linux-kernel - Re: [PATCH v3 05/11] clk: davinci - add dm644x clock initialization

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Message-ID: <5098DB0C.7000707@ti.com>
Date:	Tue, 6 Nov 2012 15:10:28 +0530
From:	Sekhar Nori <nsekhar@...com>
To:	Murali Karicheri <m-karicheri2@...com>
CC:	<mturquette@...aro.org>, <arnd@...db.de>,
	<akpm@...ux-foundation.org>, <shawn.guo@...aro.org>,
	<rob.herring@...xeda.com>, <linus.walleij@...aro.org>,
	<viresh.linux@...il.com>, <linux-kernel@...r.kernel.org>,
	<khilman@...com>, <linux@....linux.org.uk>, <sshtylyov@...sta.com>,
	<davinci-linux-open-source@...ux.davincidsp.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-keystone@...t.ti.com>
Subject: Re: [PATCH v3 05/11] clk: davinci - add dm644x clock initialization

On 11/6/2012 4:53 AM, Murali Karicheri wrote:
> On 11/03/2012 09:30 AM, Sekhar Nori wrote:
>> On 10/25/2012 9:41 PM, Murali Karicheri wrote:
>>> This patch adds dm644x clock initialization code that consists of
>>> clocks data for various clocks and clock register callouts to
>>> various clock drivers. It uses following clk drivers for this
>>>
>>>   1. clk-fixed-rate - for ref clock
>>>   2. clk-mux - for mux at the input and output of main pll
>>>   3. davinci specific clk-pll for main pll clock
>>>   4. davinci specific clk-div for pll divider clock
>>>   5. clk-fixed-factor for fixed factor clock such as auxclk
>>>   6. davinci specific clk-psc for psc clocks
>>>
>>> This patch also moves all of the PLL and PSC register definitions
>>> from clock.h and psc.h under davinci to the clk/davinci folder so
>>> that various soc specific clock initialization code can share these
>>> definitions.
>> Except this patch does not move the defines, it creates a copy of them
>> (which is bad since you quickly lose track of which is the correct
>> copy). Is this done to avoid including mach/ header files here? It will
>> actually be better to include the mach/ files here as a temporary
>> solution and then remove the include mach/ files once all the SoCs have
>> been converted over.
>>
>>> Signed-off-by: Murali Karicheri <m-karicheri2@...com>
>>> ---
>>>   drivers/clk/davinci/dm644x-clock.c |  304
>>> ++++++++++++++++++++++++++++++++++++
>>>   drivers/clk/davinci/pll.h          |   83 ++++++++++
>>>   drivers/clk/davinci/psc.h          |  215 +++++++++++++++++++++++++
>>>   3 files changed, 602 insertions(+)
>>>   create mode 100644 drivers/clk/davinci/dm644x-clock.c
>>>   create mode 100644 drivers/clk/davinci/pll.h
>>>   create mode 100644 drivers/clk/davinci/psc.h
>>>
>>> +/* all clocks available in DM644x SoCs */
>>> +enum dm644x_clk {
>>> +    clkin, oscin, ref_clk_mux, pll1, pll1_plldiv_clk_mux, auxclk,
>>> +    clk_pll1_sysclk1, clk_pll1_sysclk2, clk_pll1_sysclk3,
>>> clk_pll1_sysclk4,
>>> +    clk_pll1_sysclk5, clk_pll1_sysclkbp, pll2, pll2_plldiv_clk_mux,
>>> +    clk_pll2_sysclk1, clk_pll2_sysclk2, clk_pll2_sysclkbp, dsp, arm,
>>> vicp,
>>> +    vpss_master, vpss_slave, uart0, uart1, uart2, emac, i2c, ide, asp,
>>> +    mmcsd, spi, gpio, usb, vlynq, aemif, pwm0, pwm1, pwm2, timer0,
>>> timer1,
>>> +    timer2, clk_max
>>> +};
>>> +
>>> +static struct davinci_clk *psc_clocks[] = {
>>> +    &clk_dsp, &clk_arm, &clk_vicp, &clk_vpss_master, &clk_vpss_slave,
>>> +    &clk_uart0, &clk_uart1, &clk_uart2, &clk_emac, &clk_i2c, &clk_ide,
>>> +    &clk_asp0, &clk_mmcsd, &clk_spi, &clk_gpio, &clk_usb, &clk_vlynq,
>>> +    &clk_aemif, &clk_pwm0, &clk_pwm1, &clk_pwm2, &clk_timer0,
>>> &clk_timer1,
>>> +    &clk_timer2
>>> +};
>> You rely on perfect order between this array and dm644x_clk enum above.
>> Can you initialize this array using the enum as the index so that it is
>> clear. Current method is too error prone.
> Are you expecting something like this?
> 
> static struct davinci_clk *psc_clocks[] = {
>     [dsp - dsp]        = &clk_dsp,
>     [arm - dsp]        = &clk_arm,
>     [vicp - dsp]        = &clk_vicp,
>     [vpss_maste - dsp]    = &clk_vpss_master,
>     [vpss_slave - dsp]    = &clk_vpss_slave,
>     [uart0 - dsp]        = &clk_uart0,
>     [uart1 - dsp]        = &clk_uart1,

Well, sort of! But the '- dsp' is really ugly. You can either define the
array for the full list of clocks (like 'clks') or move the psc clocks
to the beginning of the enum (less preferable to me).

Thanks,
Sekhar
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