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"); 271