higher OPP without actually raising the voltage on DCDC2,
leading to a hang.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/boot/dts/am43x-epos-evm.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/am43x-epos-evm.dts b/arch/arm/boot/dts/am43x-epos-evm.dts
index a74b09f17a1a..e7cd99793bc6 100644
--- a/arch/arm/boot/dts/am43x-epos-evm.dts
+++ b/arch/arm/boot/dts/am43x-epos-evm.dts
@@ -411,7 +411,7 @@
 	status = "okay";
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c0_pins>;
-	clock-frequency = <400000>;
+	clock-frequency = <100000>;
 
 	tps65218: tps65218@24 {
 		reg = <0x24>;
-- 
2.30.2


  parent reply	other threads:[~2021-08-24 17:40 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 17:07 [PATCH 4.4 00/31] 4.4.282-rc1 review Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 01/31] ASoC: intel: atom: Fix reference to PCM buffer address Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 02/31] i2c: dev: zero out array used for i2c reads from userspace Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 03/31] net: Fix memory leak in ieee802154_raw_deliver Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 04/31] xen/events: Fix race in set_evtchn_to_irq Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 05/31] x86/tools: Fix objdump version check again Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 06/31] PCI/MSI: Enable and mask MSI-X early Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 07/31] PCI/MSI: Do not set invalid bits in MSI mask Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 08/31] PCI/MSI: Correct misleading comments Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 09/31] PCI/MSI: Use msi_mask_irq() in pci_msi_shutdown() Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 10/31] PCI/MSI: Protect msi_desc::masked for multi-MSI Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 11/31] PCI/MSI: Mask all unused MSI-X entries Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 12/31] PCI/MSI: Enforce that MSI-X table entry is masked for update Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 13/31] PCI/MSI: Enforce MSI[X] entry updates to be visible Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 14/31] vmlinux.lds.h: Handle clang's module.{c,d}tor sections Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 15/31] KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653) Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 16/31] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-24 17:07 ` Sasha Levin [this message]
2021-08-24 17:07 ` [PATCH 4.4 18/31] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 19/31] scsi: megaraid_mm: Fix end of loop tests for list_for_each_entry() Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 20/31] scsi: core: Avoid printing an error if target_alloc() returns -ENXIO Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 21/31] Bluetooth: hidp: use correct wait queue when removing ctrl_wait Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 22/31] dccp: add do-while-0 stubs for dccp_pr_debug macros Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 23/31] net: 6pack: fix slab-out-of-bounds in decode_data Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 24/31] net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32 Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 25/31] mmc: dw_mmc: Wait for data transfer after response errors Sasha Levin
2021-08-26 11:59   ` Nobuhiro Iwamatsu
2021-08-26 12:31     ` Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 26/31] mmc: dw_mmc: call the dw_mci_prep_stop_abort() by default Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 27/31] mmc: dw_mmc: Fix hang on data CRC error Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 28/31] ALSA: hda - fix the 'Capture Switch' value change notifications Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 29/31] ipack: tpci200: fix many double free issues in tpci200_pci_probe Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 30/31] ASoC: intel: atom: Fix breakage for PCM buffer address setup Sasha Levin
2021-08-24 17:07 ` [PATCH 4.4 31/31] Linux 4.4.282-rc1 Sasha Levin
2021-08-25  7:33 ` [PATCH 4.4 00/31] 4.4.282-rc1 review Pavel Machek
2021-08-25 20:27 ` Guenter Roeck
2021-08-25 21:18 ` Daniel Díaz
2021-08-25 22:38 ` Shuah Khan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210824170743.710957-18-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=d-gerlach@ti.com \
    --cc=khilman@baylibre.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=tony@atomide.com \
    --subject='Re: [PATCH 4.4 17/31] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).