2 * Copyright 2012 Freescale Semiconductor, Inc.
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:
8 * http://www.opensource.org/licenses/gpl-license.html
9 * http://www.gnu.org/copyleft/gpl.html
12 #include <linux/clk.h>
13 #include <linux/err.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
18 #include <linux/of_address.h>
19 #include <linux/pinctrl/consumer.h>
20 #include <linux/platform_device.h>
21 #include <linux/pwm.h>
22 #include <linux/slab.h>
23 #include <linux/stmp_device.h>
30 #define PWM_ACTIVE0 0x10
31 #define PWM_PERIOD0 0x20
32 #define PERIOD_PERIOD(p) ((p) & 0xffff)
33 #define PERIOD_PERIOD_MAX 0x10000
34 #define PERIOD_ACTIVE_HIGH (3 << 16)
35 #define PERIOD_INACTIVE_LOW (2 << 18)
36 #define PERIOD_CDIV(div) (((div) & 0x7) << 20)
37 #define PERIOD_CDIV_MAX 8
46 #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
48 static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
49 int duty_ns, int period_ns)
51 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
53 unsigned int period_cycles, duty_cycles;
57 rate = clk_get_rate(mxs->clk);
59 c = rate / (1 << div);
61 do_div(c, 1000000000);
62 if (c < PERIOD_PERIOD_MAX)
65 if (div > PERIOD_CDIV_MAX)
75 * If the PWM channel is disabled, make sure to turn on the clock
76 * before writing the register. Otherwise, keep it enabled.
78 if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
79 ret = clk_prepare_enable(mxs->clk);
84 writel(duty_cycles << 16,
85 mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
86 writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
87 PERIOD_INACTIVE_LOW | PERIOD_CDIV(div),
88 mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
91 * If the PWM is not enabled, turn the clock off again to save power.
93 if (!test_bit(PWMF_ENABLED, &pwm->flags))
94 clk_disable_unprepare(mxs->clk);
99 static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
101 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
104 ret = clk_prepare_enable(mxs->clk);
108 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
113 static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
115 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
117 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
119 clk_disable_unprepare(mxs->clk);
122 static const struct pwm_ops mxs_pwm_ops = {
123 .config = mxs_pwm_config,
124 .enable = mxs_pwm_enable,
125 .disable = mxs_pwm_disable,
126 .owner = THIS_MODULE,
129 static int mxs_pwm_probe(struct platform_device *pdev)
131 struct device_node *np = pdev->dev.of_node;
132 struct mxs_pwm_chip *mxs;
133 struct resource *res;
134 struct pinctrl *pinctrl;
137 mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
141 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
142 mxs->base = devm_request_and_ioremap(&pdev->dev, res);
144 return -EADDRNOTAVAIL;
146 pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
148 return PTR_ERR(pinctrl);
150 mxs->clk = devm_clk_get(&pdev->dev, NULL);
151 if (IS_ERR(mxs->clk))
152 return PTR_ERR(mxs->clk);
154 mxs->chip.dev = &pdev->dev;
155 mxs->chip.ops = &mxs_pwm_ops;
157 ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
159 dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
163 ret = pwmchip_add(&mxs->chip);
165 dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
169 mxs->dev = &pdev->dev;
170 platform_set_drvdata(pdev, mxs);
172 stmp_reset_block(mxs->base);
177 static int __devexit mxs_pwm_remove(struct platform_device *pdev)
179 struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
181 return pwmchip_remove(&mxs->chip);
184 static struct of_device_id mxs_pwm_dt_ids[] = {
185 { .compatible = "fsl,imx23-pwm", },
188 MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids);
190 static struct platform_driver mxs_pwm_driver = {
193 .of_match_table = of_match_ptr(mxs_pwm_dt_ids),
195 .probe = mxs_pwm_probe,
196 .remove = __devexit_p(mxs_pwm_remove),
198 module_platform_driver(mxs_pwm_driver);
200 MODULE_ALIAS("platform:mxs-pwm");
201 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
202 MODULE_DESCRIPTION("Freescale MXS PWM Driver");
203 MODULE_LICENSE("GPL v2");