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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 NXP
4 *
5 * Clock driver for LS1028A Display output interfaces(LCD, DPHY).
6 */
7
8#include <linux/clk-provider.h>
9#include <linux/device.h>
10#include <linux/module.h>
11#include <linux/err.h>
12#include <linux/io.h>
13#include <linux/iopoll.h>
14#include <linux/of.h>
15#include <linux/of_address.h>
16#include <linux/of_device.h>
17#include <linux/platform_device.h>
18#include <linux/slab.h>
19#include <linux/bitfield.h>
20
21/* PLLDIG register offsets and bit masks */
22#define PLLDIG_REG_PLLSR 0x24
23#define PLLDIG_LOCK_MASK BIT(2)
24#define PLLDIG_REG_PLLDV 0x28
25#define PLLDIG_MFD_MASK GENMASK(7, 0)
26#define PLLDIG_RFDPHI1_MASK GENMASK(30, 25)
27#define PLLDIG_REG_PLLFM 0x2c
28#define PLLDIG_SSCGBYP_ENABLE BIT(30)
29#define PLLDIG_REG_PLLFD 0x30
30#define PLLDIG_FDEN BIT(30)
31#define PLLDIG_FRAC_MASK GENMASK(15, 0)
32#define PLLDIG_REG_PLLCAL1 0x38
33#define PLLDIG_REG_PLLCAL2 0x3c
34
35/* Range of the VCO frequencies, in Hz */
36#define PLLDIG_MIN_VCO_FREQ 650000000
37#define PLLDIG_MAX_VCO_FREQ 1300000000
38
39/* Range of the output frequencies, in Hz */
40#define PHI1_MIN_FREQ 27000000UL
41#define PHI1_MAX_FREQ 600000000UL
42
43/* Maximum value of the reduced frequency divider */
44#define MAX_RFDPHI1 63UL
45
46/* Best value of multiplication factor divider */
47#define PLLDIG_DEFAULT_MFD 44
48
49/*
50 * Denominator part of the fractional part of the
51 * loop multiplication factor.
52 */
53#define MFDEN 20480
54
55static const struct clk_parent_data parent_data[] = {
56 { .index = 0 },
57};
58
59struct clk_plldig {
60 struct clk_hw hw;
61 void __iomem *regs;
62 unsigned int vco_freq;
63};
64
65#define to_clk_plldig(_hw) container_of(_hw, struct clk_plldig, hw)
66
67static int plldig_enable(struct clk_hw *hw)
68{
69 struct clk_plldig *data = to_clk_plldig(hw);
70 u32 val;
71
72 val = readl(data->regs + PLLDIG_REG_PLLFM);
73 /*
74 * Use Bypass mode with PLL off by default, the frequency overshoot
75 * detector output was disable. SSCG Bypass mode should be enable.
76 */
77 val |= PLLDIG_SSCGBYP_ENABLE;
78 writel(val, data->regs + PLLDIG_REG_PLLFM);
79
80 return 0;
81}
82
83static void plldig_disable(struct clk_hw *hw)
84{
85 struct clk_plldig *data = to_clk_plldig(hw);
86 u32 val;
87
88 val = readl(data->regs + PLLDIG_REG_PLLFM);
89
90 val &= ~PLLDIG_SSCGBYP_ENABLE;
91 val |= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0);
92
93 writel(val, data->regs + PLLDIG_REG_PLLFM);
94}
95
96static int plldig_is_enabled(struct clk_hw *hw)
97{
98 struct clk_plldig *data = to_clk_plldig(hw);
99
100 return readl(data->regs + PLLDIG_REG_PLLFM) &
101 PLLDIG_SSCGBYP_ENABLE;
102}
103
104static unsigned long plldig_recalc_rate(struct clk_hw *hw,
105 unsigned long parent_rate)
106{
107 struct clk_plldig *data = to_clk_plldig(hw);
108 u32 val, rfdphi1;
109
110 val = readl(data->regs + PLLDIG_REG_PLLDV);
111
112 /* Check if PLL is bypassed */
113 if (val & PLLDIG_SSCGBYP_ENABLE)
114 return parent_rate;
115
116 rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val);
117
118 /*
119 * If RFDPHI1 has a value of 1 the VCO frequency is also divided by
120 * one.
121 */
122 if (!rfdphi1)
123 rfdphi1 = 1;
124
125 return DIV_ROUND_UP(data->vco_freq, rfdphi1);
126}
127
128static unsigned long plldig_calc_target_div(unsigned long vco_freq,
129 unsigned long target_rate)
130{
131 unsigned long div;
132
133 div = DIV_ROUND_CLOSEST(vco_freq, target_rate);
134 div = clamp(div, 1UL, MAX_RFDPHI1);
135
136 return div;
137}
138
139static int plldig_determine_rate(struct clk_hw *hw,
140 struct clk_rate_request *req)
141{
142 struct clk_plldig *data = to_clk_plldig(hw);
143 unsigned int div;
144
145 req->rate = clamp(req->rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
146 div = plldig_calc_target_div(data->vco_freq, req->rate);
147 req->rate = DIV_ROUND_UP(data->vco_freq, div);
148
149 return 0;
150}
151
152static int plldig_set_rate(struct clk_hw *hw, unsigned long rate,
153 unsigned long parent_rate)
154{
155 struct clk_plldig *data = to_clk_plldig(hw);
156 unsigned int val, cond;
157 unsigned int rfdphi1;
158
159 rate = clamp(rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ);
160 rfdphi1 = plldig_calc_target_div(data->vco_freq, rate);
161
162 /* update the divider value */
163 val = readl(data->regs + PLLDIG_REG_PLLDV);
164 val &= ~PLLDIG_RFDPHI1_MASK;
165 val |= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1);
166 writel(val, data->regs + PLLDIG_REG_PLLDV);
167
168 /* waiting for old lock state to clear */
169 udelay(200);
170
171 /* Wait until PLL is locked or timeout */
172 return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond,
173 cond & PLLDIG_LOCK_MASK, 0,
174 USEC_PER_MSEC);
175}
176
177static const struct clk_ops plldig_clk_ops = {
178 .enable = plldig_enable,
179 .disable = plldig_disable,
180 .is_enabled = plldig_is_enabled,
181 .recalc_rate = plldig_recalc_rate,
182 .determine_rate = plldig_determine_rate,
183 .set_rate = plldig_set_rate,
184};
185
186static int plldig_init(struct clk_hw *hw)
187{
188 struct clk_plldig *data = to_clk_plldig(hw);
189 struct clk_hw *parent = clk_hw_get_parent(hw);
190 unsigned long parent_rate;
191 unsigned long val;
192 unsigned long long lltmp;
193 unsigned int mfd, fracdiv = 0;
194
195 if (!parent)
196 return -EINVAL;
197
198 parent_rate = clk_hw_get_rate(parent);
199
200 if (data->vco_freq) {
201 mfd = data->vco_freq / parent_rate;
202 lltmp = data->vco_freq % parent_rate;
203 lltmp *= MFDEN;
204 do_div(lltmp, parent_rate);
205 fracdiv = lltmp;
206 } else {
207 mfd = PLLDIG_DEFAULT_MFD;
208 data->vco_freq = parent_rate * mfd;
209 }
210
211 val = FIELD_PREP(PLLDIG_MFD_MASK, mfd);
212 writel(val, data->regs + PLLDIG_REG_PLLDV);
213
214 /* Enable fractional divider */
215 if (fracdiv) {
216 val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv);
217 val |= PLLDIG_FDEN;
218 writel(val, data->regs + PLLDIG_REG_PLLFD);
219 }
220
221 return 0;
222}
223
224static int plldig_clk_probe(struct platform_device *pdev)
225{
226 struct clk_plldig *data;
227 struct device *dev = &pdev->dev;
228 int ret;
229
230 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
231 if (!data)
232 return -ENOMEM;
233
234 data->regs = devm_platform_ioremap_resource(pdev, 0);
235 if (IS_ERR(data->regs))
236 return PTR_ERR(data->regs);
237
238 data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk",
239 parent_data,
240 &plldig_clk_ops,
241 0);
242
243 ret = devm_clk_hw_register(dev, &data->hw);
244 if (ret) {
245 dev_err(dev, "failed to register %s clock\n",
246 dev->of_node->name);
247 return ret;
248 }
249
250 ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
251 &data->hw);
252 if (ret) {
253 dev_err(dev, "unable to add clk provider\n");
254 return ret;
255 }
256
257 /*
258 * The frequency of the VCO cannot be changed during runtime.
259 * Therefore, let the user specify a desired frequency.
260 */
261 if (!of_property_read_u32(dev->of_node, "fsl,vco-hz",
262 &data->vco_freq)) {
263 if (data->vco_freq < PLLDIG_MIN_VCO_FREQ ||
264 data->vco_freq > PLLDIG_MAX_VCO_FREQ)
265 return -EINVAL;
266 }
267
268 return plldig_init(&data->hw);
269}
270
271static const struct of_device_id plldig_clk_id[] = {
272 { .compatible = "fsl,ls1028a-plldig" },
273 { }
274};
275MODULE_DEVICE_TABLE(of, plldig_clk_id);
276
277static struct platform_driver plldig_clk_driver = {
278 .driver = {
279 .name = "plldig-clock",
280 .of_match_table = plldig_clk_id,
281 },
282 .probe = plldig_clk_probe,
283};
284module_platform_driver(plldig_clk_driver);
285
286MODULE_LICENSE("GPL v2");
287MODULE_AUTHOR("Wen He <wen.he_1@nxp.com>");
288MODULE_DESCRIPTION("LS1028A Display output interface pixel clock driver");