2 * Intel Low Power Subsystem PWM controller driver
4 * Copyright (C) 2014, Intel Corporation
5 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
6 * Author: Chew Kean Ho <kean.ho.chew@intel.com>
7 * Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
8 * Author: Chew Chiau Ee <chiau.ee.chew@intel.com>
9 * Author: Alan Cox <alan@linux.intel.com>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
16 #include <linux/acpi.h>
17 #include <linux/device.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/pwm.h>
21 #include <linux/platform_device.h>
22 #include <linux/pci.h>
24 static int pci_drv
, plat_drv
; /* So we know which drivers registered */
26 #define PWM 0x00000000
27 #define PWM_ENABLE BIT(31)
28 #define PWM_SW_UPDATE BIT(30)
29 #define PWM_BASE_UNIT_SHIFT 8
30 #define PWM_BASE_UNIT_MASK 0x00ffff00
31 #define PWM_ON_TIME_DIV_MASK 0x000000ff
32 #define PWM_DIVISION_CORRECTION 0x2
33 #define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION)
34 #define NSECS_PER_SEC 1000000000UL
36 struct pwm_lpss_chip
{
39 unsigned long clk_rate
;
42 struct pwm_lpss_boardinfo
{
43 unsigned long clk_rate
;
47 static const struct pwm_lpss_boardinfo byt_info
= {
51 static inline struct pwm_lpss_chip
*to_lpwm(struct pwm_chip
*chip
)
53 return container_of(chip
, struct pwm_lpss_chip
, chip
);
56 static int pwm_lpss_config(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
57 int duty_ns
, int period_ns
)
59 struct pwm_lpss_chip
*lpwm
= to_lpwm(chip
);
62 unsigned long long base_unit
, freq
= NSECS_PER_SEC
;
65 do_div(freq
, period_ns
);
67 /* The equation is: base_unit = ((freq / c) * 65536) + correction */
68 base_unit
= freq
* 65536;
75 base_unit
+= PWM_DIVISION_CORRECTION
;
76 if (base_unit
> PWM_LIMIT
)
81 on_time_div
= 255 - (255 * duty_ns
/ period_ns
);
83 ctrl
= readl(lpwm
->regs
+ PWM
);
84 ctrl
&= ~(PWM_BASE_UNIT_MASK
| PWM_ON_TIME_DIV_MASK
);
85 ctrl
|= (u16
) base_unit
<< PWM_BASE_UNIT_SHIFT
;
87 /* request PWM to update on next cycle */
88 ctrl
|= PWM_SW_UPDATE
;
89 writel(ctrl
, lpwm
->regs
+ PWM
);
94 static int pwm_lpss_enable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
96 struct pwm_lpss_chip
*lpwm
= to_lpwm(chip
);
99 ctrl
= readl(lpwm
->regs
+ PWM
);
100 writel(ctrl
| PWM_ENABLE
, lpwm
->regs
+ PWM
);
105 static void pwm_lpss_disable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
107 struct pwm_lpss_chip
*lpwm
= to_lpwm(chip
);
110 ctrl
= readl(lpwm
->regs
+ PWM
);
111 writel(ctrl
& ~PWM_ENABLE
, lpwm
->regs
+ PWM
);
114 static const struct pwm_ops pwm_lpss_ops
= {
115 .config
= pwm_lpss_config
,
116 .enable
= pwm_lpss_enable
,
117 .disable
= pwm_lpss_disable
,
118 .owner
= THIS_MODULE
,
121 static struct pwm_lpss_chip
*pwm_lpss_probe(struct device
*dev
,
123 const struct pwm_lpss_boardinfo
*info
)
125 struct pwm_lpss_chip
*lpwm
;
128 lpwm
= devm_kzalloc(dev
, sizeof(*lpwm
), GFP_KERNEL
);
130 return ERR_PTR(-ENOMEM
);
132 lpwm
->regs
= devm_ioremap_resource(dev
, r
);
133 if (IS_ERR(lpwm
->regs
))
134 return ERR_CAST(lpwm
->regs
);
136 lpwm
->clk_rate
= info
->clk_rate
;
137 lpwm
->chip
.dev
= dev
;
138 lpwm
->chip
.ops
= &pwm_lpss_ops
;
139 lpwm
->chip
.base
= -1;
142 ret
= pwmchip_add(&lpwm
->chip
);
144 dev_err(dev
, "failed to add PWM chip: %d\n", ret
);
151 static int pwm_lpss_remove(struct pwm_lpss_chip
*lpwm
)
155 ctrl
= readl(lpwm
->regs
+ PWM
);
156 writel(ctrl
& ~PWM_ENABLE
, lpwm
->regs
+ PWM
);
158 return pwmchip_remove(&lpwm
->chip
);
161 static int pwm_lpss_probe_pci(struct pci_dev
*pdev
,
162 const struct pci_device_id
*id
)
164 const struct pwm_lpss_boardinfo
*info
;
165 struct pwm_lpss_chip
*lpwm
;
168 err
= pci_enable_device(pdev
);
172 info
= (struct pwm_lpss_boardinfo
*)id
->driver_data
;
173 lpwm
= pwm_lpss_probe(&pdev
->dev
, &pdev
->resource
[0], info
);
175 return PTR_ERR(lpwm
);
177 pci_set_drvdata(pdev
, lpwm
);
181 static void pwm_lpss_remove_pci(struct pci_dev
*pdev
)
183 struct pwm_lpss_chip
*lpwm
= pci_get_drvdata(pdev
);
185 pwm_lpss_remove(lpwm
);
186 pci_disable_device(pdev
);
189 static struct pci_device_id pwm_lpss_pci_ids
[] = {
190 { PCI_VDEVICE(INTEL
, 0x0f08), (unsigned long)&byt_info
},
191 { PCI_VDEVICE(INTEL
, 0x0f09), (unsigned long)&byt_info
},
194 MODULE_DEVICE_TABLE(pci
, pwm_lpss_pci_ids
);
196 static struct pci_driver pwm_lpss_driver_pci
= {
198 .id_table
= pwm_lpss_pci_ids
,
199 .probe
= pwm_lpss_probe_pci
,
200 .remove
= pwm_lpss_remove_pci
,
203 static int pwm_lpss_probe_platform(struct platform_device
*pdev
)
205 const struct pwm_lpss_boardinfo
*info
;
206 const struct acpi_device_id
*id
;
207 struct pwm_lpss_chip
*lpwm
;
210 id
= acpi_match_device(pdev
->dev
.driver
->acpi_match_table
, &pdev
->dev
);
214 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
216 info
= (struct pwm_lpss_boardinfo
*)id
->driver_data
;
217 lpwm
= pwm_lpss_probe(&pdev
->dev
, r
, info
);
219 return PTR_ERR(lpwm
);
221 platform_set_drvdata(pdev
, lpwm
);
225 static int pwm_lpss_remove_platform(struct platform_device
*pdev
)
227 struct pwm_lpss_chip
*lpwm
= platform_get_drvdata(pdev
);
229 return pwm_lpss_remove(lpwm
);
232 static const struct acpi_device_id pwm_lpss_acpi_match
[] = {
233 { "80860F09", (unsigned long)&byt_info
},
236 MODULE_DEVICE_TABLE(acpi
, pwm_lpss_acpi_match
);
238 static struct platform_driver pwm_lpss_driver_platform
= {
241 .acpi_match_table
= pwm_lpss_acpi_match
,
243 .probe
= pwm_lpss_probe_platform
,
244 .remove
= pwm_lpss_remove_platform
,
247 static int __init
pwm_init(void)
249 pci_drv
= pci_register_driver(&pwm_lpss_driver_pci
);
250 plat_drv
= platform_driver_register(&pwm_lpss_driver_platform
);
251 if (pci_drv
&& plat_drv
)
256 module_init(pwm_init
);
258 static void __exit
pwm_exit(void)
261 pci_unregister_driver(&pwm_lpss_driver_pci
);
263 platform_driver_unregister(&pwm_lpss_driver_platform
);
265 module_exit(pwm_exit
);
267 MODULE_DESCRIPTION("PWM driver for Intel LPSS");
268 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
269 MODULE_LICENSE("GPL v2");
270 MODULE_ALIAS("platform:pwm-lpss");