LXR linux/drivers/clk/clk-twl6040.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3* TWL6040 clock module driver for OMAP4 McPDM functional clock
   4*
   5* Copyright (C) 2012 Texas Instruments Inc.
   6* Peter Ujfalusi <peter.ujfalusi@ti.com>
   7*/
   8
   9#include <linux/module.h>
  10#include <linux/slab.h>
  11#include <linux/platform_device.h>
  12#include <linux/mfd/twl6040.h>
  13#include <linux/clk-provider.h>
  14
  15struct twl6040_pdmclk {
  16        struct twl6040 *twl6040;
  17        struct device *dev;
  18        struct clk_hw pdmclk_hw;
  19        int enabled;
  20};
  21
  22static int twl6040_pdmclk_is_prepared(struct clk_hw *hw)
  23{
  24        struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  25                                                     pdmclk_hw);
  26
  27        return pdmclk->enabled;
  28}
  29
  30static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk,
  31                                          unsigned int reg)
  32{
  33        const u8 reset_mask = TWL6040_HPLLRST;  /* Same for HPPLL and LPPLL */
  34        int ret;
  35
  36        ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask);
  37        if (ret < 0)
  38                return ret;
  39
  40        ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask);
  41        if (ret < 0)
  42                return ret;
  43
  44        return 0;
  45}
  46
  47/*
  48 * TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At
  49 * Cold Temperature". This affects cold boot and deeper idle states it
  50 * seems. The workaround consists of resetting HPPLL and LPPLL.
  51 */
  52static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk)
  53{
  54        int ret;
  55
  56        ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL);
  57        if (ret)
  58                return ret;
  59
  60        ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL);
  61        if (ret)
  62                return ret;
  63
  64        return 0;
  65}
  66
  67static int twl6040_pdmclk_prepare(struct clk_hw *hw)
  68{
  69        struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  70                                                     pdmclk_hw);
  71        int ret;
  72
  73        ret = twl6040_power(pdmclk->twl6040, 1);
  74        if (ret)
  75                return ret;
  76
  77        ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk);
  78        if (ret)
  79                goto out_err;
  80
  81        pdmclk->enabled = 1;
  82
  83        return 0;
  84
  85out_err:
  86        dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret);
  87        twl6040_power(pdmclk->twl6040, 0);
  88
  89        return ret;
  90}
  91
  92static void twl6040_pdmclk_unprepare(struct clk_hw *hw)
  93{
  94        struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  95                                                     pdmclk_hw);
  96        int ret;
  97
  98        ret = twl6040_power(pdmclk->twl6040, 0);
  99        if (!ret)
 100                pdmclk->enabled = 0;
 101
 102}
 103
 104static unsigned long twl6040_pdmclk_recalc_rate(struct clk_hw *hw,
 105                                                unsigned long parent_rate)
 106{
 107        struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
 108                                                     pdmclk_hw);
 109
 110        return twl6040_get_sysclk(pdmclk->twl6040);
 111}
 112
 113static const struct clk_ops twl6040_pdmclk_ops = {
 114        .is_prepared = twl6040_pdmclk_is_prepared,
 115        .prepare = twl6040_pdmclk_prepare,
 116        .unprepare = twl6040_pdmclk_unprepare,
 117        .recalc_rate = twl6040_pdmclk_recalc_rate,
 118};
 119
 120static const struct clk_init_data twl6040_pdmclk_init = {
 121        .name = "pdmclk",
 122        .ops = &twl6040_pdmclk_ops,
 123        .flags = CLK_GET_RATE_NOCACHE,
 124};
 125
 126static int twl6040_pdmclk_probe(struct platform_device *pdev)
 127{
 128        struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent);
 129        struct twl6040_pdmclk *clkdata;
 130        int ret;
 131
 132        clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
 133        if (!clkdata)
 134                return -ENOMEM;
 135
 136        clkdata->dev = &pdev->dev;
 137        clkdata->twl6040 = twl6040;
 138
 139        clkdata->pdmclk_hw.init = &twl6040_pdmclk_init;
 140        ret = devm_clk_hw_register(&pdev->dev, &clkdata->pdmclk_hw);
 141        if (ret)
 142                return ret;
 143
 144        platform_set_drvdata(pdev, clkdata);
 145
 146        return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get,
 147                                           &clkdata->pdmclk_hw);
 148}
 149
 150static struct platform_driver twl6040_pdmclk_driver = {
 151        .driver = {
 152                .name = "twl6040-pdmclk",
 153        },
 154        .probe = twl6040_pdmclk_probe,
 155};
 156
 157module_platform_driver(twl6040_pdmclk_driver);
 158
 159MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock");
 160MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 161MODULE_ALIAS("platform:twl6040-pdmclk");
 162MODULE_LICENSE("GPL");
 163