149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
/*
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* Driver for the ICST307 VCO clock found in the ARM Reference designs.
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* We wrap the custom interface from <asm/hardware/icst.h> into the generic
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* clock framework.
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*
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* Copyright (C) 2012 Linus Walleij
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* TODO: when all ARM reference designs are migrated to generic clocks, the
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* ICST clock code from the ARM tree should probably be merged into this
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* file.
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*/
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#include <linux/clk.h>
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#include <linux/clkdev.h>
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#include <linux/err.h>
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#include <linux/clk-provider.h>
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#include <linux/io.h>
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#include "clk-icst.h"
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/**
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* struct clk_icst - ICST VCO clock wrapper
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* @hw: corresponding clock hardware entry
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* @vcoreg: VCO register address
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* @lockreg: VCO lock register address
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* @params: parameters for this ICST instance
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* @rate: current rate
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*/
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struct clk_icst {
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struct clk_hw hw;
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void __iomem *vcoreg;
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void __iomem *lockreg;
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const struct icst_params *params;
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unsigned long rate;
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};
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#define to_icst(_hw) container_of(_hw, struct clk_icst, hw)
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/**
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* vco_get() - get ICST VCO settings from a certain register
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* @vcoreg: register containing the VCO settings
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*/
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static struct icst_vco vco_get(void __iomem *vcoreg)
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{
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u32 val;
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struct icst_vco vco;
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val = readl(vcoreg);
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vco.v = val & 0x1ff;
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vco.r = (val >> 9) & 0x7f;
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vco.s = (val >> 16) & 03;
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return vco;
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}
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/**
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* vco_set() - commit changes to an ICST VCO
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* @locreg: register to poke to unlock the VCO for writing
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* @vcoreg: register containing the VCO settings
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* @vco: ICST VCO parameters to commit
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*/
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static void vco_set(void __iomem *lockreg,
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void __iomem *vcoreg,
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struct icst_vco vco)
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{
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u32 val;
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val = readl(vcoreg) & ~0x7ffff;
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val |= vco.v | (vco.r << 9) | (vco.s << 16);
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/* This magic unlocks the VCO so it can be controlled */
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writel(0xa05f, lockreg);
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writel(val, vcoreg);
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/* This locks the VCO again */
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writel(0, lockreg);
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}
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static unsigned long icst_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct clk_icst *icst = to_icst(hw);
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struct icst_vco vco;
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vco = vco_get(icst->vcoreg);
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icst->rate = icst_hz(icst->params, vco);
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return icst->rate;
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}
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static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *prate)
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{
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struct clk_icst *icst = to_icst(hw);
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struct icst_vco vco;
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vco = icst_hz_to_vco(icst->params, rate);
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return icst_hz(icst->params, vco);
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}
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static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long parent_rate)
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{
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struct clk_icst *icst = to_icst(hw);
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struct icst_vco vco;
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vco = icst_hz_to_vco(icst->params, rate);
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icst->rate = icst_hz(icst->params, vco);
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vco_set(icst->vcoreg, icst->lockreg, vco);
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return 0;
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}
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static const struct clk_ops icst_ops = {
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.recalc_rate = icst_recalc_rate,
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.round_rate = icst_round_rate,
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.set_rate = icst_set_rate,
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};
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struct clk *icst_clk_register(struct device *dev,
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const struct clk_icst_desc *desc,
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void __iomem *base)
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{
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struct clk *clk;
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struct clk_icst *icst;
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struct clk_init_data init;
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icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
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if (!icst) {
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pr_err("could not allocate ICST clock!\n");
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return ERR_PTR(-ENOMEM);
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}
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init.name = "icst";
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init.ops = &icst_ops;
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init.flags = CLK_IS_ROOT;
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init.parent_names = NULL;
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init.num_parents = 0;
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icst->hw.init = &init;
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icst->params = desc->params;
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icst->vcoreg = base + desc->vco_offset;
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icst->lockreg = base + desc->lock_offset;
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clk = clk_register(dev, &icst->hw);
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if (IS_ERR(clk))
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kfree(icst);
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return clk;
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}
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