[U-Boot] [PATCH v2 2/2] Tegra114: Do not program CPCON field for PLLX

Thierry Reding thierry.reding at gmail.com
Tue Oct 1 17:06:38 CEST 2013


On Mon, Sep 30, 2013 at 02:25:57PM -0700, Tom Warren wrote:
> Thierry,
> 
> > -----Original Message-----
> > From: Thierry Reding [mailto:thierry.reding at gmail.com]
> > Sent: Monday, September 23, 2013 1:08 PM
> > To: Tom Warren
> > Cc: u-boot at lists.denx.de
> > Subject: [PATCH v2 2/2] Tegra114: Do not program CPCON field for PLLX
> > 
> > PLLX no longer has the CPCON field on Tegra114, so do not attempt to
> > program it.
> > 
> > Signed-off-by: Thierry Reding <treding at nvidia.com>
> > ---
> > Changes in v2:
> > - new patch
> > 
> >  arch/arm/cpu/arm720t/tegra-common/cpu.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/cpu/arm720t/tegra-common/cpu.c
> > b/arch/arm/cpu/arm720t/tegra-common/cpu.c
> > index aa1e04f..5ab2ebf 100644
> > --- a/arch/arm/cpu/arm720t/tegra-common/cpu.c
> > +++ b/arch/arm/cpu/arm720t/tegra-common/cpu.c
> > @@ -135,6 +135,7 @@ void adjust_pllp_out_freqs(void)  int
> > pllx_set_rate(struct clk_pll_simple *pll , u32 divn, u32 divm,
> >  		u32 divp, u32 cpcon)
> >  {
> > +	int chip = tegra_get_chip();
> >  	u32 reg;
> > 
> >  	/* If PLLX is already enabled, just return */ @@ -151,7 +152,8 @@ int
> > pllx_set_rate(struct clk_pll_simple *pll , u32 divn, u32 divm,
> >  	writel(reg, &pll->pll_base);
> > 
> >  	/* Set cpcon to PLLX_MISC */
> > -	reg = (cpcon << PLL_CPCON_SHIFT);
> > +	if (chip == CHIPID_TEGRA20 || chip == CHIPID_TEGRA30)
> > +		reg = (cpcon << PLL_CPCON_SHIFT);
> If it's not a T20/T30, reg is still set to the PLLX_BASE setting from above. It'll then be written to PLLX_MISC w/bad bits below.
> You need to set a default, or read pllx_misc first.

Ugh... you're right of course. Sent a v3 with reg = 0 in the else
branch.

Thanks,
Thierry
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