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");