1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * drivers/pwm/pwm-pxa.c |
4 | * |
5 | * simple driver for PWM (Pulse Width Modulator) controller |
6 | * |
7 | * 2008-02-13 initial version |
8 | * eric miao <eric.miao@marvell.com> |
9 | * |
10 | * Links to reference manuals for some of the supported PWM chips can be found |
11 | * in Documentation/arch/arm/marvell.rst. |
12 | * |
13 | * Limitations: |
14 | * - When PWM is stopped, the current PWM period stops abruptly at the next |
15 | * input clock (PWMCR_SD is set) and the output is driven to inactive. |
16 | */ |
17 | |
18 | #include <linux/mod_devicetable.h> |
19 | #include <linux/module.h> |
20 | #include <linux/kernel.h> |
21 | #include <linux/platform_device.h> |
22 | #include <linux/slab.h> |
23 | #include <linux/err.h> |
24 | #include <linux/clk.h> |
25 | #include <linux/io.h> |
26 | #include <linux/pwm.h> |
27 | #include <linux/of.h> |
28 | |
29 | #include <asm/div64.h> |
30 | |
31 | #define HAS_SECONDARY_PWM 0x10 |
32 | |
33 | static const struct platform_device_id pwm_id_table[] = { |
34 | /* PWM has_secondary_pwm? */ |
35 | { "pxa25x-pwm" , 0 }, |
36 | { "pxa27x-pwm" , HAS_SECONDARY_PWM }, |
37 | { "pxa168-pwm" , 0 }, |
38 | { "pxa910-pwm" , 0 }, |
39 | { }, |
40 | }; |
41 | MODULE_DEVICE_TABLE(platform, pwm_id_table); |
42 | |
43 | /* PWM registers and bits definitions */ |
44 | #define PWMCR (0x00) |
45 | #define PWMDCR (0x04) |
46 | #define PWMPCR (0x08) |
47 | |
48 | #define PWMCR_SD (1 << 6) |
49 | #define PWMDCR_FD (1 << 10) |
50 | |
51 | struct pxa_pwm_chip { |
52 | struct device *dev; |
53 | |
54 | struct clk *clk; |
55 | void __iomem *mmio_base; |
56 | }; |
57 | |
58 | static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip) |
59 | { |
60 | return pwmchip_get_drvdata(chip); |
61 | } |
62 | |
63 | /* |
64 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE |
65 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE |
66 | */ |
67 | static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
68 | u64 duty_ns, u64 period_ns) |
69 | { |
70 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
71 | unsigned long long c; |
72 | unsigned long period_cycles, prescale, pv, dc; |
73 | unsigned long offset; |
74 | |
75 | offset = pwm->hwpwm ? 0x10 : 0; |
76 | |
77 | c = clk_get_rate(clk: pc->clk); |
78 | c = c * period_ns; |
79 | do_div(c, 1000000000); |
80 | period_cycles = c; |
81 | |
82 | if (period_cycles < 1) |
83 | period_cycles = 1; |
84 | prescale = (period_cycles - 1) / 1024; |
85 | pv = period_cycles / (prescale + 1) - 1; |
86 | |
87 | if (prescale > 63) |
88 | return -EINVAL; |
89 | |
90 | if (duty_ns == period_ns) |
91 | dc = PWMDCR_FD; |
92 | else |
93 | dc = mul_u64_u64_div_u64(a: pv + 1, mul: duty_ns, div: period_ns); |
94 | |
95 | writel(val: prescale | PWMCR_SD, addr: pc->mmio_base + offset + PWMCR); |
96 | writel(val: dc, addr: pc->mmio_base + offset + PWMDCR); |
97 | writel(val: pv, addr: pc->mmio_base + offset + PWMPCR); |
98 | |
99 | return 0; |
100 | } |
101 | |
102 | static int pxa_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, |
103 | const struct pwm_state *state) |
104 | { |
105 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
106 | u64 duty_cycle; |
107 | int err; |
108 | |
109 | if (state->polarity != PWM_POLARITY_NORMAL) |
110 | return -EINVAL; |
111 | |
112 | err = clk_prepare_enable(clk: pc->clk); |
113 | if (err) |
114 | return err; |
115 | |
116 | duty_cycle = state->enabled ? state->duty_cycle : 0; |
117 | |
118 | err = pxa_pwm_config(chip, pwm, duty_ns: duty_cycle, period_ns: state->period); |
119 | if (err) { |
120 | clk_disable_unprepare(clk: pc->clk); |
121 | return err; |
122 | } |
123 | |
124 | if (state->enabled && !pwm->state.enabled) |
125 | return 0; |
126 | |
127 | clk_disable_unprepare(clk: pc->clk); |
128 | |
129 | if (!state->enabled && pwm->state.enabled) |
130 | clk_disable_unprepare(clk: pc->clk); |
131 | |
132 | return 0; |
133 | } |
134 | |
135 | static const struct pwm_ops pxa_pwm_ops = { |
136 | .apply = pxa_pwm_apply, |
137 | }; |
138 | |
139 | #ifdef CONFIG_OF |
140 | /* |
141 | * Device tree users must create one device instance for each PWM channel. |
142 | * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver |
143 | * code that this is a single channel pxa25x-pwm. Currently all devices are |
144 | * supported identically. |
145 | */ |
146 | static const struct of_device_id pwm_of_match[] = { |
147 | { .compatible = "marvell,pxa250-pwm" , .data = &pwm_id_table[0]}, |
148 | { .compatible = "marvell,pxa270-pwm" , .data = &pwm_id_table[0]}, |
149 | { .compatible = "marvell,pxa168-pwm" , .data = &pwm_id_table[0]}, |
150 | { .compatible = "marvell,pxa910-pwm" , .data = &pwm_id_table[0]}, |
151 | { } |
152 | }; |
153 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
154 | #else |
155 | #define pwm_of_match NULL |
156 | #endif |
157 | |
158 | static int pwm_probe(struct platform_device *pdev) |
159 | { |
160 | const struct platform_device_id *id = platform_get_device_id(pdev); |
161 | struct pwm_chip *chip; |
162 | struct pxa_pwm_chip *pc; |
163 | int ret = 0; |
164 | |
165 | if (IS_ENABLED(CONFIG_OF) && id == NULL) |
166 | id = of_device_get_match_data(dev: &pdev->dev); |
167 | |
168 | if (id == NULL) |
169 | return -EINVAL; |
170 | |
171 | chip = devm_pwmchip_alloc(parent: &pdev->dev, |
172 | npwm: (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1, |
173 | sizeof_priv: sizeof(*pc)); |
174 | if (IS_ERR(ptr: chip)) |
175 | return PTR_ERR(ptr: chip); |
176 | pc = to_pxa_pwm_chip(chip); |
177 | |
178 | pc->clk = devm_clk_get(dev: &pdev->dev, NULL); |
179 | if (IS_ERR(ptr: pc->clk)) |
180 | return PTR_ERR(ptr: pc->clk); |
181 | |
182 | chip->ops = &pxa_pwm_ops; |
183 | |
184 | if (IS_ENABLED(CONFIG_OF)) |
185 | chip->of_xlate = of_pwm_single_xlate; |
186 | |
187 | pc->mmio_base = devm_platform_ioremap_resource(pdev, index: 0); |
188 | if (IS_ERR(ptr: pc->mmio_base)) |
189 | return PTR_ERR(ptr: pc->mmio_base); |
190 | |
191 | ret = devm_pwmchip_add(&pdev->dev, chip); |
192 | if (ret < 0) { |
193 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n" , ret); |
194 | return ret; |
195 | } |
196 | |
197 | return 0; |
198 | } |
199 | |
200 | static struct platform_driver pwm_driver = { |
201 | .driver = { |
202 | .name = "pxa25x-pwm" , |
203 | .of_match_table = pwm_of_match, |
204 | }, |
205 | .probe = pwm_probe, |
206 | .id_table = pwm_id_table, |
207 | }; |
208 | |
209 | module_platform_driver(pwm_driver); |
210 | |
211 | MODULE_LICENSE("GPL v2" ); |
212 | |