Re: [PATCH v7 1/4] mfd: add support for Diolan DLN-2 devices

[Joe Perches <joe@perches.com>]

On Thu, 2014-10-09 at 22:22 +0300, Octavian Purdila wrote:
> This patch implements the USB part of the Diolan USB-I2C/SPI/GPIO
> Master Adapter DLN-2. Details about the device can be found here:

trivia:

> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
[]
> +config MFD_DLN2
> +	tristate "Diolan DLN2 support"
> +	select MFD_CORE
> +	depends on USB
> +	help
> +	  This adds support for Diolan USB-I2C/SPI/GPIO Master Adapter DLN-2.
> +	  Additional drivers must be enabled in order to use the functionality
> +	  of the device.

additional drivers like...

> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
[]
+struct dln2_mod_rx_slots {
+       /* RX slots bitmap */
+       unsigned long bmap;

Probably better as:
	DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);

Then a lot of &ptr->bmap uses can be ptr->bmap

> +struct dln2_dev {
> +	struct usb_device *usb_dev;
> +	struct usb_interface *interface;
> +	u8 ep_in;
> +	u8 ep_out;
> +
> +	struct urb *rx_urb[DLN2_MAX_URBS];
> +	void *rx_buf[DLN2_MAX_URBS];
> +
> +	struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];
> +
> +	struct list_head event_cb_list;
> +	spinlock_t event_cb_lock;
> +
> +	bool disconnect;
> +	int active_transfers;
> +	wait_queue_head_t disconnect_wq;
> +	spinlock_t disconnect_lock;
> +};

Maybe reorder the bools and u8s to pack this a bit better?

> +int dln2_register_event_cb(struct platform_device *pdev, u16 id,
> +			   dln2_event_cb_t rx_cb)
> +{
> +	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
> +	struct dln2_event_cb_entry *i, *new;

new isn't a very good name

> +static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
> +				     void *data, int len)
> +{
> +	struct dln2_event_cb_entry *i;
> +
> +	rcu_read_lock();
> +
> +	list_for_each_entry_rcu(i, &dln2->event_cb_list, list)
> +		if (i->id == id)
> +			i->callback(i->pdev, echo, data, len);

probably nicer with braces

> +static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
> +			      struct usb_host_interface *hostif)
> +{
> +	int i;
> +	const int rx_max_size = DLN2_RX_BUF_SIZE;
> +
> +	for (i = 0; i < DLN2_MAX_URBS; i++) {
> +		int ret;
> +		struct device *dev = &dln2->interface->dev;
> +
> +		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
> +		if (!dln2->rx_buf[i])
> +			return -ENOMEM;

memory leaks on failure?