Re: [PATCH 2/2] clk: davinci: psc-dm365: fix few clocks

[David Lechner <david@lechnology.com>]

On 05/11/2018 09:10 AM, Sekhar Nori wrote:
> Fix parent of emac and voice codec PSC clocks. This now matches
> existing implementation in arch/arm/mach-davinci/dm365.c
> 
> Also, there is only one power domain on DM365. Fix the power
> domain of voice codec and vpss dac modules.
> 
> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
> ---
>   drivers/clk/davinci/psc-dm365.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/davinci/psc-dm365.c b/drivers/clk/davinci/psc-dm365.c
> index 5b5b55b0b59a..beeda10fd2f0 100644
> --- a/drivers/clk/davinci/psc-dm365.c
> +++ b/drivers/clk/davinci/psc-dm365.c
> @@ -65,9 +65,9 @@ static const struct davinci_lpsc_clk_info dm365_psc_info[] = {
>   	LPSC(31, 0, arm,         pll2_sysclk2, NULL,               LPSC_ALWAYS_ENABLED),
>   	LPSC(38, 0, spi3,        pll1_sysclk4, spi3_clkdev,        0),
>   	LPSC(39, 0, spi4,        pll1_auxclk,  spi4_clkdev,        0),
> -	LPSC(40, 0, emac,        pll2_sysclk4, emac_clkdev,        0),
> -	LPSC(44, 1, voice_codec, pll1_sysclk3, voice_codec_clkdev, 0),
> -	LPSC(46, 1, vpss_dac,    pll1_sysclk3, vpss_dac_clkdev,    0),
> +	LPSC(40, 0, emac,        pll1_sysclk4, emac_clkdev,        0),
> +	LPSC(44, 0, voice_codec, pll2_sysclk4, voice_codec_clkdev, 0),
> +	LPSC(46, 0, vpss_dac,    pll1_sysclk3, vpss_dac_clkdev,    0),
>   	LPSC(47, 0, vpss_master, pll1_sysclk5, vpss_master_clkdev, 0),
>   	LPSC(50, 0, mjcp,        pll1_sysclk3, NULL,               0),
>   	{ }
> 

Slightly off topic...

Hmm... Looking at the TRM, I see that there are a bunch of mux clocks that we
have not implemented for the DM365 (all of the clocks in the VPSS_CLK_CTRL and
PERI_CLKCTL registers). I'm wondering if we should be creating drivers for
those like the DA8XX CFGCHIP clock driver.

Back on topic...

The emac fix here looks good.

The TRM (sprufg5a.pdf) shows that there is a DIV2 clock (part of the
PERI_CLKCTL register) between PLL2 SYSCLK4 and Voice Codec in Figure 5,
It also shows PLL1 SYSCLK4 as a second parent clock to Voice Codec, however
this dependency has probably gone unnoticed because so many other devices
also use that same clock, it will pretty much always be on. In Figure 38,
on the other hand, PLL1 SYSCLK4 is shown as the only parent of Voice Codec.

So, I am thinking that pll1_sysclk4 is the correct parent for the
voice_codec clock here since it is the only one listed in Figure 38
(which is in the PSC section of the TRM). The pll2_sysclk4 clock should
probably be used by the video codec device driver directly (well, the
DIV2 clock really, but we don't have a driver for that yet).

The vpss_dac clock in not very clear in the TRM. In Table 39, the name
for LPSC 46, which we are calling "vpss_dac", is "VDAC CLK". In Figure
37, however, there is not a node that matches exactly. There is "VIDEO
DAC", which I take to be the same clock though. This has parent clocks
of PLL1 SYSCLK6 and PLL1 AUXCLK. So, I am guessing that pll1_sysclk6
should be the parent here rather than pll1_sysclk3. According to Figure
5, PLL1 SYSCLK3 only feeds HDVPID and MJCP, which I don't think are the
same as the video DAC since they are also listed separately in Figure 5.