diff options
| author | Dmitry Osipenko <digetx@gmail.com> | 2020-03-19 22:02:20 +0300 |
|---|---|---|
| committer | Thierry Reding <treding@nvidia.com> | 2020-05-12 22:48:43 +0200 |
| commit | dec15c9901382f9a2ec548ff0a7ed639d4be0a38 (patch) | |
| tree | 18aa85491eea6b3639ef7a4016ed085a8e5d5ef2 /drivers/clk/tegra | |
| parent | 9157abe74b05b9c2ede8f07ad4c7f89b717ff303 (diff) | |
clk: tegra: cclk: Add helpers for handling PLLX rate changes
CCLK should be re-parented away from PLLX if PLLX's rate is changing.
The PLLP parent is a common safe CPU parent for all Tegra SoCs, thus
CCLK will be re-parented to PLLP before PLLX rate-change begins and then
switched back to PLLX after the rate-change completion. This patch adds
helper functions which perform CCLK re-parenting, these helpers will be
utilized by further patches.
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Marcel Ziswiler <marcel@ziswiler.com>
Tested-by: Jasper Korten <jja2000@gmail.com>
Tested-by: David Heidelberg <david@ixit.cz>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'drivers/clk/tegra')
| -rw-r--r-- | drivers/clk/tegra/clk-tegra-super-cclk.c | 34 | ||||
| -rw-r--r-- | drivers/clk/tegra/clk.h | 2 |
2 files changed, 36 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-tegra-super-cclk.c b/drivers/clk/tegra/clk-tegra-super-cclk.c index 7bcb9e8d0860..a03119c30456 100644 --- a/drivers/clk/tegra/clk-tegra-super-cclk.c +++ b/drivers/clk/tegra/clk-tegra-super-cclk.c @@ -25,6 +25,9 @@ #define SUPER_CDIV_ENB BIT(31) +static struct tegra_clk_super_mux *cclk_super; +static bool cclk_on_pllx; + static u8 cclk_super_get_parent(struct clk_hw *hw) { return tegra_clk_super_ops.get_parent(hw); @@ -115,6 +118,9 @@ struct clk *tegra_clk_register_super_cclk(const char *name, struct clk_init_data init; u32 val; + if (WARN_ON(cclk_super)) + return ERR_PTR(-EBUSY); + super = kzalloc(sizeof(*super), GFP_KERNEL); if (!super) return ERR_PTR(-ENOMEM); @@ -173,6 +179,34 @@ struct clk *tegra_clk_register_super_cclk(const char *name, clk = clk_register(NULL, &super->hw); if (IS_ERR(clk)) kfree(super); + else + cclk_super = super; return clk; } + +int tegra_cclk_pre_pllx_rate_change(void) +{ + if (IS_ERR_OR_NULL(cclk_super)) + return -EINVAL; + + if (cclk_super_get_parent(&cclk_super->hw) == PLLX_INDEX) + cclk_on_pllx = true; + else + cclk_on_pllx = false; + + /* + * CPU needs to be temporarily re-parented away from PLLX if PLLX + * changes its rate. PLLP is a safe parent for CPU on all Tegra SoCs. + */ + if (cclk_on_pllx) + cclk_super_set_parent(&cclk_super->hw, PLLP_INDEX); + + return 0; +} + +void tegra_cclk_post_pllx_rate_change(void) +{ + if (cclk_on_pllx) + cclk_super_set_parent(&cclk_super->hw, PLLX_INDEX); +} diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h index 87a6fb21aafa..6b565f6b5f66 100644 --- a/drivers/clk/tegra/clk.h +++ b/drivers/clk/tegra/clk.h @@ -771,6 +771,8 @@ struct clk *tegra_clk_register_super_cclk(const char *name, const char * const *parent_names, u8 num_parents, unsigned long flags, void __iomem *reg, u8 clk_super_flags, spinlock_t *lock); +int tegra_cclk_pre_pllx_rate_change(void); +void tegra_cclk_post_pllx_rate_change(void); /** * struct tegra_sdmmc_mux - switch divider with Low Jitter inputs for SDMMC |