1 /* 2 * PWM framework driver for Cirrus Logic EP93xx 3 * 4 * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com> 5 * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com> 6 * 7 * EP9301/02 have only one channel: 8 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) 9 * 10 * EP9307 has only one channel: 11 * platform device ep93xx-pwm.0 - PWMOUT 12 * 13 * EP9312/15 have two channels: 14 * platform device ep93xx-pwm.0 - PWMOUT 15 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) 16 * 17 * This program is free software; you can redistribute it and/or 18 * modify it under the terms of the GNU General Public License 19 * as published by the Free Software Foundation; either version 20 * 2 of the License, or (at your option) any later version. 21 * 22 * This program is distributed in the hope that it will be useful, 23 * but WITHOUT ANY WARRANTY; without even the implied warranty of 24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 25 * GNU General Public License for more details. 26 */ 27 28 #include <linux/module.h> 29 #include <linux/platform_device.h> 30 #include <linux/slab.h> 31 #include <linux/clk.h> 32 #include <linux/err.h> 33 #include <linux/io.h> 34 #include <linux/pwm.h> 35 36 #include <asm/div64.h> 37 38 #include <mach/platform.h> /* for ep93xx_pwm_{acquire,release}_gpio() */ 39 40 #define EP93XX_PWMx_TERM_COUNT 0x00 41 #define EP93XX_PWMx_DUTY_CYCLE 0x04 42 #define EP93XX_PWMx_ENABLE 0x08 43 #define EP93XX_PWMx_INVERT 0x0c 44 45 struct ep93xx_pwm { 46 void __iomem *base; 47 struct clk *clk; 48 struct pwm_chip chip; 49 }; 50 51 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) 52 { 53 return container_of(chip, struct ep93xx_pwm, chip); 54 } 55 56 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 57 { 58 struct platform_device *pdev = to_platform_device(chip->dev); 59 60 return ep93xx_pwm_acquire_gpio(pdev); 61 } 62 63 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 64 { 65 struct platform_device *pdev = to_platform_device(chip->dev); 66 67 ep93xx_pwm_release_gpio(pdev); 68 } 69 70 static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 71 int duty_ns, int period_ns) 72 { 73 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 74 void __iomem *base = ep93xx_pwm->base; 75 unsigned long long c; 76 unsigned long period_cycles; 77 unsigned long duty_cycles; 78 unsigned long term; 79 int ret = 0; 80 81 /* 82 * The clock needs to be enabled to access the PWM registers. 83 * Configuration can be changed at any time. 84 */ 85 if (!test_bit(PWMF_ENABLED, &pwm->flags)) { 86 ret = clk_enable(ep93xx_pwm->clk); 87 if (ret) 88 return ret; 89 } 90 91 c = clk_get_rate(ep93xx_pwm->clk); 92 c *= period_ns; 93 do_div(c, 1000000000); 94 period_cycles = c; 95 96 c = period_cycles; 97 c *= duty_ns; 98 do_div(c, period_ns); 99 duty_cycles = c; 100 101 if (period_cycles < 0x10000 && duty_cycles < 0x10000) { 102 term = readw(base + EP93XX_PWMx_TERM_COUNT); 103 104 /* Order is important if PWM is running */ 105 if (period_cycles > term) { 106 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 107 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 108 } else { 109 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 110 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 111 } 112 } else { 113 ret = -EINVAL; 114 } 115 116 if (!test_bit(PWMF_ENABLED, &pwm->flags)) 117 clk_disable(ep93xx_pwm->clk); 118 119 return ret; 120 } 121 122 static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm, 123 enum pwm_polarity polarity) 124 { 125 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 126 int ret; 127 128 /* 129 * The clock needs to be enabled to access the PWM registers. 130 * Polarity can only be changed when the PWM is disabled. 131 */ 132 ret = clk_enable(ep93xx_pwm->clk); 133 if (ret) 134 return ret; 135 136 if (polarity == PWM_POLARITY_INVERSED) 137 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 138 else 139 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 140 141 clk_disable(ep93xx_pwm->clk); 142 143 return 0; 144 } 145 146 static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 147 { 148 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 149 int ret; 150 151 ret = clk_enable(ep93xx_pwm->clk); 152 if (ret) 153 return ret; 154 155 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 156 157 return 0; 158 } 159 160 static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 161 { 162 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 163 164 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 165 clk_disable(ep93xx_pwm->clk); 166 } 167 168 static const struct pwm_ops ep93xx_pwm_ops = { 169 .request = ep93xx_pwm_request, 170 .free = ep93xx_pwm_free, 171 .config = ep93xx_pwm_config, 172 .set_polarity = ep93xx_pwm_polarity, 173 .enable = ep93xx_pwm_enable, 174 .disable = ep93xx_pwm_disable, 175 .owner = THIS_MODULE, 176 }; 177 178 static int ep93xx_pwm_probe(struct platform_device *pdev) 179 { 180 struct ep93xx_pwm *ep93xx_pwm; 181 struct resource *res; 182 int ret; 183 184 ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL); 185 if (!ep93xx_pwm) 186 return -ENOMEM; 187 188 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 189 ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res); 190 if (IS_ERR(ep93xx_pwm->base)) 191 return PTR_ERR(ep93xx_pwm->base); 192 193 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); 194 if (IS_ERR(ep93xx_pwm->clk)) 195 return PTR_ERR(ep93xx_pwm->clk); 196 197 ep93xx_pwm->chip.dev = &pdev->dev; 198 ep93xx_pwm->chip.ops = &ep93xx_pwm_ops; 199 ep93xx_pwm->chip.base = -1; 200 ep93xx_pwm->chip.npwm = 1; 201 202 ret = pwmchip_add(&ep93xx_pwm->chip); 203 if (ret < 0) 204 return ret; 205 206 platform_set_drvdata(pdev, ep93xx_pwm); 207 return 0; 208 } 209 210 static int ep93xx_pwm_remove(struct platform_device *pdev) 211 { 212 struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev); 213 214 return pwmchip_remove(&ep93xx_pwm->chip); 215 } 216 217 static struct platform_driver ep93xx_pwm_driver = { 218 .driver = { 219 .name = "ep93xx-pwm", 220 }, 221 .probe = ep93xx_pwm_probe, 222 .remove = ep93xx_pwm_remove, 223 }; 224 module_platform_driver(ep93xx_pwm_driver); 225 226 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); 227 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); 228 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); 229 MODULE_ALIAS("platform:ep93xx-pwm"); 230 MODULE_LICENSE("GPL"); 231