Merge branch 'dt-regressions' into omap-for-v3.13/fixes-take4
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / pwm / pwm-mxs.c
1 /*
2  * Copyright 2012 Freescale Semiconductor, Inc.
3  *
4  * The code contained herein is licensed under the GNU General Public
5  * License. You may obtain a copy of the GNU General Public License
6  * Version 2 or later at the following locations:
7  *
8  * http://www.opensource.org/licenses/gpl-license.html
9  * http://www.gnu.org/copyleft/gpl.html
10  */
11
12 #include <linux/clk.h>
13 #include <linux/err.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/platform_device.h>
20 #include <linux/pwm.h>
21 #include <linux/slab.h>
22 #include <linux/stmp_device.h>
23
24 #define SET     0x4
25 #define CLR     0x8
26 #define TOG     0xc
27
28 #define PWM_CTRL                0x0
29 #define PWM_ACTIVE0             0x10
30 #define PWM_PERIOD0             0x20
31 #define  PERIOD_PERIOD(p)       ((p) & 0xffff)
32 #define  PERIOD_PERIOD_MAX      0x10000
33 #define  PERIOD_ACTIVE_HIGH     (3 << 16)
34 #define  PERIOD_INACTIVE_LOW    (2 << 18)
35 #define  PERIOD_CDIV(div)       (((div) & 0x7) << 20)
36 #define  PERIOD_CDIV_MAX        8
37
38 struct mxs_pwm_chip {
39         struct pwm_chip chip;
40         struct clk *clk;
41         void __iomem *base;
42 };
43
44 #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
45
46 static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
47                           int duty_ns, int period_ns)
48 {
49         struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
50         int ret, div = 0;
51         unsigned int period_cycles, duty_cycles;
52         unsigned long rate;
53         unsigned long long c;
54
55         rate = clk_get_rate(mxs->clk);
56         while (1) {
57                 c = rate / (1 << div);
58                 c = c * period_ns;
59                 do_div(c, 1000000000);
60                 if (c < PERIOD_PERIOD_MAX)
61                         break;
62                 div++;
63                 if (div > PERIOD_CDIV_MAX)
64                         return -EINVAL;
65         }
66
67         period_cycles = c;
68         c *= duty_ns;
69         do_div(c, period_ns);
70         duty_cycles = c;
71
72         /*
73          * If the PWM channel is disabled, make sure to turn on the clock
74          * before writing the register. Otherwise, keep it enabled.
75          */
76         if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
77                 ret = clk_prepare_enable(mxs->clk);
78                 if (ret)
79                         return ret;
80         }
81
82         writel(duty_cycles << 16,
83                         mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
84         writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
85                PERIOD_INACTIVE_LOW | PERIOD_CDIV(div),
86                         mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
87
88         /*
89          * If the PWM is not enabled, turn the clock off again to save power.
90          */
91         if (!test_bit(PWMF_ENABLED, &pwm->flags))
92                 clk_disable_unprepare(mxs->clk);
93
94         return 0;
95 }
96
97 static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
98 {
99         struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
100         int ret;
101
102         ret = clk_prepare_enable(mxs->clk);
103         if (ret)
104                 return ret;
105
106         writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
107
108         return 0;
109 }
110
111 static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
112 {
113         struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
114
115         writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
116
117         clk_disable_unprepare(mxs->clk);
118 }
119
120 static const struct pwm_ops mxs_pwm_ops = {
121         .config = mxs_pwm_config,
122         .enable = mxs_pwm_enable,
123         .disable = mxs_pwm_disable,
124         .owner = THIS_MODULE,
125 };
126
127 static int mxs_pwm_probe(struct platform_device *pdev)
128 {
129         struct device_node *np = pdev->dev.of_node;
130         struct mxs_pwm_chip *mxs;
131         struct resource *res;
132         int ret;
133
134         mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
135         if (!mxs)
136                 return -ENOMEM;
137
138         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
139         mxs->base = devm_ioremap_resource(&pdev->dev, res);
140         if (IS_ERR(mxs->base))
141                 return PTR_ERR(mxs->base);
142
143         mxs->clk = devm_clk_get(&pdev->dev, NULL);
144         if (IS_ERR(mxs->clk))
145                 return PTR_ERR(mxs->clk);
146
147         mxs->chip.dev = &pdev->dev;
148         mxs->chip.ops = &mxs_pwm_ops;
149         mxs->chip.base = -1;
150         ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
151         if (ret < 0) {
152                 dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
153                 return ret;
154         }
155
156         ret = pwmchip_add(&mxs->chip);
157         if (ret < 0) {
158                 dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
159                 return ret;
160         }
161
162         platform_set_drvdata(pdev, mxs);
163
164         ret = stmp_reset_block(mxs->base);
165         if (ret)
166                 goto pwm_remove;
167
168         return 0;
169
170 pwm_remove:
171         pwmchip_remove(&mxs->chip);
172         return ret;
173 }
174
175 static int mxs_pwm_remove(struct platform_device *pdev)
176 {
177         struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
178
179         return pwmchip_remove(&mxs->chip);
180 }
181
182 static const struct of_device_id mxs_pwm_dt_ids[] = {
183         { .compatible = "fsl,imx23-pwm", },
184         { /* sentinel */ }
185 };
186 MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids);
187
188 static struct platform_driver mxs_pwm_driver = {
189         .driver = {
190                 .name = "mxs-pwm",
191                 .owner = THIS_MODULE,
192                 .of_match_table = mxs_pwm_dt_ids,
193         },
194         .probe = mxs_pwm_probe,
195         .remove = mxs_pwm_remove,
196 };
197 module_platform_driver(mxs_pwm_driver);
198
199 MODULE_ALIAS("platform:mxs-pwm");
200 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
201 MODULE_DESCRIPTION("Freescale MXS PWM Driver");
202 MODULE_LICENSE("GPL v2");