From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jun Gao Subject: [PATCH 2/3] i2c: Add helper to ease DMA handling Date: Sat, 7 Jul 2018 10:49:12 +0800 Message-ID: <1530931753-8264-3-git-send-email-jun.gao@mediatek.com> References: <1530931753-8264-1-git-send-email-jun.gao@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1530931753-8264-1-git-send-email-jun.gao@mediatek.com> Sender: linux-kernel-owner@vger.kernel.org To: Wolfram Sang Cc: srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, Jun Gao List-Id: devicetree@vger.kernel.org From: Jun Gao This function is needed by i2c_get_dma_safe_msg_buf() potentially. It is used to free DMA safe buffer when DMA operation fails. Signed-off-by: Jun Gao --- drivers/i2c/i2c-core-base.c | 14 ++++++++++++++ include/linux/i2c.h | 1 + 2 files changed, 15 insertions(+) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 31d16ad..2b518ea 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -2288,6 +2288,20 @@ void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf) } EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf); +/** + * i2c_free_dma_safe_msg_buf - free DMA safe buffer + * @msg: the message related to DMA safe buffer + * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL. + */ +void i2c_free_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf) +{ + if (!buf || buf == msg->buf) + return; + + kfree(buf); +} +EXPORT_SYMBOL_GPL(i2c_free_dma_safe_msg_buf); + MODULE_AUTHOR("Simon G. Vogl "); MODULE_DESCRIPTION("I2C-Bus main module"); MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 254cd34..6d62f93 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -860,6 +860,7 @@ static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg) u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold); void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf); +void i2c_free_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf); int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr); /** -- 1.8.1.1