2 * drivers/pwm/pwm-pxa.c
4 * simple driver for PWM (Pulse Width Modulator) controller
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * 2008-02-13 initial version
11 * eric miao <eric.miao@marvell.com>
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/err.h>
19 #include <linux/clk.h>
21 #include <linux/pwm.h>
23 #include <asm/div64.h>
25 #define HAS_SECONDARY_PWM 0x10
26 #define PWM_ID_BASE(d) ((d) & 0xf)
28 static const struct platform_device_id pwm_id_table
[] = {
29 /* PWM has_secondary_pwm? */
31 { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM
},
36 MODULE_DEVICE_TABLE(platform
, pwm_id_table
);
38 /* PWM registers and bits definitions */
43 #define PWMCR_SD (1 << 6)
44 #define PWMDCR_FD (1 << 10)
51 void __iomem
*mmio_base
;
54 static inline struct pxa_pwm_chip
*to_pxa_pwm_chip(struct pwm_chip
*chip
)
56 return container_of(chip
, struct pxa_pwm_chip
, chip
);
60 * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
61 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
63 static int pxa_pwm_config(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
64 int duty_ns
, int period_ns
)
66 struct pxa_pwm_chip
*pc
= to_pxa_pwm_chip(chip
);
68 unsigned long period_cycles
, prescale
, pv
, dc
;
72 offset
= pwm
->hwpwm
? 0x10 : 0;
74 c
= clk_get_rate(pc
->clk
);
76 do_div(c
, 1000000000);
79 if (period_cycles
< 1)
81 prescale
= (period_cycles
- 1) / 1024;
82 pv
= period_cycles
/ (prescale
+ 1) - 1;
87 if (duty_ns
== period_ns
)
90 dc
= (pv
+ 1) * duty_ns
/ period_ns
;
92 /* NOTE: the clock to PWM has to be enabled first
93 * before writing to the registers
95 rc
= clk_prepare_enable(pc
->clk
);
99 writel(prescale
, pc
->mmio_base
+ offset
+ PWMCR
);
100 writel(dc
, pc
->mmio_base
+ offset
+ PWMDCR
);
101 writel(pv
, pc
->mmio_base
+ offset
+ PWMPCR
);
103 clk_disable_unprepare(pc
->clk
);
107 static int pxa_pwm_enable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
109 struct pxa_pwm_chip
*pc
= to_pxa_pwm_chip(chip
);
111 return clk_prepare_enable(pc
->clk
);
114 static void pxa_pwm_disable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
116 struct pxa_pwm_chip
*pc
= to_pxa_pwm_chip(chip
);
118 clk_disable_unprepare(pc
->clk
);
121 static struct pwm_ops pxa_pwm_ops
= {
122 .config
= pxa_pwm_config
,
123 .enable
= pxa_pwm_enable
,
124 .disable
= pxa_pwm_disable
,
125 .owner
= THIS_MODULE
,
128 static int pwm_probe(struct platform_device
*pdev
)
130 const struct platform_device_id
*id
= platform_get_device_id(pdev
);
131 struct pxa_pwm_chip
*pwm
;
135 pwm
= devm_kzalloc(&pdev
->dev
, sizeof(*pwm
), GFP_KERNEL
);
137 dev_err(&pdev
->dev
, "failed to allocate memory\n");
141 pwm
->clk
= devm_clk_get(&pdev
->dev
, NULL
);
142 if (IS_ERR(pwm
->clk
))
143 return PTR_ERR(pwm
->clk
);
145 pwm
->chip
.dev
= &pdev
->dev
;
146 pwm
->chip
.ops
= &pxa_pwm_ops
;
148 pwm
->chip
.npwm
= (id
->driver_data
& HAS_SECONDARY_PWM
) ? 2 : 1;
150 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
152 dev_err(&pdev
->dev
, "no memory resource defined\n");
156 pwm
->mmio_base
= devm_ioremap_resource(&pdev
->dev
, r
);
157 if (IS_ERR(pwm
->mmio_base
))
158 return PTR_ERR(pwm
->mmio_base
);
160 ret
= pwmchip_add(&pwm
->chip
);
162 dev_err(&pdev
->dev
, "pwmchip_add() failed: %d\n", ret
);
166 platform_set_drvdata(pdev
, pwm
);
170 static int pwm_remove(struct platform_device
*pdev
)
172 struct pxa_pwm_chip
*chip
;
174 chip
= platform_get_drvdata(pdev
);
178 return pwmchip_remove(&chip
->chip
);
181 static struct platform_driver pwm_driver
= {
183 .name
= "pxa25x-pwm",
184 .owner
= THIS_MODULE
,
187 .remove
= pwm_remove
,
188 .id_table
= pwm_id_table
,
191 static int __init
pwm_init(void)
193 return platform_driver_register(&pwm_driver
);
195 arch_initcall(pwm_init
);
197 static void __exit
pwm_exit(void)
199 platform_driver_unregister(&pwm_driver
);
201 module_exit(pwm_exit
);
203 MODULE_LICENSE("GPL v2");