Re: [PATCH 04/12] tty: serial: samsung: Init USI to keep clocks running
From: Sam Protsenko <semen.protsenko@linaro.org>
Date: 2021-08-03 11:41:44
Also in:
linux-clk, linux-devicetree, linux-gpio, linux-samsung-soc, linux-serial, lkml
On Tue, 3 Aug 2021 at 10:37, Krzysztof Kozlowski [off-list ref] wrote:
On 03/08/2021 01:06, Sam Protsenko wrote: (...)quoted
quoted
quoted
diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h index f6c3323fc4c5..013c2646863e 100644 --- a/include/linux/serial_s3c.h +++ b/include/linux/serial_s3c.h@@ -28,6 +28,15 @@ #define S3C2410_UFSTAT (0x18) #define S3C2410_UMSTAT (0x1C) +/* USI Control Register offset */ +#define USI_CON (0xC4) +/* USI Option Register offset */ +#define USI_OPTION (0xC8) +/* USI_CON[0] = 0b0: clear USI global software reset (Active High) */ +#define USI_RESET (0<<0)Just 0x0. I understand you wanted to hint it is a bit field, but the shift of 0 actually creates more questions.After some consideration I decided to adhere to existing style and do something like this (in v2): 8<--------------------------------------------------------------------->8 #define USI_CON (0xC4) #define USI_OPTION (0xC8) #define USI_CON_RESET_CLEAR (0<<0) #define USI_CON_RESET_SET (1<<0) #define USI_CON_RESET_MASK (1<<0) #define USI_OPTION_HWACG_CLKREQ_ON (1<<1) #define USI_OPTION_HWACG_CLKSTOP_ON (1<<2) #define USI_OPTION_HWACG_MASK (3<<1) 8<--------------------------------------------------------------------->8 The whole reason for those comments was missing public TRM. But in the end I decided it just looks ugly. Also, this way I can do RMW operation (discussed above) in more logical way. Please let me know if code snippets above look good to you.Please skip the USI_CON_RESET_CLEAR. There is no such pattern in the code. Clearing bit is an obvious operation and such code is already everywhere: val &= ~USI_CON_RESET (or &= ~USI_RESET_MASK) Therefore for USI_CON_RESET only: #define USI_CON_RESET (1<<0) #define USI_CON_RESET_MASK (1<<0)
Sure, I'll make it so.
Best regards, Krzysztof
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