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 }; 40 41 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) 42 { 43 return pwmchip_get_drvdata(chip); 44 } 45 46 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 47 { 48 struct platform_device *pdev = to_platform_device(pwmchip_parent(chip)); 49 50 return ep93xx_pwm_acquire_gpio(pdev); 51 } 52 53 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 54 { 55 struct platform_device *pdev = to_platform_device(pwmchip_parent(chip)); 56 57 ep93xx_pwm_release_gpio(pdev); 58 } 59 60 static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 61 const struct pwm_state *state) 62 { 63 int ret; 64 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 65 bool enabled = state->enabled; 66 void __iomem *base = ep93xx_pwm->base; 67 unsigned long long c; 68 unsigned long period_cycles; 69 unsigned long duty_cycles; 70 unsigned long term; 71 72 if (state->polarity != pwm->state.polarity) { 73 if (enabled) { 74 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 75 clk_disable_unprepare(ep93xx_pwm->clk); 76 enabled = false; 77 } 78 79 /* 80 * The clock needs to be enabled to access the PWM registers. 81 * Polarity can only be changed when the PWM is disabled. 82 */ 83 ret = clk_prepare_enable(ep93xx_pwm->clk); 84 if (ret) 85 return ret; 86 87 if (state->polarity == PWM_POLARITY_INVERSED) 88 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 89 else 90 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 91 92 clk_disable_unprepare(ep93xx_pwm->clk); 93 } 94 95 if (!state->enabled) { 96 if (enabled) { 97 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 98 clk_disable_unprepare(ep93xx_pwm->clk); 99 } 100 101 return 0; 102 } 103 104 /* 105 * The clock needs to be enabled to access the PWM registers. 106 * Configuration can be changed at any time. 107 */ 108 if (!pwm_is_enabled(pwm)) { 109 ret = clk_prepare_enable(ep93xx_pwm->clk); 110 if (ret) 111 return ret; 112 } 113 114 c = clk_get_rate(ep93xx_pwm->clk); 115 c *= state->period; 116 do_div(c, 1000000000); 117 period_cycles = c; 118 119 c = period_cycles; 120 c *= state->duty_cycle; 121 do_div(c, state->period); 122 duty_cycles = c; 123 124 if (period_cycles < 0x10000 && duty_cycles < 0x10000) { 125 term = readw(base + EP93XX_PWMx_TERM_COUNT); 126 127 /* Order is important if PWM is running */ 128 if (period_cycles > term) { 129 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 130 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 131 } else { 132 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 133 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 134 } 135 ret = 0; 136 } else { 137 ret = -EINVAL; 138 } 139 140 if (!pwm_is_enabled(pwm)) 141 clk_disable_unprepare(ep93xx_pwm->clk); 142 143 if (ret) 144 return ret; 145 146 if (!enabled) { 147 ret = clk_prepare_enable(ep93xx_pwm->clk); 148 if (ret) 149 return ret; 150 151 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 152 } 153 154 return 0; 155 } 156 157 static const struct pwm_ops ep93xx_pwm_ops = { 158 .request = ep93xx_pwm_request, 159 .free = ep93xx_pwm_free, 160 .apply = ep93xx_pwm_apply, 161 }; 162 163 static int ep93xx_pwm_probe(struct platform_device *pdev) 164 { 165 struct pwm_chip *chip; 166 struct ep93xx_pwm *ep93xx_pwm; 167 int ret; 168 169 chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ep93xx_pwm)); 170 if (IS_ERR(chip)) 171 return PTR_ERR(chip); 172 ep93xx_pwm = to_ep93xx_pwm(chip); 173 174 ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0); 175 if (IS_ERR(ep93xx_pwm->base)) 176 return PTR_ERR(ep93xx_pwm->base); 177 178 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); 179 if (IS_ERR(ep93xx_pwm->clk)) 180 return PTR_ERR(ep93xx_pwm->clk); 181 182 chip->ops = &ep93xx_pwm_ops; 183 184 ret = devm_pwmchip_add(&pdev->dev, chip); 185 if (ret < 0) 186 return ret; 187 188 return 0; 189 } 190 191 static struct platform_driver ep93xx_pwm_driver = { 192 .driver = { 193 .name = "ep93xx-pwm", 194 }, 195 .probe = ep93xx_pwm_probe, 196 }; 197 module_platform_driver(ep93xx_pwm_driver); 198 199 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); 200 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); 201 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); 202 MODULE_ALIAS("platform:ep93xx-pwm"); 203 MODULE_LICENSE("GPL"); 204