On Thu, Jun 06, 2024 at 05:58:03PM +0530, Radhey Shyam Pandey wrote:
> PATCH] usb: misc: add Microchip usb5744 SMBus programming support
usb: misc: onboard_usb_dev: ...
>
> usb5744 supports SMBus Configuration and it may be configured via the
> SMBus slave interface during the hub’s start-up configuration stage.
>
> To program it introduce i2c initialization hook and set usb5744 platform
> data with function having required smbus initialization sequence. Core
> driver uses i2c-bus phandle (added in commit '02be19e914b8 dt-bindings:
> usb: Add support for Microchip usb5744 hub controller') to get i2c client
> device and then calls usb5744 i2c default initialization sequence.
>
> Apart from the USB command attach, prevent the hub from suspend.
> when the “USB Attach with SMBus (0xAA56)” command is issued to the hub,
> the hub is getting enumerated and then it puts in a suspend mode.
> This causes the hub to NAK any SMBus access made by the SMBus Master
> during this period and not able to see the hub's slave address while
> running the "i2c probe" command.
>
> Prevent the MCU from the putting the HUB in suspend mode through
> register write. The BYPASS_UDC_SUSPEND bit (Bit 3) of the RuntimeFlags2
> register at address 0x411D controls this aspect of the hub. The
> BYPASS_UDC_SUSPEND bit in register 0x411Dh must be set to ensure that the
> MCU is always enabled and ready to respond to SMBus runtime commands.
> This register needs to be written before the USB attach command is issued.
>
> The byte sequence is as follows:
> Slave addr: 0x2d 00 00 05 00 01 41 1D 08
> Slave addr: 0x2d 99 37 00
> Slave addr: 0x2d AA 56 00
>
> In addition to SMBus programming sequence also update post reset
> delay as without it there is a failure on first SMBus write.
> i2c 2-002d: error -ENXIO: BYPASS_UDC_SUSPEND bit configuration failed
>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> ---
> ---
> drivers/usb/misc/onboard_usb_dev.c | 46 ++++++++++++++++++++++++++++++
> drivers/usb/misc/onboard_usb_dev.h | 8 +++++-
> 2 files changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c
> index f2bcc1a8b95f..5621c1273a12 100644
> --- a/drivers/usb/misc/onboard_usb_dev.c
> +++ b/drivers/usb/misc/onboard_usb_dev.c
> @@ -98,6 +98,7 @@ static int onboard_dev_power_on(struct onboard_dev *onboard_dev)
>
> fsleep(onboard_dev->pdata->reset_us);
> gpiod_set_value_cansleep(onboard_dev->reset_gpio, 0);
> + fsleep(onboard_dev->pdata->reset_us);
This also impacts devices that don't require a delay, plus requirements for
this delay are not necessarily the same as the reset delay.
Better add a dedicated field like 'power_on_delay_us'.
>
> onboard_dev->is_powered_on = true;
>
> @@ -296,10 +297,34 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work)
> pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
> }
>
> +int onboard_dev_5744_i2c_init(struct i2c_client *client)
static int
We probably want to move hardware specific code to a dedicated file
as there is added more, but I for now it's ok to have it in the main
driver.
> +{
> + struct device *dev = &client->dev;
> + int ret;
> +
> + char wr_buf[7] = {0x00, 0x05, 0x00, 0x01, 0x41, 0x1D, 0x08};
Please use constants for the different bits instead of magic values. I know
the magic values are explained in the commit message, but that's something
people have to dig up.
> +
> + ret = i2c_smbus_write_block_data(client, 0, sizeof(wr_buf), wr_buf);
> + if (ret)
> + return dev_err_probe(dev, ret, "BYPASS_UDC_SUSPEND bit configuration failed\n");
> +
> + ret = i2c_smbus_write_word_data(client, 0x99, htons(0x3700));
ditto, no magic values please
> + if (ret)
> + return dev_err_probe(dev, ret, "Configuration Register Access Command failed\n");
> +
> + /* Send SMBus command to boot hub. */
> + ret = i2c_smbus_write_word_data(client, 0xAA, htons(0x5600));
ditto
> + if (ret < 0)
> + return dev_err_probe(dev, ret, "USB Attach with SMBus command failed\n");
> +
> + return ret;
return 0;
> +}
> +
> static int onboard_dev_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct onboard_dev *onboard_dev;
> + struct device_node *i2c_node;
> int err;
>
> onboard_dev = devm_kzalloc(dev, sizeof(*onboard_dev), GFP_KERNEL);
> @@ -339,6 +364,23 @@ static int onboard_dev_probe(struct platform_device *pdev)
> if (err)
> return err;
>
> + i2c_node = of_parse_phandle(pdev->dev.of_node, "i2c-bus", 0);
> + if (i2c_node) {
> + struct i2c_client *client;
> +
> + client = of_find_i2c_device_by_node(i2c_node);
> + of_node_put(i2c_node);
> +
> + if (!client) {
> + err = -EPROBE_DEFER;
> + goto err_dev_power_off;
nit: err_power_off
> + }
> + err = onboard_dev->pdata->onboard_dev_i2c_init(client);
> + put_device(&client->dev);
> + if (err < 0)
> + goto err_dev_power_off;
> + }
> +
> /*
> * The USB driver might have been detached from the USB devices by
> * onboard_dev_remove() (e.g. through an 'unbind' by userspace),
> @@ -350,6 +392,10 @@ static int onboard_dev_probe(struct platform_device *pdev)
> schedule_work(&attach_usb_driver_work);
>
> return 0;
> +
> +err_dev_power_off:
> + onboard_dev_power_off(onboard_dev);
> + return err;
> }
>
> static void onboard_dev_remove(struct platform_device *pdev)
> diff --git a/drivers/usb/misc/onboard_usb_dev.h b/drivers/usb/misc/onboard_usb_dev.h
> index fbba549c0f47..17311ea7bacd 100644
> --- a/drivers/usb/misc/onboard_usb_dev.h
> +++ b/drivers/usb/misc/onboard_usb_dev.h
> @@ -6,6 +6,8 @@
> #ifndef _USB_MISC_ONBOARD_USB_DEV_H
> #define _USB_MISC_ONBOARD_USB_DEV_H
>
> +#include <linux/i2c.h>
> +
> #define MAX_SUPPLIES 2
>
> struct onboard_dev_pdata {
> @@ -13,6 +15,7 @@ struct onboard_dev_pdata {
> unsigned int num_supplies; /* number of supplies */
> const char * const supply_names[MAX_SUPPLIES];
> bool is_hub;
> + int (*onboard_dev_i2c_init)(struct i2c_client *client);
> };
>
> static const struct onboard_dev_pdata microchip_usb424_data = {
> @@ -22,11 +25,14 @@ static const struct onboard_dev_pdata microchip_usb424_data = {
> .is_hub = true,
> };
>
> +int onboard_dev_5744_i2c_init(struct i2c_client *client);
> +
> static const struct onboard_dev_pdata microchip_usb5744_data = {
> - .reset_us = 0,
> + .reset_us = 10000,
That's one reason why I don't think it's a good idea to use 'reset_us'
twice. In this case the total delay would go from formerly 0ms to 20ms,
when a delay of 10ms after the reset should be sufficient.
> .num_supplies = 2,
> .supply_names = { "vdd", "vdd2" },
> .is_hub = true,
> + .onboard_dev_i2c_init = onboard_dev_5744_i2c_init,
> };
>
> static const struct onboard_dev_pdata realtek_rts5411_data = {
> --
> 2.34.1
>
