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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 | // SPDX-License-Identifier: GPL-2.0-or-later /* * PWM framework driver for Cirrus Logic EP93xx * * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com> * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com> * * EP9301/02 have only one channel: * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) * * EP9307 has only one channel: * platform device ep93xx-pwm.0 - PWMOUT * * EP9312/15 have two channels: * platform device ep93xx-pwm.0 - PWMOUT * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) */ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <linux/pwm.h> #include <asm/div64.h> #include <linux/soc/cirrus/ep93xx.h> /* for ep93xx_pwm_{acquire,release}_gpio() */ #define EP93XX_PWMx_TERM_COUNT 0x00 #define EP93XX_PWMx_DUTY_CYCLE 0x04 #define EP93XX_PWMx_ENABLE 0x08 #define EP93XX_PWMx_INVERT 0x0c struct ep93xx_pwm { void __iomem *base; struct clk *clk; }; static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) { return pwmchip_get_drvdata(chip); } static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct platform_device *pdev = to_platform_device(pwmchip_parent(chip)); return ep93xx_pwm_acquire_gpio(pdev); } static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct platform_device *pdev = to_platform_device(pwmchip_parent(chip)); ep93xx_pwm_release_gpio(pdev); } static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { int ret; struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); bool enabled = state->enabled; void __iomem *base = ep93xx_pwm->base; unsigned long long c; unsigned long period_cycles; unsigned long duty_cycles; unsigned long term; if (state->polarity != pwm->state.polarity) { if (enabled) { writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); clk_disable_unprepare(ep93xx_pwm->clk); enabled = false; } /* * The clock needs to be enabled to access the PWM registers. * Polarity can only be changed when the PWM is disabled. */ ret = clk_prepare_enable(ep93xx_pwm->clk); if (ret) return ret; if (state->polarity == PWM_POLARITY_INVERSED) writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); else writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); clk_disable_unprepare(ep93xx_pwm->clk); } if (!state->enabled) { if (enabled) { writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); clk_disable_unprepare(ep93xx_pwm->clk); } return 0; } /* * The clock needs to be enabled to access the PWM registers. * Configuration can be changed at any time. */ if (!pwm_is_enabled(pwm)) { ret = clk_prepare_enable(ep93xx_pwm->clk); if (ret) return ret; } c = clk_get_rate(ep93xx_pwm->clk); c *= state->period; do_div(c, 1000000000); period_cycles = c; c = period_cycles; c *= state->duty_cycle; do_div(c, state->period); duty_cycles = c; if (period_cycles < 0x10000 && duty_cycles < 0x10000) { term = readw(base + EP93XX_PWMx_TERM_COUNT); /* Order is important if PWM is running */ if (period_cycles > term) { writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); } else { writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); } ret = 0; } else { ret = -EINVAL; } if (!pwm_is_enabled(pwm)) clk_disable_unprepare(ep93xx_pwm->clk); if (ret) return ret; if (!enabled) { ret = clk_prepare_enable(ep93xx_pwm->clk); if (ret) return ret; writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); } return 0; } static const struct pwm_ops ep93xx_pwm_ops = { .request = ep93xx_pwm_request, .free = ep93xx_pwm_free, .apply = ep93xx_pwm_apply, }; static int ep93xx_pwm_probe(struct platform_device *pdev) { struct pwm_chip *chip; struct ep93xx_pwm *ep93xx_pwm; int ret; chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ep93xx_pwm)); if (IS_ERR(chip)) return PTR_ERR(chip); ep93xx_pwm = to_ep93xx_pwm(chip); ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(ep93xx_pwm->base)) return PTR_ERR(ep93xx_pwm->base); ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); if (IS_ERR(ep93xx_pwm->clk)) return PTR_ERR(ep93xx_pwm->clk); chip->ops = &ep93xx_pwm_ops; ret = devm_pwmchip_add(&pdev->dev, chip); if (ret < 0) return ret; return 0; } static struct platform_driver ep93xx_pwm_driver = { .driver = { .name = "ep93xx-pwm", }, .probe = ep93xx_pwm_probe, }; module_platform_driver(ep93xx_pwm_driver); MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); MODULE_ALIAS("platform:ep93xx-pwm"); MODULE_LICENSE("GPL"); |