From: Peter Rosin <peda@axentia.se>
To: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>,
robh@kernel.org, linux-serial@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org, magnus.damm@gmail.com,
laurent.pinchart@ideasonboard.com, wsa@the-dreams.de,
linux-i2c@vger.kernel.org
Subject: Re: [RFC 3/4] max9260: add driver for i2c over GMSL passthrough
Date: Thu, 15 Jun 2017 09:09:34 +0200 [thread overview]
Message-ID: <e2742752-19d2-95ed-ada9-ba4ad3c54379@axentia.se> (raw)
In-Reply-To: <1497451130-7741-4-git-send-email-ulrich.hecht+renesas@gmail.com>
On 2017-06-14 16:38, Ulrich Hecht wrote:
> This driver implements tunnelling of i2c requests over GMSL via a
> MAX9260 deserializer. It provides an i2c adapter that can be used
> to reach devices on the far side of the link.
>
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
> ---
> drivers/media/i2c/Kconfig | 6 +
> drivers/media/i2c/Makefile | 1 +
> drivers/media/i2c/max9260.c | 294 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 301 insertions(+)
> create mode 100644 drivers/media/i2c/max9260.c
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 7c23b7a..743f8ee 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -400,6 +400,12 @@ config VIDEO_VPX3220
> To compile this driver as a module, choose M here: the
> module will be called vpx3220.
>
> +config VIDEO_MAX9260
> + tristate "Maxim MAX9260 GMSL deserializer support"
> + depends on I2C
> + ---help---
> + This driver supports the Maxim MAX9260 GMSL deserializer.
> +
> comment "Video and audio decoders"
>
> config VIDEO_SAA717X
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index 62323ec..9b2fd13 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -86,3 +86,4 @@ obj-$(CONFIG_VIDEO_IR_I2C) += ir-kbd-i2c.o
> obj-$(CONFIG_VIDEO_ML86V7667) += ml86v7667.o
> obj-$(CONFIG_VIDEO_OV2659) += ov2659.o
> obj-$(CONFIG_VIDEO_TC358743) += tc358743.o
> +obj-$(CONFIG_VIDEO_MAX9260) += max9260.o
> diff --git a/drivers/media/i2c/max9260.c b/drivers/media/i2c/max9260.c
> new file mode 100644
> index 0000000..2030eb0
> --- /dev/null
> +++ b/drivers/media/i2c/max9260.c
> @@ -0,0 +1,294 @@
> +/*
> + * Maxim MAX9260 GMSL Deserializer Driver
> + *
> + * Copyright (C) 2017 Ulrich Hecht
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/serdev.h>
> +#include <linux/slab.h>
> +#include <linux/tty.h>
> +
> +#define SYNC 0x79
> +#define ACK 0xc3
> +
> +#define RX_FINISHED 0
> +#define RX_FRAME_ERROR 1
> +#define RX_EXPECT_ACK 2
> +#define RX_EXPECT_ACK_DATA 3
> +#define RX_EXPECT_DATA 4
> +
> +struct max9260_device {
> + struct serdev_device *serdev;
> + u8 *rx_buf;
> + int rx_len;
> + int rx_state;
> + wait_queue_head_t rx_wq;
> + struct i2c_adapter adap;
> +};
> +
> +static void wait_for_transaction(struct max9260_device *dev)
> +{
> + wait_event_interruptible_timeout(dev->rx_wq,
> + dev->rx_state <= RX_FRAME_ERROR,
> + HZ/2);
> +}
> +
> +static void transact(struct max9260_device *dev,
> + int expect,
> + u8 *request, int len)
> +{
> + serdev_device_mux_select(dev->serdev);
You don't check the return value here...
> +
> + serdev_device_set_baudrate(dev->serdev, 115200);
> + serdev_device_set_parity(dev->serdev, 1, 0);
> +
> + dev->rx_state = expect;
> + serdev_device_write_buf(dev->serdev, request, len);
> +
> + wait_for_transaction(dev);
> +
> + serdev_device_mux_deselect(dev->serdev);
...and unconditionally deselect the mux here. I.e. a potential
unlock of an unlocked mutex...
Cheers,
peda
> +}
> +
> +static int max9260_read_reg(struct max9260_device *dev, int reg)
> +{
> + u8 request[] = { 0x79, 0x91, reg, 1 };
> + u8 rx;
> +
> + dev->rx_len = 1;
> + dev->rx_buf = ℞
> +
> + transact(dev, RX_EXPECT_ACK_DATA, request, 4);
> +
> + if (dev->rx_state == RX_FINISHED)
> + return rx;
> +
> + return -1;
> +}
> +
> +static int max9260_setup(struct max9260_device *dev)
> +{
> + int ret;
> +
> + ret = max9260_read_reg(dev, 0x1e);
> +
> + if (ret != 0x02) {
> + dev_err(&dev->serdev->dev,
> + "device does not identify as MAX9260\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static void max9260_uart_write_wakeup(struct serdev_device *serdev)
> +{
> +}
> +
> +static int max9260_uart_receive_buf(struct serdev_device *serdev,
> + const u8 *data, size_t count)
> +{
> + struct max9260_device *dev = serdev_device_get_drvdata(serdev);
> + int accepted;
> +
> + switch (dev->rx_state) {
> + case RX_FINISHED:
> + dev_dbg(&dev->serdev->dev, "excess data ignored\n");
> + return count;
> +
> + case RX_EXPECT_ACK:
> + case RX_EXPECT_ACK_DATA:
> + if (data[0] != ACK) {
> + dev_dbg(&dev->serdev->dev, "frame error");
> + dev->rx_state = RX_FRAME_ERROR;
> + wake_up_interruptible(&dev->rx_wq);
> + return 1;
> + }
> + switch (dev->rx_state) {
> + case RX_EXPECT_ACK_DATA:
> + dev->rx_state = RX_EXPECT_DATA;
> + break;
> + case RX_EXPECT_ACK:
> + dev->rx_state = RX_FINISHED;
> + wake_up_interruptible(&dev->rx_wq);
> + break;
> + }
> + return 1;
> +
> + case RX_EXPECT_DATA:
> + accepted = dev->rx_len < count ? dev->rx_len : count;
> +
> + memcpy(dev->rx_buf, data, accepted);
> +
> + dev->rx_len -= accepted;
> + dev->rx_buf += accepted;
> +
> + if (!dev->rx_len) {
> + dev->rx_state = RX_FINISHED;
> + wake_up_interruptible(&dev->rx_wq);
> + }
> +
> + return accepted;
> +
> + case RX_FRAME_ERROR:
> + dev_dbg(&dev->serdev->dev, "%d bytes ignored\n", count);
> + return count;
> +
> + }
> + return 0;
> +}
> +
> +struct serdev_device_ops max9260_serdev_client_ops = {
> + .receive_buf = max9260_uart_receive_buf,
> + .write_wakeup = max9260_uart_write_wakeup,
> +};
> +
> +static u32 max9260_i2c_func(struct i2c_adapter *adapter)
> +{
> + return I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static s32 max9260_smbus_xfer(struct i2c_adapter *adap, u16 addr,
> + unsigned short flags, char read_write, u8 command, int size,
> + union i2c_smbus_data *data)
> +{
> + u8 request[] = { SYNC,
> + (addr << 1) + (read_write == I2C_SMBUS_READ),
> + command, 0, 0 };
> + struct max9260_device *dev = i2c_get_adapdata(adap);
> +
> + switch (size) {
> + case I2C_SMBUS_BYTE:
> + if (read_write == I2C_SMBUS_WRITE) {
> + transact(dev, RX_EXPECT_ACK, request, 4);
> + dev_dbg(&adap->dev,
> + "smbus byte - addr 0x%02x, wrote 0x%02x.\n",
> + addr, command);
> + } else {
> + /* TBD */
> + return -EOPNOTSUPP;
> + }
> + break;
> +
> + case I2C_SMBUS_BYTE_DATA:
> + request[3] = 1;
> + if (read_write == I2C_SMBUS_WRITE) {
> + request[4] = data->byte;
> + transact(dev, RX_EXPECT_ACK, request, 5);
> + dev_dbg(&adap->dev,
> + "smbus byte data - addr 0x%02x, wrote 0x%02x at 0x%02x.\n",
> + addr, data->byte, command);
> + } else {
> + dev->rx_len = 1;
> + dev->rx_buf = &data->byte;
> + transact(dev, RX_EXPECT_ACK_DATA, request, 4);
> + dev_dbg(&adap->dev,
> + "smbus byte data - addr 0x%02x, read 0x%02x at 0x%02x.\n",
> + addr, data->byte, command);
> + }
> + break;
> + default:
> + dev_dbg(&adap->dev,
> + "Unsupported I2C/SMBus command %d\n", size);
> + return -EOPNOTSUPP;
> + }
> +
> + if (dev->rx_state != RX_FINISHED) {
> + dev_dbg(&adap->dev, "xfer timed out\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static const struct i2c_algorithm max9260_i2c_algorithm = {
> + .functionality = max9260_i2c_func,
> + .smbus_xfer = max9260_smbus_xfer,
> +};
> +
> +static int max9260_probe(struct serdev_device *serdev)
> +{
> + struct max9260_device *dev;
> + struct i2c_adapter *adap;
> + int ret;
> +
> + dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> + if (!dev)
> + return -ENOMEM;
> +
> + init_waitqueue_head(&dev->rx_wq);
> +
> + dev->serdev = serdev;
> + serdev_device_open(serdev);
> + serdev_device_set_drvdata(serdev, dev);
> +
> + serdev_device_set_client_ops(serdev, &max9260_serdev_client_ops);
> +
> + ret = max9260_setup(dev);
> +
> + if (ret < 0)
> + goto err_free;
> +
> + adap = &dev->adap;
> + i2c_set_adapdata(adap, dev);
> +
> + adap->owner = THIS_MODULE;
> + adap->algo = &max9260_i2c_algorithm;
> + adap->dev.parent = &serdev->dev;
> + adap->retries = 5;
> + adap->nr = -1;
> + strlcpy(adap->name, dev_name(&serdev->dev), sizeof(adap->name));
> +
> + ret = i2c_add_numbered_adapter(adap);
> + if (ret < 0) {
> + dev_err(&serdev->dev, "failed to register i2c adapter\n");
> + return ret;
> + }
> +
> + return 0;
> +
> +err_free:
> + kfree(dev);
> + return ret;
> +}
> +
> +static void max9260_remove(struct serdev_device *serdev)
> +{
> + struct max9260_device *dev = serdev_device_get_drvdata(serdev);
> +
> + serdev_device_close(dev->serdev);
> +
> + kfree(dev);
> +}
> +
> +static const struct of_device_id max9260_dt_ids[] = {
> + { .compatible = "maxim,max9260" },
> + {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, max9260_dt_ids);
> +
> +static struct serdev_device_driver max9260_driver = {
> + .probe = max9260_probe,
> + .remove = max9260_remove,
> + .driver = {
> + .name = "max9260",
> + .of_match_table = of_match_ptr(max9260_dt_ids),
> + },
> +};
> +
> +module_serdev_device_driver(max9260_driver);
> +
> +MODULE_DESCRIPTION("Maxim MAX9260 GMSL Deserializer Driver");
> +MODULE_AUTHOR("Ulrich Hecht");
> +MODULE_LICENSE("GPL");
>
next prev parent reply other threads:[~2017-06-15 7:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-14 14:38 [RFC 0/4] serdev GPIO-based multiplexing support Ulrich Hecht
2017-06-14 14:38 ` [RFC 1/4] serdev: add method to set parity Ulrich Hecht
2017-06-14 14:38 ` [RFC 2/4] serdev: add GPIO-based multiplexer support Ulrich Hecht
2017-06-15 9:34 ` Geert Uytterhoeven
2017-06-14 14:38 ` [RFC 3/4] max9260: add driver for i2c over GMSL passthrough Ulrich Hecht
2017-06-15 7:09 ` Peter Rosin [this message]
2017-06-15 15:37 ` Wolfram Sang
2017-06-14 14:38 ` [RFC 4/4] ARM: dts: blanche: add SCIF1 and MAX9260 deserializer Ulrich Hecht
2017-06-15 13:05 ` Rob Herring
2017-06-15 7:07 ` [RFC 0/4] serdev GPIO-based multiplexing support Peter Rosin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e2742752-19d2-95ed-ada9-ba4ad3c54379@axentia.se \
--to=peda@axentia.se \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-renesas-soc@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=magnus.damm@gmail.com \
--cc=robh@kernel.org \
--cc=ulrich.hecht+renesas@gmail.com \
--cc=wsa@the-dreams.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.