xref: /openbmc/linux/drivers/clk/tegra/clk-tegra-fixed.c (revision ead5d1f4d877e92c051e1a1ade623d0d30e71619)
1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * Copyright (c) 2012, 2013, NVIDIA CORPORATION.  All rights reserved.
4   */
5  
6  #include <linux/io.h>
7  #include <linux/clk-provider.h>
8  #include <linux/of.h>
9  #include <linux/of_address.h>
10  #include <linux/delay.h>
11  #include <linux/export.h>
12  #include <linux/clk/tegra.h>
13  
14  #include "clk.h"
15  #include "clk-id.h"
16  
17  #define OSC_CTRL			0x50
18  #define OSC_CTRL_OSC_FREQ_SHIFT		28
19  #define OSC_CTRL_PLL_REF_DIV_SHIFT	26
20  #define OSC_CTRL_MASK			(0x3f2 |	\
21  					(0xf << OSC_CTRL_OSC_FREQ_SHIFT))
22  
23  static u32 osc_ctrl_ctx;
24  
tegra_osc_clk_init(void __iomem * clk_base,struct tegra_clk * clks,unsigned long * input_freqs,unsigned int num,unsigned int clk_m_div,unsigned long * osc_freq,unsigned long * pll_ref_freq)25  int __init tegra_osc_clk_init(void __iomem *clk_base, struct tegra_clk *clks,
26  			      unsigned long *input_freqs, unsigned int num,
27  			      unsigned int clk_m_div, unsigned long *osc_freq,
28  			      unsigned long *pll_ref_freq)
29  {
30  	struct clk *clk, *osc;
31  	struct clk **dt_clk;
32  	u32 val, pll_ref_div;
33  	unsigned osc_idx;
34  
35  	val = readl_relaxed(clk_base + OSC_CTRL);
36  	osc_ctrl_ctx = val & OSC_CTRL_MASK;
37  	osc_idx = val >> OSC_CTRL_OSC_FREQ_SHIFT;
38  
39  	if (osc_idx < num)
40  		*osc_freq = input_freqs[osc_idx];
41  	else
42  		*osc_freq = 0;
43  
44  	if (!*osc_freq) {
45  		WARN_ON(1);
46  		return -EINVAL;
47  	}
48  
49  	dt_clk = tegra_lookup_dt_id(tegra_clk_osc, clks);
50  	if (!dt_clk)
51  		return 0;
52  
53  	osc = clk_register_fixed_rate(NULL, "osc", NULL, 0, *osc_freq);
54  	*dt_clk = osc;
55  
56  	/* osc_div2 */
57  	dt_clk = tegra_lookup_dt_id(tegra_clk_osc_div2, clks);
58  	if (dt_clk) {
59  		clk = clk_register_fixed_factor(NULL, "osc_div2", "osc",
60  						0, 1, 2);
61  		*dt_clk = clk;
62  	}
63  
64  	/* osc_div4 */
65  	dt_clk = tegra_lookup_dt_id(tegra_clk_osc_div4, clks);
66  	if (dt_clk) {
67  		clk = clk_register_fixed_factor(NULL, "osc_div4", "osc",
68  						0, 1, 4);
69  		*dt_clk = clk;
70  	}
71  
72  	dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m, clks);
73  	if (!dt_clk)
74  		return 0;
75  
76  	clk = clk_register_fixed_factor(NULL, "clk_m", "osc",
77  					0, 1, clk_m_div);
78  	*dt_clk = clk;
79  
80  	/* pll_ref */
81  	val = (val >> OSC_CTRL_PLL_REF_DIV_SHIFT) & 3;
82  	pll_ref_div = 1 << val;
83  	dt_clk = tegra_lookup_dt_id(tegra_clk_pll_ref, clks);
84  	if (!dt_clk)
85  		return 0;
86  
87  	clk = clk_register_fixed_factor(NULL, "pll_ref", "osc",
88  					0, 1, pll_ref_div);
89  	*dt_clk = clk;
90  
91  	if (pll_ref_freq)
92  		*pll_ref_freq = *osc_freq / pll_ref_div;
93  
94  	return 0;
95  }
96  
tegra_fixed_clk_init(struct tegra_clk * tegra_clks)97  void __init tegra_fixed_clk_init(struct tegra_clk *tegra_clks)
98  {
99  	struct clk *clk;
100  	struct clk **dt_clk;
101  
102  	/* clk_32k */
103  	dt_clk = tegra_lookup_dt_id(tegra_clk_clk_32k, tegra_clks);
104  	if (dt_clk) {
105  		clk = clk_register_fixed_rate(NULL, "clk_32k", NULL, 0, 32768);
106  		*dt_clk = clk;
107  	}
108  }
109  
tegra_clk_osc_resume(void __iomem * clk_base)110  void tegra_clk_osc_resume(void __iomem *clk_base)
111  {
112  	u32 val;
113  
114  	val = readl_relaxed(clk_base + OSC_CTRL) & ~OSC_CTRL_MASK;
115  	val |= osc_ctrl_ctx;
116  	writel_relaxed(val, clk_base + OSC_CTRL);
117  	fence_udelay(2, clk_base);
118  }
119