4 * Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/module.h>
22 #include <linux/platform_device.h>
24 #include <linux/err.h>
25 #include <linux/clk.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/pwm.h>
29 /* ECAP registers and bits definitions */
35 #define ECCTL2_APWM_MODE BIT(9)
36 #define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
37 #define ECCTL2_TSCTR_FREERUN BIT(4)
39 struct ecap_pwm_chip {
41 unsigned int clk_rate;
42 void __iomem *mmio_base;
45 static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
47 return container_of(chip, struct ecap_pwm_chip, chip);
51 * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
52 * duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
54 static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
55 int duty_ns, int period_ns)
57 struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
59 unsigned long period_cycles, duty_cycles;
62 if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
67 do_div(c, NSEC_PER_SEC);
68 period_cycles = (unsigned long)c;
70 if (period_cycles < 1) {
76 do_div(c, NSEC_PER_SEC);
77 duty_cycles = (unsigned long)c;
80 pm_runtime_get_sync(pc->chip.dev);
82 reg_val = readw(pc->mmio_base + ECCTL2);
84 /* Configure APWM mode & disable sync option */
85 reg_val |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
87 writew(reg_val, pc->mmio_base + ECCTL2);
89 if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
90 /* Update active registers if not running */
91 writel(duty_cycles, pc->mmio_base + CAP2);
92 writel(period_cycles, pc->mmio_base + CAP1);
95 * Update shadow registers to configure period and
96 * compare values. This helps current PWM period to
97 * complete on reconfiguring
99 writel(duty_cycles, pc->mmio_base + CAP4);
100 writel(period_cycles, pc->mmio_base + CAP3);
103 pm_runtime_put_sync(pc->chip.dev);
107 static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
109 struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
110 unsigned int reg_val;
112 /* Leave clock enabled on enabling PWM */
113 pm_runtime_get_sync(pc->chip.dev);
116 * Enable 'Free run Time stamp counter mode' to start counter
117 * and 'APWM mode' to enable APWM output
119 reg_val = readw(pc->mmio_base + ECCTL2);
120 reg_val |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
121 writew(reg_val, pc->mmio_base + ECCTL2);
125 static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
127 struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
128 unsigned int reg_val;
131 * Disable 'Free run Time stamp counter mode' to stop counter
132 * and 'APWM mode' to put APWM output to low
134 reg_val = readw(pc->mmio_base + ECCTL2);
135 reg_val &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
136 writew(reg_val, pc->mmio_base + ECCTL2);
138 /* Disable clock on PWM disable */
139 pm_runtime_put_sync(pc->chip.dev);
142 static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
144 if (test_bit(PWMF_ENABLED, &pwm->flags)) {
145 dev_warn(chip->dev, "Removing PWM device without disabling\n");
146 pm_runtime_put_sync(chip->dev);
150 static const struct pwm_ops ecap_pwm_ops = {
151 .free = ecap_pwm_free,
152 .config = ecap_pwm_config,
153 .enable = ecap_pwm_enable,
154 .disable = ecap_pwm_disable,
155 .owner = THIS_MODULE,
158 static int __devinit ecap_pwm_probe(struct platform_device *pdev)
163 struct ecap_pwm_chip *pc;
165 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
167 dev_err(&pdev->dev, "failed to allocate memory\n");
171 clk = devm_clk_get(&pdev->dev, "fck");
173 dev_err(&pdev->dev, "failed to get clock\n");
177 pc->clk_rate = clk_get_rate(clk);
179 dev_err(&pdev->dev, "failed to get clock rate\n");
183 pc->chip.dev = &pdev->dev;
184 pc->chip.ops = &ecap_pwm_ops;
188 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
190 dev_err(&pdev->dev, "no memory resource defined\n");
194 pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
196 return -EADDRNOTAVAIL;
198 ret = pwmchip_add(&pc->chip);
200 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
204 pm_runtime_enable(&pdev->dev);
205 platform_set_drvdata(pdev, pc);
209 static int __devexit ecap_pwm_remove(struct platform_device *pdev)
211 struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
213 pm_runtime_put_sync(&pdev->dev);
214 pm_runtime_disable(&pdev->dev);
215 return pwmchip_remove(&pc->chip);
218 static struct platform_driver ecap_pwm_driver = {
222 .probe = ecap_pwm_probe,
223 .remove = __devexit_p(ecap_pwm_remove),
226 module_platform_driver(ecap_pwm_driver);
228 MODULE_DESCRIPTION("ECAP PWM driver");
229 MODULE_AUTHOR("Texas Instruments");
230 MODULE_LICENSE("GPL");