diff options
Diffstat (limited to 'drivers/clk/versatile/clk-icst.c')
| -rw-r--r-- | drivers/clk/versatile/clk-icst.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/clk/versatile/clk-icst.c b/drivers/clk/versatile/clk-icst.c new file mode 100644 index 000000000..bc96f103b --- /dev/null +++ b/drivers/clk/versatile/clk-icst.c @@ -0,0 +1,164 @@ +/* + * 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); |