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_device.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 pwm_chip chip; |
53 | struct device *dev; |
54 | |
55 | struct clk *clk; |
56 | void __iomem *mmio_base; |
57 | }; |
58 | |
59 | static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip) |
60 | { |
61 | return container_of(chip, struct pxa_pwm_chip, chip); |
62 | } |
63 | |
64 | /* |
65 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE |
66 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE |
67 | */ |
68 | static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
69 | u64 duty_ns, u64 period_ns) |
70 | { |
71 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
72 | unsigned long long c; |
73 | unsigned long period_cycles, prescale, pv, dc; |
74 | unsigned long offset; |
75 | |
76 | offset = pwm->hwpwm ? 0x10 : 0; |
77 | |
78 | c = clk_get_rate(clk: pc->clk); |
79 | c = c * period_ns; |
80 | do_div(c, 1000000000); |
81 | period_cycles = c; |
82 | |
83 | if (period_cycles < 1) |
84 | period_cycles = 1; |
85 | prescale = (period_cycles - 1) / 1024; |
86 | pv = period_cycles / (prescale + 1) - 1; |
87 | |
88 | if (prescale > 63) |
89 | return -EINVAL; |
90 | |
91 | if (duty_ns == period_ns) |
92 | dc = PWMDCR_FD; |
93 | else |
94 | dc = mul_u64_u64_div_u64(a: pv + 1, mul: duty_ns, div: period_ns); |
95 | |
96 | writel(val: prescale | PWMCR_SD, addr: pc->mmio_base + offset + PWMCR); |
97 | writel(val: dc, addr: pc->mmio_base + offset + PWMDCR); |
98 | writel(val: pv, addr: pc->mmio_base + offset + PWMPCR); |
99 | |
100 | return 0; |
101 | } |
102 | |
103 | static int pxa_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, |
104 | const struct pwm_state *state) |
105 | { |
106 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); |
107 | u64 duty_cycle; |
108 | int err; |
109 | |
110 | if (state->polarity != PWM_POLARITY_NORMAL) |
111 | return -EINVAL; |
112 | |
113 | err = clk_prepare_enable(clk: pc->clk); |
114 | if (err) |
115 | return err; |
116 | |
117 | duty_cycle = state->enabled ? state->duty_cycle : 0; |
118 | |
119 | err = pxa_pwm_config(chip, pwm, duty_ns: duty_cycle, period_ns: state->period); |
120 | if (err) { |
121 | clk_disable_unprepare(clk: pc->clk); |
122 | return err; |
123 | } |
124 | |
125 | if (state->enabled && !pwm->state.enabled) |
126 | return 0; |
127 | |
128 | clk_disable_unprepare(clk: pc->clk); |
129 | |
130 | if (!state->enabled && pwm->state.enabled) |
131 | clk_disable_unprepare(clk: pc->clk); |
132 | |
133 | return 0; |
134 | } |
135 | |
136 | static const struct pwm_ops pxa_pwm_ops = { |
137 | .apply = pxa_pwm_apply, |
138 | .owner = THIS_MODULE, |
139 | }; |
140 | |
141 | #ifdef CONFIG_OF |
142 | /* |
143 | * Device tree users must create one device instance for each PWM channel. |
144 | * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver |
145 | * code that this is a single channel pxa25x-pwm. Currently all devices are |
146 | * supported identically. |
147 | */ |
148 | static const struct of_device_id pwm_of_match[] = { |
149 | { .compatible = "marvell,pxa250-pwm" , .data = &pwm_id_table[0]}, |
150 | { .compatible = "marvell,pxa270-pwm" , .data = &pwm_id_table[0]}, |
151 | { .compatible = "marvell,pxa168-pwm" , .data = &pwm_id_table[0]}, |
152 | { .compatible = "marvell,pxa910-pwm" , .data = &pwm_id_table[0]}, |
153 | { } |
154 | }; |
155 | MODULE_DEVICE_TABLE(of, pwm_of_match); |
156 | #else |
157 | #define pwm_of_match NULL |
158 | #endif |
159 | |
160 | static int pwm_probe(struct platform_device *pdev) |
161 | { |
162 | const struct platform_device_id *id = platform_get_device_id(pdev); |
163 | struct pxa_pwm_chip *pc; |
164 | int ret = 0; |
165 | |
166 | if (IS_ENABLED(CONFIG_OF) && id == NULL) |
167 | id = of_device_get_match_data(dev: &pdev->dev); |
168 | |
169 | if (id == NULL) |
170 | return -EINVAL; |
171 | |
172 | pc = devm_kzalloc(dev: &pdev->dev, size: sizeof(*pc), GFP_KERNEL); |
173 | if (pc == NULL) |
174 | return -ENOMEM; |
175 | |
176 | pc->clk = devm_clk_get(dev: &pdev->dev, NULL); |
177 | if (IS_ERR(ptr: pc->clk)) |
178 | return PTR_ERR(ptr: pc->clk); |
179 | |
180 | pc->chip.dev = &pdev->dev; |
181 | pc->chip.ops = &pxa_pwm_ops; |
182 | pc->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1; |
183 | |
184 | if (IS_ENABLED(CONFIG_OF)) { |
185 | pc->chip.of_xlate = of_pwm_single_xlate; |
186 | pc->chip.of_pwm_n_cells = 1; |
187 | } |
188 | |
189 | pc->mmio_base = devm_platform_ioremap_resource(pdev, index: 0); |
190 | if (IS_ERR(ptr: pc->mmio_base)) |
191 | return PTR_ERR(ptr: pc->mmio_base); |
192 | |
193 | ret = devm_pwmchip_add(dev: &pdev->dev, chip: &pc->chip); |
194 | if (ret < 0) { |
195 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n" , ret); |
196 | return ret; |
197 | } |
198 | |
199 | return 0; |
200 | } |
201 | |
202 | static struct platform_driver pwm_driver = { |
203 | .driver = { |
204 | .name = "pxa25x-pwm" , |
205 | .of_match_table = pwm_of_match, |
206 | }, |
207 | .probe = pwm_probe, |
208 | .id_table = pwm_id_table, |
209 | }; |
210 | |
211 | module_platform_driver(pwm_driver); |
212 | |
213 | MODULE_LICENSE("GPL v2" ); |
214 | |