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 
twl6040_pdmclk_is_prepared(struct clk_hw * hw)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 
twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk * pdmclk,unsigned int reg)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  */
twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk * pdmclk)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 
twl6040_pdmclk_prepare(struct clk_hw * hw)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 
twl6040_pdmclk_unprepare(struct clk_hw * hw)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 
twl6040_pdmclk_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)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 
twl6040_pdmclk_probe(struct platform_device * pdev)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");
163