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152 lines
3.4 KiB
152 lines
3.4 KiB
/* |
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* Copyright (C) 2012 ST Microelectronics |
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* Viresh Kumar <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public |
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* License version 2. This program is licensed "as is" without any |
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* warranty of any kind, whether express or implied. |
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* |
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* General Purpose Timer Synthesizer clock implementation |
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*/ |
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#define pr_fmt(fmt) "clk-gpt-synth: " fmt |
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#include <linux/clk-provider.h> |
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#include <linux/slab.h> |
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#include <linux/io.h> |
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#include <linux/err.h> |
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#include "clk.h" |
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#define GPT_MSCALE_MASK 0xFFF |
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#define GPT_NSCALE_SHIFT 12 |
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#define GPT_NSCALE_MASK 0xF |
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/* |
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* DOC: General Purpose Timer Synthesizer clock |
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* |
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* Calculates gpt synth clk rate for different values of mscale and nscale |
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* |
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* Fout= Fin/((2 ^ (N+1)) * (M+1)) |
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*/ |
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#define to_clk_gpt(_hw) container_of(_hw, struct clk_gpt, hw) |
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static unsigned long gpt_calc_rate(struct clk_hw *hw, unsigned long prate, |
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int index) |
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{ |
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struct clk_gpt *gpt = to_clk_gpt(hw); |
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struct gpt_rate_tbl *rtbl = gpt->rtbl; |
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prate /= ((1 << (rtbl[index].nscale + 1)) * (rtbl[index].mscale + 1)); |
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return prate; |
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} |
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static long clk_gpt_round_rate(struct clk_hw *hw, unsigned long drate, |
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unsigned long *prate) |
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{ |
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struct clk_gpt *gpt = to_clk_gpt(hw); |
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int unused; |
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return clk_round_rate_index(hw, drate, *prate, gpt_calc_rate, |
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gpt->rtbl_cnt, &unused); |
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} |
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static unsigned long clk_gpt_recalc_rate(struct clk_hw *hw, |
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unsigned long parent_rate) |
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{ |
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struct clk_gpt *gpt = to_clk_gpt(hw); |
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unsigned long flags = 0; |
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unsigned int div = 1, val; |
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if (gpt->lock) |
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spin_lock_irqsave(gpt->lock, flags); |
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val = readl_relaxed(gpt->reg); |
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if (gpt->lock) |
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spin_unlock_irqrestore(gpt->lock, flags); |
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div += val & GPT_MSCALE_MASK; |
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div *= 1 << (((val >> GPT_NSCALE_SHIFT) & GPT_NSCALE_MASK) + 1); |
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if (!div) |
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return 0; |
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return parent_rate / div; |
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} |
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/* Configures new clock rate of gpt */ |
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static int clk_gpt_set_rate(struct clk_hw *hw, unsigned long drate, |
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unsigned long prate) |
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{ |
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struct clk_gpt *gpt = to_clk_gpt(hw); |
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struct gpt_rate_tbl *rtbl = gpt->rtbl; |
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unsigned long flags = 0, val; |
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int i; |
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clk_round_rate_index(hw, drate, prate, gpt_calc_rate, gpt->rtbl_cnt, |
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&i); |
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if (gpt->lock) |
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spin_lock_irqsave(gpt->lock, flags); |
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val = readl(gpt->reg) & ~GPT_MSCALE_MASK; |
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val &= ~(GPT_NSCALE_MASK << GPT_NSCALE_SHIFT); |
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val |= rtbl[i].mscale & GPT_MSCALE_MASK; |
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val |= (rtbl[i].nscale & GPT_NSCALE_MASK) << GPT_NSCALE_SHIFT; |
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writel_relaxed(val, gpt->reg); |
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if (gpt->lock) |
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spin_unlock_irqrestore(gpt->lock, flags); |
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return 0; |
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} |
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static const struct clk_ops clk_gpt_ops = { |
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.recalc_rate = clk_gpt_recalc_rate, |
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.round_rate = clk_gpt_round_rate, |
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.set_rate = clk_gpt_set_rate, |
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}; |
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struct clk *clk_register_gpt(const char *name, const char *parent_name, unsigned |
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long flags, void __iomem *reg, struct gpt_rate_tbl *rtbl, u8 |
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rtbl_cnt, spinlock_t *lock) |
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{ |
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struct clk_init_data init; |
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struct clk_gpt *gpt; |
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struct clk *clk; |
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if (!name || !parent_name || !reg || !rtbl || !rtbl_cnt) { |
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pr_err("Invalid arguments passed\n"); |
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return ERR_PTR(-EINVAL); |
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} |
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gpt = kzalloc(sizeof(*gpt), GFP_KERNEL); |
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if (!gpt) |
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return ERR_PTR(-ENOMEM); |
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/* struct clk_gpt assignments */ |
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gpt->reg = reg; |
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gpt->rtbl = rtbl; |
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gpt->rtbl_cnt = rtbl_cnt; |
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gpt->lock = lock; |
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gpt->hw.init = &init; |
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init.name = name; |
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init.ops = &clk_gpt_ops; |
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init.flags = flags; |
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init.parent_names = &parent_name; |
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init.num_parents = 1; |
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clk = clk_register(NULL, &gpt->hw); |
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if (!IS_ERR_OR_NULL(clk)) |
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return clk; |
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pr_err("clk register failed\n"); |
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kfree(gpt); |
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return NULL; |
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}
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