From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Eric Anholt <eric@anholt.net>,
Stefan Wahren <stefan.wahren@i2se.com>,
Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>,
f.fainelli@gmail.com, rjui@broadcom.com, sbranden@broadcom.com,
bcm-kernel-feedback-list@broadcom.com, nsaenz@kernel.org,
prabhakar.mahadev-lad.rj@bp.renesas.com,
linux-i2c@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.16 04/30] i2c: bcm2835: Avoid clock stretching timeouts
Date: Tue, 22 Feb 2022 21:27:53 -0500 [thread overview]
Message-ID: <20220223022820.240649-4-sashal@kernel.org> (raw)
In-Reply-To: <20220223022820.240649-1-sashal@kernel.org>
From: Eric Anholt <eric@anholt.net>
[ Upstream commit 9495b9b31abe525ebd93da58de2c88b9f66d3a0e ]
The CLKT register contains at poweron 0x40, which at our typical 100kHz
bus rate means .64ms. But there is no specified limit to how long devices
should be able to stretch the clocks, so just disable the timeout. We
still have a timeout wrapping the entire transfer.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
BugLink: https://github.com/raspberrypi/linux/issues/3064
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/i2c/busses/i2c-bcm2835.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index 37443edbf7546..ad3b124a2e376 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -23,6 +23,11 @@
#define BCM2835_I2C_FIFO 0x10
#define BCM2835_I2C_DIV 0x14
#define BCM2835_I2C_DEL 0x18
+/*
+ * 16-bit field for the number of SCL cycles to wait after rising SCL
+ * before deciding the slave is not responding. 0 disables the
+ * timeout detection.
+ */
#define BCM2835_I2C_CLKT 0x1c
#define BCM2835_I2C_C_READ BIT(0)
@@ -477,6 +482,12 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
adap->dev.of_node = pdev->dev.of_node;
adap->quirks = of_device_get_match_data(&pdev->dev);
+ /*
+ * Disable the hardware clock stretching timeout. SMBUS
+ * specifies a limit for how long the device can stretch the
+ * clock, but core I2C doesn't.
+ */
+ bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_CLKT, 0);
bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);
ret = i2c_add_adapter(adap);
--
2.34.1
next prev parent reply other threads:[~2022-02-23 2:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-23 2:27 [PATCH AUTOSEL 5.16 01/30] HID: apple: Set the tilde quirk flag on the Wellspring 5 and later Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 02/30] mac80211_hwsim: report NOACK frames in tx_status Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 03/30] mac80211_hwsim: initialize ieee80211_tx_info at hw_scan_work Sasha Levin
2022-02-23 2:27 ` Sasha Levin [this message]
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 05/30] ASoC: rt5682s: do not block workqueue if card is unbound Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 06/30] ASoC: rt5668: " Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 07/30] ASoC: rt5682: " Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 08/30] regulator: core: fix false positive in regulator_late_cleanup() Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 09/30] Input: clear BTN_RIGHT/MIDDLE on buttonpads Sasha Levin
2022-02-23 2:27 ` [PATCH AUTOSEL 5.16 10/30] btrfs: get rid of warning on transaction commit when using flushoncommit Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 11/30] KVM: arm64: vgic: Read HW interrupt pending state from the HW Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 12/30] block: loop:use kstatfs.f_bsize of backing file to set discard granularity Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 13/30] tipc: fix a bit overflow in tipc_crypto_key_rcv() Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 14/30] cifs: do not use uninitialized data in the owner/group sid Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 15/30] cifs: fix double free race when mount fails in cifs_get_root() Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 16/30] USB: zaurus: support another broken Zaurus Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 17/30] HID: amd_sfh: Handle amd_sfh work buffer in PM ops Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 18/30] HID: amd_sfh: Add functionality to clear interrupts Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 19/30] HID: amd_sfh: Add interrupt handler to process interrupts Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 20/30] cifs: modefromsids must add an ACE for authenticated users Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 21/30] selftests/seccomp: Fix seccomp failure by adding missing headers Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 22/30] drm/amd/pm: correct UMD pstate clocks for Dimgrey Cavefish and Beige Goby Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 23/30] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 24/30] dmaengine: shdma: Fix runtime PM imbalance on error Sasha Levin
2022-02-24 22:39 ` Pavel Machek
2022-02-25 6:25 ` 刘永志
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 25/30] i2c: cadence: allow COMPILE_TEST Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 26/30] i2c: imx: " Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 27/30] i2c: qup: " Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 28/30] CDC-NCM: avoid overflow in sanity checking Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 29/30] net: usb: cdc_mbim: avoid altsetting toggling for Telit FN990 Sasha Levin
2022-02-23 2:28 ` [PATCH AUTOSEL 5.16 30/30] block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern Sasha Levin
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