1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * System Control and Power Interface (SCPI) Protocol based clock driver 4 * 5 * Copyright (C) 2015 ARM Ltd. 6 */ 7 8 #include <linux/clk-provider.h> 9 #include <linux/device.h> 10 #include <linux/err.h> 11 #include <linux/of.h> 12 #include <linux/module.h> 13 #include <linux/of_platform.h> 14 #include <linux/platform_device.h> 15 #include <linux/scpi_protocol.h> 16 17 struct scpi_clk { 18 u32 id; 19 struct clk_hw hw; 20 struct scpi_dvfs_info *info; 21 struct scpi_ops *scpi_ops; 22 }; 23 24 #define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw) 25 26 static struct platform_device *cpufreq_dev; 27 28 static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw, 29 unsigned long parent_rate) 30 { 31 struct scpi_clk *clk = to_scpi_clk(hw); 32 33 return clk->scpi_ops->clk_get_val(clk->id); 34 } 35 36 static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate, 37 unsigned long *parent_rate) 38 { 39 /* 40 * We can't figure out what rate it will be, so just return the 41 * rate back to the caller. scpi_clk_recalc_rate() will be called 42 * after the rate is set and we'll know what rate the clock is 43 * running at then. 44 */ 45 return rate; 46 } 47 48 static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate, 49 unsigned long parent_rate) 50 { 51 struct scpi_clk *clk = to_scpi_clk(hw); 52 53 return clk->scpi_ops->clk_set_val(clk->id, rate); 54 } 55 56 static const struct clk_ops scpi_clk_ops = { 57 .recalc_rate = scpi_clk_recalc_rate, 58 .round_rate = scpi_clk_round_rate, 59 .set_rate = scpi_clk_set_rate, 60 }; 61 62 /* find closest match to given frequency in OPP table */ 63 static long __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate) 64 { 65 int idx; 66 unsigned long fmin = 0, fmax = ~0, ftmp; 67 const struct scpi_opp *opp = clk->info->opps; 68 69 for (idx = 0; idx < clk->info->count; idx++, opp++) { 70 ftmp = opp->freq; 71 if (ftmp >= rate) { 72 if (ftmp <= fmax) 73 fmax = ftmp; 74 break; 75 } else if (ftmp >= fmin) { 76 fmin = ftmp; 77 } 78 } 79 return fmax != ~0 ? fmax : fmin; 80 } 81 82 static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw, 83 unsigned long parent_rate) 84 { 85 struct scpi_clk *clk = to_scpi_clk(hw); 86 int idx = clk->scpi_ops->dvfs_get_idx(clk->id); 87 const struct scpi_opp *opp; 88 89 if (idx < 0) 90 return 0; 91 92 opp = clk->info->opps + idx; 93 return opp->freq; 94 } 95 96 static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate, 97 unsigned long *parent_rate) 98 { 99 struct scpi_clk *clk = to_scpi_clk(hw); 100 101 return __scpi_dvfs_round_rate(clk, rate); 102 } 103 104 static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate) 105 { 106 int idx, max_opp = clk->info->count; 107 const struct scpi_opp *opp = clk->info->opps; 108 109 for (idx = 0; idx < max_opp; idx++, opp++) 110 if (opp->freq == rate) 111 return idx; 112 return -EINVAL; 113 } 114 115 static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate, 116 unsigned long parent_rate) 117 { 118 struct scpi_clk *clk = to_scpi_clk(hw); 119 int ret = __scpi_find_dvfs_index(clk, rate); 120 121 if (ret < 0) 122 return ret; 123 return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret); 124 } 125 126 static const struct clk_ops scpi_dvfs_ops = { 127 .recalc_rate = scpi_dvfs_recalc_rate, 128 .round_rate = scpi_dvfs_round_rate, 129 .set_rate = scpi_dvfs_set_rate, 130 }; 131 132 static const struct of_device_id scpi_clk_match[] __maybe_unused = { 133 { .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, }, 134 { .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, }, 135 {} 136 }; 137 138 static int 139 scpi_clk_ops_init(struct device *dev, const struct of_device_id *match, 140 struct scpi_clk *sclk, const char *name) 141 { 142 struct clk_init_data init; 143 unsigned long min = 0, max = 0; 144 int ret; 145 146 init.name = name; 147 init.flags = 0; 148 init.num_parents = 0; 149 init.ops = match->data; 150 sclk->hw.init = &init; 151 sclk->scpi_ops = get_scpi_ops(); 152 153 if (init.ops == &scpi_dvfs_ops) { 154 sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id); 155 if (IS_ERR(sclk->info)) 156 return PTR_ERR(sclk->info); 157 } else if (init.ops == &scpi_clk_ops) { 158 if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max) 159 return -EINVAL; 160 } else { 161 return -EINVAL; 162 } 163 164 ret = devm_clk_hw_register(dev, &sclk->hw); 165 if (!ret && max) 166 clk_hw_set_rate_range(&sclk->hw, min, max); 167 return ret; 168 } 169 170 struct scpi_clk_data { 171 struct scpi_clk **clk; 172 unsigned int clk_num; 173 }; 174 175 static struct clk_hw * 176 scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data) 177 { 178 struct scpi_clk *sclk; 179 struct scpi_clk_data *clk_data = data; 180 unsigned int idx = clkspec->args[0], count; 181 182 for (count = 0; count < clk_data->clk_num; count++) { 183 sclk = clk_data->clk[count]; 184 if (idx == sclk->id) 185 return &sclk->hw; 186 } 187 188 return ERR_PTR(-EINVAL); 189 } 190 191 static int scpi_clk_add(struct device *dev, struct device_node *np, 192 const struct of_device_id *match) 193 { 194 int idx, count, err; 195 struct scpi_clk_data *clk_data; 196 197 count = of_property_count_strings(np, "clock-output-names"); 198 if (count < 0) { 199 dev_err(dev, "%pOFn: invalid clock output count\n", np); 200 return -EINVAL; 201 } 202 203 clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL); 204 if (!clk_data) 205 return -ENOMEM; 206 207 clk_data->clk_num = count; 208 clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk), 209 GFP_KERNEL); 210 if (!clk_data->clk) 211 return -ENOMEM; 212 213 for (idx = 0; idx < count; idx++) { 214 struct scpi_clk *sclk; 215 const char *name; 216 u32 val; 217 218 sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL); 219 if (!sclk) 220 return -ENOMEM; 221 222 if (of_property_read_string_index(np, "clock-output-names", 223 idx, &name)) { 224 dev_err(dev, "invalid clock name @ %pOFn\n", np); 225 return -EINVAL; 226 } 227 228 if (of_property_read_u32_index(np, "clock-indices", 229 idx, &val)) { 230 dev_err(dev, "invalid clock index @ %pOFn\n", np); 231 return -EINVAL; 232 } 233 234 sclk->id = val; 235 236 err = scpi_clk_ops_init(dev, match, sclk, name); 237 if (err) { 238 dev_err(dev, "failed to register clock '%s'\n", name); 239 return err; 240 } 241 242 dev_dbg(dev, "Registered clock '%s'\n", name); 243 clk_data->clk[idx] = sclk; 244 } 245 246 return of_clk_add_hw_provider(np, scpi_of_clk_src_get, clk_data); 247 } 248 249 static void scpi_clocks_remove(struct platform_device *pdev) 250 { 251 struct device *dev = &pdev->dev; 252 struct device_node *child, *np = dev->of_node; 253 254 if (cpufreq_dev) { 255 platform_device_unregister(cpufreq_dev); 256 cpufreq_dev = NULL; 257 } 258 259 for_each_available_child_of_node(np, child) 260 of_clk_del_provider(np); 261 } 262 263 static int scpi_clocks_probe(struct platform_device *pdev) 264 { 265 int ret; 266 struct device *dev = &pdev->dev; 267 struct device_node *child, *np = dev->of_node; 268 const struct of_device_id *match; 269 270 if (!get_scpi_ops()) 271 return -ENXIO; 272 273 for_each_available_child_of_node(np, child) { 274 match = of_match_node(scpi_clk_match, child); 275 if (!match) 276 continue; 277 ret = scpi_clk_add(dev, child, match); 278 if (ret) { 279 scpi_clocks_remove(pdev); 280 of_node_put(child); 281 return ret; 282 } 283 284 if (match->data != &scpi_dvfs_ops) 285 continue; 286 /* Add the virtual cpufreq device if it's DVFS clock provider */ 287 cpufreq_dev = platform_device_register_simple("scpi-cpufreq", 288 -1, NULL, 0); 289 if (IS_ERR(cpufreq_dev)) 290 pr_warn("unable to register cpufreq device"); 291 } 292 return 0; 293 } 294 295 static const struct of_device_id scpi_clocks_ids[] = { 296 { .compatible = "arm,scpi-clocks", }, 297 {} 298 }; 299 MODULE_DEVICE_TABLE(of, scpi_clocks_ids); 300 301 static struct platform_driver scpi_clocks_driver = { 302 .driver = { 303 .name = "scpi_clocks", 304 .of_match_table = scpi_clocks_ids, 305 }, 306 .probe = scpi_clocks_probe, 307 .remove_new = scpi_clocks_remove, 308 }; 309 module_platform_driver(scpi_clocks_driver); 310 311 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 312 MODULE_DESCRIPTION("ARM SCPI clock driver"); 313 MODULE_LICENSE("GPL v2"); 314