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
);
195 if (!pc
->mmio_base
) {
196 dev_err(&pdev
->dev
, "failed to ioremap() registers\n");
197 return -EADDRNOTAVAIL
;
200 ret
= pwmchip_add(&pc
->chip
);
202 dev_err(&pdev
->dev
, "pwmchip_add() failed: %d\n", ret
);
206 pm_runtime_enable(&pdev
->dev
);
207 platform_set_drvdata(pdev
, pc
);
211 static int __devexit
ecap_pwm_remove(struct platform_device
*pdev
)
213 struct ecap_pwm_chip
*pc
= platform_get_drvdata(pdev
);
215 pm_runtime_put_sync(&pdev
->dev
);
216 pm_runtime_disable(&pdev
->dev
);
217 return pwmchip_remove(&pc
->chip
);
220 static struct platform_driver ecap_pwm_driver
= {
224 .probe
= ecap_pwm_probe
,
225 .remove
= __devexit_p(ecap_pwm_remove
),
228 module_platform_driver(ecap_pwm_driver
);
230 MODULE_DESCRIPTION("ECAP PWM driver");
231 MODULE_AUTHOR("Texas Instruments");
232 MODULE_LICENSE("GPL");