Commit | Line | Data |
---|---|---|
166091b1 SH |
1 | /* |
2 | * simple driver for PWM (Pulse Width Modulator) controller | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com> | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/platform_device.h> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
166091b1 SH |
15 | #include <linux/err.h> |
16 | #include <linux/clk.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/pwm.h> | |
c010dba8 HS |
19 | #include <mach/hardware.h> |
20 | ||
21 | ||
22 | /* i.MX1 and i.MX21 share the same PWM function block: */ | |
23 | ||
24 | #define MX1_PWMC 0x00 /* PWM Control Register */ | |
25 | #define MX1_PWMS 0x04 /* PWM Sample Register */ | |
26 | #define MX1_PWMP 0x08 /* PWM Period Register */ | |
27 | ||
66ad6a61 | 28 | #define MX1_PWMC_EN (1 << 4) |
c010dba8 HS |
29 | |
30 | /* i.MX27, i.MX31, i.MX35 share the same PWM function block: */ | |
31 | ||
32 | #define MX3_PWMCR 0x00 /* PWM Control Register */ | |
33 | #define MX3_PWMSAR 0x0C /* PWM Sample Register */ | |
34 | #define MX3_PWMPR 0x10 /* PWM Period Register */ | |
35 | #define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4) | |
c0d96aed JC |
36 | #define MX3_PWMCR_DOZEEN (1 << 24) |
37 | #define MX3_PWMCR_WAITEN (1 << 23) | |
38 | #define MX3_PWMCR_DBGEN (1 << 22) | |
c010dba8 | 39 | #define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16) |
a058cbc1 | 40 | #define MX3_PWMCR_CLKSRC_IPG (1 << 16) |
c010dba8 HS |
41 | #define MX3_PWMCR_EN (1 << 0) |
42 | ||
29693248 | 43 | struct imx_chip { |
166091b1 SH |
44 | struct clk *clk; |
45 | ||
140827c1 | 46 | int enabled; |
166091b1 SH |
47 | void __iomem *mmio_base; |
48 | ||
29693248 | 49 | struct pwm_chip chip; |
19e73333 SH |
50 | |
51 | int (*config)(struct pwm_chip *chip, | |
52 | struct pwm_device *pwm, int duty_ns, int period_ns); | |
66ad6a61 | 53 | void (*set_enable)(struct pwm_chip *chip, bool enable); |
166091b1 SH |
54 | }; |
55 | ||
29693248 SH |
56 | #define to_imx_chip(chip) container_of(chip, struct imx_chip, chip) |
57 | ||
19e73333 | 58 | static int imx_pwm_config_v1(struct pwm_chip *chip, |
29693248 | 59 | struct pwm_device *pwm, int duty_ns, int period_ns) |
166091b1 | 60 | { |
29693248 | 61 | struct imx_chip *imx = to_imx_chip(chip); |
166091b1 | 62 | |
19e73333 SH |
63 | /* |
64 | * The PWM subsystem allows for exact frequencies. However, | |
65 | * I cannot connect a scope on my device to the PWM line and | |
66 | * thus cannot provide the program the PWM controller | |
67 | * exactly. Instead, I'm relying on the fact that the | |
68 | * Bootloader (u-boot or WinCE+haret) has programmed the PWM | |
69 | * function group already. So I'll just modify the PWM sample | |
70 | * register to follow the ratio of duty_ns vs. period_ns | |
71 | * accordingly. | |
72 | * | |
73 | * This is good enough for programming the brightness of | |
74 | * the LCD backlight. | |
75 | * | |
76 | * The real implementation would divide PERCLK[0] first by | |
77 | * both the prescaler (/1 .. /128) and then by CLKSEL | |
78 | * (/2 .. /16). | |
79 | */ | |
80 | u32 max = readl(imx->mmio_base + MX1_PWMP); | |
81 | u32 p = max * duty_ns / period_ns; | |
82 | writel(max - p, imx->mmio_base + MX1_PWMS); | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
66ad6a61 SH |
87 | static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable) |
88 | { | |
89 | struct imx_chip *imx = to_imx_chip(chip); | |
90 | u32 val; | |
91 | ||
92 | val = readl(imx->mmio_base + MX1_PWMC); | |
93 | ||
94 | if (enable) | |
95 | val |= MX1_PWMC_EN; | |
96 | else | |
97 | val &= ~MX1_PWMC_EN; | |
98 | ||
99 | writel(val, imx->mmio_base + MX1_PWMC); | |
100 | } | |
101 | ||
19e73333 SH |
102 | static int imx_pwm_config_v2(struct pwm_chip *chip, |
103 | struct pwm_device *pwm, int duty_ns, int period_ns) | |
104 | { | |
105 | struct imx_chip *imx = to_imx_chip(chip); | |
106 | unsigned long long c; | |
107 | unsigned long period_cycles, duty_cycles, prescale; | |
108 | u32 cr; | |
109 | ||
110 | c = clk_get_rate(imx->clk); | |
111 | c = c * period_ns; | |
112 | do_div(c, 1000000000); | |
113 | period_cycles = c; | |
114 | ||
115 | prescale = period_cycles / 0x10000 + 1; | |
116 | ||
117 | period_cycles /= prescale; | |
118 | c = (unsigned long long)period_cycles * duty_ns; | |
119 | do_div(c, period_ns); | |
120 | duty_cycles = c; | |
121 | ||
122 | /* | |
123 | * according to imx pwm RM, the real period value should be | |
124 | * PERIOD value in PWMPR plus 2. | |
125 | */ | |
126 | if (period_cycles > 2) | |
127 | period_cycles -= 2; | |
128 | else | |
129 | period_cycles = 0; | |
130 | ||
131 | writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); | |
132 | writel(period_cycles, imx->mmio_base + MX3_PWMPR); | |
133 | ||
134 | cr = MX3_PWMCR_PRESCALER(prescale) | | |
135 | MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | | |
66ad6a61 SH |
136 | MX3_PWMCR_DBGEN; |
137 | ||
138 | if (imx->enabled) | |
139 | cr |= MX3_PWMCR_EN; | |
19e73333 SH |
140 | |
141 | if (cpu_is_mx25()) | |
142 | cr |= MX3_PWMCR_CLKSRC_IPG; | |
143 | else | |
144 | cr |= MX3_PWMCR_CLKSRC_IPG_HIGH; | |
145 | ||
146 | writel(cr, imx->mmio_base + MX3_PWMCR); | |
166091b1 SH |
147 | |
148 | return 0; | |
149 | } | |
166091b1 | 150 | |
66ad6a61 SH |
151 | static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable) |
152 | { | |
153 | struct imx_chip *imx = to_imx_chip(chip); | |
154 | u32 val; | |
155 | ||
156 | val = readl(imx->mmio_base + MX3_PWMCR); | |
157 | ||
158 | if (enable) | |
159 | val |= MX3_PWMCR_EN; | |
160 | else | |
161 | val &= ~MX3_PWMCR_EN; | |
162 | ||
163 | writel(val, imx->mmio_base + MX3_PWMCR); | |
164 | } | |
165 | ||
19e73333 SH |
166 | static int imx_pwm_config(struct pwm_chip *chip, |
167 | struct pwm_device *pwm, int duty_ns, int period_ns) | |
168 | { | |
169 | struct imx_chip *imx = to_imx_chip(chip); | |
170 | ||
171 | return imx->config(chip, pwm, duty_ns, period_ns); | |
172 | } | |
173 | ||
29693248 | 174 | static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
166091b1 | 175 | { |
29693248 | 176 | struct imx_chip *imx = to_imx_chip(chip); |
140827c1 | 177 | int ret; |
166091b1 | 178 | |
140827c1 SH |
179 | ret = clk_prepare_enable(imx->clk); |
180 | if (ret) | |
181 | return ret; | |
182 | ||
66ad6a61 SH |
183 | imx->set_enable(chip, true); |
184 | ||
140827c1 SH |
185 | imx->enabled = 1; |
186 | ||
187 | return 0; | |
166091b1 | 188 | } |
166091b1 | 189 | |
29693248 | 190 | static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
166091b1 | 191 | { |
29693248 | 192 | struct imx_chip *imx = to_imx_chip(chip); |
166091b1 | 193 | |
66ad6a61 | 194 | imx->set_enable(chip, false); |
166091b1 | 195 | |
140827c1 SH |
196 | clk_disable_unprepare(imx->clk); |
197 | imx->enabled = 0; | |
166091b1 | 198 | } |
166091b1 | 199 | |
29693248 SH |
200 | static struct pwm_ops imx_pwm_ops = { |
201 | .enable = imx_pwm_enable, | |
202 | .disable = imx_pwm_disable, | |
203 | .config = imx_pwm_config, | |
204 | .owner = THIS_MODULE, | |
205 | }; | |
166091b1 | 206 | |
29693248 | 207 | static int __devinit imx_pwm_probe(struct platform_device *pdev) |
166091b1 | 208 | { |
29693248 | 209 | struct imx_chip *imx; |
166091b1 SH |
210 | struct resource *r; |
211 | int ret = 0; | |
212 | ||
a9970e3b | 213 | imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL); |
29693248 | 214 | if (imx == NULL) { |
166091b1 SH |
215 | dev_err(&pdev->dev, "failed to allocate memory\n"); |
216 | return -ENOMEM; | |
217 | } | |
218 | ||
a9970e3b | 219 | imx->clk = devm_clk_get(&pdev->dev, "pwm"); |
166091b1 | 220 | |
a9970e3b AL |
221 | if (IS_ERR(imx->clk)) |
222 | return PTR_ERR(imx->clk); | |
166091b1 | 223 | |
29693248 SH |
224 | imx->chip.ops = &imx_pwm_ops; |
225 | imx->chip.dev = &pdev->dev; | |
226 | imx->chip.base = -1; | |
227 | imx->chip.npwm = 1; | |
166091b1 | 228 | |
166091b1 SH |
229 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
230 | if (r == NULL) { | |
231 | dev_err(&pdev->dev, "no memory resource defined\n"); | |
a9970e3b | 232 | return -ENODEV; |
166091b1 SH |
233 | } |
234 | ||
a9970e3b AL |
235 | imx->mmio_base = devm_request_and_ioremap(&pdev->dev, r); |
236 | if (imx->mmio_base == NULL) | |
237 | return -EADDRNOTAVAIL; | |
166091b1 | 238 | |
66ad6a61 | 239 | if (cpu_is_mx1() || cpu_is_mx21()) { |
19e73333 | 240 | imx->config = imx_pwm_config_v1; |
66ad6a61 SH |
241 | imx->set_enable = imx_pwm_set_enable_v1; |
242 | } else { | |
19e73333 | 243 | imx->config = imx_pwm_config_v2; |
66ad6a61 SH |
244 | imx->set_enable = imx_pwm_set_enable_v2; |
245 | } | |
19e73333 | 246 | |
29693248 SH |
247 | ret = pwmchip_add(&imx->chip); |
248 | if (ret < 0) | |
a9970e3b | 249 | return ret; |
166091b1 | 250 | |
29693248 | 251 | platform_set_drvdata(pdev, imx); |
166091b1 | 252 | return 0; |
166091b1 SH |
253 | } |
254 | ||
29693248 | 255 | static int __devexit imx_pwm_remove(struct platform_device *pdev) |
166091b1 | 256 | { |
29693248 | 257 | struct imx_chip *imx; |
166091b1 | 258 | |
29693248 SH |
259 | imx = platform_get_drvdata(pdev); |
260 | if (imx == NULL) | |
166091b1 SH |
261 | return -ENODEV; |
262 | ||
a9970e3b | 263 | return pwmchip_remove(&imx->chip); |
166091b1 SH |
264 | } |
265 | ||
29693248 | 266 | static struct platform_driver imx_pwm_driver = { |
166091b1 SH |
267 | .driver = { |
268 | .name = "mxc_pwm", | |
269 | }, | |
29693248 SH |
270 | .probe = imx_pwm_probe, |
271 | .remove = __devexit_p(imx_pwm_remove), | |
166091b1 SH |
272 | }; |
273 | ||
29693248 | 274 | static int __init imx_pwm_init(void) |
166091b1 | 275 | { |
29693248 | 276 | return platform_driver_register(&imx_pwm_driver); |
166091b1 | 277 | } |
29693248 | 278 | arch_initcall(imx_pwm_init); |
166091b1 | 279 | |
29693248 | 280 | static void __exit imx_pwm_exit(void) |
166091b1 | 281 | { |
29693248 | 282 | platform_driver_unregister(&imx_pwm_driver); |
166091b1 | 283 | } |
29693248 | 284 | module_exit(imx_pwm_exit); |
166091b1 SH |
285 | |
286 | MODULE_LICENSE("GPL v2"); | |
287 | MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); |