linux-kernel - Re: [PATCH v3 2/4] clk: at91: sckc: add support to specify registers bit offsets

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Message-ID: <b99b1782-30be-b6b9-0df2-f14125be22ac@microchip.com>
Date:   Thu, 16 May 2019 08:10:34 +0000
From:   <Claudiu.Beznea@...rochip.com>
To:     <alexandre.belloni@...tlin.com>
CC:     <mturquette@...libre.com>, <sboyd@...nel.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>,
        <Nicolas.Ferre@...rochip.com>, <linux-clk@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/4] clk: at91: sckc: add support to specify registers
 bit offsets



On 11.05.2019 00:32, Alexandre Belloni wrote:
> On 10/05/2019 11:23:31+0000, Claudiu.Beznea@...rochip.com wrote:
>> From: Claudiu Beznea <claudiu.beznea@...rochip.com>
>>
>> Different IPs uses different bit offsets in registers for the same
>> functionality, thus adapt the driver to support this.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
>> ---
>>  drivers/clk/at91/sckc.c | 100 ++++++++++++++++++++++++++++++++----------------
>>  1 file changed, 67 insertions(+), 33 deletions(-)
>>
>> diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c
>> index 6c55a7a86f79..2a4ac548de80 100644
>> --- a/drivers/clk/at91/sckc.c
>> +++ b/drivers/clk/at91/sckc.c
>> @@ -22,15 +22,23 @@
>>  #define SLOWCK_SW_TIME_USEC	((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \
>>  				 SLOW_CLOCK_FREQ)
>>  
>> -#define	AT91_SCKC_CR			0x00
>> -#define		AT91_SCKC_RCEN		(1 << 0)
>> -#define		AT91_SCKC_OSC32EN	(1 << 1)
>> -#define		AT91_SCKC_OSC32BYP	(1 << 2)
>> -#define		AT91_SCKC_OSCSEL	(1 << 3)
>> +#define	AT91_SCKC_CR		0x00
>> +#define		AT91_SCKC_RCEN(off)	((off)->cr_rcen)
>> +#define		AT91_SCKC_OSC32EN(off)	((off)->cr_osc32en)
>> +#define		AT91_SCKC_OSC32BYP(off)	((off)->cr_osc32byp)
>> +#define		AT91_SCKC_OSCSEL(off)	((off)->cr_oscsel)
>> +
>> +struct clk_slow_bits {
>> +	u32 cr_rcen;
> 
> This bit is only used on sam9x5 so I wouldn't bother having it in the
> structure, especially since its use will always be quite separate from
> the other ones as it is controlling a separate clock.
> 
>> +	u32 cr_osc32en;
>> +	u32 cr_osc32byp;
>> +	u32 cr_oscsel;
>> +};
>>  
>>  struct clk_slow_osc {
>>  	struct clk_hw hw;
>>  	void __iomem *sckcr;
>> +	const struct clk_slow_bits *bits;
>>  	unsigned long startup_usec;
>>  };
>>  
>> @@ -39,6 +47,7 @@ struct clk_slow_osc {
>>  struct clk_sama5d4_slow_osc {
>>  	struct clk_hw hw;
>>  	void __iomem *sckcr;
>> +	const struct clk_slow_bits *bits;
>>  	unsigned long startup_usec;
>>  	bool prepared;
>>  };
>> @@ -48,6 +57,7 @@ struct clk_sama5d4_slow_osc {
>>  struct clk_slow_rc_osc {
>>  	struct clk_hw hw;
>>  	void __iomem *sckcr;
>> +	const struct clk_slow_bits *bits;
>>  	unsigned long frequency;
>>  	unsigned long accuracy;
>>  	unsigned long startup_usec;
>> @@ -58,6 +68,7 @@ struct clk_slow_rc_osc {
>>  struct clk_sam9x5_slow {
>>  	struct clk_hw hw;
>>  	void __iomem *sckcr;
>> +	const struct clk_slow_bits *bits;
>>  	u8 parent;
>>  };
>>  
>> @@ -69,10 +80,11 @@ static int clk_slow_osc_prepare(struct clk_hw *hw)
>>  	void __iomem *sckcr = osc->sckcr;
>>  	u32 tmp = readl(sckcr);
>>  
>> -	if (tmp & (AT91_SCKC_OSC32BYP | AT91_SCKC_OSC32EN))
>> +	if (tmp & (AT91_SCKC_OSC32BYP(osc->bits) |
>> +		   AT91_SCKC_OSC32EN(osc->bits)))
> 
> I still find that:
> 
> 	if (tmp & (osc->bits->cr_osc32byp | osc->bits->cr_osc32en))
> 
> would be shorter and easier to read and still fits on one line.

Agree, but I thought to use the same interface everywhere. Anyway, tell me
if you want to resend with these changes.

>