drivers/pwm/pwm-lpss.c

   1 /*
   2  * Intel Low Power Subsystem PWM controller driver
   3  *
   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>
  10  *
  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.
  14  */
  15
  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>
  23
  24 static int pci_drv, plat_drv;   /* So we know which drivers registered */
  25
  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
  35
  36 struct pwm_lpss_chip {
  37         struct pwm_chip chip;
  38         void __iomem *regs;
  39         unsigned long clk_rate;
  40 };
  41
  42 struct pwm_lpss_boardinfo {
  43         unsigned long clk_rate;
  44 };
  45
  46 /* BayTrail */
  47 static const struct pwm_lpss_boardinfo byt_info = {
  48         25000000
  49 };
  50
  51 /* Braswell */
  52 static const struct pwm_lpss_boardinfo bsw_info = {
  53         19200000
  54 };
  55
  56 static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
  57 {
  58         return container_of(chip, struct pwm_lpss_chip, chip);
  59 }
  60
  61 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
  62                            int duty_ns, int period_ns)
  63 {
  64         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
  65         u8 on_time_div;
  66         unsigned long c;
  67         unsigned long long base_unit, freq = NSECS_PER_SEC;
  68         u32 ctrl;
  69
  70         do_div(freq, period_ns);
  71
  72         /* The equation is: base_unit = ((freq / c) * 65536) + correction */
  73         base_unit = freq * 65536;
  74
  75         c = lpwm->clk_rate;
  76         if (!c)
  77                 return -EINVAL;
  78
  79         do_div(base_unit, c);
  80         base_unit += PWM_DIVISION_CORRECTION;
  81         if (base_unit > PWM_LIMIT)
  82                 return -EINVAL;
  83
  84         if (duty_ns <= 0)
  85                 duty_ns = 1;
  86         on_time_div = 255 - (255 * duty_ns / period_ns);
  87
  88         ctrl = readl(lpwm->regs + PWM);
  89         ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
  90         ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
  91         ctrl |= on_time_div;
  92         /* request PWM to update on next cycle */
  93         ctrl |= PWM_SW_UPDATE;
  94         writel(ctrl, lpwm->regs + PWM);
  95
  96         return 0;
  97 }
  98
  99 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 100 {
 101         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 102         u32 ctrl;
 103
 104         ctrl = readl(lpwm->regs + PWM);
 105         writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
 106
 107         return 0;
 108 }
 109
 110 static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 111 {
 112         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 113         u32 ctrl;
 114
 115         ctrl = readl(lpwm->regs + PWM);
 116         writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
 117 }
 118
 119 static const struct pwm_ops pwm_lpss_ops = {
 120         .config = pwm_lpss_config,
 121         .enable = pwm_lpss_enable,
 122         .disable = pwm_lpss_disable,
 123         .owner = THIS_MODULE,
 124 };
 125
 126 static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
 127                                             struct resource *r,
 128                                             const struct pwm_lpss_boardinfo *info)
 129 {
 130         struct pwm_lpss_chip *lpwm;
 131         int ret;
 132
 133         lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
 134         if (!lpwm)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         lpwm->regs = devm_ioremap_resource(dev, r);
 138         if (IS_ERR(lpwm->regs))
 139                 return ERR_CAST(lpwm->regs);
 140
 141         lpwm->clk_rate = info->clk_rate;
 142         lpwm->chip.dev = dev;
 143         lpwm->chip.ops = &pwm_lpss_ops;
 144         lpwm->chip.base = -1;
 145         lpwm->chip.npwm = 1;
 146
 147         ret = pwmchip_add(&lpwm->chip);
 148         if (ret) {
 149                 dev_err(dev, "failed to add PWM chip: %d\n", ret);
 150                 return ERR_PTR(ret);
 151         }
 152
 153         return lpwm;
 154 }
 155
 156 static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
 157 {
 158         u32 ctrl;
 159
 160         ctrl = readl(lpwm->regs + PWM);
 161         writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
 162
 163         return pwmchip_remove(&lpwm->chip);
 164 }
 165
 166 static int pwm_lpss_probe_pci(struct pci_dev *pdev,
 167                               const struct pci_device_id *id)
 168 {
 169         const struct pwm_lpss_boardinfo *info;
 170         struct pwm_lpss_chip *lpwm;
 171         int err;
 172
 173         err = pci_enable_device(pdev);
 174         if (err < 0)
 175                 return err;
 176
 177         info = (struct pwm_lpss_boardinfo *)id->driver_data;
 178         lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
 179         if (IS_ERR(lpwm))
 180                 return PTR_ERR(lpwm);
 181
 182         pci_set_drvdata(pdev, lpwm);
 183         return 0;
 184 }
 185
 186 static void pwm_lpss_remove_pci(struct pci_dev *pdev)
 187 {
 188         struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
 189
 190         pwm_lpss_remove(lpwm);
 191         pci_disable_device(pdev);
 192 }
 193
 194 static struct pci_device_id pwm_lpss_pci_ids[] = {
 195         { PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&byt_info},
 196         { PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&byt_info},
 197         { PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&bsw_info},
 198         { PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&bsw_info},
 199         { },
 200 };
 201 MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
 202
 203 static struct pci_driver pwm_lpss_driver_pci = {
 204         .name = "pwm-lpss",
 205         .id_table = pwm_lpss_pci_ids,
 206         .probe = pwm_lpss_probe_pci,
 207         .remove = pwm_lpss_remove_pci,
 208 };
 209
 210 static int pwm_lpss_probe_platform(struct platform_device *pdev)
 211 {
 212         const struct pwm_lpss_boardinfo *info;
 213         const struct acpi_device_id *id;
 214         struct pwm_lpss_chip *lpwm;
 215         struct resource *r;
 216
 217         id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
 218         if (!id)
 219                 return -ENODEV;
 220
 221         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 222
 223         info = (struct pwm_lpss_boardinfo *)id->driver_data;
 224         lpwm = pwm_lpss_probe(&pdev->dev, r, info);
 225         if (IS_ERR(lpwm))
 226                 return PTR_ERR(lpwm);
 227
 228         platform_set_drvdata(pdev, lpwm);
 229         return 0;
 230 }
 231
 232 static int pwm_lpss_remove_platform(struct platform_device *pdev)
 233 {
 234         struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
 235
 236         return pwm_lpss_remove(lpwm);
 237 }
 238
 239 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
 240         { "80860F09", (unsigned long)&byt_info },
 241         { "80862288", (unsigned long)&bsw_info },
 242         { },
 243 };
 244 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
 245
 246 static struct platform_driver pwm_lpss_driver_platform = {
 247         .driver = {
 248                 .name = "pwm-lpss",
 249                 .acpi_match_table = pwm_lpss_acpi_match,
 250         },
 251         .probe = pwm_lpss_probe_platform,
 252         .remove = pwm_lpss_remove_platform,
 253 };
 254
 255 static int __init pwm_init(void)
 256 {
 257         pci_drv = pci_register_driver(&pwm_lpss_driver_pci);
 258         plat_drv = platform_driver_register(&pwm_lpss_driver_platform);
 259         if (pci_drv && plat_drv)
 260                 return pci_drv;
 261
 262         return 0;
 263 }
 264 module_init(pwm_init);
 265
 266 static void __exit pwm_exit(void)
 267 {
 268         if (!pci_drv)
 269                 pci_unregister_driver(&pwm_lpss_driver_pci);
 270         if (!plat_drv)
 271                 platform_driver_unregister(&pwm_lpss_driver_platform);
 272 }
 273 module_exit(pwm_exit);
 274
 275 MODULE_DESCRIPTION("PWM driver for Intel LPSS");
 276 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
 277 MODULE_LICENSE("GPL v2");
 278 MODULE_ALIAS("platform:pwm-lpss");