[[PATCH] tty/serial: at91: restore dynamic driver binding] On 23/02/2016 (Tue 17:59) Romain Izard wrote:
> In commit c39dfebc7798956fd2140ae6321786ff35da30c3, the modular support
> code for atmel_serial was removed, as the driver cannot be built as a
> module. Because no use case was proposed, the dynamic driver binding
> support was removed as well.
>
> The atmel_serial driver can manage up to 7 serial controllers, which are
> multiplexed with other functions. For example, in the Atmel SAMA5D2, the
> Flexcom controllers can work as USART, SPI or I2C controllers, and on
> all Atmel devices serial lines can be reconfigured as GPIOs.
>
> My use case uses GPIOs to transfer a firmware update using a custom
> protocol on the lines used as a serial port during the normal life of
> the device. If it is not possible to unbind the atmel_serial driver, the
> GPIO lines remain reserved and prevent this case from working.
>
> This patch reinstates the atmel_serial_remove function, and fixes it as
> it failed to clear the "clk" field on removal, triggering an oops when
> a device was bound again after being unbound.
I'd suggest that you add a comment above the remove fcn that gives the
executive summary of the above; i.e. an unbind allows a fw update via
blah blah and hence the .remove makes sense even though the driver is
not modular.
P.
--
>
> Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
> ---
> drivers/tty/serial/atmel_serial.c | 30 +++++++++++++++++++++++++++---
> 1 file changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 1c0884d8ef32..59e241723edc 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -2759,14 +2759,38 @@ err:
> return ret;
> }
>
> +static int atmel_serial_remove(struct platform_device *pdev)
> +{
> + struct uart_port *port = platform_get_drvdata(pdev);
> + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> + int ret = 0;
> +
> + tasklet_kill(&atmel_port->tasklet);
> +
> + device_init_wakeup(&pdev->dev, 0);
> +
> + ret = uart_remove_one_port(&atmel_uart, port);
> +
> + kfree(atmel_port->rx_ring.buf);
> +
> + /* "port" is allocated statically, so we shouldn't free it */
> +
> + clear_bit(port->line, atmel_ports_in_use);
> +
> + clk_put(atmel_port->clk);
> + atmel_port->clk = NULL;
> +
> + return ret;
> +}
> +
> static struct platform_driver atmel_serial_driver = {
> .probe = atmel_serial_probe,
> + .remove = atmel_serial_remove,
> .suspend = atmel_serial_suspend,
> .resume = atmel_serial_resume,
> .driver = {
> - .name = "atmel_usart",
> - .of_match_table = of_match_ptr(atmel_serial_dt_ids),
> - .suppress_bind_attrs = true,
> + .name = "atmel_usart",
> + .of_match_table = of_match_ptr(atmel_serial_dt_ids),
> },
> };
>
> --
> 2.5.0
>
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