Re: [PATCH v1 13/50] clk: samsung: add DPLL rate table in Exynos5420

From: Chanwoo Choi
Date: Tue Jul 16 2019 - 05:28:06 EST


Hi,

Also, you better to merge patch13/patch15/patch16 to one patch
in order to add the PLL table for DPLL/MPLL/SPLL.

And I have a question. Are there any use-case to change
the PLL frequency for DPLL/MPLL/SPLL?

On 19. 7. 15. ìí 9:43, Lukasz Luba wrote:
> The DPLL has fixed frequency left by the bootloader and it is not possible
> to change it. With this patch the DPLL gets rate table the same for the
> whole PLL family (similar as APLL, KPLL according to RM) so the frequency
> might be changed to one of the values defined there.
> It is needed for further patches which change the DPLL frequency to feed
> the clocks with proper base.
> It also sets CLK_IS_CRITICAL for SCLK_DPLL due to some drivers which could
> disable master clock, which is then populated higher and tries to disable
> PLL, which casues system crash. The flag is needed for this kind of use
> cases.
>
> Signed-off-by: Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/clk/samsung/clk-exynos5420.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
> index 7f8221527633..2395b02ce8c5 100644
> --- a/drivers/clk/samsung/clk-exynos5420.c
> +++ b/drivers/clk/samsung/clk-exynos5420.c
> @@ -694,7 +694,8 @@ static const struct samsung_mux_clock exynos5x_mux_clks[] __initconst = {
> MUX(0, "mout_sclk_rpll", mout_rpll_p, SRC_TOP6, 16, 1),
> MUX_F(CLK_MOUT_EPLL, "mout_sclk_epll", mout_epll_p, SRC_TOP6, 20, 1,
> CLK_SET_RATE_PARENT, 0),
> - MUX(0, "mout_sclk_dpll", mout_dpll_p, SRC_TOP6, 24, 1),
> + MUX_F(CLK_MOUT_SCLK_DPLL, "mout_sclk_dpll", mout_dpll_p,
> + SRC_TOP6, 24, 1, CLK_IS_CRITICAL, 0),
> MUX(0, "mout_sclk_cpll", mout_cpll_p, SRC_TOP6, 28, 1),
>
> MUX(CLK_MOUT_SW_ACLK400_ISP, "mout_sw_aclk400_isp",
> @@ -1514,6 +1515,7 @@ static void __init exynos5x_clk_init(struct device_node *np,
>
> if (_get_rate("fin_pll") == 24 * MHZ) {
> exynos5x_plls[apll].rate_table = exynos5420_pll2550x_24mhz_tbl;
> + exynos5x_plls[dpll].rate_table = exynos5420_pll2550x_24mhz_tbl;
> exynos5x_plls[epll].rate_table = exynos5420_epll_24mhz_tbl;
> exynos5x_plls[kpll].rate_table = exynos5420_pll2550x_24mhz_tbl;
> }
>


--
Best Regards,
Chanwoo Choi
Samsung Electronics