1 /*
2 * MediaTek display pulse-width-modulation controller driver.
3 * Copyright (c) 2015 MediaTek Inc.
4 * Author: YH Huang <yh.huang@mediatek.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16 #include <linux/clk.h>
17 #include <linux/err.h>
18 #include <linux/io.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/pwm.h>
23 #include <linux/slab.h>
24
25 #define DISP_PWM_EN 0x00
26 #define PWM_ENABLE_MASK BIT(0)
27
28 #define DISP_PWM_COMMIT 0x08
29 #define PWM_COMMIT_MASK BIT(0)
30
31 #define DISP_PWM_CON_0 0x10
32 #define PWM_CLKDIV_SHIFT 16
33 #define PWM_CLKDIV_MAX 0x3ff
34 #define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
35
36 #define DISP_PWM_CON_1 0x14
37 #define PWM_PERIOD_BIT_WIDTH 12
38 #define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_WIDTH) - 1)
39
40 #define PWM_HIGH_WIDTH_SHIFT 16
41 #define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT)
42
43 struct mtk_disp_pwm {
44 struct pwm_chip chip;
45 struct clk *clk_main;
46 struct clk *clk_mm;
47 void __iomem *base;
48 };
49
to_mtk_disp_pwm(struct pwm_chip * chip)50 static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
51 {
52 return container_of(chip, struct mtk_disp_pwm, chip);
53 }
54
mtk_disp_pwm_update_bits(struct mtk_disp_pwm * mdp,u32 offset,u32 mask,u32 data)55 static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
56 u32 mask, u32 data)
57 {
58 void __iomem *address = mdp->base + offset;
59 u32 value;
60
61 value = readl(address);
62 value &= ~mask;
63 value |= data;
64 writel(value, address);
65 }
66
mtk_disp_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)67 static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
68 int duty_ns, int period_ns)
69 {
70 struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
71 u32 clk_div, period, high_width, value;
72 u64 div, rate;
73 int err;
74
75 /*
76 * Find period, high_width and clk_div to suit duty_ns and period_ns.
77 * Calculate proper div value to keep period value in the bound.
78 *
79 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
80 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
81 *
82 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
83 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
84 */
85 rate = clk_get_rate(mdp->clk_main);
86 clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
87 PWM_PERIOD_BIT_WIDTH;
88 if (clk_div > PWM_CLKDIV_MAX)
89 return -EINVAL;
90
91 div = NSEC_PER_SEC * (clk_div + 1);
92 period = div64_u64(rate * period_ns, div);
93 if (period > 0)
94 period--;
95
96 high_width = div64_u64(rate * duty_ns, div);
97 value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
98
99 err = clk_enable(mdp->clk_main);
100 if (err < 0)
101 return err;
102
103 err = clk_enable(mdp->clk_mm);
104 if (err < 0) {
105 clk_disable(mdp->clk_main);
106 return err;
107 }
108
109 mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
110 clk_div << PWM_CLKDIV_SHIFT);
111 mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
112 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
113 mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
114 mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
115
116 clk_disable(mdp->clk_mm);
117 clk_disable(mdp->clk_main);
118
119 return 0;
120 }
121
mtk_disp_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)122 static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
123 {
124 struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
125 int err;
126
127 err = clk_enable(mdp->clk_main);
128 if (err < 0)
129 return err;
130
131 err = clk_enable(mdp->clk_mm);
132 if (err < 0) {
133 clk_disable(mdp->clk_main);
134 return err;
135 }
136
137 mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
138
139 return 0;
140 }
141
mtk_disp_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)142 static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
143 {
144 struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
145
146 mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
147
148 clk_disable(mdp->clk_mm);
149 clk_disable(mdp->clk_main);
150 }
151
152 static const struct pwm_ops mtk_disp_pwm_ops = {
153 .config = mtk_disp_pwm_config,
154 .enable = mtk_disp_pwm_enable,
155 .disable = mtk_disp_pwm_disable,
156 .owner = THIS_MODULE,
157 };
158
mtk_disp_pwm_probe(struct platform_device * pdev)159 static int mtk_disp_pwm_probe(struct platform_device *pdev)
160 {
161 struct mtk_disp_pwm *mdp;
162 struct resource *r;
163 int ret;
164
165 mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
166 if (!mdp)
167 return -ENOMEM;
168
169 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
170 mdp->base = devm_ioremap_resource(&pdev->dev, r);
171 if (IS_ERR(mdp->base))
172 return PTR_ERR(mdp->base);
173
174 mdp->clk_main = devm_clk_get(&pdev->dev, "main");
175 if (IS_ERR(mdp->clk_main))
176 return PTR_ERR(mdp->clk_main);
177
178 mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
179 if (IS_ERR(mdp->clk_mm))
180 return PTR_ERR(mdp->clk_mm);
181
182 ret = clk_prepare(mdp->clk_main);
183 if (ret < 0)
184 return ret;
185
186 ret = clk_prepare(mdp->clk_mm);
187 if (ret < 0)
188 goto disable_clk_main;
189
190 mdp->chip.dev = &pdev->dev;
191 mdp->chip.ops = &mtk_disp_pwm_ops;
192 mdp->chip.base = -1;
193 mdp->chip.npwm = 1;
194
195 ret = pwmchip_add(&mdp->chip);
196 if (ret < 0) {
197 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
198 goto disable_clk_mm;
199 }
200
201 platform_set_drvdata(pdev, mdp);
202
203 return 0;
204
205 disable_clk_mm:
206 clk_unprepare(mdp->clk_mm);
207 disable_clk_main:
208 clk_unprepare(mdp->clk_main);
209 return ret;
210 }
211
mtk_disp_pwm_remove(struct platform_device * pdev)212 static int mtk_disp_pwm_remove(struct platform_device *pdev)
213 {
214 struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
215 int ret;
216
217 ret = pwmchip_remove(&mdp->chip);
218 clk_unprepare(mdp->clk_mm);
219 clk_unprepare(mdp->clk_main);
220
221 return ret;
222 }
223
224 static const struct of_device_id mtk_disp_pwm_of_match[] = {
225 { .compatible = "mediatek,mt8173-disp-pwm" },
226 { .compatible = "mediatek,mt6595-disp-pwm" },
227 { }
228 };
229 MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
230
231 static struct platform_driver mtk_disp_pwm_driver = {
232 .driver = {
233 .name = "mediatek-disp-pwm",
234 .of_match_table = mtk_disp_pwm_of_match,
235 },
236 .probe = mtk_disp_pwm_probe,
237 .remove = mtk_disp_pwm_remove,
238 };
239 module_platform_driver(mtk_disp_pwm_driver);
240
241 MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
242 MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
243 MODULE_LICENSE("GPL v2");
244