Re: [PATCH v2 22/25] tty: serial: samsung_tty: Add support for Apple UARTs

Hector Martin
2021-02-18T14:18:37Z

On 16/02/2021 04.13, Krzysztof Kozlowski wrote:
> On Mon, Feb 15, 2021 at 09:17:10PM +0900, Hector Martin wrote:
>> @@ -389,10 +396,12 @@ static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
>> ucon = rd_regl(port, S3C2410_UCON);
>> ucon &= ~(S3C64XX_UCON_TXMODE_MASK);
>> ucon |= S3C64XX_UCON_TXMODE_CPU;
>> - wr_regl(port, S3C2410_UCON, ucon);
>>
>> /* Unmask Tx interrupt */
>> switch (ourport->info->type) {
>> + case TYPE_APPLE_S5L:
>> + ucon |= APPLE_S5L_UCON_TXTHRESH_ENA_MSK;
>> + break;
>> case TYPE_S3C6400:
>> s3c24xx_clear_bit(port, S3C64XX_UINTM_TXD, S3C64XX_UINTM);
>> break;
>> @@ -401,7 +410,16 @@ static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
>> break;
>> }
>>
>> + wr_regl(port, S3C2410_UCON, ucon);
>
> You are now configuring the PIO mode after unmasking interrupt. I don't
> think it's a good idea to change the order... and if it were, it
> would deserve a separate patch.

For v3 I moved the wr_regl back and just write it again in the
TYPE_APPLE_S5L branch; that way, setting the PIO mode and unmasking the
interrupt are two discrete operations on S5L, like they are on other types.

>> /* Keep all interrupts masked and cleared */
>> switch (ourport->info->type) {
>> + case TYPE_APPLE_S5L: {
>
> Usually you put TYPE_APPLE at the end of switch, so please keep it
> consistent. Can be first or last - just everywhere the same, unless you
> have a fall-through on purpose.

Good point, thanks, moved it for v3. It was actually inconsistent in
more places, I made all the orders the same (the enum order, and
default: always goes at the end).

>> @@ -2179,6 +2329,32 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
>> if (port) {
>> /* restore IRQ mask */
>> switch (ourport->info->type) {
>> + case TYPE_APPLE_S5L: {
>> + unsigned int ucon;
>> +
>> + clk_prepare_enable(ourport->clk);
>> + if (!IS_ERR(ourport->baudclk))
>> + clk_prepare_enable(ourport->baudclk);
>
> We should start checking the return values of clk operations. I know
> that existing code does it only in few places, so basically you are not
> making it worse...

Added error checking for these for v3, thanks.

>> +#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)&s5l_serial_drv_data)
>> +#else
>> +#define S5L_SERIAL_DRV_DATA ((kernel_ulong_t)NULL)
>> +#endif
>> +
>> +
>
> Only one line break.

Fixed in v3.

Thank you for the reviews!

--
Hector Martin (marcan@marcan.st)
Public Key: https://mrcn.st/pub