From: Ray Jui <ray.jui@broadcom.com> To: Wolfram Sang <wsa@the-dreams.de>, Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> Cc: Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, Florian Fainelli <f.fainelli@gmail.com>, Lori Hikichi <lori.hikichi@broadcom.com>, Icarus Chau <icarus.chau@broadcom.com>, Shivaraj Shetty <sshetty1@broadcom.com> Subject: Re: [PATCH v1 1/1] i2c: iproc: Add i2c repeated start capability Date: Fri, 30 Aug 2019 11:35:08 -0700 [thread overview] Message-ID: <3e70fa7e-de13-4edd-2e17-b7c56e91d220@broadcom.com> (raw) In-Reply-To: <20190830125626.GC2870@ninjato> On 8/30/19 5:56 AM, Wolfram Sang wrote: > Hi everyone, > >> +/* >> + * If 'process_call' is true, then this is a multi-msg transfer that requires >> + * a repeated start between the messages. >> + * More specifically, it must be a write (reg) followed by a read (data). >> + * The i2c quirks are set to enforce this rule. >> + */ > > With all the limitations in place, I wonder if it might be easier to > implement an smbus_xfer callback instead? What is left that makes this > controller more than SMBus and real I2C? > Right. But what is the implication of using smbus_xfer instead of master_xfer in our driver? Does it mean it will break existing functions of the i2c app that our customers developed based on i2cdev (e.g., I2C_RDWR)? 1) Does >> + /* Process the read message if this is process call */ > > Also, the term "process call" here seriously sounds like SMBus. > >> + addr = msg->addr << 1 | 1; > > addr = i2c_8bit_addr_from_msg(msg); > >> + u32 protocol; > > Hmm, another SMBus terminology. > > >> + if (num > 2) { >> + dev_err(iproc_i2c->device, >> + "Only support up to 2 messages. Current msg count %d\n", >> + num); >> + return -EOPNOTSUPP; >> + } > > With your quirks flags set, the core checks it for you. > > Kind regards, > > Wolfram >
WARNING: multiple messages have this Message-ID (diff)
From: Ray Jui <ray.jui@broadcom.com> To: Wolfram Sang <wsa@the-dreams.de>, Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com> Cc: Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org, Lori Hikichi <lori.hikichi@broadcom.com>, Florian Fainelli <f.fainelli@gmail.com>, Shivaraj Shetty <sshetty1@broadcom.com>, linux-kernel@vger.kernel.org, Icarus Chau <icarus.chau@broadcom.com>, Rob Herring <robh+dt@kernel.org>, bcm-kernel-feedback-list@broadcom.com, linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v1 1/1] i2c: iproc: Add i2c repeated start capability Date: Fri, 30 Aug 2019 11:35:08 -0700 [thread overview] Message-ID: <3e70fa7e-de13-4edd-2e17-b7c56e91d220@broadcom.com> (raw) In-Reply-To: <20190830125626.GC2870@ninjato> On 8/30/19 5:56 AM, Wolfram Sang wrote: > Hi everyone, > >> +/* >> + * If 'process_call' is true, then this is a multi-msg transfer that requires >> + * a repeated start between the messages. >> + * More specifically, it must be a write (reg) followed by a read (data). >> + * The i2c quirks are set to enforce this rule. >> + */ > > With all the limitations in place, I wonder if it might be easier to > implement an smbus_xfer callback instead? What is left that makes this > controller more than SMBus and real I2C? > Right. But what is the implication of using smbus_xfer instead of master_xfer in our driver? Does it mean it will break existing functions of the i2c app that our customers developed based on i2cdev (e.g., I2C_RDWR)? 1) Does >> + /* Process the read message if this is process call */ > > Also, the term "process call" here seriously sounds like SMBus. > >> + addr = msg->addr << 1 | 1; > > addr = i2c_8bit_addr_from_msg(msg); > >> + u32 protocol; > > Hmm, another SMBus terminology. > > >> + if (num > 2) { >> + dev_err(iproc_i2c->device, >> + "Only support up to 2 messages. Current msg count %d\n", >> + num); >> + return -EOPNOTSUPP; >> + } > > With your quirks flags set, the core checks it for you. > > Kind regards, > > Wolfram > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-08-30 18:35 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-07 4:09 [PATCH v1 1/1] i2c: iproc: Add i2c repeated start capability Rayagonda Kokatanur 2019-08-07 4:09 ` Rayagonda Kokatanur 2019-08-07 4:09 ` Rayagonda Kokatanur 2019-08-12 17:33 ` Ray Jui 2019-08-12 17:33 ` Ray Jui 2019-08-29 20:41 ` Wolfram Sang 2019-08-29 20:41 ` Wolfram Sang 2019-08-30 12:56 ` Wolfram Sang 2019-08-30 12:56 ` Wolfram Sang 2019-08-30 18:35 ` Ray Jui [this message] 2019-08-30 18:35 ` Ray Jui 2019-08-31 9:49 ` Wolfram Sang 2019-08-31 9:49 ` Wolfram Sang 2019-09-03 23:11 ` Ray Jui 2019-09-03 23:11 ` Ray Jui 2019-09-04 21:37 ` Wolfram Sang 2019-09-04 21:37 ` Wolfram Sang 2019-09-24 17:23 ` Ray Jui 2019-09-24 17:23 ` Ray Jui 2019-09-24 18:57 ` Wolfram Sang 2019-09-24 18:57 ` Wolfram Sang 2019-09-24 22:23 ` Ray Jui 2019-09-24 22:23 ` Ray Jui
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