linux/drivers/clk/hisilicon/clk-hi3660-stub.c
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   1/*
   2 * Hisilicon clock driver
   3 *
   4 * Copyright (c) 2013-2017 Hisilicon Limited.
   5 * Copyright (c) 2017 Linaro Limited.
   6 *
   7 * Author: Kai Zhao <zhaokai1@hisilicon.com>
   8 *          Tao Wang <kevin.wangtao@hisilicon.com>
   9 *          Leo Yan <leo.yan@linaro.org>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 */
  22
  23#include <linux/clk-provider.h>
  24#include <linux/device.h>
  25#include <linux/err.h>
  26#include <linux/init.h>
  27#include <linux/mailbox_client.h>
  28#include <linux/module.h>
  29#include <linux/of.h>
  30#include <linux/platform_device.h>
  31#include <dt-bindings/clock/hi3660-clock.h>
  32
  33#define HI3660_STUB_CLOCK_DATA          (0x70)
  34#define MHZ                             (1000 * 1000)
  35
  36#define DEFINE_CLK_STUB(_id, _cmd, _name)                       \
  37        {                                                       \
  38                .id = (_id),                                    \
  39                .cmd = (_cmd),                                  \
  40                .hw.init = &(struct clk_init_data) {            \
  41                        .name = #_name,                         \
  42                        .ops = &hi3660_stub_clk_ops,            \
  43                        .num_parents = 0,                       \
  44                        .flags = CLK_GET_RATE_NOCACHE,          \
  45                },                                              \
  46        },
  47
  48#define to_stub_clk(_hw) container_of(_hw, struct hi3660_stub_clk, hw)
  49
  50struct hi3660_stub_clk_chan {
  51        struct mbox_client cl;
  52        struct mbox_chan *mbox;
  53};
  54
  55struct hi3660_stub_clk {
  56        unsigned int id;
  57        struct clk_hw hw;
  58        unsigned int cmd;
  59        unsigned int msg[8];
  60        unsigned int rate;
  61};
  62
  63static void __iomem *freq_reg;
  64static struct hi3660_stub_clk_chan stub_clk_chan;
  65
  66static unsigned long hi3660_stub_clk_recalc_rate(struct clk_hw *hw,
  67                                                 unsigned long parent_rate)
  68{
  69        struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  70
  71        /*
  72         * LPM3 writes back the CPU frequency in shared SRAM so read
  73         * back the frequency.
  74         */
  75        stub_clk->rate = readl(freq_reg + (stub_clk->id << 2)) * MHZ;
  76        return stub_clk->rate;
  77}
  78
  79static long hi3660_stub_clk_round_rate(struct clk_hw *hw, unsigned long rate,
  80                                       unsigned long *prate)
  81{
  82        /*
  83         * LPM3 handles rate rounding so just return whatever
  84         * rate is requested.
  85         */
  86        return rate;
  87}
  88
  89static int hi3660_stub_clk_set_rate(struct clk_hw *hw, unsigned long rate,
  90                                    unsigned long parent_rate)
  91{
  92        struct hi3660_stub_clk *stub_clk = to_stub_clk(hw);
  93
  94        stub_clk->msg[0] = stub_clk->cmd;
  95        stub_clk->msg[1] = rate / MHZ;
  96
  97        dev_dbg(stub_clk_chan.cl.dev, "set rate msg[0]=0x%x msg[1]=0x%x\n",
  98                stub_clk->msg[0], stub_clk->msg[1]);
  99
 100        mbox_send_message(stub_clk_chan.mbox, stub_clk->msg);
 101        mbox_client_txdone(stub_clk_chan.mbox, 0);
 102
 103        stub_clk->rate = rate;
 104        return 0;
 105}
 106
 107static const struct clk_ops hi3660_stub_clk_ops = {
 108        .recalc_rate    = hi3660_stub_clk_recalc_rate,
 109        .round_rate     = hi3660_stub_clk_round_rate,
 110        .set_rate       = hi3660_stub_clk_set_rate,
 111};
 112
 113static struct hi3660_stub_clk hi3660_stub_clks[HI3660_CLK_STUB_NUM] = {
 114        DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER0, 0x0001030A, "cpu-cluster.0")
 115        DEFINE_CLK_STUB(HI3660_CLK_STUB_CLUSTER1, 0x0002030A, "cpu-cluster.1")
 116        DEFINE_CLK_STUB(HI3660_CLK_STUB_GPU, 0x0003030A, "clk-g3d")
 117        DEFINE_CLK_STUB(HI3660_CLK_STUB_DDR, 0x00040309, "clk-ddrc")
 118};
 119
 120static struct clk_hw *hi3660_stub_clk_hw_get(struct of_phandle_args *clkspec,
 121                                             void *data)
 122{
 123        unsigned int idx = clkspec->args[0];
 124
 125        if (idx >= HI3660_CLK_STUB_NUM) {
 126                pr_err("%s: invalid index %u\n", __func__, idx);
 127                return ERR_PTR(-EINVAL);
 128        }
 129
 130        return &hi3660_stub_clks[idx].hw;
 131}
 132
 133static int hi3660_stub_clk_probe(struct platform_device *pdev)
 134{
 135        struct device *dev = &pdev->dev;
 136        struct resource *res;
 137        unsigned int i;
 138        int ret;
 139
 140        /* Use mailbox client without blocking */
 141        stub_clk_chan.cl.dev = dev;
 142        stub_clk_chan.cl.tx_done = NULL;
 143        stub_clk_chan.cl.tx_block = false;
 144        stub_clk_chan.cl.knows_txdone = false;
 145
 146        /* Allocate mailbox channel */
 147        stub_clk_chan.mbox = mbox_request_channel(&stub_clk_chan.cl, 0);
 148        if (IS_ERR(stub_clk_chan.mbox))
 149                return PTR_ERR(stub_clk_chan.mbox);
 150
 151        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 152        if (!res)
 153                return -EINVAL;
 154        freq_reg = devm_ioremap(dev, res->start, resource_size(res));
 155        if (!freq_reg)
 156                return -ENOMEM;
 157
 158        freq_reg += HI3660_STUB_CLOCK_DATA;
 159
 160        for (i = 0; i < HI3660_CLK_STUB_NUM; i++) {
 161                ret = devm_clk_hw_register(&pdev->dev, &hi3660_stub_clks[i].hw);
 162                if (ret)
 163                        return ret;
 164        }
 165
 166        return devm_of_clk_add_hw_provider(&pdev->dev, hi3660_stub_clk_hw_get,
 167                                           hi3660_stub_clks);
 168}
 169
 170static const struct of_device_id hi3660_stub_clk_of_match[] = {
 171        { .compatible = "hisilicon,hi3660-stub-clk", },
 172        {}
 173};
 174
 175static struct platform_driver hi3660_stub_clk_driver = {
 176        .probe  = hi3660_stub_clk_probe,
 177        .driver = {
 178                .name = "hi3660-stub-clk",
 179                .of_match_table = hi3660_stub_clk_of_match,
 180        },
 181};
 182
 183static int __init hi3660_stub_clk_init(void)
 184{
 185        return platform_driver_register(&hi3660_stub_clk_driver);
 186}
 187subsys_initcall(hi3660_stub_clk_init);
 188