1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Analog Devices ADP5585 PWM driver
4 *
5 * Copyright 2022 NXP
6 * Copyright 2024 Ideas on Board Oy
7 *
8 * Limitations:
9 * - The .apply() operation executes atomically, but may not wait for the
10 * period to complete (this is not documented and would need to be tested).
11 * - Disabling the PWM drives the output pin to a low level immediately.
12 * - The hardware can only generate normal polarity output.
13 */
14
15#include <asm/byteorder.h>
16
17#include <linux/device.h>
18#include <linux/err.h>
19#include <linux/math64.h>
20#include <linux/mfd/adp5585.h>
21#include <linux/minmax.h>
22#include <linux/module.h>
23#include <linux/mod_devicetable.h>
24#include <linux/platform_device.h>
25#include <linux/pwm.h>
26#include <linux/regmap.h>
27#include <linux/time.h>
28#include <linux/types.h>
29
30#define ADP5585_PWM_CHAN_NUM 1
31
32#define ADP5585_PWM_OSC_FREQ_HZ 1000000U
33#define ADP5585_PWM_MIN_PERIOD_NS (2ULL * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ)
34#define ADP5585_PWM_MAX_PERIOD_NS (2ULL * 0xffff * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ)
35
36struct adp5585_pwm_chip {
37 unsigned int pwm_cfg;
38 unsigned int pwm_offt_low;
39 unsigned int pwm_ont_low;
40};
41
42struct adp5585_pwm {
43 const struct adp5585_pwm_chip *info;
44 struct regmap *regmap;
45 unsigned int ext_cfg;
46};
47
48static int pwm_adp5585_request(struct pwm_chip *chip, struct pwm_device *pwm)
49{
50 struct adp5585_pwm *adp5585_pwm = pwmchip_get_drvdata(chip);
51
52 /* Configure the R3 pin as PWM output. */
53 return regmap_update_bits(map: adp5585_pwm->regmap, reg: adp5585_pwm->ext_cfg,
54 ADP5585_R3_EXTEND_CFG_MASK,
55 ADP5585_R3_EXTEND_CFG_PWM_OUT);
56}
57
58static void pwm_adp5585_free(struct pwm_chip *chip, struct pwm_device *pwm)
59{
60 struct adp5585_pwm *adp5585_pwm = pwmchip_get_drvdata(chip);
61
62 regmap_update_bits(map: adp5585_pwm->regmap, reg: adp5585_pwm->ext_cfg,
63 ADP5585_R3_EXTEND_CFG_MASK,
64 ADP5585_R3_EXTEND_CFG_GPIO4);
65}
66
67static int pwm_adp5585_apply(struct pwm_chip *chip,
68 struct pwm_device *pwm,
69 const struct pwm_state *state)
70{
71 struct adp5585_pwm *adp5585_pwm = pwmchip_get_drvdata(chip);
72 const struct adp5585_pwm_chip *info = adp5585_pwm->info;
73 struct regmap *regmap = adp5585_pwm->regmap;
74 u64 period, duty_cycle;
75 u32 on, off;
76 __le16 val;
77 int ret;
78
79 if (!state->enabled) {
80 regmap_clear_bits(map: regmap, reg: info->pwm_cfg, ADP5585_PWM_EN);
81 return 0;
82 }
83
84 if (state->polarity != PWM_POLARITY_NORMAL)
85 return -EINVAL;
86
87 if (state->period < ADP5585_PWM_MIN_PERIOD_NS)
88 return -EINVAL;
89
90 period = min(state->period, ADP5585_PWM_MAX_PERIOD_NS);
91 duty_cycle = min(state->duty_cycle, period);
92
93 /*
94 * Compute the on and off time. As the internal oscillator frequency is
95 * 1MHz, the calculation can be simplified without loss of precision.
96 */
97 on = div_u64(dividend: duty_cycle, NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ);
98 off = div_u64(dividend: period, NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ) - on;
99
100 val = cpu_to_le16(off);
101 ret = regmap_bulk_write(map: regmap, reg: info->pwm_offt_low, val: &val, val_count: 2);
102 if (ret)
103 return ret;
104
105 val = cpu_to_le16(on);
106 ret = regmap_bulk_write(map: regmap, reg: info->pwm_ont_low, val: &val, val_count: 2);
107 if (ret)
108 return ret;
109
110 /* Enable PWM in continuous mode and no external AND'ing. */
111 ret = regmap_update_bits(map: regmap, reg: info->pwm_cfg,
112 ADP5585_PWM_IN_AND | ADP5585_PWM_MODE |
113 ADP5585_PWM_EN, ADP5585_PWM_EN);
114 if (ret)
115 return ret;
116
117 return regmap_set_bits(map: regmap, reg: info->pwm_cfg, ADP5585_PWM_EN);
118}
119
120static int pwm_adp5585_get_state(struct pwm_chip *chip,
121 struct pwm_device *pwm,
122 struct pwm_state *state)
123{
124 struct adp5585_pwm *adp5585_pwm = pwmchip_get_drvdata(chip);
125 const struct adp5585_pwm_chip *info = adp5585_pwm->info;
126 struct regmap *regmap = adp5585_pwm->regmap;
127 unsigned int on, off;
128 unsigned int val;
129 __le16 on_off;
130 int ret;
131
132 ret = regmap_bulk_read(map: regmap, reg: info->pwm_offt_low, val: &on_off, val_count: 2);
133 if (ret)
134 return ret;
135 off = le16_to_cpu(on_off);
136
137 ret = regmap_bulk_read(map: regmap, reg: info->pwm_ont_low, val: &on_off, val_count: 2);
138 if (ret)
139 return ret;
140 on = le16_to_cpu(on_off);
141
142 state->duty_cycle = on * (NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ);
143 state->period = (on + off) * (NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ);
144
145 state->polarity = PWM_POLARITY_NORMAL;
146
147 regmap_read(map: regmap, reg: info->pwm_cfg, val: &val);
148 state->enabled = !!(val & ADP5585_PWM_EN);
149
150 return 0;
151}
152
153static const struct pwm_ops adp5585_pwm_ops = {
154 .request = pwm_adp5585_request,
155 .free = pwm_adp5585_free,
156 .apply = pwm_adp5585_apply,
157 .get_state = pwm_adp5585_get_state,
158};
159
160static int adp5585_pwm_probe(struct platform_device *pdev)
161{
162 const struct platform_device_id *id = platform_get_device_id(pdev);
163 struct device *dev = &pdev->dev;
164 struct adp5585_dev *adp5585 = dev_get_drvdata(dev: dev->parent);
165 struct adp5585_pwm *adp5585_pwm;
166 struct pwm_chip *chip;
167 int ret;
168
169 chip = devm_pwmchip_alloc(parent: dev, ADP5585_PWM_CHAN_NUM,
170 sizeof_priv: sizeof(*adp5585_pwm));
171 if (IS_ERR(ptr: chip))
172 return PTR_ERR(ptr: chip);
173
174 adp5585_pwm = pwmchip_get_drvdata(chip);
175 adp5585_pwm->regmap = adp5585->regmap;
176 adp5585_pwm->ext_cfg = adp5585->regs->ext_cfg;
177
178 adp5585_pwm->info = (const struct adp5585_pwm_chip *)id->driver_data;
179 if (!adp5585_pwm->info)
180 return -ENODEV;
181
182 device_set_of_node_from_dev(dev, dev2: dev->parent);
183
184 chip->ops = &adp5585_pwm_ops;
185
186 ret = devm_pwmchip_add(dev, chip);
187 if (ret)
188 return dev_err_probe(dev, err: ret, fmt: "failed to add PWM chip\n");
189
190 return 0;
191}
192
193static const struct adp5585_pwm_chip adp5585_pwm_chip_info = {
194 .pwm_cfg = ADP5585_PWM_CFG,
195 .pwm_offt_low = ADP5585_PWM_OFFT_LOW,
196 .pwm_ont_low = ADP5585_PWM_ONT_LOW,
197};
198
199static const struct adp5585_pwm_chip adp5589_pwm_chip_info = {
200 .pwm_cfg = ADP5589_PWM_CFG,
201 .pwm_offt_low = ADP5589_PWM_OFFT_LOW,
202 .pwm_ont_low = ADP5589_PWM_ONT_LOW,
203};
204
205static const struct platform_device_id adp5585_pwm_id_table[] = {
206 { "adp5585-pwm", (kernel_ulong_t)&adp5585_pwm_chip_info },
207 { "adp5589-pwm", (kernel_ulong_t)&adp5589_pwm_chip_info },
208 { /* Sentinel */ }
209};
210MODULE_DEVICE_TABLE(platform, adp5585_pwm_id_table);
211
212static struct platform_driver adp5585_pwm_driver = {
213 .driver = {
214 .name = "adp5585-pwm",
215 },
216 .probe = adp5585_pwm_probe,
217 .id_table = adp5585_pwm_id_table,
218};
219module_platform_driver(adp5585_pwm_driver);
220
221MODULE_AUTHOR("Xiaoning Wang <xiaoning.wang@nxp.com>");
222MODULE_DESCRIPTION("ADP5585 PWM Driver");
223MODULE_LICENSE("GPL");
224

source code of linux/drivers/pwm/pwm-adp5585.c