drivers/clk/sunxi-ng/ccu-sun6i-rtc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 //
   3 // Copyright (c) 2021 Samuel Holland <samuel@sholland.org>
   4 //
   5
   6 #include <linux/clk.h>
   7 #include <linux/clk-provider.h>
   8 #include <linux/device.h>
   9 #include <linux/io.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/of_device.h>
  13
  14 #include <linux/clk/sunxi-ng.h>
  15
  16 #include "ccu_common.h"
  17
  18 #include "ccu_div.h"
  19 #include "ccu_gate.h"
  20 #include "ccu_mux.h"
  21
  22 #include "ccu-sun6i-rtc.h"
  23
  24 #define IOSC_ACCURACY                   300000000 /* 30% */
  25 #define IOSC_RATE                       16000000
  26
  27 #define LOSC_RATE                       32768
  28 #define LOSC_RATE_SHIFT                 15
  29
  30 #define LOSC_CTRL_REG                   0x0
  31 #define LOSC_CTRL_KEY                   0x16aa0000
  32
  33 #define IOSC_32K_CLK_DIV_REG            0x8
  34 #define IOSC_32K_CLK_DIV                GENMASK(4, 0)
  35 #define IOSC_32K_PRE_DIV                32
  36
  37 #define IOSC_CLK_CALI_REG               0xc
  38 #define IOSC_CLK_CALI_DIV_ONES          22
  39 #define IOSC_CLK_CALI_EN                BIT(1)
  40 #define IOSC_CLK_CALI_SRC_SEL           BIT(0)
  41
  42 #define LOSC_OUT_GATING_REG             0x60
  43
  44 #define DCXO_CTRL_REG                   0x160
  45 #define DCXO_CTRL_CLK16M_RC_EN          BIT(0)
  46
  47 struct sun6i_rtc_match_data {
  48         bool                            have_ext_osc32k         : 1;
  49         bool                            have_iosc_calibration   : 1;
  50         bool                            rtc_32k_single_parent   : 1;
  51         const struct clk_parent_data    *osc32k_fanout_parents;
  52         u8                              osc32k_fanout_nparents;
  53 };
  54
  55 static bool have_iosc_calibration;
  56
  57 static int ccu_iosc_enable(struct clk_hw *hw)
  58 {
  59         struct ccu_common *cm = hw_to_ccu_common(hw);
  60
  61         return ccu_gate_helper_enable(cm, DCXO_CTRL_CLK16M_RC_EN);
  62 }
  63
  64 static void ccu_iosc_disable(struct clk_hw *hw)
  65 {
  66         struct ccu_common *cm = hw_to_ccu_common(hw);
  67
  68         return ccu_gate_helper_disable(cm, DCXO_CTRL_CLK16M_RC_EN);
  69 }
  70
  71 static int ccu_iosc_is_enabled(struct clk_hw *hw)
  72 {
  73         struct ccu_common *cm = hw_to_ccu_common(hw);
  74
  75         return ccu_gate_helper_is_enabled(cm, DCXO_CTRL_CLK16M_RC_EN);
  76 }
  77
  78 static unsigned long ccu_iosc_recalc_rate(struct clk_hw *hw,
  79                                           unsigned long parent_rate)
  80 {
  81         struct ccu_common *cm = hw_to_ccu_common(hw);
  82
  83         if (have_iosc_calibration) {
  84                 u32 reg = readl(cm->base + IOSC_CLK_CALI_REG);
  85
  86                 /*
  87                  * Recover the IOSC frequency by shifting the ones place of
  88                  * (fixed-point divider * 32768) into bit zero.
  89                  */
  90                 if (reg & IOSC_CLK_CALI_EN)
  91                         return reg >> (IOSC_CLK_CALI_DIV_ONES - LOSC_RATE_SHIFT);
  92         }
  93
  94         return IOSC_RATE;
  95 }
  96
  97 static unsigned long ccu_iosc_recalc_accuracy(struct clk_hw *hw,
  98                                               unsigned long parent_accuracy)
  99 {
 100         return IOSC_ACCURACY;
 101 }
 102
 103 static const struct clk_ops ccu_iosc_ops = {
 104         .enable                 = ccu_iosc_enable,
 105         .disable                = ccu_iosc_disable,
 106         .is_enabled             = ccu_iosc_is_enabled,
 107         .recalc_rate            = ccu_iosc_recalc_rate,
 108         .recalc_accuracy        = ccu_iosc_recalc_accuracy,
 109 };
 110
 111 static struct ccu_common iosc_clk = {
 112         .reg            = DCXO_CTRL_REG,
 113         .hw.init        = CLK_HW_INIT_NO_PARENT("iosc", &ccu_iosc_ops,
 114                                                 CLK_GET_RATE_NOCACHE),
 115 };
 116
 117 static int ccu_iosc_32k_prepare(struct clk_hw *hw)
 118 {
 119         struct ccu_common *cm = hw_to_ccu_common(hw);
 120         u32 val;
 121
 122         if (!have_iosc_calibration)
 123                 return 0;
 124
 125         val = readl(cm->base + IOSC_CLK_CALI_REG);
 126         writel(val | IOSC_CLK_CALI_EN | IOSC_CLK_CALI_SRC_SEL,
 127                cm->base + IOSC_CLK_CALI_REG);
 128
 129         return 0;
 130 }
 131
 132 static void ccu_iosc_32k_unprepare(struct clk_hw *hw)
 133 {
 134         struct ccu_common *cm = hw_to_ccu_common(hw);
 135         u32 val;
 136
 137         if (!have_iosc_calibration)
 138                 return;
 139
 140         val = readl(cm->base + IOSC_CLK_CALI_REG);
 141         writel(val & ~(IOSC_CLK_CALI_EN | IOSC_CLK_CALI_SRC_SEL),
 142                cm->base + IOSC_CLK_CALI_REG);
 143 }
 144
 145 static unsigned long ccu_iosc_32k_recalc_rate(struct clk_hw *hw,
 146                                               unsigned long parent_rate)
 147 {
 148         struct ccu_common *cm = hw_to_ccu_common(hw);
 149         u32 val;
 150
 151         if (have_iosc_calibration) {
 152                 val = readl(cm->base + IOSC_CLK_CALI_REG);
 153
 154                 /* Assume the calibrated 32k clock is accurate. */
 155                 if (val & IOSC_CLK_CALI_SRC_SEL)
 156                         return LOSC_RATE;
 157         }
 158
 159         val = readl(cm->base + IOSC_32K_CLK_DIV_REG) & IOSC_32K_CLK_DIV;
 160
 161         return parent_rate / IOSC_32K_PRE_DIV / (val + 1);
 162 }
 163
 164 static unsigned long ccu_iosc_32k_recalc_accuracy(struct clk_hw *hw,
 165                                                   unsigned long parent_accuracy)
 166 {
 167         struct ccu_common *cm = hw_to_ccu_common(hw);
 168         u32 val;
 169
 170         if (have_iosc_calibration) {
 171                 val = readl(cm->base + IOSC_CLK_CALI_REG);
 172
 173                 /* Assume the calibrated 32k clock is accurate. */
 174                 if (val & IOSC_CLK_CALI_SRC_SEL)
 175                         return 0;
 176         }
 177
 178         return parent_accuracy;
 179 }
 180
 181 static const struct clk_ops ccu_iosc_32k_ops = {
 182         .prepare                = ccu_iosc_32k_prepare,
 183         .unprepare              = ccu_iosc_32k_unprepare,
 184         .recalc_rate            = ccu_iosc_32k_recalc_rate,
 185         .recalc_accuracy        = ccu_iosc_32k_recalc_accuracy,
 186 };
 187
 188 static struct ccu_common iosc_32k_clk = {
 189         .hw.init        = CLK_HW_INIT_HW("iosc-32k", &iosc_clk.hw,
 190                                          &ccu_iosc_32k_ops,
 191                                          CLK_GET_RATE_NOCACHE),
 192 };
 193
 194 static const struct clk_hw *ext_osc32k[] = { NULL }; /* updated during probe */
 195
 196 static SUNXI_CCU_GATE_HWS(ext_osc32k_gate_clk, "ext-osc32k-gate",
 197                           ext_osc32k, 0x0, BIT(4), 0);
 198
 199 static const struct clk_hw *osc32k_parents[] = {
 200         &iosc_32k_clk.hw,
 201         &ext_osc32k_gate_clk.common.hw
 202 };
 203
 204 static struct clk_init_data osc32k_init_data = {
 205         .name           = "osc32k",
 206         .ops            = &ccu_mux_ops,
 207         .parent_hws     = osc32k_parents,
 208         .num_parents    = ARRAY_SIZE(osc32k_parents), /* updated during probe */
 209 };
 210
 211 static struct ccu_mux osc32k_clk = {
 212         .mux    = _SUNXI_CCU_MUX(0, 1),
 213         .common = {
 214                 .reg            = LOSC_CTRL_REG,
 215                 .features       = CCU_FEATURE_KEY_FIELD,
 216                 .hw.init        = &osc32k_init_data,
 217         },
 218 };
 219
 220 /* This falls back to the global name for fwnodes without a named reference. */
 221 static const struct clk_parent_data osc24M[] = {
 222         { .fw_name = "hosc", .name = "osc24M" }
 223 };
 224
 225 static struct ccu_gate osc24M_32k_clk = {
 226         .enable = BIT(16),
 227         .common = {
 228                 .reg            = LOSC_OUT_GATING_REG,
 229                 .prediv         = 750,
 230                 .features       = CCU_FEATURE_ALL_PREDIV,
 231                 .hw.init        = CLK_HW_INIT_PARENTS_DATA("osc24M-32k", osc24M,
 232                                                            &ccu_gate_ops, 0),
 233         },
 234 };
 235
 236 static const struct clk_hw *rtc_32k_parents[] = {
 237         &osc32k_clk.common.hw,
 238         &osc24M_32k_clk.common.hw
 239 };
 240
 241 static struct clk_init_data rtc_32k_init_data = {
 242         .name           = "rtc-32k",
 243         .ops            = &ccu_mux_ops,
 244         .parent_hws     = rtc_32k_parents,
 245         .num_parents    = ARRAY_SIZE(rtc_32k_parents), /* updated during probe */
 246         .flags          = CLK_IS_CRITICAL,
 247 };
 248
 249 static struct ccu_mux rtc_32k_clk = {
 250         .mux    = _SUNXI_CCU_MUX(1, 1),
 251         .common = {
 252                 .reg            = LOSC_CTRL_REG,
 253                 .features       = CCU_FEATURE_KEY_FIELD,
 254                 .hw.init        = &rtc_32k_init_data,
 255         },
 256 };
 257
 258 static struct clk_init_data osc32k_fanout_init_data = {
 259         .name           = "osc32k-fanout",
 260         .ops            = &ccu_mux_ops,
 261         /* parents are set during probe */
 262 };
 263
 264 static struct ccu_mux osc32k_fanout_clk = {
 265         .enable = BIT(0),
 266         .mux    = _SUNXI_CCU_MUX(1, 2),
 267         .common = {
 268                 .reg            = LOSC_OUT_GATING_REG,
 269                 .hw.init        = &osc32k_fanout_init_data,
 270         },
 271 };
 272
 273 static struct ccu_common *sun6i_rtc_ccu_clks[] = {
 274         &iosc_clk,
 275         &iosc_32k_clk,
 276         &ext_osc32k_gate_clk.common,
 277         &osc32k_clk.common,
 278         &osc24M_32k_clk.common,
 279         &rtc_32k_clk.common,
 280         &osc32k_fanout_clk.common,
 281 };
 282
 283 static struct clk_hw_onecell_data sun6i_rtc_ccu_hw_clks = {
 284         .num = CLK_NUMBER,
 285         .hws = {
 286                 [CLK_OSC32K]            = &osc32k_clk.common.hw,
 287                 [CLK_OSC32K_FANOUT]     = &osc32k_fanout_clk.common.hw,
 288                 [CLK_IOSC]              = &iosc_clk.hw,
 289                 [CLK_IOSC_32K]          = &iosc_32k_clk.hw,
 290                 [CLK_EXT_OSC32K_GATE]   = &ext_osc32k_gate_clk.common.hw,
 291                 [CLK_OSC24M_32K]        = &osc24M_32k_clk.common.hw,
 292                 [CLK_RTC_32K]           = &rtc_32k_clk.common.hw,
 293         },
 294 };
 295
 296 static const struct sunxi_ccu_desc sun6i_rtc_ccu_desc = {
 297         .ccu_clks       = sun6i_rtc_ccu_clks,
 298         .num_ccu_clks   = ARRAY_SIZE(sun6i_rtc_ccu_clks),
 299
 300         .hw_clks        = &sun6i_rtc_ccu_hw_clks,
 301 };
 302
 303 static const struct clk_parent_data sun50i_h616_osc32k_fanout_parents[] = {
 304         { .hw = &osc32k_clk.common.hw },
 305         { .fw_name = "pll-32k" },
 306         { .hw = &osc24M_32k_clk.common.hw }
 307 };
 308
 309 static const struct clk_parent_data sun50i_r329_osc32k_fanout_parents[] = {
 310         { .hw = &osc32k_clk.common.hw },
 311         { .hw = &ext_osc32k_gate_clk.common.hw },
 312         { .hw = &osc24M_32k_clk.common.hw }
 313 };
 314
 315 static const struct sun6i_rtc_match_data sun50i_h616_rtc_ccu_data = {
 316         .have_iosc_calibration  = true,
 317         .rtc_32k_single_parent  = true,
 318         .osc32k_fanout_parents  = sun50i_h616_osc32k_fanout_parents,
 319         .osc32k_fanout_nparents = ARRAY_SIZE(sun50i_h616_osc32k_fanout_parents),
 320 };
 321
 322 static const struct sun6i_rtc_match_data sun50i_r329_rtc_ccu_data = {
 323         .have_ext_osc32k        = true,
 324         .osc32k_fanout_parents  = sun50i_r329_osc32k_fanout_parents,
 325         .osc32k_fanout_nparents = ARRAY_SIZE(sun50i_r329_osc32k_fanout_parents),
 326 };
 327
 328 static const struct of_device_id sun6i_rtc_ccu_match[] = {
 329         {
 330                 .compatible     = "allwinner,sun50i-h616-rtc",
 331                 .data           = &sun50i_h616_rtc_ccu_data,
 332         },
 333         {
 334                 .compatible     = "allwinner,sun50i-r329-rtc",
 335                 .data           = &sun50i_r329_rtc_ccu_data,
 336         },
 337         {},
 338 };
 339 MODULE_DEVICE_TABLE(of, sun6i_rtc_ccu_match);
 340
 341 int sun6i_rtc_ccu_probe(struct device *dev, void __iomem *reg)
 342 {
 343         const struct sun6i_rtc_match_data *data;
 344         struct clk *ext_osc32k_clk = NULL;
 345         const struct of_device_id *match;
 346
 347         /* This driver is only used for newer variants of the hardware. */
 348         match = of_match_device(sun6i_rtc_ccu_match, dev);
 349         if (!match)
 350                 return 0;
 351
 352         data = match->data;
 353         have_iosc_calibration = data->have_iosc_calibration;
 354
 355         if (data->have_ext_osc32k) {
 356                 const char *fw_name;
 357
 358                 /* ext-osc32k was the only input clock in the old binding. */
 359                 fw_name = of_property_present(dev->of_node, "clock-names")
 360                         ? "ext-osc32k" : NULL;
 361                 ext_osc32k_clk = devm_clk_get_optional(dev, fw_name);
 362                 if (IS_ERR(ext_osc32k_clk))
 363                         return PTR_ERR(ext_osc32k_clk);
 364         }
 365
 366         if (ext_osc32k_clk) {
 367                 /* Link ext-osc32k-gate to its parent. */
 368                 *ext_osc32k = __clk_get_hw(ext_osc32k_clk);
 369         } else {
 370                 /* ext-osc32k-gate is an orphan, so do not register it. */
 371                 sun6i_rtc_ccu_hw_clks.hws[CLK_EXT_OSC32K_GATE] = NULL;
 372                 osc32k_init_data.num_parents = 1;
 373         }
 374
 375         if (data->rtc_32k_single_parent)
 376                 rtc_32k_init_data.num_parents = 1;
 377
 378         osc32k_fanout_init_data.parent_data = data->osc32k_fanout_parents;
 379         osc32k_fanout_init_data.num_parents = data->osc32k_fanout_nparents;
 380
 381         return devm_sunxi_ccu_probe(dev, reg, &sun6i_rtc_ccu_desc);
 382 }
 383
 384 MODULE_IMPORT_NS("SUNXI_CCU");
 385 MODULE_DESCRIPTION("Support for the Allwinner H616/R329 RTC CCU");
 386 MODULE_LICENSE("GPL");