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