1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PWM framework driver for Cirrus Logic EP93xx 4 * 5 * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com> 6 * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com> 7 * 8 * EP9301/02 have only one channel: 9 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) 10 * 11 * EP9307 has only one channel: 12 * platform device ep93xx-pwm.0 - PWMOUT 13 * 14 * EP9312/15 have two channels: 15 * platform device ep93xx-pwm.0 - PWMOUT 16 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) 17 */ 18 19 #include <linux/module.h> 20 #include <linux/platform_device.h> 21 #include <linux/slab.h> 22 #include <linux/clk.h> 23 #include <linux/err.h> 24 #include <linux/io.h> 25 #include <linux/pwm.h> 26 27 #include <asm/div64.h> 28 29 #include <linux/soc/cirrus/ep93xx.h> /* for ep93xx_pwm_{acquire,release}_gpio() */ 30 31 #define EP93XX_PWMx_TERM_COUNT 0x00 32 #define EP93XX_PWMx_DUTY_CYCLE 0x04 33 #define EP93XX_PWMx_ENABLE 0x08 34 #define EP93XX_PWMx_INVERT 0x0c 35 36 struct ep93xx_pwm { 37 void __iomem *base; 38 struct clk *clk; 39 struct pwm_chip chip; 40 }; 41 42 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) 43 { 44 return container_of(chip, struct ep93xx_pwm, chip); 45 } 46 47 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 48 { 49 struct platform_device *pdev = to_platform_device(chip->dev); 50 51 return ep93xx_pwm_acquire_gpio(pdev); 52 } 53 54 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 55 { 56 struct platform_device *pdev = to_platform_device(chip->dev); 57 58 ep93xx_pwm_release_gpio(pdev); 59 } 60 61 static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 62 int duty_ns, int period_ns) 63 { 64 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 65 void __iomem *base = ep93xx_pwm->base; 66 unsigned long long c; 67 unsigned long period_cycles; 68 unsigned long duty_cycles; 69 unsigned long term; 70 int ret = 0; 71 72 /* 73 * The clock needs to be enabled to access the PWM registers. 74 * Configuration can be changed at any time. 75 */ 76 if (!pwm_is_enabled(pwm)) { 77 ret = clk_enable(ep93xx_pwm->clk); 78 if (ret) 79 return ret; 80 } 81 82 c = clk_get_rate(ep93xx_pwm->clk); 83 c *= period_ns; 84 do_div(c, 1000000000); 85 period_cycles = c; 86 87 c = period_cycles; 88 c *= duty_ns; 89 do_div(c, period_ns); 90 duty_cycles = c; 91 92 if (period_cycles < 0x10000 && duty_cycles < 0x10000) { 93 term = readw(base + EP93XX_PWMx_TERM_COUNT); 94 95 /* Order is important if PWM is running */ 96 if (period_cycles > term) { 97 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 98 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 99 } else { 100 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 101 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 102 } 103 } else { 104 ret = -EINVAL; 105 } 106 107 if (!pwm_is_enabled(pwm)) 108 clk_disable(ep93xx_pwm->clk); 109 110 return ret; 111 } 112 113 static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm, 114 enum pwm_polarity polarity) 115 { 116 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 117 int ret; 118 119 /* 120 * The clock needs to be enabled to access the PWM registers. 121 * Polarity can only be changed when the PWM is disabled. 122 */ 123 ret = clk_enable(ep93xx_pwm->clk); 124 if (ret) 125 return ret; 126 127 if (polarity == PWM_POLARITY_INVERSED) 128 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 129 else 130 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 131 132 clk_disable(ep93xx_pwm->clk); 133 134 return 0; 135 } 136 137 static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 138 { 139 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 140 int ret; 141 142 ret = clk_enable(ep93xx_pwm->clk); 143 if (ret) 144 return ret; 145 146 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 147 148 return 0; 149 } 150 151 static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 152 { 153 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 154 155 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 156 clk_disable(ep93xx_pwm->clk); 157 } 158 159 static const struct pwm_ops ep93xx_pwm_ops = { 160 .request = ep93xx_pwm_request, 161 .free = ep93xx_pwm_free, 162 .config = ep93xx_pwm_config, 163 .set_polarity = ep93xx_pwm_polarity, 164 .enable = ep93xx_pwm_enable, 165 .disable = ep93xx_pwm_disable, 166 .owner = THIS_MODULE, 167 }; 168 169 static int ep93xx_pwm_probe(struct platform_device *pdev) 170 { 171 struct ep93xx_pwm *ep93xx_pwm; 172 struct resource *res; 173 int ret; 174 175 ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL); 176 if (!ep93xx_pwm) 177 return -ENOMEM; 178 179 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 180 ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res); 181 if (IS_ERR(ep93xx_pwm->base)) 182 return PTR_ERR(ep93xx_pwm->base); 183 184 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); 185 if (IS_ERR(ep93xx_pwm->clk)) 186 return PTR_ERR(ep93xx_pwm->clk); 187 188 ep93xx_pwm->chip.dev = &pdev->dev; 189 ep93xx_pwm->chip.ops = &ep93xx_pwm_ops; 190 ep93xx_pwm->chip.base = -1; 191 ep93xx_pwm->chip.npwm = 1; 192 193 ret = pwmchip_add(&ep93xx_pwm->chip); 194 if (ret < 0) 195 return ret; 196 197 platform_set_drvdata(pdev, ep93xx_pwm); 198 return 0; 199 } 200 201 static int ep93xx_pwm_remove(struct platform_device *pdev) 202 { 203 struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev); 204 205 return pwmchip_remove(&ep93xx_pwm->chip); 206 } 207 208 static struct platform_driver ep93xx_pwm_driver = { 209 .driver = { 210 .name = "ep93xx-pwm", 211 }, 212 .probe = ep93xx_pwm_probe, 213 .remove = ep93xx_pwm_remove, 214 }; 215 module_platform_driver(ep93xx_pwm_driver); 216 217 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); 218 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); 219 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); 220 MODULE_ALIAS("platform:ep93xx-pwm"); 221 MODULE_LICENSE("GPL"); 222