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d16a5aa9 MW |
1 | /* |
2 | * Intel Low Power Subsystem PWM controller driver | |
3 | * | |
4 | * Copyright (C) 2014, Intel Corporation | |
5 | * Author: Mika Westerberg <mika.westerberg@linux.intel.com> | |
6 | * Author: Chew Kean Ho <kean.ho.chew@intel.com> | |
7 | * Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com> | |
8 | * Author: Chew Chiau Ee <chiau.ee.chew@intel.com> | |
093e00bb | 9 | * Author: Alan Cox <alan@linux.intel.com> |
d16a5aa9 MW |
10 | * |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as | |
13 | * published by the Free Software Foundation. | |
14 | */ | |
15 | ||
d16a5aa9 MW |
16 | #include <linux/kernel.h> |
17 | #include <linux/module.h> | |
093e00bb | 18 | |
c558e39e | 19 | #include "pwm-lpss.h" |
d16a5aa9 MW |
20 | |
21 | #define PWM 0x00000000 | |
22 | #define PWM_ENABLE BIT(31) | |
23 | #define PWM_SW_UPDATE BIT(30) | |
24 | #define PWM_BASE_UNIT_SHIFT 8 | |
25 | #define PWM_BASE_UNIT_MASK 0x00ffff00 | |
26 | #define PWM_ON_TIME_DIV_MASK 0x000000ff | |
27 | #define PWM_DIVISION_CORRECTION 0x2 | |
28 | #define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION) | |
29 | #define NSECS_PER_SEC 1000000000UL | |
30 | ||
31 | struct pwm_lpss_chip { | |
32 | struct pwm_chip chip; | |
33 | void __iomem *regs; | |
093e00bb AC |
34 | unsigned long clk_rate; |
35 | }; | |
36 | ||
093e00bb | 37 | /* BayTrail */ |
c558e39e | 38 | const struct pwm_lpss_boardinfo pwm_lpss_byt_info = { |
093e00bb | 39 | 25000000 |
d16a5aa9 | 40 | }; |
c558e39e | 41 | EXPORT_SYMBOL_GPL(pwm_lpss_byt_info); |
d16a5aa9 | 42 | |
373c5782 | 43 | /* Braswell */ |
c558e39e | 44 | const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = { |
373c5782 AC |
45 | 19200000 |
46 | }; | |
c558e39e | 47 | EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info); |
373c5782 | 48 | |
d16a5aa9 MW |
49 | static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip) |
50 | { | |
51 | return container_of(chip, struct pwm_lpss_chip, chip); | |
52 | } | |
53 | ||
54 | static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm, | |
55 | int duty_ns, int period_ns) | |
56 | { | |
57 | struct pwm_lpss_chip *lpwm = to_lpwm(chip); | |
58 | u8 on_time_div; | |
59 | unsigned long c; | |
60 | unsigned long long base_unit, freq = NSECS_PER_SEC; | |
61 | u32 ctrl; | |
62 | ||
63 | do_div(freq, period_ns); | |
64 | ||
65 | /* The equation is: base_unit = ((freq / c) * 65536) + correction */ | |
66 | base_unit = freq * 65536; | |
67 | ||
093e00bb | 68 | c = lpwm->clk_rate; |
d16a5aa9 MW |
69 | if (!c) |
70 | return -EINVAL; | |
71 | ||
72 | do_div(base_unit, c); | |
73 | base_unit += PWM_DIVISION_CORRECTION; | |
74 | if (base_unit > PWM_LIMIT) | |
75 | return -EINVAL; | |
76 | ||
77 | if (duty_ns <= 0) | |
78 | duty_ns = 1; | |
79 | on_time_div = 255 - (255 * duty_ns / period_ns); | |
80 | ||
81 | ctrl = readl(lpwm->regs + PWM); | |
82 | ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK); | |
83 | ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT; | |
84 | ctrl |= on_time_div; | |
85 | /* request PWM to update on next cycle */ | |
86 | ctrl |= PWM_SW_UPDATE; | |
87 | writel(ctrl, lpwm->regs + PWM); | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm) | |
93 | { | |
94 | struct pwm_lpss_chip *lpwm = to_lpwm(chip); | |
95 | u32 ctrl; | |
d16a5aa9 MW |
96 | |
97 | ctrl = readl(lpwm->regs + PWM); | |
98 | writel(ctrl | PWM_ENABLE, lpwm->regs + PWM); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
103 | static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm) | |
104 | { | |
105 | struct pwm_lpss_chip *lpwm = to_lpwm(chip); | |
106 | u32 ctrl; | |
107 | ||
108 | ctrl = readl(lpwm->regs + PWM); | |
109 | writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); | |
d16a5aa9 MW |
110 | } |
111 | ||
112 | static const struct pwm_ops pwm_lpss_ops = { | |
113 | .config = pwm_lpss_config, | |
114 | .enable = pwm_lpss_enable, | |
115 | .disable = pwm_lpss_disable, | |
116 | .owner = THIS_MODULE, | |
117 | }; | |
118 | ||
c558e39e AS |
119 | struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, |
120 | const struct pwm_lpss_boardinfo *info) | |
d16a5aa9 MW |
121 | { |
122 | struct pwm_lpss_chip *lpwm; | |
d16a5aa9 MW |
123 | int ret; |
124 | ||
093e00bb | 125 | lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL); |
d16a5aa9 | 126 | if (!lpwm) |
093e00bb | 127 | return ERR_PTR(-ENOMEM); |
d16a5aa9 | 128 | |
093e00bb | 129 | lpwm->regs = devm_ioremap_resource(dev, r); |
d16a5aa9 | 130 | if (IS_ERR(lpwm->regs)) |
89c0339e | 131 | return ERR_CAST(lpwm->regs); |
093e00bb | 132 | |
65accd87 | 133 | lpwm->clk_rate = info->clk_rate; |
093e00bb | 134 | lpwm->chip.dev = dev; |
d16a5aa9 MW |
135 | lpwm->chip.ops = &pwm_lpss_ops; |
136 | lpwm->chip.base = -1; | |
137 | lpwm->chip.npwm = 1; | |
138 | ||
139 | ret = pwmchip_add(&lpwm->chip); | |
140 | if (ret) { | |
093e00bb AC |
141 | dev_err(dev, "failed to add PWM chip: %d\n", ret); |
142 | return ERR_PTR(ret); | |
d16a5aa9 MW |
143 | } |
144 | ||
093e00bb | 145 | return lpwm; |
d16a5aa9 | 146 | } |
c558e39e | 147 | EXPORT_SYMBOL_GPL(pwm_lpss_probe); |
d16a5aa9 | 148 | |
c558e39e | 149 | int pwm_lpss_remove(struct pwm_lpss_chip *lpwm) |
d16a5aa9 | 150 | { |
d16a5aa9 MW |
151 | u32 ctrl; |
152 | ||
153 | ctrl = readl(lpwm->regs + PWM); | |
154 | writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); | |
155 | ||
156 | return pwmchip_remove(&lpwm->chip); | |
157 | } | |
c558e39e | 158 | EXPORT_SYMBOL_GPL(pwm_lpss_remove); |
d16a5aa9 MW |
159 | |
160 | MODULE_DESCRIPTION("PWM driver for Intel LPSS"); | |
161 | MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>"); | |
162 | MODULE_LICENSE("GPL v2"); |