xref: /openbmc/u-boot/drivers/pwm/sunxi_pwm.c (revision d66ff4ba)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2017-2018 Vasily Khoruzhick <anarsoul@gmail.com>
4  */
5 
6 #include <common.h>
7 #include <div64.h>
8 #include <dm.h>
9 #include <pwm.h>
10 #include <regmap.h>
11 #include <syscon.h>
12 #include <asm/io.h>
13 #include <asm/arch/pwm.h>
14 #include <asm/arch/gpio.h>
15 #include <power/regulator.h>
16 
17 DECLARE_GLOBAL_DATA_PTR;
18 
19 #define OSC_24MHZ 24000000
20 
21 struct sunxi_pwm_priv {
22 	struct sunxi_pwm *regs;
23 	bool invert;
24 	u32 prescaler;
25 };
26 
27 static const u32 prescaler_table[] = {
28 	120,	/* 0000 */
29 	180,	/* 0001 */
30 	240,	/* 0010 */
31 	360,	/* 0011 */
32 	480,	/* 0100 */
33 	0,	/* 0101 */
34 	0,	/* 0110 */
35 	0,	/* 0111 */
36 	12000,	/* 1000 */
37 	24000,	/* 1001 */
38 	36000,	/* 1010 */
39 	48000,	/* 1011 */
40 	72000,	/* 1100 */
41 	0,	/* 1101 */
42 	0,	/* 1110 */
43 	1,	/* 1111 */
44 };
45 
46 static int sunxi_pwm_config_pinmux(void)
47 {
48 #ifdef CONFIG_MACH_SUN50I
49 	sunxi_gpio_set_cfgpin(SUNXI_GPD(22), SUNXI_GPD_PWM);
50 #endif
51 	return 0;
52 }
53 
54 static int sunxi_pwm_set_invert(struct udevice *dev, uint channel,
55 				bool polarity)
56 {
57 	struct sunxi_pwm_priv *priv = dev_get_priv(dev);
58 
59 	debug("%s: polarity=%u\n", __func__, polarity);
60 	priv->invert = polarity;
61 
62 	return 0;
63 }
64 
65 static int sunxi_pwm_set_config(struct udevice *dev, uint channel,
66 				uint period_ns, uint duty_ns)
67 {
68 	struct sunxi_pwm_priv *priv = dev_get_priv(dev);
69 	struct sunxi_pwm *regs = priv->regs;
70 	int best_prescaler = 0;
71 	u32 v, best_period = 0, duty;
72 	u64 best_scaled_freq = 0;
73 	const u32 nsecs_per_sec = 1000000000U;
74 
75 	debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns);
76 
77 	for (int prescaler = 0; prescaler <= SUNXI_PWM_CTRL_PRESCALE0_MASK;
78 	     prescaler++) {
79 		u32 period = 0;
80 		u64 scaled_freq = 0;
81 		if (!prescaler_table[prescaler])
82 			continue;
83 		scaled_freq = lldiv(OSC_24MHZ, prescaler_table[prescaler]);
84 		period = lldiv(scaled_freq * period_ns, nsecs_per_sec);
85 		if ((period - 1 <= SUNXI_PWM_CH0_PERIOD_MAX) &&
86 		    best_period < period) {
87 			best_period = period;
88 			best_scaled_freq = scaled_freq;
89 			best_prescaler = prescaler;
90 		}
91 	}
92 
93 	if (best_period - 1 > SUNXI_PWM_CH0_PERIOD_MAX) {
94 		debug("%s: failed to find prescaler value\n", __func__);
95 		return -EINVAL;
96 	}
97 
98 	duty = lldiv(best_scaled_freq * duty_ns, nsecs_per_sec);
99 
100 	if (priv->prescaler != best_prescaler) {
101 		/* Mask clock to update prescaler */
102 		v = readl(&regs->ctrl);
103 		v &= ~SUNXI_PWM_CTRL_CLK_GATE;
104 		writel(v, &regs->ctrl);
105 		v &= ~SUNXI_PWM_CTRL_PRESCALE0_MASK;
106 		v |= (best_prescaler & SUNXI_PWM_CTRL_PRESCALE0_MASK);
107 		writel(v, &regs->ctrl);
108 		v |= SUNXI_PWM_CTRL_CLK_GATE;
109 		writel(v, &regs->ctrl);
110 		priv->prescaler = best_prescaler;
111 	}
112 
113 	writel(SUNXI_PWM_CH0_PERIOD_PRD(best_period) |
114 	       SUNXI_PWM_CH0_PERIOD_DUTY(duty), &regs->ch0_period);
115 
116 	debug("%s: prescaler: %d, period: %d, duty: %d\n",
117 	      __func__, priv->prescaler,
118 	      best_period, duty);
119 
120 	return 0;
121 }
122 
123 static int sunxi_pwm_set_enable(struct udevice *dev, uint channel, bool enable)
124 {
125 	struct sunxi_pwm_priv *priv = dev_get_priv(dev);
126 	struct sunxi_pwm *regs = priv->regs;
127 	u32 v;
128 
129 	debug("%s: Enable '%s'\n", __func__, dev->name);
130 
131 	v = readl(&regs->ctrl);
132 	if (!enable) {
133 		v &= ~SUNXI_PWM_CTRL_ENABLE0;
134 		writel(v, &regs->ctrl);
135 		return 0;
136 	}
137 
138 	sunxi_pwm_config_pinmux();
139 
140 	if (priv->invert)
141 		v &= ~SUNXI_PWM_CTRL_CH0_ACT_STA;
142 	else
143 		v |= SUNXI_PWM_CTRL_CH0_ACT_STA;
144 	v |= SUNXI_PWM_CTRL_ENABLE0;
145 	writel(v, &regs->ctrl);
146 
147 	return 0;
148 }
149 
150 static int sunxi_pwm_ofdata_to_platdata(struct udevice *dev)
151 {
152 	struct sunxi_pwm_priv *priv = dev_get_priv(dev);
153 
154 	priv->regs = (struct sunxi_pwm *)devfdt_get_addr(dev);
155 
156 	return 0;
157 }
158 
159 static int sunxi_pwm_probe(struct udevice *dev)
160 {
161 	return 0;
162 }
163 
164 static const struct pwm_ops sunxi_pwm_ops = {
165 	.set_invert	= sunxi_pwm_set_invert,
166 	.set_config	= sunxi_pwm_set_config,
167 	.set_enable	= sunxi_pwm_set_enable,
168 };
169 
170 static const struct udevice_id sunxi_pwm_ids[] = {
171 	{ .compatible = "allwinner,sun5i-a13-pwm" },
172 	{ .compatible = "allwinner,sun50i-a64-pwm" },
173 	{ }
174 };
175 
176 U_BOOT_DRIVER(sunxi_pwm) = {
177 	.name	= "sunxi_pwm",
178 	.id	= UCLASS_PWM,
179 	.of_match = sunxi_pwm_ids,
180 	.ops	= &sunxi_pwm_ops,
181 	.ofdata_to_platdata	= sunxi_pwm_ofdata_to_platdata,
182 	.probe		= sunxi_pwm_probe,
183 	.priv_auto_alloc_size	= sizeof(struct sunxi_pwm_priv),
184 };
185