From: Wolfram Sang <wsa@the-dreams.de>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: robh+dt@kernel.org, afaerber@suse.de, linus.walleij@linaro.org,
linux-i2c@vger.kernel.org, liuwei@actions-semi.com,
mp-cs@actions-semi.com, 96boards@ucrobotics.com,
devicetree@vger.kernel.org, andy.shevchenko@gmail.com,
daniel.thompson@linaro.org, amit.kucheria@linaro.org,
linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org, hzhang@ucrobotics.com,
bdong@ucrobotics.com, manivannanece23@gmail.com,
thomas.liau@actions-semi.com, jeff.chen@actions-semi.com
Subject: Re: [PATCH v7 5/6] i2c: Add Actions Semiconductor Owl family S900 I2C driver
Date: Tue, 31 Jul 2018 22:09:32 +0200 [thread overview]
Message-ID: <20180731200932.n7djds2rmqhclit5@ninjato> (raw)
In-Reply-To: <20180726154603.5089-6-manivannan.sadhasivam@linaro.org>
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Hi Manivannan,
On Thu, Jul 26, 2018 at 09:16:02PM +0530, Manivannan Sadhasivam wrote:
> Add Actions Semiconductor Owl family S900 I2C driver.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Acked-by: Peter Rosin <peda@axentia.se>
Looks mostly good already. Thanks Peter for the initial review!
> +static irqreturn_t owl_i2c_interrupt(int irq, void *_dev)
> +{
> + struct owl_i2c_dev *i2c_dev = _dev;
> + struct i2c_msg *msg = i2c_dev->msg;
> + unsigned long flags;
> + unsigned int stat, fifostat;
> +
> + spin_lock_irqsave(&i2c_dev->lock, flags);
> +
> + fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
> + if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
> + dev_dbg(&i2c_dev->adap.dev, "received NACK from device\n");
> + goto stop;
> + }
> +
> + stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
> + if (stat & OWL_I2C_STAT_BEB) {
> + dev_dbg(&i2c_dev->adap.dev, "bus error\n");
> + goto stop;
> + }
I wonder if you can't pass back the different errors to the upper
layers? Like -ENXIO for NACK and -EIO for bus error? We have a
convention for that and it seems your HW can support it. The different
error codes would then maybe also make the debug outputs obsolete.
> + /*
> + * Here, -ENXIO will be returned if interrupt occurred but no
> + * read or write happened. Else if msg_ptr equals to message length,
> + * message count will be returned.
> + */
> + ret = i2c_dev->msg_ptr == msg->len ? num : -ENXIO;
I'd think this kinda unusual construct could go then as well by just
returning the error code derived from the interrupt handler above.
> +static const struct i2c_adapter_quirks owl_i2c_quirks = {
> + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST,
> + .max_read_len = 240,
> + .max_write_len = 240,
> + .max_comb_1st_msg_len = 6,
> + .max_comb_2nd_msg_len = 240,
> +};
Yay! Good use of the i2c_adapter_quirks struct :)
Regards,
Wolfram
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next prev parent reply other threads:[~2018-07-31 20:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-26 15:45 [PATCH v7 0/6] Add Actions Semiconductor Owl S900 I2C support Manivannan Sadhasivam
2018-07-26 15:45 ` [PATCH v7 1/6] dt-bindings: i2c: Add binding for Actions Semiconductor Owl I2C controller Manivannan Sadhasivam
2018-07-26 15:45 ` [PATCH v7 2/6] arm64: dts: actions: Add pinctrl definition for S900 " Manivannan Sadhasivam
2018-07-26 15:46 ` [PATCH v7 3/6] arm64: dts: actions: Add Actions Semiconductor S900 I2C controller nodes Manivannan Sadhasivam
2018-07-26 15:46 ` [PATCH v7 4/6] arm64: dts: actions: Enable I2C1 and I2C2 in Bubblegum-96 board Manivannan Sadhasivam
2018-07-26 15:46 ` [PATCH v7 5/6] i2c: Add Actions Semiconductor Owl family S900 I2C driver Manivannan Sadhasivam
2018-07-31 20:09 ` Wolfram Sang [this message]
2018-08-01 4:56 ` Manivannan Sadhasivam
2018-07-26 15:46 ` [PATCH v7 6/6] MAINTAINERS: Add entry for Actions Semiconductor Owl " Manivannan Sadhasivam
2018-07-30 17:07 ` [PATCH v7 0/6] Add Actions Semiconductor Owl S900 I2C support Manivannan Sadhasivam
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