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_POL_LOW BIT(10)
36 #define ECCTL2_APWM_MODE BIT(9)
37 #define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
38 #define ECCTL2_TSCTR_FREERUN BIT(4)
40 struct ecap_pwm_chip
{
42 unsigned int clk_rate
;
43 void __iomem
*mmio_base
;
46 static inline struct ecap_pwm_chip
*to_ecap_pwm_chip(struct pwm_chip
*chip
)
48 return container_of(chip
, struct ecap_pwm_chip
, chip
);
52 * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
53 * duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
55 static int ecap_pwm_config(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
56 int duty_ns
, int period_ns
)
58 struct ecap_pwm_chip
*pc
= to_ecap_pwm_chip(chip
);
60 unsigned long period_cycles
, duty_cycles
;
63 if (period_ns
> NSEC_PER_SEC
)
68 do_div(c
, NSEC_PER_SEC
);
69 period_cycles
= (unsigned long)c
;
71 if (period_cycles
< 1) {
77 do_div(c
, NSEC_PER_SEC
);
78 duty_cycles
= (unsigned long)c
;
81 pm_runtime_get_sync(pc
->chip
.dev
);
83 reg_val
= readw(pc
->mmio_base
+ ECCTL2
);
85 /* Configure APWM mode & disable sync option */
86 reg_val
|= ECCTL2_APWM_MODE
| ECCTL2_SYNC_SEL_DISA
;
88 writew(reg_val
, pc
->mmio_base
+ ECCTL2
);
90 if (!test_bit(PWMF_ENABLED
, &pwm
->flags
)) {
91 /* Update active registers if not running */
92 writel(duty_cycles
, pc
->mmio_base
+ CAP2
);
93 writel(period_cycles
, pc
->mmio_base
+ CAP1
);
96 * Update shadow registers to configure period and
97 * compare values. This helps current PWM period to
98 * complete on reconfiguring
100 writel(duty_cycles
, pc
->mmio_base
+ CAP4
);
101 writel(period_cycles
, pc
->mmio_base
+ CAP3
);
104 if (!test_bit(PWMF_ENABLED
, &pwm
->flags
)) {
105 reg_val
= readw(pc
->mmio_base
+ ECCTL2
);
106 /* Disable APWM mode to put APWM output Low */
107 reg_val
&= ~ECCTL2_APWM_MODE
;
108 writew(reg_val
, pc
->mmio_base
+ ECCTL2
);
111 pm_runtime_put_sync(pc
->chip
.dev
);
115 static int ecap_pwm_set_polarity(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
116 enum pwm_polarity polarity
)
118 struct ecap_pwm_chip
*pc
= to_ecap_pwm_chip(chip
);
119 unsigned short reg_val
;
121 pm_runtime_get_sync(pc
->chip
.dev
);
122 reg_val
= readw(pc
->mmio_base
+ ECCTL2
);
123 if (polarity
== PWM_POLARITY_INVERSED
)
124 /* Duty cycle defines LOW period of PWM */
125 reg_val
|= ECCTL2_APWM_POL_LOW
;
127 /* Duty cycle defines HIGH period of PWM */
128 reg_val
&= ~ECCTL2_APWM_POL_LOW
;
130 writew(reg_val
, pc
->mmio_base
+ ECCTL2
);
131 pm_runtime_put_sync(pc
->chip
.dev
);
135 static int ecap_pwm_enable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
137 struct ecap_pwm_chip
*pc
= to_ecap_pwm_chip(chip
);
138 unsigned int reg_val
;
140 /* Leave clock enabled on enabling PWM */
141 pm_runtime_get_sync(pc
->chip
.dev
);
144 * Enable 'Free run Time stamp counter mode' to start counter
145 * and 'APWM mode' to enable APWM output
147 reg_val
= readw(pc
->mmio_base
+ ECCTL2
);
148 reg_val
|= ECCTL2_TSCTR_FREERUN
| ECCTL2_APWM_MODE
;
149 writew(reg_val
, pc
->mmio_base
+ ECCTL2
);
153 static void ecap_pwm_disable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
155 struct ecap_pwm_chip
*pc
= to_ecap_pwm_chip(chip
);
156 unsigned int reg_val
;
159 * Disable 'Free run Time stamp counter mode' to stop counter
160 * and 'APWM mode' to put APWM output to low
162 reg_val
= readw(pc
->mmio_base
+ ECCTL2
);
163 reg_val
&= ~(ECCTL2_TSCTR_FREERUN
| ECCTL2_APWM_MODE
);
164 writew(reg_val
, pc
->mmio_base
+ ECCTL2
);
166 /* Disable clock on PWM disable */
167 pm_runtime_put_sync(pc
->chip
.dev
);
170 static void ecap_pwm_free(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
172 if (test_bit(PWMF_ENABLED
, &pwm
->flags
)) {
173 dev_warn(chip
->dev
, "Removing PWM device without disabling\n");
174 pm_runtime_put_sync(chip
->dev
);
178 static const struct pwm_ops ecap_pwm_ops
= {
179 .free
= ecap_pwm_free
,
180 .config
= ecap_pwm_config
,
181 .set_polarity
= ecap_pwm_set_polarity
,
182 .enable
= ecap_pwm_enable
,
183 .disable
= ecap_pwm_disable
,
184 .owner
= THIS_MODULE
,
187 static int __devinit
ecap_pwm_probe(struct platform_device
*pdev
)
192 struct ecap_pwm_chip
*pc
;
194 pc
= devm_kzalloc(&pdev
->dev
, sizeof(*pc
), GFP_KERNEL
);
196 dev_err(&pdev
->dev
, "failed to allocate memory\n");
200 clk
= devm_clk_get(&pdev
->dev
, "fck");
202 dev_err(&pdev
->dev
, "failed to get clock\n");
206 pc
->clk_rate
= clk_get_rate(clk
);
208 dev_err(&pdev
->dev
, "failed to get clock rate\n");
212 pc
->chip
.dev
= &pdev
->dev
;
213 pc
->chip
.ops
= &ecap_pwm_ops
;
217 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
219 dev_err(&pdev
->dev
, "no memory resource defined\n");
223 pc
->mmio_base
= devm_request_and_ioremap(&pdev
->dev
, r
);
225 return -EADDRNOTAVAIL
;
227 ret
= pwmchip_add(&pc
->chip
);
229 dev_err(&pdev
->dev
, "pwmchip_add() failed: %d\n", ret
);
233 pm_runtime_enable(&pdev
->dev
);
234 platform_set_drvdata(pdev
, pc
);
238 static int __devexit
ecap_pwm_remove(struct platform_device
*pdev
)
240 struct ecap_pwm_chip
*pc
= platform_get_drvdata(pdev
);
242 pm_runtime_put_sync(&pdev
->dev
);
243 pm_runtime_disable(&pdev
->dev
);
244 return pwmchip_remove(&pc
->chip
);
247 static struct platform_driver ecap_pwm_driver
= {
251 .probe
= ecap_pwm_probe
,
252 .remove
= __devexit_p(ecap_pwm_remove
),
255 module_platform_driver(ecap_pwm_driver
);
257 MODULE_DESCRIPTION("ECAP PWM driver");
258 MODULE_AUTHOR("Texas Instruments");
259 MODULE_LICENSE("GPL");