Messages in this thread | | | Subject | Re: [PATCH v10] i2c: virtio: add a virtio i2c frontend driver | From | Jie Deng <> | Date | Wed, 30 Jun 2021 14:45:55 +0800 |
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On 2021/6/29 18:07, Wolfram Sang wrote:
> Hi, > > so some minor comments left: > >> + if (!msgs[i].len) >> + break; > I hope this can extended in the future to allow zero-length messages. If > this is impossible we need to set an adapter quirk instead.
Yes, we can support it by removing this check and call it zero-length request. It don't think it will break anything.
> >> + err = virtqueue_add_sgs(vq, sgs, outcnt, incnt, &reqs[i], GFP_KERNEL); >> + if (err < 0) { >> + pr_err("failed to add msg[%d] to virtqueue.\n", i); > Is it really helpful for the user to know that msg5 failed? We don't > even say which transfer.
OK. I will remove this print.
>> +static u32 virtio_i2c_func(struct i2c_adapter *adap) >> +{ >> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; > You are not emulating I2C_FUNC_SMBUS_QUICK, so you need to mask it out.
I will remove the check of zero-length message.
> >> + snprintf(vi->adap.name, sizeof(vi->adap.name), "Virtio I2C Adapter"); > Is there something to add so you can distinguish multiple instances? > Most people want that.
I find the I2C core will set a device name "i2c-%d" for this purpose, right?
I think this name can be used to distinguish the adapter types while "i2c-%d" can be used to
distinguish instances. Does it make sense ?
>> + vi->adap.class = I2C_CLASS_DEPRECATED; >> + vi->adap.algo = &virtio_algorithm; >> + vi->adap.dev.parent = &vdev->dev; >> + vi->adap.timeout = HZ / 10; > Why so short? HZ is the kinda default value.
Ah... I didn't know the I2C core had already set a default value. I will remove this line to use the default one.
> >> + i2c_set_adapdata(&vi->adap, vi); >> + >> + /* Setup ACPI node for controlled devices which will be probed through ACPI */ >> + ACPI_COMPANION_SET(&vi->adap.dev, ACPI_COMPANION(pdev)); >> + >> + ret = i2c_add_adapter(&vi->adap); >> + if (ret) { >> + virtio_i2c_del_vqs(vdev); >> + dev_err(&vdev->dev, "failed to add virtio-i2c adapter.\n"); > Won't the driver core print that for us?
Yes. It seems unnecessary. Will remove it.
> >> + } >> + >> + return ret; >> +} >> + >> +/* The bit 0 of the @virtio_i2c_out_hdr.@flags, used to group the requests */ >> +#define VIRTIO_I2C_FLAGS_FAIL_NEXT 0x00000001 > BIT(0)?
That's better. Thank you.
> > Happy hacking, > > Wolfram >
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