From: Sascha Hauer <s.hauer@pengutronix.de>
To: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 2/3] console: Add simplified 'serdev' framework from Linux kernel
Date: Tue, 3 Apr 2018 08:54:36 +0200 [thread overview]
Message-ID: <20180403065436.p2vec7ntdja55hts@pengutronix.de> (raw)
In-Reply-To: <20180326130915.8726-3-andrew.smirnov@gmail.com>
Hi Andrey,
Some comments inside.
On Mon, Mar 26, 2018 at 06:09:14AM -0700, Andrey Smirnov wrote:
> Port 'serdev' UART-slave deivce framework found in recent Linux
> kernels (post 4.13) in order to be able to port 'serdev' slave drivers
> from Linux.
>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> @@ -323,6 +324,17 @@ int console_register(struct console_device *newcdev)
> dev->parent = newcdev->dev;
> platform_device_register(dev);
>
> + newcdev->open_count = 0;
> +
> + /*
> + * If our console deive is a serdev, we skip the creation of
s/deive/device/
> + * corresponding entry in /dev as well as registration in
> + * console_list and just go straigh to populating child
s/straigh/straight/
> + * devices.
> + */
> + if (serdev_node)
> + return of_platform_populate(serdev_node, NULL, dev);
How is this going to be used? A serdev driver binds to the serdev_node
and then it probably needs to get a pointer to the console device,
right? How does the driver accomplish this?
> +/**
> + * struct serdev_device - Basic representation of an serdev device
> + *
> + * @dev: Corresponding device
> + * @fifo: Circular buffer used for console draining
> + * @buf: Buffer used to pass Rx data to consumers
> + * @poller Async poller used to poll this serdev
> + * @polling_interval: Async poller periodicity
> + * @polling_window: Duration of a single busy loop poll
> + * @receive_buf: Function called with data received from device;
> + * returns number of bytes accepted;
> + */
> +struct serdev_device {
> + struct device_d *dev;
> + struct kfifo *fifo;
> + unsigned char *buf;
> + struct poller_async poller;
> + uint64_t polling_interval;
> + uint64_t polling_window;
> +
> + int (*receive_buf)(struct serdev_device *, const unsigned char *,
> + size_t);
> +};
> +
> +int serdev_device_open(struct serdev_device *);
> +unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
> +int serdev_device_write(struct serdev_device *, const unsigned char *,
> + size_t, unsigned long);
So a serdev driver uses serdev_device_write() to send characters out. To
receive characters it has to implement serdev_device->receive_buf,
right? What kind of devices did you implement this for? For devices
which send data without request (GPS?) this seems the way to go. For
others a synchronous receive function might be good, no?
Sascha
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next prev parent reply other threads:[~2018-04-03 6:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 13:09 [PATCH 0/3] Linux's serdev framwork port Andrey Smirnov
2018-03-26 13:09 ` [PATCH 1/3] console: Introduce console_drain() Andrey Smirnov
2018-03-26 13:09 ` [PATCH 2/3] console: Add simplified 'serdev' framework from Linux kernel Andrey Smirnov
2018-04-03 6:54 ` Sascha Hauer [this message]
2018-04-09 16:40 ` Andrey Smirnov
2018-04-11 8:39 ` Sascha Hauer
2018-04-12 18:22 ` Andrey Smirnov
2018-03-26 13:09 ` [PATCH 3/3] serial: Check result of console_unregister() Andrey Smirnov
2018-04-03 7:04 ` Sascha Hauer
2018-04-09 16:00 ` Andrey Smirnov
2018-04-11 8:34 ` Sascha Hauer
2018-04-12 18:20 ` Andrey Smirnov
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