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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Raviteja Narayanam <raviteja.narayanam@xilinx.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Wolfram Sang <wsa@kernel.org>, Sasha Levin <sashal@kernel.org>,
	linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
Subject: [PATCH AUTOSEL 5.7 16/25] Revert "i2c: cadence: Fix the hold bit setting"
Date: Mon, 27 Jul 2020 19:23:36 -0400	[thread overview]
Message-ID: <20200727232345.717432-16-sashal@kernel.org> (raw)
In-Reply-To: <20200727232345.717432-1-sashal@kernel.org>

From: Raviteja Narayanam <raviteja.narayanam@xilinx.com>

[ Upstream commit 0db9254d6b896b587759e2c844c277fb1a6da5b9 ]

This reverts commit d358def706880defa4c9e87381c5bf086a97d5f9.

There are two issues with "i2c: cadence: Fix the hold bit setting" commit.

1. In case of combined message request from user space, when the HOLD
bit is cleared in cdns_i2c_mrecv function, a STOP condition is sent
on the bus even before the last message is started. This is because when
the HOLD bit is cleared, the FIFOS are empty and there is no pending
transfer. The STOP condition should occur only after the last message
is completed.

2. The code added by the commit is redundant. Driver is handling the
setting/clearing of HOLD bit in right way before the commit.

The setting of HOLD bit based on 'bus_hold_flag' is taken care in
cdns_i2c_master_xfer function even before cdns_i2c_msend/cdns_i2c_recv
functions.

The clearing of HOLD bit is taken care at the end of cdns_i2c_msend and
cdns_i2c_recv functions based on bus_hold_flag and byte count.
Since clearing of HOLD bit is done after the slave address is written to
the register (writing to address register triggers the message transfer),
it is ensured that STOP condition occurs at the right time after
completion of the pending transfer (last message).

Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-cadence.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 89d58f7d2a253..97a0bd6ea31f1 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -382,10 +382,8 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
 	 * Check for the message size against FIFO depth and set the
 	 * 'hold bus' bit if it is greater than FIFO depth.
 	 */
-	if ((id->recv_count > CDNS_I2C_FIFO_DEPTH)  || id->bus_hold_flag)
+	if (id->recv_count > CDNS_I2C_FIFO_DEPTH)
 		ctrl_reg |= CDNS_I2C_CR_HOLD;
-	else
-		ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
 
 	cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
 
@@ -442,11 +440,8 @@ static void cdns_i2c_msend(struct cdns_i2c *id)
 	 * Check for the message size against FIFO depth and set the
 	 * 'hold bus' bit if it is greater than FIFO depth.
 	 */
-	if ((id->send_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag)
+	if (id->send_count > CDNS_I2C_FIFO_DEPTH)
 		ctrl_reg |= CDNS_I2C_CR_HOLD;
-	else
-		ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
-
 	cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
 
 	/* Clear the interrupts in interrupt status register. */
-- 
2.25.1


  parent reply	other threads:[~2020-07-27 23:29 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 23:23 [PATCH AUTOSEL 5.7 01/25] mt76: mt7615: fix lmac queue debugsfs entry Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 02/25] iwlwifi: fix crash in iwl_dbg_tlv_alloc_trigger Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 03/25] usb: hso: Fix debug compile warning on sparc32 Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 04/25] selftests: fib_nexthop_multiprefix: fix cleanup() netns deletion Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 05/25] qed: Disable "MFW indication via attention" SPAM every 5 minutes Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 06/25] selftests: net: ip_defrag: modprobe missing nf_defrag_ipv6 support Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 07/25] io_uring: always allow drain/link/hardlink/async sqe flags Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 08/25] habanalabs: prevent possible out-of-bounds array access Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 09/25] nfc: s3fwrn5: add missing release on skb in s3fwrn5_recv_frame Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 10/25] scsi: core: Run queue in case of I/O resource contention failure Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 11/25] riscv: kasan: use local_tlb_flush_all() to avoid uninitialized __sbi_rfence Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 12/25] parisc: add support for cmpxchg on u8 pointers Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 13/25] net: ethernet: ravb: exit if re-initialization fails in tx timeout Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 14/25] selftest: txtimestamp: fix net ns entry logic Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 15/25] drivers/net/wan/x25_asy: Fix to make it work Sasha Levin
2020-07-27 23:23 ` Sasha Levin [this message]
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 17/25] i2c: cadence: Clear HOLD bit at correct time in Rx path Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 18/25] x86/unwind/orc: Fix ORC for newly forked tasks Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 19/25] x86/stacktrace: Fix reliable check for empty user task stacks Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 20/25] cxgb4: add missing release on skb in uld_send() Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 21/25] io_uring: missed req_init_async() for IOSQE_ASYNC Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 22/25] xen-netfront: fix potential deadlock in xennet_remove() Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 23/25] RISC-V: Set maximum number of mapped pages correctly Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 24/25] drivers/net/wan: lapb: Corrected the usage of skb_cow Sasha Levin
2020-07-27 23:23 ` [PATCH AUTOSEL 5.7 25/25] riscv: Parse all memory blocks to remove unusable memory Sasha Levin

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