linux/drivers/clk/microchip/clk-pic32mzda.c
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   1/*
   2 * Purna Chandra Mandal,<purna.mandal@microchip.com>
   3 * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
   4 *
   5 * This program is free software; you can distribute it and/or modify it
   6 * under the terms of the GNU General Public License (Version 2) as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 * for more details.
  13 */
  14#include <dt-bindings/clock/microchip,pic32-clock.h>
  15#include <linux/clk.h>
  16#include <linux/clk-provider.h>
  17#include <linux/clkdev.h>
  18#include <linux/module.h>
  19#include <linux/of_address.h>
  20#include <linux/of_platform.h>
  21#include <linux/platform_device.h>
  22#include <asm/traps.h>
  23
  24#include "clk-core.h"
  25
  26/* FRC Postscaler */
  27#define OSC_FRCDIV_MASK         0x07
  28#define OSC_FRCDIV_SHIFT        24
  29
  30/* SPLL fields */
  31#define PLL_ICLK_MASK           0x01
  32#define PLL_ICLK_SHIFT          7
  33
  34#define DECLARE_PERIPHERAL_CLOCK(__clk_name, __reg, __flags)    \
  35        {                                                       \
  36                .ctrl_reg = (__reg),                            \
  37                .init_data = {                                  \
  38                        .name = (__clk_name),                   \
  39                        .parent_names = (const char *[]) {      \
  40                                "sys_clk"                       \
  41                        },                                      \
  42                        .num_parents = 1,                       \
  43                        .ops = &pic32_pbclk_ops,                \
  44                        .flags = (__flags),                     \
  45                },                                              \
  46        }
  47
  48#define DECLARE_REFO_CLOCK(__clkid, __reg)                              \
  49        {                                                               \
  50                .ctrl_reg = (__reg),                                    \
  51                .init_data = {                                          \
  52                        .name = "refo" #__clkid "_clk",                 \
  53                        .parent_names = (const char *[]) {              \
  54                                "sys_clk", "pb1_clk", "posc_clk",       \
  55                                "frc_clk", "lprc_clk", "sosc_clk",      \
  56                                "sys_pll", "refi" #__clkid "_clk",      \
  57                                "bfrc_clk",                             \
  58                        },                                              \
  59                        .num_parents = 9,                               \
  60                        .flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE,\
  61                        .ops = &pic32_roclk_ops,                        \
  62                },                                                      \
  63                .parent_map = (const u32[]) {                           \
  64                        0, 1, 2, 3, 4, 5, 7, 8, 9                       \
  65                },                                                      \
  66        }
  67
  68static const struct pic32_ref_osc_data ref_clks[] = {
  69        DECLARE_REFO_CLOCK(1, 0x80),
  70        DECLARE_REFO_CLOCK(2, 0xa0),
  71        DECLARE_REFO_CLOCK(3, 0xc0),
  72        DECLARE_REFO_CLOCK(4, 0xe0),
  73        DECLARE_REFO_CLOCK(5, 0x100),
  74};
  75
  76static const struct pic32_periph_clk_data periph_clocks[] = {
  77        DECLARE_PERIPHERAL_CLOCK("pb1_clk", 0x140, 0),
  78        DECLARE_PERIPHERAL_CLOCK("pb2_clk", 0x150, CLK_IGNORE_UNUSED),
  79        DECLARE_PERIPHERAL_CLOCK("pb3_clk", 0x160, 0),
  80        DECLARE_PERIPHERAL_CLOCK("pb4_clk", 0x170, 0),
  81        DECLARE_PERIPHERAL_CLOCK("pb5_clk", 0x180, 0),
  82        DECLARE_PERIPHERAL_CLOCK("pb6_clk", 0x190, 0),
  83        DECLARE_PERIPHERAL_CLOCK("cpu_clk", 0x1a0, CLK_IGNORE_UNUSED),
  84};
  85
  86static const struct pic32_sys_clk_data sys_mux_clk = {
  87        .slew_reg = 0x1c0,
  88        .slew_div = 2, /* step of div_4 -> div_2 -> no_div */
  89        .init_data = {
  90                .name = "sys_clk",
  91                .parent_names = (const char *[]) {
  92                        "frcdiv_clk", "sys_pll", "posc_clk",
  93                        "sosc_clk", "lprc_clk", "frcdiv_clk",
  94                },
  95                .num_parents = 6,
  96                .ops = &pic32_sclk_ops,
  97        },
  98        .parent_map = (const u32[]) {
  99                0, 1, 2, 4, 5, 7,
 100        },
 101};
 102
 103static const struct pic32_sys_pll_data sys_pll = {
 104        .ctrl_reg = 0x020,
 105        .status_reg = 0x1d0,
 106        .lock_mask = BIT(7),
 107        .init_data = {
 108                .name = "sys_pll",
 109                .parent_names = (const char *[]) {
 110                        "spll_mux_clk"
 111                },
 112                .num_parents = 1,
 113                .ops = &pic32_spll_ops,
 114        },
 115};
 116
 117static const struct pic32_sec_osc_data sosc_clk = {
 118        .status_reg = 0x1d0,
 119        .enable_mask = BIT(1),
 120        .status_mask = BIT(4),
 121        .init_data = {
 122                .name = "sosc_clk",
 123                .parent_names = NULL,
 124                .ops = &pic32_sosc_ops,
 125        },
 126};
 127
 128static int pic32mzda_critical_clks[] = {
 129        PB2CLK, PB7CLK
 130};
 131
 132/* PIC32MZDA clock data */
 133struct pic32mzda_clk_data {
 134        struct clk *clks[MAXCLKS];
 135        struct pic32_clk_common core;
 136        struct clk_onecell_data onecell_data;
 137        struct notifier_block failsafe_notifier;
 138};
 139
 140static int pic32_fscm_nmi(struct notifier_block *nb,
 141                          unsigned long action, void *data)
 142{
 143        struct pic32mzda_clk_data *cd;
 144
 145        cd  = container_of(nb, struct pic32mzda_clk_data, failsafe_notifier);
 146
 147        /* SYSCLK is now running from BFRCCLK. Report clock failure. */
 148        if (readl(cd->core.iobase) & BIT(2))
 149                pr_alert("pic32-clk: FSCM detected clk failure.\n");
 150
 151        /* TODO: detect reason of failure and recover accordingly */
 152
 153        return NOTIFY_OK;
 154}
 155
 156static int pic32mzda_clk_probe(struct platform_device *pdev)
 157{
 158        const char *const pll_mux_parents[] = {"posc_clk", "frc_clk"};
 159        struct device_node *np = pdev->dev.of_node;
 160        struct pic32mzda_clk_data *cd;
 161        struct pic32_clk_common *core;
 162        struct clk *pll_mux_clk, *clk;
 163        struct clk **clks;
 164        int nr_clks, i, ret;
 165
 166        cd = devm_kzalloc(&pdev->dev, sizeof(*cd), GFP_KERNEL);
 167        if (!cd)
 168                return -ENOMEM;
 169
 170        core = &cd->core;
 171        core->iobase = of_io_request_and_map(np, 0, of_node_full_name(np));
 172        if (IS_ERR(core->iobase)) {
 173                dev_err(&pdev->dev, "pic32-clk: failed to map registers\n");
 174                return PTR_ERR(core->iobase);
 175        }
 176
 177        spin_lock_init(&core->reg_lock);
 178        core->dev = &pdev->dev;
 179        clks = &cd->clks[0];
 180
 181        /* register fixed rate clocks */
 182        clks[POSCCLK] = clk_register_fixed_rate(&pdev->dev, "posc_clk", NULL,
 183                                                0, 24000000);
 184        clks[FRCCLK] =  clk_register_fixed_rate(&pdev->dev, "frc_clk", NULL,
 185                                                0, 8000000);
 186        clks[BFRCCLK] = clk_register_fixed_rate(&pdev->dev, "bfrc_clk", NULL,
 187                                                0, 8000000);
 188        clks[LPRCCLK] = clk_register_fixed_rate(&pdev->dev, "lprc_clk", NULL,
 189                                                0, 32000);
 190        clks[UPLLCLK] = clk_register_fixed_rate(&pdev->dev, "usbphy_clk", NULL,
 191                                                0, 24000000);
 192        /* fixed rate (optional) clock */
 193        if (of_find_property(np, "microchip,pic32mzda-sosc", NULL)) {
 194                pr_info("pic32-clk: dt requests SOSC.\n");
 195                clks[SOSCCLK] = pic32_sosc_clk_register(&sosc_clk, core);
 196        }
 197        /* divider clock */
 198        clks[FRCDIVCLK] = clk_register_divider(&pdev->dev, "frcdiv_clk",
 199                                               "frc_clk", 0,
 200                                               core->iobase,
 201                                               OSC_FRCDIV_SHIFT,
 202                                               OSC_FRCDIV_MASK,
 203                                               CLK_DIVIDER_POWER_OF_TWO,
 204                                               &core->reg_lock);
 205        /* PLL ICLK mux */
 206        pll_mux_clk = clk_register_mux(&pdev->dev, "spll_mux_clk",
 207                                       pll_mux_parents, 2, 0,
 208                                       core->iobase + 0x020,
 209                                       PLL_ICLK_SHIFT, 1, 0, &core->reg_lock);
 210        if (IS_ERR(pll_mux_clk))
 211                pr_err("spll_mux_clk: clk register failed\n");
 212
 213        /* PLL */
 214        clks[PLLCLK] = pic32_spll_clk_register(&sys_pll, core);
 215        /* SYSTEM clock */
 216        clks[SCLK] = pic32_sys_clk_register(&sys_mux_clk, core);
 217        /* Peripheral bus clocks */
 218        for (nr_clks = PB1CLK, i = 0; nr_clks <= PB7CLK; i++, nr_clks++)
 219                clks[nr_clks] = pic32_periph_clk_register(&periph_clocks[i],
 220                                                          core);
 221        /* Reference oscillator clock */
 222        for (nr_clks = REF1CLK, i = 0; nr_clks <= REF5CLK; i++, nr_clks++)
 223                clks[nr_clks] = pic32_refo_clk_register(&ref_clks[i], core);
 224
 225        /* register clkdev */
 226        for (i = 0; i < MAXCLKS; i++) {
 227                if (IS_ERR(clks[i]))
 228                        continue;
 229                clk_register_clkdev(clks[i], NULL, __clk_get_name(clks[i]));
 230        }
 231
 232        /* register clock provider */
 233        cd->onecell_data.clks = clks;
 234        cd->onecell_data.clk_num = MAXCLKS;
 235        ret = of_clk_add_provider(np, of_clk_src_onecell_get,
 236                                  &cd->onecell_data);
 237        if (ret)
 238                return ret;
 239
 240        /* force enable critical clocks */
 241        for (i = 0; i < ARRAY_SIZE(pic32mzda_critical_clks); i++) {
 242                clk = clks[pic32mzda_critical_clks[i]];
 243                if (clk_prepare_enable(clk))
 244                        dev_err(&pdev->dev, "clk_prepare_enable(%s) failed\n",
 245                                __clk_get_name(clk));
 246        }
 247
 248        /* register NMI for failsafe clock monitor */
 249        cd->failsafe_notifier.notifier_call = pic32_fscm_nmi;
 250        return register_nmi_notifier(&cd->failsafe_notifier);
 251}
 252
 253static const struct of_device_id pic32mzda_clk_match_table[] = {
 254        { .compatible = "microchip,pic32mzda-clk", },
 255        { }
 256};
 257MODULE_DEVICE_TABLE(of, pic32mzda_clk_match_table);
 258
 259static struct platform_driver pic32mzda_clk_driver = {
 260        .probe          = pic32mzda_clk_probe,
 261        .driver         = {
 262                .name   = "clk-pic32mzda",
 263                .of_match_table = pic32mzda_clk_match_table,
 264        },
 265};
 266
 267static int __init microchip_pic32mzda_clk_init(void)
 268{
 269        return platform_driver_register(&pic32mzda_clk_driver);
 270}
 271core_initcall(microchip_pic32mzda_clk_init);
 272
 273MODULE_DESCRIPTION("Microchip PIC32MZDA Clock Driver");
 274MODULE_LICENSE("GPL v2");
 275MODULE_ALIAS("platform:clk-pic32mzda");
 276