From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie James Subject: Re: [PATCH v10 5/7] i2c: fsi: Add transfer implementation Date: Wed, 27 Jun 2018 08:21:30 -0500 Message-ID: <6713efb9-c4c3-f648-a1e9-7918110091e4@linux.vnet.ibm.com> References: <1528918579-27602-1-git-send-email-eajames@linux.vnet.ibm.com> <1528918579-27602-6-git-send-email-eajames@linux.vnet.ibm.com> <20180626023823.i3fmdegn2sric5kx@ninjato> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20180626023823.i3fmdegn2sric5kx@ninjato> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org, benh@kernel.crashing.org, joel@jms.id.au, mark.rutland@arm.com, gregkh@linuxfoundation.org, rdunlap@infradead.org, andy.shevchenko@gmail.com, peda@axentia.se List-Id: devicetree@vger.kernel.org On 06/25/2018 09:38 PM, Wolfram Sang wrote: > On Wed, Jun 13, 2018 at 02:36:17PM -0500, Eddie James wrote: >> Execute I2C transfers from the FSI-attached I2C master. Use polling >> instead of interrupts as we have no hardware IRQ over FSI. >> >> Signed-off-by: Eddie James >> --- >> drivers/i2c/busses/i2c-fsi.c | 195 ++++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 193 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c >> index 4611a0b..8c0a6cb 100644 >> --- a/drivers/i2c/busses/i2c-fsi.c >> +++ b/drivers/i2c/busses/i2c-fsi.c >> @@ -155,6 +155,7 @@ struct fsi_i2c_port { >> struct i2c_adapter adapter; >> struct fsi_i2c_master *master; >> u16 port; >> + u16 xfrd; >> }; >> >> static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg, >> @@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) >> return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy); >> } >> >> +static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg, >> + bool stop) >> +{ >> + struct fsi_i2c_master *i2c = port->master; >> + u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR; >> + >> + port->xfrd = 0; >> + >> + if (msg->flags & I2C_M_RD) >> + cmd |= I2C_CMD_READ; > Since you support MANGLING, I'd think you can easily support > I2C_M_REV_DIR_ADDR here, too? Hm, I don't really understand the purpose of that flag. From the docs: This toggles the Rd/Wr flag. That is, if you want to do a write, but     need to emit an Rd instead of a Wr, or vice versa, you set this     flag. For example: S Addr Rd [A] Data [A] Data [A] ... [A] Data [A] P I don't think our hardware supports this type of operation. Thanks, Eddie >