diff options
| author | Tero Kristo <t-kristo@ti.com> | 2015-11-30 16:43:25 +0200 |
|---|---|---|
| committer | Stephen Boyd <sboyd@codeaurora.org> | 2015-11-30 11:34:17 -0800 |
| commit | 07ff73a932b725b2a4675bd0cc1a86b4933e433e (patch) | |
| tree | da9e26ac88590535060e130e8ce51c4369a7c2a8 /drivers/clk/ti | |
| parent | cf81a1cf711d71daafe8f1b8eca96b54c3f5c8ed (diff) | |
| download | linux-07ff73a932b725b2a4675bd0cc1a86b4933e433e.tar.bz2 | |
clk: ti: omap5+: dpll: implement errata i810
Errata i810 states that DPLL controller can get stuck while transitioning
to a power saving state, while its M/N ratio is being re-programmed.
As a workaround, before re-programming the M/N ratio, SW has to ensure
the DPLL cannot start an idle state transition. SW can disable DPLL
idling by setting the DPLL AUTO_DPLL_MODE=0 or keeping a clock request
active by setting a dependent clock domain in SW_WKUP.
This errata impacts OMAP5 and DRA7 chips, so enable the errata for these.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers/clk/ti')
| -rw-r--r-- | drivers/clk/ti/dpll3xxx.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/drivers/clk/ti/dpll3xxx.c b/drivers/clk/ti/dpll3xxx.c index f4dec00fb684..1c300388782b 100644 --- a/drivers/clk/ti/dpll3xxx.c +++ b/drivers/clk/ti/dpll3xxx.c @@ -305,8 +305,9 @@ static void _lookup_sddiv(struct clk_hw_omap *clk, u8 *sd_div, u16 m, u8 n) static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel) { struct dpll_data *dd = clk->dpll_data; - u8 dco, sd_div; + u8 dco, sd_div, ai = 0; u32 v; + bool errata_i810; /* 3430 ES2 TRM: 4.7.6.9 DPLL Programming Sequence */ _omap3_noncore_dpll_bypass(clk); @@ -350,6 +351,25 @@ static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel) v |= sd_div << __ffs(dd->sddiv_mask); } + /* + * Errata i810 - DPLL controller can get stuck while transitioning + * to a power saving state. Software must ensure the DPLL can not + * transition to a low power state while changing M/N values. + * Easiest way to accomplish this is to prevent DPLL autoidle + * before doing the M/N re-program. + */ + errata_i810 = ti_clk_get_features()->flags & TI_CLK_ERRATA_I810; + + if (errata_i810) { + ai = omap3_dpll_autoidle_read(clk); + if (ai) { + omap3_dpll_deny_idle(clk); + + /* OCP barrier */ + omap3_dpll_autoidle_read(clk); + } + } + ti_clk_ll_ops->clk_writel(v, dd->mult_div1_reg); /* Set 4X multiplier and low-power mode */ @@ -379,6 +399,9 @@ static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel) _omap3_noncore_dpll_lock(clk); + if (errata_i810 && ai) + omap3_dpll_allow_idle(clk); + return 0; } |