2 * Driver for the ICST307 VCO clock found in the ARM Reference designs.
3 * We wrap the custom interface from <asm/hardware/icst.h> into the generic
6 * Copyright (C) 2012-2015 Linus Walleij
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * TODO: when all ARM reference designs are migrated to generic clocks, the
13 * ICST clock code from the ARM tree should probably be merged into this
16 #include <linux/kernel.h>
17 #include <linux/slab.h>
18 #include <linux/export.h>
19 #include <linux/err.h>
20 #include <linux/clk-provider.h>
22 #include <linux/regmap.h>
23 #include <linux/mfd/syscon.h>
27 /* Magic unlocking token used on all Versatile boards */
28 #define VERSATILE_LOCK_VAL 0xA05F
31 * struct clk_icst - ICST VCO clock wrapper
32 * @hw: corresponding clock hardware entry
33 * @vcoreg: VCO register address
34 * @lockreg: VCO lock register address
35 * @params: parameters for this ICST instance
43 struct icst_params *params;
47 #define to_icst(_hw) container_of(_hw, struct clk_icst, hw)
50 * vco_get() - get ICST VCO settings from a certain ICST
51 * @icst: the ICST clock to get
52 * @vco: the VCO struct to return the value in
54 static int vco_get(struct clk_icst *icst, struct icst_vco *vco)
59 ret = regmap_read(icst->map, icst->vcoreg_off, &val);
63 vco->r = (val >> 9) & 0x7f;
64 vco->s = (val >> 16) & 03;
69 * vco_set() - commit changes to an ICST VCO
70 * @icst: the ICST clock to set
71 * @vco: the VCO struct to set the changes from
73 static int vco_set(struct clk_icst *icst, struct icst_vco vco)
78 ret = regmap_read(icst->map, icst->vcoreg_off, &val);
82 /* Mask the 18 bits used by the VCO */
84 val |= vco.v | (vco.r << 9) | (vco.s << 16);
86 /* This magic unlocks the VCO so it can be controlled */
87 ret = regmap_write(icst->map, icst->lockreg_off, VERSATILE_LOCK_VAL);
90 ret = regmap_write(icst->map, icst->vcoreg_off, val);
93 /* This locks the VCO again */
94 ret = regmap_write(icst->map, icst->lockreg_off, 0);
100 static unsigned long icst_recalc_rate(struct clk_hw *hw,
101 unsigned long parent_rate)
103 struct clk_icst *icst = to_icst(hw);
108 icst->params->ref = parent_rate;
109 ret = vco_get(icst, &vco);
111 pr_err("ICST: could not get VCO setting\n");
114 icst->rate = icst_hz(icst->params, vco);
118 static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
119 unsigned long *prate)
121 struct clk_icst *icst = to_icst(hw);
124 vco = icst_hz_to_vco(icst->params, rate);
125 return icst_hz(icst->params, vco);
128 static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
129 unsigned long parent_rate)
131 struct clk_icst *icst = to_icst(hw);
135 icst->params->ref = parent_rate;
136 vco = icst_hz_to_vco(icst->params, rate);
137 icst->rate = icst_hz(icst->params, vco);
138 return vco_set(icst, vco);
141 static const struct clk_ops icst_ops = {
142 .recalc_rate = icst_recalc_rate,
143 .round_rate = icst_round_rate,
144 .set_rate = icst_set_rate,
147 static struct clk *icst_clk_setup(struct device *dev,
148 const struct clk_icst_desc *desc,
150 const char *parent_name,
154 struct clk_icst *icst;
155 struct clk_init_data init;
156 struct icst_params *pclone;
158 icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
160 pr_err("could not allocate ICST clock!\n");
161 return ERR_PTR(-ENOMEM);
164 pclone = kmemdup(desc->params, sizeof(*pclone), GFP_KERNEL);
167 pr_err("could not clone ICST params\n");
168 return ERR_PTR(-ENOMEM);
172 init.ops = &icst_ops;
174 init.parent_names = (parent_name ? &parent_name : NULL);
175 init.num_parents = (parent_name ? 1 : 0);
177 icst->hw.init = &init;
178 icst->params = pclone;
179 icst->vcoreg_off = desc->vco_offset;
180 icst->lockreg_off = desc->lock_offset;
182 clk = clk_register(dev, &icst->hw);
191 struct clk *icst_clk_register(struct device *dev,
192 const struct clk_icst_desc *desc,
194 const char *parent_name,
197 struct regmap_config icst_regmap_conf = {
204 map = regmap_init_mmio(dev, base, &icst_regmap_conf);
206 pr_err("could not initialize ICST regmap\n");
207 return ERR_CAST(map);
209 return icst_clk_setup(dev, desc, name, parent_name, map);
211 EXPORT_SYMBOL_GPL(icst_clk_register);
215 * In a device tree, an memory-mapped ICST clock appear as a child
216 * of a syscon node. Assume this and probe it only as a child of a
220 static const struct icst_params icst525_params = {
221 .vco_max = ICST525_VCO_MAX_5V,
222 .vco_min = ICST525_VCO_MIN,
227 .s2div = icst525_s2div,
228 .idx2s = icst525_idx2s,
231 static const struct icst_params icst307_params = {
232 .vco_max = ICST307_VCO_MAX,
233 .vco_min = ICST307_VCO_MIN,
238 .s2div = icst307_s2div,
239 .idx2s = icst307_idx2s,
242 static void __init of_syscon_icst_setup(struct device_node *np)
244 struct device_node *parent;
246 struct clk_icst_desc icst_desc;
247 const char *name = np->name;
248 const char *parent_name;
251 /* We do not release this reference, we are using it perpetually */
252 parent = of_get_parent(np);
254 pr_err("no parent node for syscon ICST clock\n");
257 map = syscon_node_to_regmap(parent);
259 pr_err("no regmap for syscon ICST clock parent\n");
263 if (of_property_read_u32(np, "vco-offset", &icst_desc.vco_offset)) {
264 pr_err("no VCO register offset for ICST clock\n");
267 if (of_property_read_u32(np, "lock-offset", &icst_desc.lock_offset)) {
268 pr_err("no lock register offset for ICST clock\n");
272 if (of_device_is_compatible(np, "arm,syscon-icst525"))
273 icst_desc.params = &icst525_params;
274 else if (of_device_is_compatible(np, "arm,syscon-icst307"))
275 icst_desc.params = &icst307_params;
277 pr_err("unknown ICST clock %s\n", name);
281 /* Parent clock name is not the same as node parent */
282 parent_name = of_clk_get_parent_name(np, 0);
284 regclk = icst_clk_setup(NULL, &icst_desc, name, parent_name, map);
285 if (IS_ERR(regclk)) {
286 pr_err("error setting up syscon ICST clock %s\n", name);
289 of_clk_add_provider(np, of_clk_src_simple_get, regclk);
290 pr_debug("registered syscon ICST clock %s\n", name);
293 CLK_OF_DECLARE(arm_syscon_icst525_clk,
294 "arm,syscon-icst525", of_syscon_icst_setup);
295 CLK_OF_DECLARE(arm_syscon_icst307_clk,
296 "arm,syscon-icst307", of_syscon_icst_setup);