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[109.252.138.165]) by smtp.googlemail.com with ESMTPSA id z22sm2902744lji.63.2022.02.10.12.25.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Feb 2022 12:25:24 -0800 (PST) Message-ID: Date: Thu, 10 Feb 2022 23:25:24 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH RESEND] i2c: tegra: Add SMBus block read function Content-Language: en-US To: Akhil R , christian.koenig@amd.com, jonathanh@nvidia.com, ldewangan@nvidia.com, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, mperttunen@nvidia.com, p.zabel@pengutronix.de, sumit.semwal@linaro.org, thierry.reding@gmail.com References: <20220210153603.61894-1-akhilrajeev@nvidia.com> From: Dmitry Osipenko In-Reply-To: <20220210153603.61894-1-akhilrajeev@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org 10.02.2022 18:36, Akhil R пишет: > Emulate SMBus block read using ContinueXfer to read the length byte > > Signed-off-by: Akhil R > --- > drivers/i2c/busses/i2c-tegra.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index 03cea102ab76..2941e42aa6a0 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -1233,6 +1233,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, > return err; > > i2c_dev->msg_buf = msg->buf; > + > + /* The condition true implies smbus block read and len is already read */ > + if (msg->flags & I2C_M_RECV_LEN && end_state != MSG_END_CONTINUE) > + i2c_dev->msg_buf = msg->buf + 1; > + > i2c_dev->msg_buf_remaining = msg->len; > i2c_dev->msg_err = I2C_ERR_NONE; > i2c_dev->msg_read = !!(msg->flags & I2C_M_RD); > @@ -1389,6 +1394,15 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], > else > end_type = MSG_END_REPEAT_START; > } > + /* If M_RECV_LEN use ContinueXfer to read the first byte */ > + if (msgs[i].flags & I2C_M_RECV_LEN) { > + ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], MSG_END_CONTINUE); > + if (ret) > + break; > + /* Set the read byte as msg len */ > + msgs[i].len = msgs[i].buf[0]; > + dev_dbg(i2c_dev->dev, "reading %d bytes\n", msgs[i].len); > + } > ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type); > if (ret) > break; > @@ -1416,10 +1430,10 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap) > { > struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap); > u32 ret = I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | > - I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; > + I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; > > if (i2c_dev->hw->has_continue_xfer_support) > - ret |= I2C_FUNC_NOSTART; > + ret |= I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_READ_BLOCK_DATA; > > return ret; > } Please describe how this was tested.