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/clk.h> 18 #include <linux/device.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/pwm.h> 22 #include <linux/platform_device.h> 23 #include <linux/pci.h> 24 25 static int pci_drv, plat_drv; /* So we know which drivers registered */ 26 27 #define PWM 0x00000000 28 #define PWM_ENABLE BIT(31) 29 #define PWM_SW_UPDATE BIT(30) 30 #define PWM_BASE_UNIT_SHIFT 8 31 #define PWM_BASE_UNIT_MASK 0x00ffff00 32 #define PWM_ON_TIME_DIV_MASK 0x000000ff 33 #define PWM_DIVISION_CORRECTION 0x2 34 #define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION) 35 #define NSECS_PER_SEC 1000000000UL 36 37 struct pwm_lpss_chip { 38 struct pwm_chip chip; 39 void __iomem *regs; 40 struct clk *clk; 41 unsigned long clk_rate; 42 }; 43 44 struct pwm_lpss_boardinfo { 45 unsigned long clk_rate; 46 }; 47 48 /* BayTrail */ 49 static const struct pwm_lpss_boardinfo byt_info = { 50 25000000 51 }; 52 53 static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip) 54 { 55 return container_of(chip, struct pwm_lpss_chip, chip); 56 } 57 58 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm, 59 int duty_ns, int period_ns) 60 { 61 struct pwm_lpss_chip *lpwm = to_lpwm(chip); 62 u8 on_time_div; 63 unsigned long c; 64 unsigned long long base_unit, freq = NSECS_PER_SEC; 65 u32 ctrl; 66 67 do_div(freq, period_ns); 68 69 /* The equation is: base_unit = ((freq / c) * 65536) + correction */ 70 base_unit = freq * 65536; 71 72 c = lpwm->clk_rate; 73 if (!c) 74 return -EINVAL; 75 76 do_div(base_unit, c); 77 base_unit += PWM_DIVISION_CORRECTION; 78 if (base_unit > PWM_LIMIT) 79 return -EINVAL; 80 81 if (duty_ns <= 0) 82 duty_ns = 1; 83 on_time_div = 255 - (255 * duty_ns / period_ns); 84 85 ctrl = readl(lpwm->regs + PWM); 86 ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK); 87 ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT; 88 ctrl |= on_time_div; 89 /* request PWM to update on next cycle */ 90 ctrl |= PWM_SW_UPDATE; 91 writel(ctrl, lpwm->regs + PWM); 92 93 return 0; 94 } 95 96 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm) 97 { 98 struct pwm_lpss_chip *lpwm = to_lpwm(chip); 99 u32 ctrl; 100 int ret; 101 102 ret = clk_prepare_enable(lpwm->clk); 103 if (ret) 104 return ret; 105 106 ctrl = readl(lpwm->regs + PWM); 107 writel(ctrl | PWM_ENABLE, lpwm->regs + PWM); 108 109 return 0; 110 } 111 112 static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm) 113 { 114 struct pwm_lpss_chip *lpwm = to_lpwm(chip); 115 u32 ctrl; 116 117 ctrl = readl(lpwm->regs + PWM); 118 writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); 119 120 clk_disable_unprepare(lpwm->clk); 121 } 122 123 static const struct pwm_ops pwm_lpss_ops = { 124 .config = pwm_lpss_config, 125 .enable = pwm_lpss_enable, 126 .disable = pwm_lpss_disable, 127 .owner = THIS_MODULE, 128 }; 129 130 static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, 131 struct resource *r, 132 const struct pwm_lpss_boardinfo *info) 133 { 134 struct pwm_lpss_chip *lpwm; 135 int ret; 136 137 lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL); 138 if (!lpwm) 139 return ERR_PTR(-ENOMEM); 140 141 lpwm->regs = devm_ioremap_resource(dev, r); 142 if (IS_ERR(lpwm->regs)) 143 return ERR_CAST(lpwm->regs); 144 145 if (info) { 146 lpwm->clk_rate = info->clk_rate; 147 } else { 148 lpwm->clk = devm_clk_get(dev, NULL); 149 if (IS_ERR(lpwm->clk)) { 150 dev_err(dev, "failed to get PWM clock\n"); 151 return ERR_CAST(lpwm->clk); 152 } 153 lpwm->clk_rate = clk_get_rate(lpwm->clk); 154 } 155 156 lpwm->chip.dev = dev; 157 lpwm->chip.ops = &pwm_lpss_ops; 158 lpwm->chip.base = -1; 159 lpwm->chip.npwm = 1; 160 161 ret = pwmchip_add(&lpwm->chip); 162 if (ret) { 163 dev_err(dev, "failed to add PWM chip: %d\n", ret); 164 return ERR_PTR(ret); 165 } 166 167 return lpwm; 168 } 169 170 static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm) 171 { 172 u32 ctrl; 173 174 ctrl = readl(lpwm->regs + PWM); 175 writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM); 176 177 return pwmchip_remove(&lpwm->chip); 178 } 179 180 static int pwm_lpss_probe_pci(struct pci_dev *pdev, 181 const struct pci_device_id *id) 182 { 183 const struct pwm_lpss_boardinfo *info; 184 struct pwm_lpss_chip *lpwm; 185 int err; 186 187 err = pci_enable_device(pdev); 188 if (err < 0) 189 return err; 190 191 info = (struct pwm_lpss_boardinfo *)id->driver_data; 192 lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info); 193 if (IS_ERR(lpwm)) 194 return PTR_ERR(lpwm); 195 196 pci_set_drvdata(pdev, lpwm); 197 return 0; 198 } 199 200 static void pwm_lpss_remove_pci(struct pci_dev *pdev) 201 { 202 struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev); 203 204 pwm_lpss_remove(lpwm); 205 pci_disable_device(pdev); 206 } 207 208 static struct pci_device_id pwm_lpss_pci_ids[] = { 209 { PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&byt_info}, 210 { PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&byt_info}, 211 { }, 212 }; 213 MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids); 214 215 static struct pci_driver pwm_lpss_driver_pci = { 216 .name = "pwm-lpss", 217 .id_table = pwm_lpss_pci_ids, 218 .probe = pwm_lpss_probe_pci, 219 .remove = pwm_lpss_remove_pci, 220 }; 221 222 static int pwm_lpss_probe_platform(struct platform_device *pdev) 223 { 224 struct pwm_lpss_chip *lpwm; 225 struct resource *r; 226 227 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 228 229 lpwm = pwm_lpss_probe(&pdev->dev, r, NULL); 230 if (IS_ERR(lpwm)) 231 return PTR_ERR(lpwm); 232 233 platform_set_drvdata(pdev, lpwm); 234 return 0; 235 } 236 237 static int pwm_lpss_remove_platform(struct platform_device *pdev) 238 { 239 struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev); 240 241 return pwm_lpss_remove(lpwm); 242 } 243 244 static const struct acpi_device_id pwm_lpss_acpi_match[] = { 245 { "80860F09", 0 }, 246 { }, 247 }; 248 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match); 249 250 static struct platform_driver pwm_lpss_driver_platform = { 251 .driver = { 252 .name = "pwm-lpss", 253 .acpi_match_table = pwm_lpss_acpi_match, 254 }, 255 .probe = pwm_lpss_probe_platform, 256 .remove = pwm_lpss_remove_platform, 257 }; 258 259 static int __init pwm_init(void) 260 { 261 pci_drv = pci_register_driver(&pwm_lpss_driver_pci); 262 plat_drv = platform_driver_register(&pwm_lpss_driver_platform); 263 if (pci_drv && plat_drv) 264 return pci_drv; 265 266 return 0; 267 } 268 module_init(pwm_init); 269 270 static void __exit pwm_exit(void) 271 { 272 if (!pci_drv) 273 pci_unregister_driver(&pwm_lpss_driver_pci); 274 if (!plat_drv) 275 platform_driver_unregister(&pwm_lpss_driver_platform); 276 } 277 module_exit(pwm_exit); 278 279 MODULE_DESCRIPTION("PWM driver for Intel LPSS"); 280 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>"); 281 MODULE_LICENSE("GPL v2"); 282 MODULE_ALIAS("platform:pwm-lpss"); 283