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 <[email protected]>
> ---
> 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");
>
