From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28E7A1F76AF; Tue, 21 Jan 2025 18:10:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737483040; cv=none; b=TjFWVHb2KtWyNJGPNKIL7ysFvdLcYnXKYgjLWsKW+E66AUgI7rJr9uEtYO/8tbUVp+4hXI48I11/eQf//3X6Qh14uajgF6Dx/q1aJojBzQmPY5fghp8EPakJ7HQEDUQnFSsDbr4VV1Nj0Ia1poba5BAYg6WGxyd1R/vj8swzAP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737483040; c=relaxed/simple; bh=2v4nc1GZ53z9RP0Z3kHP5SgffKdOzBKqWBW5qlTQSt0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=byr1buY5Yx8cu2hiIcXPRBjXE7p9vPEDl6XlKidZmV9BksJMORzR8qVMgcCww5bNNTTf9ewd3me06VCo3eDsTMghAEg4W5qU5r9McG+FRl8kMUDmN/h4Z4W5gCw+pwdgiZk3X45G0jJNB++AzECq49cX8VdlI+2ifh5MReKFODY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GPmGBZuc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GPmGBZuc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7312C4CEDF; Tue, 21 Jan 2025 18:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1737483040; bh=2v4nc1GZ53z9RP0Z3kHP5SgffKdOzBKqWBW5qlTQSt0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GPmGBZuck6fkCs0HwYVHMFwoLL6ipAhd3QVMmQS9eeGrImIb7jkDUGiczQ87xKAWx l/QJbjxD5y9yprV3rit7qt3VgJcUwfiuhxWPKZcMzNWKqwsMu6FKzLrgLwBismfQji xcmW7BhhYGr5gMlkbw4ukoUf3y6i2Vwb87bmu6PA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wolfram Sang , Sasha Levin Subject: [PATCH 5.15 095/127] i2c: rcar: fix NACK handling when being a target Date: Tue, 21 Jan 2025 18:52:47 +0100 Message-ID: <20250121174533.310746907@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250121174529.674452028@linuxfoundation.org> References: <20250121174529.674452028@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wolfram Sang [ Upstream commit 093f70c134f70e4632b295240f07d2b50b74e247 ] When this controller is a target, the NACK handling had two issues. First, the return value from the backend was not checked on the initial WRITE_REQUESTED. So, the driver missed to send a NACK in this case. Also, the NACK always arrives one byte late on the bus, even in the WRITE_RECEIVED case. This seems to be a HW issue. We should then not rely on the backend to correctly NACK the superfluous byte as well. Fix both issues by introducing a flag which gets set whenever the backend requests a NACK and keep sending it until we get a STOP condition. Fixes: de20d1857dd6 ("i2c: rcar: add slave support") Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-rcar.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 316dd378fb8c4..afefe99129001 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -112,6 +112,8 @@ #define ID_P_PM_BLOCKED BIT(31) #define ID_P_MASK GENMASK(31, 28) +#define ID_SLAVE_NACK BIT(0) + enum rcar_i2c_type { I2C_RCAR_GEN1, I2C_RCAR_GEN2, @@ -146,6 +148,7 @@ struct rcar_i2c_priv { int irq; struct i2c_client *host_notify_client; + u8 slave_flags; }; #define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent) @@ -576,6 +579,7 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) { u32 ssr_raw, ssr_filtered; u8 value; + int ret; ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff; ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER); @@ -591,7 +595,10 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) rcar_i2c_write(priv, ICRXTX, value); rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR); } else { - i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value); + ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value); + if (ret) + priv->slave_flags |= ID_SLAVE_NACK; + rcar_i2c_read(priv, ICRXTX); /* dummy read */ rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR); } @@ -604,18 +611,21 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) if (ssr_filtered & SSR) { i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value); rcar_i2c_write(priv, ICSCR, SIE | SDBS); /* clear our NACK */ + priv->slave_flags &= ~ID_SLAVE_NACK; rcar_i2c_write(priv, ICSIER, SAR); rcar_i2c_write(priv, ICSSR, ~SSR & 0xff); } /* master wants to write to us */ if (ssr_filtered & SDR) { - int ret; - value = rcar_i2c_read(priv, ICRXTX); ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value); - /* Send NACK in case of error */ - rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0)); + if (ret) + priv->slave_flags |= ID_SLAVE_NACK; + + /* Send NACK in case of error, but it will come 1 byte late :( */ + rcar_i2c_write(priv, ICSCR, SIE | SDBS | + (priv->slave_flags & ID_SLAVE_NACK ? FNA : 0)); rcar_i2c_write(priv, ICSSR, ~SDR & 0xff); } -- 2.39.5