diff options
Diffstat (limited to 'kernel/drivers/clk/tegra/clk-super.c')
| -rw-r--r-- | kernel/drivers/clk/tegra/clk-super.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/kernel/drivers/clk/tegra/clk-super.c b/kernel/drivers/clk/tegra/clk-super.c new file mode 100644 index 000000000..2fd924d38 --- /dev/null +++ b/kernel/drivers/clk/tegra/clk-super.c @@ -0,0 +1,166 @@ +/* + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/kernel.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/clk-provider.h> +#include <linux/clk.h> + +#include "clk.h" + +#define SUPER_STATE_IDLE 0 +#define SUPER_STATE_RUN 1 +#define SUPER_STATE_IRQ 2 +#define SUPER_STATE_FIQ 3 + +#define SUPER_STATE_SHIFT 28 +#define SUPER_STATE_MASK ((BIT(SUPER_STATE_IDLE) | BIT(SUPER_STATE_RUN) | \ + BIT(SUPER_STATE_IRQ) | BIT(SUPER_STATE_FIQ)) \ + << SUPER_STATE_SHIFT) + +#define SUPER_LP_DIV2_BYPASS (1 << 16) + +#define super_state(s) (BIT(s) << SUPER_STATE_SHIFT) +#define super_state_to_src_shift(m, s) ((m->width * s)) +#define super_state_to_src_mask(m) (((1 << m->width) - 1)) + +static u8 clk_super_get_parent(struct clk_hw *hw) +{ + struct tegra_clk_super_mux *mux = to_clk_super_mux(hw); + u32 val, state; + u8 source, shift; + + val = readl_relaxed(mux->reg); + + state = val & SUPER_STATE_MASK; + + BUG_ON((state != super_state(SUPER_STATE_RUN)) && + (state != super_state(SUPER_STATE_IDLE))); + shift = (state == super_state(SUPER_STATE_IDLE)) ? + super_state_to_src_shift(mux, SUPER_STATE_IDLE) : + super_state_to_src_shift(mux, SUPER_STATE_RUN); + + source = (val >> shift) & super_state_to_src_mask(mux); + + /* + * If LP_DIV2_BYPASS is not set and PLLX is current parent then + * PLLX/2 is the input source to CCLKLP. + */ + if ((mux->flags & TEGRA_DIVIDER_2) && !(val & SUPER_LP_DIV2_BYPASS) && + (source == mux->pllx_index)) + source = mux->div2_index; + + return source; +} + +static int clk_super_set_parent(struct clk_hw *hw, u8 index) +{ + struct tegra_clk_super_mux *mux = to_clk_super_mux(hw); + u32 val, state; + int err = 0; + u8 parent_index, shift; + unsigned long flags = 0; + + if (mux->lock) + spin_lock_irqsave(mux->lock, flags); + + val = readl_relaxed(mux->reg); + state = val & SUPER_STATE_MASK; + BUG_ON((state != super_state(SUPER_STATE_RUN)) && + (state != super_state(SUPER_STATE_IDLE))); + shift = (state == super_state(SUPER_STATE_IDLE)) ? + super_state_to_src_shift(mux, SUPER_STATE_IDLE) : + super_state_to_src_shift(mux, SUPER_STATE_RUN); + + /* + * For LP mode super-clock switch between PLLX direct + * and divided-by-2 outputs is allowed only when other + * than PLLX clock source is current parent. + */ + if ((mux->flags & TEGRA_DIVIDER_2) && ((index == mux->div2_index) || + (index == mux->pllx_index))) { + parent_index = clk_super_get_parent(hw); + if ((parent_index == mux->div2_index) || + (parent_index == mux->pllx_index)) { + err = -EINVAL; + goto out; + } + + val ^= SUPER_LP_DIV2_BYPASS; + writel_relaxed(val, mux->reg); + udelay(2); + + if (index == mux->div2_index) + index = mux->pllx_index; + } + val &= ~((super_state_to_src_mask(mux)) << shift); + val |= (index & (super_state_to_src_mask(mux))) << shift; + + writel_relaxed(val, mux->reg); + udelay(2); + +out: + if (mux->lock) + spin_unlock_irqrestore(mux->lock, flags); + + return err; +} + +const struct clk_ops tegra_clk_super_ops = { + .get_parent = clk_super_get_parent, + .set_parent = clk_super_set_parent, +}; + +struct clk *tegra_clk_register_super_mux(const char *name, + const char **parent_names, u8 num_parents, + unsigned long flags, void __iomem *reg, u8 clk_super_flags, + u8 width, u8 pllx_index, u8 div2_index, spinlock_t *lock) +{ + struct tegra_clk_super_mux *super; + struct clk *clk; + struct clk_init_data init; + + super = kzalloc(sizeof(*super), GFP_KERNEL); + if (!super) { + pr_err("%s: could not allocate super clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.ops = &tegra_clk_super_ops; + init.flags = flags; + init.parent_names = parent_names; + init.num_parents = num_parents; + + super->reg = reg; + super->pllx_index = pllx_index; + super->div2_index = div2_index; + super->lock = lock; + super->width = width; + super->flags = clk_super_flags; + + /* Data in .init is copied by clk_register(), so stack variable OK */ + super->hw.init = &init; + + clk = clk_register(NULL, &super->hw); + if (IS_ERR(clk)) + kfree(super); + + return clk; +} |