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
  15 struct twl6040_pdmclk {
  16         struct twl6040 *twl6040;
  17         struct device *dev;
  18         struct clk_hw pdmclk_hw;
  19         int enabled;
  20 };
  21
  22 static 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
  30 static 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  */
  52 static 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
  67 static 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
  85 out_err:
  86         dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret);
  87         twl6040_power(pdmclk->twl6040, 0);
  88
  89         return ret;
  90 }
  91
  92 static 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
 104 static 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
 113 static 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
 120 static const struct clk_init_data twl6040_pdmclk_init = {
 121         .name = "pdmclk",
 122         .ops = &twl6040_pdmclk_ops,
 123         .flags = CLK_GET_RATE_NOCACHE,
 124 };
 125
 126 static 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
 150 static struct platform_driver twl6040_pdmclk_driver = {
 151         .driver = {
 152                 .name = "twl6040-pdmclk",
 153         },
 154         .probe = twl6040_pdmclk_probe,
 155 };
 156
 157 module_platform_driver(twl6040_pdmclk_driver);
 158
 159 MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock");
 160 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
 161 MODULE_ALIAS("platform:twl6040-pdmclk");
 162 MODULE_LICENSE("GPL");