141 lines
3.4 KiB
C
141 lines
3.4 KiB
C
/*
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* Copyright (c) 2016-2017, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/clk.h>
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#include <linux/kernel.h>
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#include <linux/io.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/clk-provider.h>
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#include "clk.h"
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#define SKIPPER_DIVISOR 256
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#define SKIPPER_ENABLE BIT(31)
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static int calc_skipper_mul(unsigned long rate, unsigned long prate)
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{
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int mul;
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rate = rate * 256;
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mul = DIV_ROUND_UP(rate, prate);
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mul = max(mul, 1);
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mul = min(mul, 256);
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return mul;
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}
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static int clk_skipper_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long prate)
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{
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struct tegra_clk_skipper *skipper = to_clk_skipper(hw);
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unsigned long flags = 0;
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int mul;
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u32 val;
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mul = calc_skipper_mul(rate, prate);
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if (skipper->lock)
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spin_lock_irqsave(skipper->lock, flags);
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val = readl_relaxed(skipper->reg);
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val &= ~(0xff << 8);
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val |= (mul - 1) << 8;
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if (mul == SKIPPER_DIVISOR)
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val &= ~SKIPPER_ENABLE; /* disable for 1:1 */
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else
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val |= SKIPPER_ENABLE; /* enable to skip */
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writel_relaxed(val, skipper->reg);
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if (skipper->lock)
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spin_unlock_irqrestore(skipper->lock, flags);
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return 0;
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}
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static int clk_skipper_determine_rate(struct clk_hw *hw,
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struct clk_rate_request *req)
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{
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int mul;
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req->rate = max(req->rate, req->min_rate);
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req->rate = min(req->rate, req->max_rate);
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mul = calc_skipper_mul(req->rate, req->best_parent_rate);
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req->rate = (req->best_parent_rate * mul) / SKIPPER_DIVISOR;
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return 0;
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}
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static unsigned long clk_skipper_recalc_rate(struct clk_hw *hw,
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unsigned long prate)
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{
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struct tegra_clk_skipper *skipper = to_clk_skipper(hw);
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u32 val;
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int mul;
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val = readl_relaxed(skipper->reg);
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mul = ((val >> 8) & 0xff) + 1;
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return (prate * mul) / SKIPPER_DIVISOR;
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}
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const struct clk_ops tegra_clk_skipper_ops = {
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.recalc_rate = clk_skipper_recalc_rate,
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.set_rate = clk_skipper_set_rate,
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.determine_rate = clk_skipper_determine_rate,
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};
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struct clk *tegra_clk_register_skipper(const char *name,
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const char *parent_name, void __iomem *reg,
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unsigned long flags, spinlock_t *lock)
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{
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struct tegra_clk_skipper *skipper;
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struct clk *clk;
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struct clk_init_data init;
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u32 val;
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skipper = kzalloc(sizeof(*skipper), GFP_KERNEL);
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if (!skipper) {
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pr_err("%s: could not allocate skipper clk\n", __func__);
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return ERR_PTR(-ENOMEM);
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}
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init.name = name;
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init.ops = &tegra_clk_skipper_ops;
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init.flags = flags;
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init.parent_names = parent_name ? &parent_name : NULL;
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init.num_parents = parent_name ? 1 : 0;
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skipper->reg = reg;
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skipper->lock = lock;
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/* Data in .init is copied by clk_register(), so stack variable OK */
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skipper->hw.init = &init;
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val = readl_relaxed(skipper->reg) & (~SKIPPER_ENABLE);
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val |= (SKIPPER_DIVISOR - 1) << 8;
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val |= SKIPPER_DIVISOR - 1;
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writel(val, skipper->reg);
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clk = clk_register(NULL, &skipper->hw);
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if (IS_ERR(clk))
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kfree(skipper);
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return clk;
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}
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