[[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 <[email protected]> > --- > 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 >
