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 static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
  52 {
  53         return container_of(chip, struct pwm_lpss_chip, chip);
  54 }
  55
  56 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
  57                            int duty_ns, int period_ns)
  58 {
  59         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
  60         u8 on_time_div;
  61         unsigned long c;
  62         unsigned long long base_unit, freq = NSECS_PER_SEC;
  63         u32 ctrl;
  64
  65         do_div(freq, period_ns);
  66
  67         /* The equation is: base_unit = ((freq / c) * 65536) + correction */
  68         base_unit = freq * 65536;
  69
  70         c = lpwm->clk_rate;
  71         if (!c)
  72                 return -EINVAL;
  73
  74         do_div(base_unit, c);
  75         base_unit += PWM_DIVISION_CORRECTION;
  76         if (base_unit > PWM_LIMIT)
  77                 return -EINVAL;
  78
  79         if (duty_ns <= 0)
  80                 duty_ns = 1;
  81         on_time_div = 255 - (255 * duty_ns / period_ns);
  82
  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;
  86         ctrl |= on_time_div;
  87         /* request PWM to update on next cycle */
  88         ctrl |= PWM_SW_UPDATE;
  89         writel(ctrl, lpwm->regs + PWM);
  90
  91         return 0;
  92 }
  93
  94 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  95 {
  96         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
  97         u32 ctrl;
  98
  99         ctrl = readl(lpwm->regs + PWM);
 100         writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
 101
 102         return 0;
 103 }
 104
 105 static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 106 {
 107         struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 108         u32 ctrl;
 109
 110         ctrl = readl(lpwm->regs + PWM);
 111         writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
 112 }
 113
 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,
 119 };
 120
 121 static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
 122                                             struct resource *r,
 123                                             const struct pwm_lpss_boardinfo *info)
 124 {
 125         struct pwm_lpss_chip *lpwm;
 126         int ret;
 127
 128         lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
 129         if (!lpwm)
 130                 return ERR_PTR(-ENOMEM);
 131
 132         lpwm->regs = devm_ioremap_resource(dev, r);
 133         if (IS_ERR(lpwm->regs))
 134                 return ERR_CAST(lpwm->regs);
 135
 136         lpwm->clk_rate = info->clk_rate;
 137         lpwm->chip.dev = dev;
 138         lpwm->chip.ops = &pwm_lpss_ops;
 139         lpwm->chip.base = -1;
 140         lpwm->chip.npwm = 1;
 141
 142         ret = pwmchip_add(&lpwm->chip);
 143         if (ret) {
 144                 dev_err(dev, "failed to add PWM chip: %d\n", ret);
 145                 return ERR_PTR(ret);
 146         }
 147
 148         return lpwm;
 149 }
 150
 151 static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
 152 {
 153         u32 ctrl;
 154
 155         ctrl = readl(lpwm->regs + PWM);
 156         writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
 157
 158         return pwmchip_remove(&lpwm->chip);
 159 }
 160
 161 static int pwm_lpss_probe_pci(struct pci_dev *pdev,
 162                               const struct pci_device_id *id)
 163 {
 164         const struct pwm_lpss_boardinfo *info;
 165         struct pwm_lpss_chip *lpwm;
 166         int err;
 167
 168         err = pci_enable_device(pdev);
 169         if (err < 0)
 170                 return err;
 171
 172         info = (struct pwm_lpss_boardinfo *)id->driver_data;
 173         lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
 174         if (IS_ERR(lpwm))
 175                 return PTR_ERR(lpwm);
 176
 177         pci_set_drvdata(pdev, lpwm);
 178         return 0;
 179 }
 180
 181 static void pwm_lpss_remove_pci(struct pci_dev *pdev)
 182 {
 183         struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
 184
 185         pwm_lpss_remove(lpwm);
 186         pci_disable_device(pdev);
 187 }
 188
 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},
 192         { },
 193 };
 194 MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
 195
 196 static struct pci_driver pwm_lpss_driver_pci = {
 197         .name = "pwm-lpss",
 198         .id_table = pwm_lpss_pci_ids,
 199         .probe = pwm_lpss_probe_pci,
 200         .remove = pwm_lpss_remove_pci,
 201 };
 202
 203 static int pwm_lpss_probe_platform(struct platform_device *pdev)
 204 {
 205         const struct pwm_lpss_boardinfo *info;
 206         const struct acpi_device_id *id;
 207         struct pwm_lpss_chip *lpwm;
 208         struct resource *r;
 209
 210         id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
 211         if (!id)
 212                 return -ENODEV;
 213
 214         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 215
 216         info = (struct pwm_lpss_boardinfo *)id->driver_data;
 217         lpwm = pwm_lpss_probe(&pdev->dev, r, info);
 218         if (IS_ERR(lpwm))
 219                 return PTR_ERR(lpwm);
 220
 221         platform_set_drvdata(pdev, lpwm);
 222         return 0;
 223 }
 224
 225 static int pwm_lpss_remove_platform(struct platform_device *pdev)
 226 {
 227         struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
 228
 229         return pwm_lpss_remove(lpwm);
 230 }
 231
 232 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
 233         { "80860F09", (unsigned long)&byt_info },
 234         { },
 235 };
 236 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
 237
 238 static struct platform_driver pwm_lpss_driver_platform = {
 239         .driver = {
 240                 .name = "pwm-lpss",
 241                 .acpi_match_table = pwm_lpss_acpi_match,
 242         },
 243         .probe = pwm_lpss_probe_platform,
 244         .remove = pwm_lpss_remove_platform,
 245 };
 246
 247 static int __init pwm_init(void)
 248 {
 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)
 252                 return pci_drv;
 253
 254         return 0;
 255 }
 256 module_init(pwm_init);
 257
 258 static void __exit pwm_exit(void)
 259 {
 260         if (!pci_drv)
 261                 pci_unregister_driver(&pwm_lpss_driver_pci);
 262         if (!plat_drv)
 263                 platform_driver_unregister(&pwm_lpss_driver_platform);
 264 }
 265 module_exit(pwm_exit);
 266
 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");