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Sascha Hauer29693242012-03-15 10:04:35 +01001/*
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>
14#include <linux/slab.h>
15#include <linux/err.h>
16#include <linux/clk.h>
17#include <linux/io.h>
18#include <linux/pwm.h>
Philipp Zabel479e2e32012-06-25 16:16:25 +020019#include <linux/of_device.h>
Sascha Hauer29693242012-03-15 10:04:35 +010020
Sascha Hauer29693242012-03-15 10:04:35 +010021/* i.MX1 and i.MX21 share the same PWM function block: */
22
23#define MX1_PWMC 0x00 /* PWM Control Register */
24#define MX1_PWMS 0x04 /* PWM Sample Register */
25#define MX1_PWMP 0x08 /* PWM Period Register */
26
Sascha Hauer66ad6a62012-08-28 11:39:25 +020027#define MX1_PWMC_EN (1 << 4)
Sascha Hauer29693242012-03-15 10:04:35 +010028
29/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
30
31#define MX3_PWMCR 0x00 /* PWM Control Register */
32#define MX3_PWMSAR 0x0C /* PWM Sample Register */
33#define MX3_PWMPR 0x10 /* PWM Period Register */
34#define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)
35#define MX3_PWMCR_DOZEEN (1 << 24)
36#define MX3_PWMCR_WAITEN (1 << 23)
37#define MX3_PWMCR_DBGEN (1 << 22)
38#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
39#define MX3_PWMCR_CLKSRC_IPG (1 << 16)
40#define MX3_PWMCR_EN (1 << 0)
41
42struct imx_chip {
Philipp Zabel7b27c162012-06-25 16:15:20 +020043 struct clk *clk_per;
44 struct clk *clk_ipg;
Sascha Hauer29693242012-03-15 10:04:35 +010045
Sascha Hauer140827c2012-08-28 09:12:01 +020046 int enabled;
Sascha Hauer29693242012-03-15 10:04:35 +010047 void __iomem *mmio_base;
48
49 struct pwm_chip chip;
Sascha Hauer19e73332012-07-03 17:28:14 +020050
51 int (*config)(struct pwm_chip *chip,
52 struct pwm_device *pwm, int duty_ns, int period_ns);
Sascha Hauer66ad6a62012-08-28 11:39:25 +020053 void (*set_enable)(struct pwm_chip *chip, bool enable);
Sascha Hauer29693242012-03-15 10:04:35 +010054};
55
56#define to_imx_chip(chip) container_of(chip, struct imx_chip, chip)
57
Sascha Hauer19e73332012-07-03 17:28:14 +020058static int imx_pwm_config_v1(struct pwm_chip *chip,
59 struct pwm_device *pwm, int duty_ns, int period_ns)
60{
61 struct imx_chip *imx = to_imx_chip(chip);
62
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
Sascha Hauer66ad6a62012-08-28 11:39:25 +020087static 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
Sascha Hauer19e73332012-07-03 17:28:14 +0200102static 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
Philipp Zabel7b27c162012-06-25 16:15:20 +0200110 c = clk_get_rate(imx->clk_per);
Sascha Hauer19e73332012-07-03 17:28:14 +0200111 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 |
Sascha Hauer8d1c24b2012-08-28 12:03:29 +0200136 MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH;
Sascha Hauer66ad6a62012-08-28 11:39:25 +0200137
138 if (imx->enabled)
139 cr |= MX3_PWMCR_EN;
Sascha Hauer19e73332012-07-03 17:28:14 +0200140
Sascha Hauer19e73332012-07-03 17:28:14 +0200141 writel(cr, imx->mmio_base + MX3_PWMCR);
142
143 return 0;
144}
145
Sascha Hauer66ad6a62012-08-28 11:39:25 +0200146static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
147{
148 struct imx_chip *imx = to_imx_chip(chip);
149 u32 val;
150
151 val = readl(imx->mmio_base + MX3_PWMCR);
152
153 if (enable)
154 val |= MX3_PWMCR_EN;
155 else
156 val &= ~MX3_PWMCR_EN;
157
158 writel(val, imx->mmio_base + MX3_PWMCR);
159}
160
Sascha Hauer29693242012-03-15 10:04:35 +0100161static int imx_pwm_config(struct pwm_chip *chip,
162 struct pwm_device *pwm, int duty_ns, int period_ns)
163{
164 struct imx_chip *imx = to_imx_chip(chip);
Philipp Zabel7b27c162012-06-25 16:15:20 +0200165 int ret;
Sascha Hauer29693242012-03-15 10:04:35 +0100166
Philipp Zabel7b27c162012-06-25 16:15:20 +0200167 ret = clk_prepare_enable(imx->clk_ipg);
168 if (ret)
169 return ret;
170
171 ret = imx->config(chip, pwm, duty_ns, period_ns);
172
173 clk_disable_unprepare(imx->clk_ipg);
174
175 return ret;
Sascha Hauer29693242012-03-15 10:04:35 +0100176}
177
178static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
179{
180 struct imx_chip *imx = to_imx_chip(chip);
Sascha Hauer140827c2012-08-28 09:12:01 +0200181 int ret;
Sascha Hauer29693242012-03-15 10:04:35 +0100182
Philipp Zabel7b27c162012-06-25 16:15:20 +0200183 ret = clk_prepare_enable(imx->clk_per);
Sascha Hauer140827c2012-08-28 09:12:01 +0200184 if (ret)
185 return ret;
186
Sascha Hauer66ad6a62012-08-28 11:39:25 +0200187 imx->set_enable(chip, true);
188
Sascha Hauer140827c2012-08-28 09:12:01 +0200189 imx->enabled = 1;
190
191 return 0;
Sascha Hauer29693242012-03-15 10:04:35 +0100192}
193
194static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
195{
196 struct imx_chip *imx = to_imx_chip(chip);
197
Sascha Hauer66ad6a62012-08-28 11:39:25 +0200198 imx->set_enable(chip, false);
Sascha Hauer29693242012-03-15 10:04:35 +0100199
Philipp Zabel7b27c162012-06-25 16:15:20 +0200200 clk_disable_unprepare(imx->clk_per);
Sascha Hauer140827c2012-08-28 09:12:01 +0200201 imx->enabled = 0;
Sascha Hauer29693242012-03-15 10:04:35 +0100202}
203
204static struct pwm_ops imx_pwm_ops = {
205 .enable = imx_pwm_enable,
206 .disable = imx_pwm_disable,
207 .config = imx_pwm_config,
208 .owner = THIS_MODULE,
209};
210
Philipp Zabel479e2e32012-06-25 16:16:25 +0200211struct imx_pwm_data {
212 int (*config)(struct pwm_chip *chip,
213 struct pwm_device *pwm, int duty_ns, int period_ns);
214 void (*set_enable)(struct pwm_chip *chip, bool enable);
215};
216
217static struct imx_pwm_data imx_pwm_data_v1 = {
218 .config = imx_pwm_config_v1,
219 .set_enable = imx_pwm_set_enable_v1,
220};
221
222static struct imx_pwm_data imx_pwm_data_v2 = {
223 .config = imx_pwm_config_v2,
224 .set_enable = imx_pwm_set_enable_v2,
225};
226
227static const struct of_device_id imx_pwm_dt_ids[] = {
228 { .compatible = "fsl,imx1-pwm", .data = &imx_pwm_data_v1, },
229 { .compatible = "fsl,imx27-pwm", .data = &imx_pwm_data_v2, },
230 { /* sentinel */ }
231};
232MODULE_DEVICE_TABLE(of, imx_pwm_dt_ids);
233
Bill Pemberton3e9fe832012-11-19 13:23:14 -0500234static int imx_pwm_probe(struct platform_device *pdev)
Sascha Hauer29693242012-03-15 10:04:35 +0100235{
Philipp Zabel479e2e32012-06-25 16:16:25 +0200236 const struct of_device_id *of_id =
237 of_match_device(imx_pwm_dt_ids, &pdev->dev);
Lothar Waßmann983290b2012-12-05 16:34:41 +0100238 const struct imx_pwm_data *data;
Sascha Hauer29693242012-03-15 10:04:35 +0100239 struct imx_chip *imx;
240 struct resource *r;
241 int ret = 0;
242
Philipp Zabel479e2e32012-06-25 16:16:25 +0200243 if (!of_id)
244 return -ENODEV;
245
Axel Lina9970e32012-07-01 08:27:23 +0800246 imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
Sascha Hauer29693242012-03-15 10:04:35 +0100247 if (imx == NULL) {
248 dev_err(&pdev->dev, "failed to allocate memory\n");
249 return -ENOMEM;
250 }
251
Philipp Zabel7b27c162012-06-25 16:15:20 +0200252 imx->clk_per = devm_clk_get(&pdev->dev, "per");
253 if (IS_ERR(imx->clk_per)) {
254 dev_err(&pdev->dev, "getting per clock failed with %ld\n",
255 PTR_ERR(imx->clk_per));
256 return PTR_ERR(imx->clk_per);
257 }
Sascha Hauer29693242012-03-15 10:04:35 +0100258
Philipp Zabel7b27c162012-06-25 16:15:20 +0200259 imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
260 if (IS_ERR(imx->clk_ipg)) {
261 dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
262 PTR_ERR(imx->clk_ipg));
263 return PTR_ERR(imx->clk_ipg);
264 }
Sascha Hauer29693242012-03-15 10:04:35 +0100265
266 imx->chip.ops = &imx_pwm_ops;
267 imx->chip.dev = &pdev->dev;
268 imx->chip.base = -1;
269 imx->chip.npwm = 1;
270
Sascha Hauer29693242012-03-15 10:04:35 +0100271 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
272 if (r == NULL) {
273 dev_err(&pdev->dev, "no memory resource defined\n");
Axel Lina9970e32012-07-01 08:27:23 +0800274 return -ENODEV;
Sascha Hauer29693242012-03-15 10:04:35 +0100275 }
276
Thierry Reding6d4294d2013-01-21 11:09:16 +0100277 imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
278 if (IS_ERR(imx->mmio_base))
279 return PTR_ERR(imx->mmio_base);
Sascha Hauer29693242012-03-15 10:04:35 +0100280
Philipp Zabel479e2e32012-06-25 16:16:25 +0200281 data = of_id->data;
282 imx->config = data->config;
283 imx->set_enable = data->set_enable;
Sascha Hauer19e73332012-07-03 17:28:14 +0200284
Sascha Hauer29693242012-03-15 10:04:35 +0100285 ret = pwmchip_add(&imx->chip);
286 if (ret < 0)
Axel Lina9970e32012-07-01 08:27:23 +0800287 return ret;
Sascha Hauer29693242012-03-15 10:04:35 +0100288
289 platform_set_drvdata(pdev, imx);
290 return 0;
Sascha Hauer29693242012-03-15 10:04:35 +0100291}
292
Bill Pemberton77f37912012-11-19 13:26:09 -0500293static int imx_pwm_remove(struct platform_device *pdev)
Sascha Hauer29693242012-03-15 10:04:35 +0100294{
295 struct imx_chip *imx;
Sascha Hauer29693242012-03-15 10:04:35 +0100296
297 imx = platform_get_drvdata(pdev);
298 if (imx == NULL)
299 return -ENODEV;
300
Axel Lina9970e32012-07-01 08:27:23 +0800301 return pwmchip_remove(&imx->chip);
Sascha Hauer29693242012-03-15 10:04:35 +0100302}
303
304static struct platform_driver imx_pwm_driver = {
305 .driver = {
Philipp Zabel479e2e32012-06-25 16:16:25 +0200306 .name = "imx-pwm",
307 .of_match_table = of_match_ptr(imx_pwm_dt_ids),
Sascha Hauer29693242012-03-15 10:04:35 +0100308 },
309 .probe = imx_pwm_probe,
Bill Pembertonfd109112012-11-19 13:21:28 -0500310 .remove = imx_pwm_remove,
Sascha Hauer29693242012-03-15 10:04:35 +0100311};
312
Sascha Hauer208d0382012-08-28 08:27:40 +0200313module_platform_driver(imx_pwm_driver);
Sascha Hauer29693242012-03-15 10:04:35 +0100314
315MODULE_LICENSE("GPL v2");
316MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");