Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4B3BA272E53; Thu, 20 Aug 2026 16:33:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787243631; cv=none; b=ftrTkx9YAkvmQw4vdrfXKsoGjMQP4m+DUB2MsuC+rJ8q579vktum+Yf69heAtF+hhHaAQEmzwXzqqEE9sKVI5e1KwTHiQQ8+zX37O9PsmkqILmFkXasfMTY9k7iLDjbtxap5FxI8SKy5EWpgVvQqg3aahv2T/4kFSjzJOlPZqJU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787243631; c=relaxed/simple; bh=6ivk7S/BeKMY0hdaZfJPncS7RShd0slNhSxCowaqjYk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E/RouYCbG8pBvuChMypV35Kn/i3f2X5EUmWPay9tDMbtRfaz/i/ifQ8rD8Ayw0q8TfdLof+DPYo2uhv8RE0LdVitLpRWFcqvmKO1ykA7a7a8ZF7gUxxpPi1HZSVRF/yeMzlyMMEaC/SEeV5XjaYnvcnSR4CMj/FyiNqJw4kJPrI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=j9w1y4+k; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="j9w1y4+k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A65671F000E9; Thu, 20 Aug 2026 16:33:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787243630; bh=L3WBOgUM7xZao8UkdXlPuVpm1FNU3d7Y5xp4EmrhTss=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=j9w1y4+kjgiveNA4NfmAbPZPwUoWjN6kjz972VN3l5vIArxLsbmjWoW5wY3cJPeE3 /zxNdw2FWcUsM+fe2mYXNwoSKYw8sxNDxIv0hrPIjTYUMTmIyN8asOQ7x9OxHiMbv0 zpjSLjRE2c92b/49T7JTvrEVKzben1syOr7VE0I4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefan Eichenberger , Frank Li , Oleksij Rempel , Andi Shyti , Sasha Levin Subject: [PATCH 5.15 123/272] i2c: imx: separate atomic, dma and non-dma use case Date: Thu, 20 Aug 2026 16:55:07 +0200 Message-ID: <20260820145234.953850640@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145231.229664293@linuxfoundation.org> References: <20260820145231.229664293@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Stefan Eichenberger [ Upstream commit b460b15b3cc23ef3639cc51043bf8b2a70ca1878 ] Separate the atomic, dma and non-dma use case as a preparation step for moving the non-dma use case to the isr to avoid rescheduling while a transfer is in progress. Signed-off-by: Stefan Eichenberger Reviewed-by: Frank Li Acked-by: Oleksij Rempel Signed-off-by: Andi Shyti Stable-dep-of: cb2fc3785769 ("i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-imx.c | 107 ++++++++++++++++++++++++++++--------------- 1 file changed, 70 insertions(+), 37 deletions(-) --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -979,6 +979,43 @@ static int i2c_imx_dma_write(struct imx_ return i2c_imx_acked(i2c_imx); } +static int i2c_imx_prepare_read(struct imx_i2c_struct *i2c_imx, + struct i2c_msg *msgs, bool atomic, + bool use_dma) +{ + int result; + unsigned int temp = 0; + + /* write slave address */ + imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR); + result = i2c_imx_trx_complete(i2c_imx, atomic); + if (result) + return result; + result = i2c_imx_acked(i2c_imx); + if (result) + return result; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__); + + /* setup bus to read data */ + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + temp &= ~I2CR_MTX; + + /* + * Reset the I2CR_TXAK flag initially for SMBus block read since the + * length is unknown + */ + if (msgs->len - 1) + temp &= ~I2CR_TXAK; + if (use_dma) + temp |= I2CR_DMAEN; + + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); + imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */ + + return 0; +} + static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg) { @@ -989,6 +1026,11 @@ static int i2c_imx_dma_read(struct imx_i struct imx_i2c_dma *dma = i2c_imx->dma; struct device *dev = &i2c_imx->adapter.dev; + result = i2c_imx_prepare_read(i2c_imx, msgs, false, true); + if (result) + return result; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); dma->chan_using = dma->chan_rx; dma->dma_transfer_dir = DMA_DEV_TO_MEM; @@ -1099,50 +1141,24 @@ static int i2c_imx_write(struct imx_i2c_ return 0; } +static int i2c_imx_atomic_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) +{ + return i2c_imx_write(i2c_imx, msgs, true); +} + static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg, bool atomic) { int i, result; unsigned int temp; int block_data = msgs->flags & I2C_M_RECV_LEN; - int use_dma = i2c_imx->dma && msgs->flags & I2C_M_DMA_SAFE && - msgs->len >= DMA_THRESHOLD && !block_data; - - dev_dbg(&i2c_imx->adapter.dev, - "<%s> write slave address: addr=0x%x\n", - __func__, i2c_8bit_addr_from_msg(msgs)); - /* write slave address */ - imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR); - result = i2c_imx_trx_complete(i2c_imx, atomic); - if (result) - return result; - result = i2c_imx_acked(i2c_imx); + result = i2c_imx_prepare_read(i2c_imx, msgs, atomic, false); if (result) return result; - dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__); - - /* setup bus to read data */ - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); - temp &= ~I2CR_MTX; - - /* - * Reset the I2CR_TXAK flag initially for SMBus block read since the - * length is unknown - */ - if ((msgs->len - 1) || block_data) - temp &= ~I2CR_TXAK; - if (use_dma) - temp |= I2CR_DMAEN; - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */ - dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); - if (use_dma) - return i2c_imx_dma_read(i2c_imx, msgs, is_lastmsg); - /* read data */ for (i = 0; i < msgs->len; i++) { u8 len = 0; @@ -1209,6 +1225,12 @@ static int i2c_imx_read(struct imx_i2c_s return 0; } +static int i2c_imx_atomic_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, + bool is_lastmsg) +{ + return i2c_imx_read(i2c_imx, msgs, is_lastmsg, true); +} + static int i2c_imx_xfer_common(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num, bool atomic) { @@ -1216,6 +1238,7 @@ static int i2c_imx_xfer_common(struct i2 int result; bool is_lastmsg = false; struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter); + int use_dma = 0; /* Start I2C transfer */ result = i2c_imx_start(i2c_imx, atomic); @@ -1268,15 +1291,25 @@ static int i2c_imx_xfer_common(struct i2 (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0), (temp & I2SR_RXAK ? 1 : 0)); #endif + + use_dma = i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD && + msgs[i].flags & I2C_M_DMA_SAFE; if (msgs[i].flags & I2C_M_RD) { - result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg, atomic); + int block_data = msgs->flags & I2C_M_RECV_LEN; + + if (atomic) + result = i2c_imx_atomic_read(i2c_imx, &msgs[i], is_lastmsg); + else if (use_dma && !block_data) + result = i2c_imx_dma_read(i2c_imx, &msgs[i], is_lastmsg); + else + result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg, false); } else { - if (!atomic && - i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD && - msgs[i].flags & I2C_M_DMA_SAFE) + if (atomic) + result = i2c_imx_atomic_write(i2c_imx, &msgs[i]); + else if (use_dma) result = i2c_imx_dma_write(i2c_imx, &msgs[i]); else - result = i2c_imx_write(i2c_imx, &msgs[i], atomic); + result = i2c_imx_write(i2c_imx, &msgs[i], false); } if (result) goto fail0;