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_apply(struct pwm_chip *chip, struct pwm_device *pwm, 62 const struct pwm_state *state) 63 { 64 int ret; 65 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); 66 bool enabled = state->enabled; 67 void __iomem *base = ep93xx_pwm->base; 68 unsigned long long c; 69 unsigned long period_cycles; 70 unsigned long duty_cycles; 71 unsigned long term; 72 73 if (state->polarity != pwm->state.polarity) { 74 if (enabled) { 75 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 76 clk_disable_unprepare(ep93xx_pwm->clk); 77 enabled = false; 78 } 79 80 /* 81 * The clock needs to be enabled to access the PWM registers. 82 * Polarity can only be changed when the PWM is disabled. 83 */ 84 ret = clk_prepare_enable(ep93xx_pwm->clk); 85 if (ret) 86 return ret; 87 88 if (state->polarity == PWM_POLARITY_INVERSED) 89 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 90 else 91 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); 92 93 clk_disable_unprepare(ep93xx_pwm->clk); 94 } 95 96 if (!state->enabled) { 97 if (enabled) { 98 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 99 clk_disable_unprepare(ep93xx_pwm->clk); 100 } 101 102 return 0; 103 } 104 105 /* 106 * The clock needs to be enabled to access the PWM registers. 107 * Configuration can be changed at any time. 108 */ 109 if (!pwm_is_enabled(pwm)) { 110 ret = clk_prepare_enable(ep93xx_pwm->clk); 111 if (ret) 112 return ret; 113 } 114 115 c = clk_get_rate(ep93xx_pwm->clk); 116 c *= state->period; 117 do_div(c, 1000000000); 118 period_cycles = c; 119 120 c = period_cycles; 121 c *= state->duty_cycle; 122 do_div(c, state->period); 123 duty_cycles = c; 124 125 if (period_cycles < 0x10000 && duty_cycles < 0x10000) { 126 term = readw(base + EP93XX_PWMx_TERM_COUNT); 127 128 /* Order is important if PWM is running */ 129 if (period_cycles > term) { 130 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 131 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 132 } else { 133 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); 134 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); 135 } 136 ret = 0; 137 } else { 138 ret = -EINVAL; 139 } 140 141 if (!pwm_is_enabled(pwm)) 142 clk_disable_unprepare(ep93xx_pwm->clk); 143 144 if (ret) 145 return ret; 146 147 if (!enabled) { 148 ret = clk_prepare_enable(ep93xx_pwm->clk); 149 if (ret) 150 return ret; 151 152 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); 153 } 154 155 return 0; 156 } 157 158 static const struct pwm_ops ep93xx_pwm_ops = { 159 .request = ep93xx_pwm_request, 160 .free = ep93xx_pwm_free, 161 .apply = ep93xx_pwm_apply, 162 }; 163 164 static int ep93xx_pwm_probe(struct platform_device *pdev) 165 { 166 struct ep93xx_pwm *ep93xx_pwm; 167 int ret; 168 169 ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL); 170 if (!ep93xx_pwm) 171 return -ENOMEM; 172 173 ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0); 174 if (IS_ERR(ep93xx_pwm->base)) 175 return PTR_ERR(ep93xx_pwm->base); 176 177 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); 178 if (IS_ERR(ep93xx_pwm->clk)) 179 return PTR_ERR(ep93xx_pwm->clk); 180 181 ep93xx_pwm->chip.dev = &pdev->dev; 182 ep93xx_pwm->chip.ops = &ep93xx_pwm_ops; 183 ep93xx_pwm->chip.npwm = 1; 184 185 ret = devm_pwmchip_add(&pdev->dev, &ep93xx_pwm->chip); 186 if (ret < 0) 187 return ret; 188 189 return 0; 190 } 191 192 static struct platform_driver ep93xx_pwm_driver = { 193 .driver = { 194 .name = "ep93xx-pwm", 195 }, 196 .probe = ep93xx_pwm_probe, 197 }; 198 module_platform_driver(ep93xx_pwm_driver); 199 200 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); 201 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); 202 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); 203 MODULE_ALIAS("platform:ep93xx-pwm"); 204 MODULE_LICENSE("GPL"); 205