1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * PWM framework driver for Cirrus Logic EP93xx
4 *
5 * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com>
6 * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com>
7 *
8 * EP9301/02 have only one channel:
9 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
10 *
11 * EP9307 has only one channel:
12 * platform device ep93xx-pwm.0 - PWMOUT
13 *
14 * EP9312/15 have two channels:
15 * platform device ep93xx-pwm.0 - PWMOUT
16 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
17 */
18
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/slab.h>
22 #include <linux/clk.h>
23 #include <linux/err.h>
24 #include <linux/io.h>
25 #include <linux/pwm.h>
26
27 #include <asm/div64.h>
28
29 #include <linux/soc/cirrus/ep93xx.h> /* for ep93xx_pwm_{acquire,release}_gpio() */
30
31 #define EP93XX_PWMx_TERM_COUNT 0x00
32 #define EP93XX_PWMx_DUTY_CYCLE 0x04
33 #define EP93XX_PWMx_ENABLE 0x08
34 #define EP93XX_PWMx_INVERT 0x0c
35
36 struct ep93xx_pwm {
37 void __iomem *base;
38 struct clk *clk;
39 };
40
to_ep93xx_pwm(struct pwm_chip * chip)41 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
42 {
43 return pwmchip_get_drvdata(chip);
44 }
45
ep93xx_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)46 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
47 {
48 struct platform_device *pdev = to_platform_device(pwmchip_parent(chip));
49
50 return ep93xx_pwm_acquire_gpio(pdev);
51 }
52
ep93xx_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)53 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
54 {
55 struct platform_device *pdev = to_platform_device(pwmchip_parent(chip));
56
57 ep93xx_pwm_release_gpio(pdev);
58 }
59
ep93xx_pwm_apply(struct pwm_chip * chip,struct pwm_device * pwm,const struct pwm_state * state)60 static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
61 const struct pwm_state *state)
62 {
63 int ret;
64 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
65 bool enabled = state->enabled;
66 void __iomem *base = ep93xx_pwm->base;
67 unsigned long long c;
68 unsigned long period_cycles;
69 unsigned long duty_cycles;
70 unsigned long term;
71
72 if (state->polarity != pwm->state.polarity) {
73 if (enabled) {
74 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
75 clk_disable_unprepare(ep93xx_pwm->clk);
76 enabled = false;
77 }
78
79 /*
80 * The clock needs to be enabled to access the PWM registers.
81 * Polarity can only be changed when the PWM is disabled.
82 */
83 ret = clk_prepare_enable(ep93xx_pwm->clk);
84 if (ret)
85 return ret;
86
87 if (state->polarity == PWM_POLARITY_INVERSED)
88 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
89 else
90 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
91
92 clk_disable_unprepare(ep93xx_pwm->clk);
93 }
94
95 if (!state->enabled) {
96 if (enabled) {
97 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
98 clk_disable_unprepare(ep93xx_pwm->clk);
99 }
100
101 return 0;
102 }
103
104 /*
105 * The clock needs to be enabled to access the PWM registers.
106 * Configuration can be changed at any time.
107 */
108 if (!pwm_is_enabled(pwm)) {
109 ret = clk_prepare_enable(ep93xx_pwm->clk);
110 if (ret)
111 return ret;
112 }
113
114 c = clk_get_rate(ep93xx_pwm->clk);
115 c *= state->period;
116 do_div(c, 1000000000);
117 period_cycles = c;
118
119 c = period_cycles;
120 c *= state->duty_cycle;
121 do_div(c, state->period);
122 duty_cycles = c;
123
124 if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
125 term = readw(base + EP93XX_PWMx_TERM_COUNT);
126
127 /* Order is important if PWM is running */
128 if (period_cycles > term) {
129 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
130 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
131 } else {
132 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
133 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
134 }
135 ret = 0;
136 } else {
137 ret = -EINVAL;
138 }
139
140 if (!pwm_is_enabled(pwm))
141 clk_disable_unprepare(ep93xx_pwm->clk);
142
143 if (ret)
144 return ret;
145
146 if (!enabled) {
147 ret = clk_prepare_enable(ep93xx_pwm->clk);
148 if (ret)
149 return ret;
150
151 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
152 }
153
154 return 0;
155 }
156
157 static const struct pwm_ops ep93xx_pwm_ops = {
158 .request = ep93xx_pwm_request,
159 .free = ep93xx_pwm_free,
160 .apply = ep93xx_pwm_apply,
161 };
162
ep93xx_pwm_probe(struct platform_device * pdev)163 static int ep93xx_pwm_probe(struct platform_device *pdev)
164 {
165 struct pwm_chip *chip;
166 struct ep93xx_pwm *ep93xx_pwm;
167 int ret;
168
169 chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ep93xx_pwm));
170 if (IS_ERR(chip))
171 return PTR_ERR(chip);
172 ep93xx_pwm = to_ep93xx_pwm(chip);
173
174 ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);
175 if (IS_ERR(ep93xx_pwm->base))
176 return PTR_ERR(ep93xx_pwm->base);
177
178 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
179 if (IS_ERR(ep93xx_pwm->clk))
180 return PTR_ERR(ep93xx_pwm->clk);
181
182 chip->ops = &ep93xx_pwm_ops;
183
184 ret = devm_pwmchip_add(&pdev->dev, chip);
185 if (ret < 0)
186 return ret;
187
188 return 0;
189 }
190
191 static struct platform_driver ep93xx_pwm_driver = {
192 .driver = {
193 .name = "ep93xx-pwm",
194 },
195 .probe = ep93xx_pwm_probe,
196 };
197 module_platform_driver(ep93xx_pwm_driver);
198
199 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
200 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
201 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
202 MODULE_ALIAS("platform:ep93xx-pwm");
203 MODULE_LICENSE("GPL");
204