On Mon, Jan 24, 2022 at 12:33:43PM -0500, Sean Anderson wrote:
> This adds a debugfs file for ULPI devices which contains a dump of their
> registers. This is useful for debugging basic connectivity problems. The
> file is created in ulpi_register because many devices will never have a
> driver bound (as they are managed in hardware by the USB controller
> device).
>
> This also modifies the error handling in ulpi_register a bit to ensure
> that ulpi->dev.of_node is always put.
>
> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
> ---
>
> Changes in v2:
> - Always create debugfs files and ignore errors
> - Look up dentries dynamically
>
> drivers/usb/common/ulpi.c | 71 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 70 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
> index 4169cf40a03b..87deb514eb78 100644
> --- a/drivers/usb/common/ulpi.c
> +++ b/drivers/usb/common/ulpi.c
> @@ -13,6 +13,7 @@
> #include <linux/module.h>
> #include <linux/slab.h>
> #include <linux/acpi.h>
> +#include <linux/debugfs.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/clk/clk-conf.h>
> @@ -228,9 +229,64 @@ static int ulpi_read_id(struct ulpi *ulpi)
> return 0;
> }
>
> +static int ulpi_regs_read(struct seq_file *seq, void *data)
> +{
> + struct ulpi *ulpi = seq->private;
> +
> +#define ulpi_print(name, reg) do { \
> + int ret = ulpi_read(ulpi, reg); \
> + if (ret < 0) \
> + return ret; \
> + seq_printf(seq, name " %.02x\n", ret); \
> +} while (0)
> +
> + ulpi_print("Vendor ID Low ", ULPI_VENDOR_ID_LOW);
> + ulpi_print("Vendor ID High ", ULPI_VENDOR_ID_HIGH);
> + ulpi_print("Product ID Low ", ULPI_PRODUCT_ID_LOW);
> + ulpi_print("Product ID High ", ULPI_PRODUCT_ID_HIGH);
> + ulpi_print("Function Control ", ULPI_FUNC_CTRL);
> + ulpi_print("Interface Control ", ULPI_IFC_CTRL);
> + ulpi_print("OTG Control ", ULPI_OTG_CTRL);
> + ulpi_print("USB Interrupt Enable Rising ", ULPI_USB_INT_EN_RISE);
> + ulpi_print("USB Interrupt Enable Falling", ULPI_USB_INT_EN_FALL);
> + ulpi_print("USB Interrupt Status ", ULPI_USB_INT_STS);
> + ulpi_print("USB Interrupt Latch ", ULPI_USB_INT_LATCH);
> + ulpi_print("Debug ", ULPI_DEBUG);
> + ulpi_print("Scratch Register ", ULPI_SCRATCH);
> + ulpi_print("Carkit Control ", ULPI_CARKIT_CTRL);
> + ulpi_print("Carkit Interrupt Delay ", ULPI_CARKIT_INT_DELAY);
> + ulpi_print("Carkit Interrupt Enable ", ULPI_CARKIT_INT_EN);
> + ulpi_print("Carkit Interrupt Status ", ULPI_CARKIT_INT_STS);
> + ulpi_print("Carkit Interrupt Latch ", ULPI_CARKIT_INT_LATCH);
> + ulpi_print("Carkit Pulse Control ", ULPI_CARKIT_PLS_CTRL);
> + ulpi_print("Transmit Positive Width ", ULPI_TX_POS_WIDTH);
> + ulpi_print("Transmit Negative Width ", ULPI_TX_NEG_WIDTH);
> + ulpi_print("Receive Polarity Recovery ", ULPI_POLARITY_RECOVERY);
> +
> + return 0;
> +}
> +
> +static int ulpi_regs_open(struct inode *inode, struct file *f)
> +{
> + struct ulpi *ulpi = inode->i_private;
> +
> + return single_open(f, ulpi_regs_read, ulpi);
> +}
> +
> +static const struct file_operations ulpi_regs_ops = {
> + .owner = THIS_MODULE,
> + .open = ulpi_regs_open,
> + .release = single_release,
> + .read = seq_read,
> + .llseek = seq_lseek
> +};
> +
> +#define ULPI_ROOT debugfs_lookup(KBUILD_MODNAME, NULL)
> +
> static int ulpi_register(struct device *dev, struct ulpi *ulpi)
> {
> int ret;
> + struct dentry *root;
>
> ulpi->dev.parent = dev; /* needed early for ops */
> ulpi->dev.bus = &ulpi_bus;
> @@ -251,6 +307,9 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
> if (ret)
> return ret;
>
> + root = debugfs_create_dir(dev_name(dev), ULPI_ROOT);
> + debugfs_create_file("regs", 0444, root, ulpi, &ulpi_regs_ops);
> +
> dev_dbg(&ulpi->dev, "registered ULPI PHY: vendor %04x, product %04x\n",
> ulpi->id.vendor, ulpi->id.product);
>
> @@ -296,6 +355,8 @@ EXPORT_SYMBOL_GPL(ulpi_register_interface);
> */
> void ulpi_unregister_interface(struct ulpi *ulpi)
> {
> + debugfs_remove_recursive(debugfs_lookup(dev_name(&ulpi->dev),
> + ULPI_ROOT));
> of_node_put(ulpi->dev.of_node);
> device_unregister(&ulpi->dev);
> }
> @@ -305,13 +366,21 @@ EXPORT_SYMBOL_GPL(ulpi_unregister_interface);
>
> static int __init ulpi_init(void)
> {
> - return bus_register(&ulpi_bus);
> + int ret;
> + struct dentry *root;
> +
> + root = debugfs_create_dir(KBUILD_MODNAME, NULL);
The file could be accesed now, but you don't register the bus until
after this returns:
> + ret = bus_register(&ulpi_bus);
> + if (ret)
> + debugfs_remove(root);
Can you flip the order around please?
thanks,
greg k-h
