/* * Driver for the ICST307 VCO clock found in the ARM Reference designs. * We wrap the custom interface from <asm/hardware/icst.h> into the generic * clock framework. * * Copyright (C) 2012 Linus Walleij * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * TODO: when all ARM reference designs are migrated to generic clocks, the * ICST clock code from the ARM tree should probably be merged into this * file. */ #include <linux/clk.h> #include <linux/clkdev.h> #include <linux/err.h> #include <linux/clk-provider.h> #include <linux/io.h> #include "clk-icst.h" /** * struct clk_icst - ICST VCO clock wrapper * @hw: corresponding clock hardware entry * @vcoreg: VCO register address * @lockreg: VCO lock register address * @params: parameters for this ICST instance * @rate: current rate */ struct clk_icst { struct clk_hw hw; void __iomem *vcoreg; void __iomem *lockreg; struct icst_params *params; unsigned long rate; }; #define to_icst(_hw) container_of(_hw, struct clk_icst, hw) /** * vco_get() - get ICST VCO settings from a certain register * @vcoreg: register containing the VCO settings */ static struct icst_vco vco_get(void __iomem *vcoreg) { u32 val; struct icst_vco vco; val = readl(vcoreg); vco.v = val & 0x1ff; vco.r = (val >> 9) & 0x7f; vco.s = (val >> 16) & 03; return vco; } /** * vco_set() - commit changes to an ICST VCO * @locreg: register to poke to unlock the VCO for writing * @vcoreg: register containing the VCO settings * @vco: ICST VCO parameters to commit */ static void vco_set(void __iomem *lockreg, void __iomem *vcoreg, struct icst_vco vco) { u32 val; val = readl(vcoreg) & ~0x7ffff; val |= vco.v | (vco.r << 9) | (vco.s << 16); /* This magic unlocks the VCO so it can be controlled */ writel(0xa05f, lockreg); writel(val, vcoreg); /* This locks the VCO again */ writel(0, lockreg); } static unsigned long icst_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct clk_icst *icst = to_icst(hw); struct icst_vco vco; if (parent_rate) icst->params->ref = parent_rate; vco = vco_get(icst->vcoreg); icst->rate = icst_hz(icst->params, vco); return icst->rate; } static long icst_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *prate) { struct clk_icst *icst = to_icst(hw); struct icst_vco vco; vco = icst_hz_to_vco(icst->params, rate); return icst_hz(icst->params, vco); } static int icst_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct clk_icst *icst = to_icst(hw); struct icst_vco vco; if (parent_rate) icst->params->ref = parent_rate; vco = icst_hz_to_vco(icst->params, rate); icst->rate = icst_hz(icst->params, vco); vco_set(icst->lockreg, icst->vcoreg, vco); return 0; } static const struct clk_ops icst_ops = { .recalc_rate = icst_recalc_rate, .round_rate = icst_round_rate, .set_rate = icst_set_rate, }; struct clk *icst_clk_register(struct device *dev, const struct clk_icst_desc *desc, const char *name, const char *parent_name, void __iomem *base) { struct clk *clk; struct clk_icst *icst; struct clk_init_data init; struct icst_params *pclone; icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL); if (!icst) { pr_err("could not allocate ICST clock!\n"); return ERR_PTR(-ENOMEM); } pclone = kmemdup(desc->params, sizeof(*pclone), GFP_KERNEL); if (!pclone) { kfree(icst); pr_err("could not clone ICST params\n"); return ERR_PTR(-ENOMEM); } init.name = name; init.ops = &icst_ops; init.flags = CLK_IS_ROOT; init.parent_names = (parent_name ? &parent_name : NULL); init.num_parents = (parent_name ? 1 : 0); icst->hw.init = &init; icst->params = pclone; icst->vcoreg = base + desc->vco_offset; icst->lockreg = base + desc->lock_offset; clk = clk_register(dev, &icst->hw); if (IS_ERR(clk)) kfree(icst); return clk; } EXPORT_SYMBOL_GPL(icst_clk_register);