Merge tag 'for-6.2-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...
[platform/kernel/linux-starfive.git] / drivers / pwm / pwm-intel-lgm.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2020 Intel Corporation.
4  *
5  * Limitations:
6  * - The hardware supports fixed period & configures only 2-wire mode.
7  * - Supports normal polarity. Does not support changing polarity.
8  * - When PWM is disabled, output of PWM will become 0(inactive). It doesn't
9  *   keep track of running period.
10  * - When duty cycle is changed, PWM output may be a mix of previous setting
11  *   and new setting for the first period. From second period, the output is
12  *   based on new setting.
13  * - It is a dedicated PWM fan controller. There are no other consumers for
14  *   this PWM controller.
15  */
16 #include <linux/bitfield.h>
17 #include <linux/clk.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/mod_devicetable.h>
21 #include <linux/pwm.h>
22 #include <linux/regmap.h>
23 #include <linux/reset.h>
24
25 #define LGM_PWM_FAN_CON0                0x0
26 #define LGM_PWM_FAN_EN_EN               BIT(0)
27 #define LGM_PWM_FAN_EN_DIS              0x0
28 #define LGM_PWM_FAN_EN_MSK              BIT(0)
29 #define LGM_PWM_FAN_MODE_2WIRE          0x0
30 #define LGM_PWM_FAN_MODE_MSK            BIT(1)
31 #define LGM_PWM_FAN_DC_MSK              GENMASK(23, 16)
32
33 #define LGM_PWM_FAN_CON1                0x4
34 #define LGM_PWM_FAN_MAX_RPM_MSK         GENMASK(15, 0)
35
36 #define LGM_PWM_MAX_RPM                 (BIT(16) - 1)
37 #define LGM_PWM_DEFAULT_RPM             4000
38 #define LGM_PWM_MAX_DUTY_CYCLE          (BIT(8) - 1)
39
40 #define LGM_PWM_DC_BITS                 8
41
42 #define LGM_PWM_PERIOD_2WIRE_NS         (40 * NSEC_PER_MSEC)
43
44 struct lgm_pwm_chip {
45         struct pwm_chip chip;
46         struct regmap *regmap;
47         u32 period;
48 };
49
50 static inline struct lgm_pwm_chip *to_lgm_pwm_chip(struct pwm_chip *chip)
51 {
52         return container_of(chip, struct lgm_pwm_chip, chip);
53 }
54
55 static int lgm_pwm_enable(struct pwm_chip *chip, bool enable)
56 {
57         struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
58         struct regmap *regmap = pc->regmap;
59
60         return regmap_update_bits(regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_EN_MSK,
61                                   enable ? LGM_PWM_FAN_EN_EN : LGM_PWM_FAN_EN_DIS);
62 }
63
64 static int lgm_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
65                          const struct pwm_state *state)
66 {
67         struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
68         u32 duty_cycle, val;
69         int ret;
70
71         /* The hardware only supports normal polarity and fixed period. */
72         if (state->polarity != PWM_POLARITY_NORMAL || state->period < pc->period)
73                 return -EINVAL;
74
75         if (!state->enabled)
76                 return lgm_pwm_enable(chip, 0);
77
78         duty_cycle = min_t(u64, state->duty_cycle, pc->period);
79         val = duty_cycle * LGM_PWM_MAX_DUTY_CYCLE / pc->period;
80
81         ret = regmap_update_bits(pc->regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_DC_MSK,
82                                  FIELD_PREP(LGM_PWM_FAN_DC_MSK, val));
83         if (ret)
84                 return ret;
85
86         return lgm_pwm_enable(chip, 1);
87 }
88
89 static int lgm_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
90                              struct pwm_state *state)
91 {
92         struct lgm_pwm_chip *pc = to_lgm_pwm_chip(chip);
93         u32 duty, val;
94
95         state->enabled = regmap_test_bits(pc->regmap, LGM_PWM_FAN_CON0,
96                                           LGM_PWM_FAN_EN_EN);
97         state->polarity = PWM_POLARITY_NORMAL;
98         state->period = pc->period; /* fixed period */
99
100         regmap_read(pc->regmap, LGM_PWM_FAN_CON0, &val);
101         duty = FIELD_GET(LGM_PWM_FAN_DC_MSK, val);
102         state->duty_cycle = DIV_ROUND_UP(duty * pc->period, LGM_PWM_MAX_DUTY_CYCLE);
103
104         return 0;
105 }
106
107 static const struct pwm_ops lgm_pwm_ops = {
108         .get_state = lgm_pwm_get_state,
109         .apply = lgm_pwm_apply,
110         .owner = THIS_MODULE,
111 };
112
113 static void lgm_pwm_init(struct lgm_pwm_chip *pc)
114 {
115         struct regmap *regmap = pc->regmap;
116         u32 con0_val;
117
118         con0_val = FIELD_PREP(LGM_PWM_FAN_MODE_MSK, LGM_PWM_FAN_MODE_2WIRE);
119         pc->period = LGM_PWM_PERIOD_2WIRE_NS;
120         regmap_update_bits(regmap, LGM_PWM_FAN_CON1, LGM_PWM_FAN_MAX_RPM_MSK,
121                            LGM_PWM_DEFAULT_RPM);
122         regmap_update_bits(regmap, LGM_PWM_FAN_CON0, LGM_PWM_FAN_MODE_MSK,
123                            con0_val);
124 }
125
126 static const struct regmap_config lgm_pwm_regmap_config = {
127         .reg_bits = 32,
128         .reg_stride = 4,
129         .val_bits = 32,
130 };
131
132 static void lgm_clk_release(void *data)
133 {
134         struct clk *clk = data;
135
136         clk_disable_unprepare(clk);
137 }
138
139 static int lgm_clk_enable(struct device *dev, struct clk *clk)
140 {
141         int ret;
142
143         ret = clk_prepare_enable(clk);
144         if (ret)
145                 return ret;
146
147         return devm_add_action_or_reset(dev, lgm_clk_release, clk);
148 }
149
150 static void lgm_reset_control_release(void *data)
151 {
152         struct reset_control *rst = data;
153
154         reset_control_assert(rst);
155 }
156
157 static int lgm_reset_control_deassert(struct device *dev, struct reset_control *rst)
158 {
159         int ret;
160
161         ret = reset_control_deassert(rst);
162         if (ret)
163                 return ret;
164
165         return devm_add_action_or_reset(dev, lgm_reset_control_release, rst);
166 }
167
168 static int lgm_pwm_probe(struct platform_device *pdev)
169 {
170         struct device *dev = &pdev->dev;
171         struct reset_control *rst;
172         struct lgm_pwm_chip *pc;
173         void __iomem *io_base;
174         struct clk *clk;
175         int ret;
176
177         pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
178         if (!pc)
179                 return -ENOMEM;
180
181         io_base = devm_platform_ioremap_resource(pdev, 0);
182         if (IS_ERR(io_base))
183                 return PTR_ERR(io_base);
184
185         pc->regmap = devm_regmap_init_mmio(dev, io_base, &lgm_pwm_regmap_config);
186         if (IS_ERR(pc->regmap))
187                 return dev_err_probe(dev, PTR_ERR(pc->regmap),
188                                      "failed to init register map\n");
189
190         clk = devm_clk_get(dev, NULL);
191         if (IS_ERR(clk))
192                 return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n");
193
194         ret = lgm_clk_enable(dev, clk);
195         if (ret)
196                 return dev_err_probe(dev, ret, "failed to enable clock\n");
197
198         rst = devm_reset_control_get_exclusive(dev, NULL);
199         if (IS_ERR(rst))
200                 return dev_err_probe(dev, PTR_ERR(rst),
201                                      "failed to get reset control\n");
202
203         ret = lgm_reset_control_deassert(dev, rst);
204         if (ret)
205                 return dev_err_probe(dev, ret, "cannot deassert reset control\n");
206
207         pc->chip.dev = dev;
208         pc->chip.ops = &lgm_pwm_ops;
209         pc->chip.npwm = 1;
210
211         lgm_pwm_init(pc);
212
213         ret = devm_pwmchip_add(dev, &pc->chip);
214         if (ret < 0)
215                 return dev_err_probe(dev, ret, "failed to add PWM chip\n");
216
217         return 0;
218 }
219
220 static const struct of_device_id lgm_pwm_of_match[] = {
221         { .compatible = "intel,lgm-pwm" },
222         { }
223 };
224 MODULE_DEVICE_TABLE(of, lgm_pwm_of_match);
225
226 static struct platform_driver lgm_pwm_driver = {
227         .driver = {
228                 .name = "intel-pwm",
229                 .of_match_table = lgm_pwm_of_match,
230         },
231         .probe = lgm_pwm_probe,
232 };
233 module_platform_driver(lgm_pwm_driver);
234
235 MODULE_LICENSE("GPL v2");