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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 | ||
37670676 | 16 | #include <linux/delay.h> |
e0c86a3b | 17 | #include <linux/io.h> |
10d56a4c | 18 | #include <linux/iopoll.h> |
d16a5aa9 MW |
19 | #include <linux/kernel.h> |
20 | #include <linux/module.h> | |
f080be27 | 21 | #include <linux/pm_runtime.h> |
883e4d07 | 22 | #include <linux/time.h> |
093e00bb | 23 | |
c558e39e | 24 | #include "pwm-lpss.h" |
d16a5aa9 MW |
25 | |
26 | #define PWM 0x00000000 | |
27 | #define PWM_ENABLE BIT(31) | |
28 | #define PWM_SW_UPDATE BIT(30) | |
29 | #define PWM_BASE_UNIT_SHIFT 8 | |
d16a5aa9 | 30 | #define PWM_ON_TIME_DIV_MASK 0x000000ff |
d16a5aa9 | 31 | |
4e11f5ac MW |
32 | /* Size of each PWM register space if multiple */ |
33 | #define PWM_SIZE 0x400 | |
34 | ||
d16a5aa9 MW |
35 | struct pwm_lpss_chip { |
36 | struct pwm_chip chip; | |
37 | void __iomem *regs; | |
883e4d07 | 38 | const struct pwm_lpss_boardinfo *info; |
093e00bb AC |
39 | }; |
40 | ||
d16a5aa9 MW |
41 | static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip) |
42 | { | |
43 | return container_of(chip, struct pwm_lpss_chip, chip); | |
44 | } | |
45 | ||
4e11f5ac MW |
46 | static inline u32 pwm_lpss_read(const struct pwm_device *pwm) |
47 | { | |
48 | struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip); | |
49 | ||
50 | return readl(lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM); | |
51 | } | |
52 | ||
53 | static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value) | |
54 | { | |
55 | struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip); | |
56 | ||
57 | writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM); | |
58 | } | |
59 | ||
10d56a4c | 60 | static int pwm_lpss_update(struct pwm_device *pwm) |
37670676 | 61 | { |
10d56a4c IK |
62 | struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip); |
63 | const void __iomem *addr = lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM; | |
64 | const unsigned int ms = 500 * USEC_PER_MSEC; | |
65 | u32 val; | |
66 | int err; | |
67 | ||
68 | pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE); | |
69 | ||
b14e8cef | 70 | /* |
10d56a4c IK |
71 | * PWM Configuration register has SW_UPDATE bit that is set when a new |
72 | * configuration is written to the register. The bit is automatically | |
73 | * cleared at the start of the next output cycle by the IP block. | |
74 | * | |
75 | * If one writes a new configuration to the register while it still has | |
76 | * the bit enabled, PWM may freeze. That is, while one can still write | |
77 | * to the register, it won't have an effect. Thus, we try to sleep long | |
78 | * enough that the bit gets cleared and make sure the bit is not | |
79 | * enabled while we update the configuration. | |
b14e8cef | 80 | */ |
10d56a4c IK |
81 | err = readl_poll_timeout(addr, val, !(val & PWM_SW_UPDATE), 40, ms); |
82 | if (err) | |
83 | dev_err(pwm->chip->dev, "PWM_SW_UPDATE was not cleared\n"); | |
b14e8cef | 84 | |
10d56a4c IK |
85 | return err; |
86 | } | |
87 | ||
88 | static inline int pwm_lpss_is_updating(struct pwm_device *pwm) | |
89 | { | |
90 | return (pwm_lpss_read(pwm) & PWM_SW_UPDATE) ? -EBUSY : 0; | |
37670676 MW |
91 | } |
92 | ||
b14e8cef AS |
93 | static void pwm_lpss_prepare(struct pwm_lpss_chip *lpwm, struct pwm_device *pwm, |
94 | int duty_ns, int period_ns) | |
d16a5aa9 | 95 | { |
ab248b60 | 96 | unsigned long long on_time_div; |
d9cd4a73 | 97 | unsigned long c = lpwm->info->clk_rate, base_unit_range; |
883e4d07 | 98 | unsigned long long base_unit, freq = NSEC_PER_SEC; |
d16a5aa9 MW |
99 | u32 ctrl; |
100 | ||
101 | do_div(freq, period_ns); | |
102 | ||
883e4d07 | 103 | /* |
104 | * The equation is: | |
e5ca4245 | 105 | * base_unit = round(base_unit_range * freq / c) |
883e4d07 | 106 | */ |
684309e5 | 107 | base_unit_range = BIT(lpwm->info->base_unit_bits) - 1; |
e5ca4245 | 108 | freq *= base_unit_range; |
d16a5aa9 | 109 | |
e5ca4245 | 110 | base_unit = DIV_ROUND_CLOSEST_ULL(freq, c); |
d16a5aa9 | 111 | |
ab248b60 MW |
112 | on_time_div = 255ULL * duty_ns; |
113 | do_div(on_time_div, period_ns); | |
114 | on_time_div = 255ULL - on_time_div; | |
d16a5aa9 | 115 | |
4e11f5ac | 116 | ctrl = pwm_lpss_read(pwm); |
883e4d07 | 117 | ctrl &= ~PWM_ON_TIME_DIV_MASK; |
684309e5 AS |
118 | ctrl &= ~(base_unit_range << PWM_BASE_UNIT_SHIFT); |
119 | base_unit &= base_unit_range; | |
883e4d07 | 120 | ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT; |
d16a5aa9 | 121 | ctrl |= on_time_div; |
4e11f5ac | 122 | pwm_lpss_write(pwm, ctrl); |
d16a5aa9 MW |
123 | } |
124 | ||
b14e8cef AS |
125 | static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm, |
126 | struct pwm_state *state) | |
d16a5aa9 | 127 | { |
b14e8cef | 128 | struct pwm_lpss_chip *lpwm = to_lpwm(chip); |
10d56a4c | 129 | int ret; |
37670676 | 130 | |
b14e8cef AS |
131 | if (state->enabled) { |
132 | if (!pwm_is_enabled(pwm)) { | |
133 | pm_runtime_get_sync(chip->dev); | |
10d56a4c IK |
134 | ret = pwm_lpss_is_updating(pwm); |
135 | if (ret) { | |
136 | pm_runtime_put(chip->dev); | |
137 | return ret; | |
138 | } | |
b14e8cef | 139 | pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period); |
10d56a4c IK |
140 | ret = pwm_lpss_update(pwm); |
141 | if (ret) { | |
142 | pm_runtime_put(chip->dev); | |
143 | return ret; | |
144 | } | |
b14e8cef AS |
145 | pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE); |
146 | } else { | |
10d56a4c IK |
147 | ret = pwm_lpss_is_updating(pwm); |
148 | if (ret) | |
149 | return ret; | |
b14e8cef | 150 | pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period); |
10d56a4c | 151 | return pwm_lpss_update(pwm); |
b14e8cef AS |
152 | } |
153 | } else if (pwm_is_enabled(pwm)) { | |
154 | pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE); | |
155 | pm_runtime_put(chip->dev); | |
156 | } | |
d16a5aa9 | 157 | |
b14e8cef | 158 | return 0; |
d16a5aa9 MW |
159 | } |
160 | ||
161 | static const struct pwm_ops pwm_lpss_ops = { | |
b14e8cef | 162 | .apply = pwm_lpss_apply, |
d16a5aa9 MW |
163 | .owner = THIS_MODULE, |
164 | }; | |
165 | ||
c558e39e AS |
166 | struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, |
167 | const struct pwm_lpss_boardinfo *info) | |
d16a5aa9 MW |
168 | { |
169 | struct pwm_lpss_chip *lpwm; | |
d9cd4a73 | 170 | unsigned long c; |
d16a5aa9 MW |
171 | int ret; |
172 | ||
093e00bb | 173 | lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL); |
d16a5aa9 | 174 | if (!lpwm) |
093e00bb | 175 | return ERR_PTR(-ENOMEM); |
d16a5aa9 | 176 | |
093e00bb | 177 | lpwm->regs = devm_ioremap_resource(dev, r); |
d16a5aa9 | 178 | if (IS_ERR(lpwm->regs)) |
89c0339e | 179 | return ERR_CAST(lpwm->regs); |
093e00bb | 180 | |
883e4d07 | 181 | lpwm->info = info; |
d9cd4a73 AS |
182 | |
183 | c = lpwm->info->clk_rate; | |
184 | if (!c) | |
185 | return ERR_PTR(-EINVAL); | |
186 | ||
093e00bb | 187 | lpwm->chip.dev = dev; |
d16a5aa9 MW |
188 | lpwm->chip.ops = &pwm_lpss_ops; |
189 | lpwm->chip.base = -1; | |
4e11f5ac | 190 | lpwm->chip.npwm = info->npwm; |
d16a5aa9 MW |
191 | |
192 | ret = pwmchip_add(&lpwm->chip); | |
193 | if (ret) { | |
093e00bb AC |
194 | dev_err(dev, "failed to add PWM chip: %d\n", ret); |
195 | return ERR_PTR(ret); | |
d16a5aa9 MW |
196 | } |
197 | ||
093e00bb | 198 | return lpwm; |
d16a5aa9 | 199 | } |
c558e39e | 200 | EXPORT_SYMBOL_GPL(pwm_lpss_probe); |
d16a5aa9 | 201 | |
c558e39e | 202 | int pwm_lpss_remove(struct pwm_lpss_chip *lpwm) |
d16a5aa9 | 203 | { |
d16a5aa9 MW |
204 | return pwmchip_remove(&lpwm->chip); |
205 | } | |
c558e39e | 206 | EXPORT_SYMBOL_GPL(pwm_lpss_remove); |
d16a5aa9 MW |
207 | |
208 | MODULE_DESCRIPTION("PWM driver for Intel LPSS"); | |
209 | MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>"); | |
210 | MODULE_LICENSE("GPL v2"); |