cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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clk-twl6040.c (3822B)

      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");