On 07/03/2022 09:40, Krzysztof Kozlowski wrote: > On 07/03/2022 09:33, Jiri Slaby wrote: >> On 07. 03. 22, 9:09, Krzysztof Kozlowski wrote: >>> The driver data (struct s3c24xx_serial_drv_data) is only used to >>> initialize the driver properly and is not modified. Make it const. >> ... >>> @@ -2755,9 +2755,9 @@ static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = { >>> }, >>> .fifosize = { 256, 64, 16, 16 }, >>> }; >>> -#define S5PV210_SERIAL_DRV_DATA ((kernel_ulong_t)&s5pv210_serial_drv_data) >>> +#define S5PV210_SERIAL_DRV_DATA (&s5pv210_serial_drv_data) >>> #else >>> -#define S5PV210_SERIAL_DRV_DATA (kernel_ulong_t)NULL >>> +#define S5PV210_SERIAL_DRV_DATA NULL >> >> Yet, I still don't see why the switch from ulong->ptr happens in this >> "constify it" patch? > > All these defines S5PV210_SERIAL_DRV_DATA and so on are now const and > are assigned to of_device_id.data (s3c24xx_uart_dt_match). Before, these > were assigned with a cast: > > static const struct of_device_id s3c24xx_uart_dt_match[] = { > { .compatible = "samsung,s5pv210-uart", > > .data = (void *)S5PV210_SERIAL_DRV_DATA } > > but since the actual data structure is const, I want to drop the cast. > Casting const via (void *) might hide some possible issues, e.g. if > of_device_id.data becomes actually non-const. There is no particular > issue here, because of_device_id.data and S5PV210_SERIAL_DRV_DATA are > const. But also because they are both const now, I want to drop the cast > via void *. > > When (void *) is dropped, the S5PV210_SERIAL_DRV_DATA cannot be > kernel_ulong_t: > > ../drivers/tty/serial/samsung_tty.c:2753:33: warning: initialization of > ‘const void *’ from ‘long unsigned int’ makes pointer from integer > without a cast [-Wint-conversion] > > 2753 | #define S5PV210_SERIAL_DRV_DATA (kernel_ulong_t)NULL > I will split the casts removal to separate patch. I hope this clarifies a bit. Best regards, Krzysztof