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");