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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 | // SPDX-License-Identifier: GPL-2.0 OR MIT /* * Driver for the Apple SoC PWM controller * * Copyright The Asahi Linux Contributors * * Limitations: * - The writes to cycle registers are shadowed until a write to * the control register. * - If both OFF_CYCLES and ON_CYCLES are set to 0, the output * is a constant off signal. * - When APPLE_PWM_CTRL is set to 0, the output is constant low */ #include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/io.h> #include <linux/clk.h> #include <linux/math64.h> #define APPLE_PWM_CTRL 0x00 #define APPLE_PWM_ON_CYCLES 0x1c #define APPLE_PWM_OFF_CYCLES 0x18 #define APPLE_PWM_CTRL_ENABLE BIT(0) #define APPLE_PWM_CTRL_MODE BIT(2) #define APPLE_PWM_CTRL_UPDATE BIT(5) #define APPLE_PWM_CTRL_TRIGGER BIT(9) #define APPLE_PWM_CTRL_INVERT BIT(10) #define APPLE_PWM_CTRL_OUTPUT_ENABLE BIT(14) struct apple_pwm { struct pwm_chip chip; void __iomem *base; u64 clkrate; }; static inline struct apple_pwm *to_apple_pwm(struct pwm_chip *chip) { return container_of(chip, struct apple_pwm, chip); } static int apple_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { struct apple_pwm *fpwm; if (state->polarity == PWM_POLARITY_INVERSED) return -EINVAL; fpwm = to_apple_pwm(chip); if (state->enabled) { u64 on_cycles, off_cycles; on_cycles = mul_u64_u64_div_u64(fpwm->clkrate, state->duty_cycle, NSEC_PER_SEC); if (on_cycles > 0xFFFFFFFF) on_cycles = 0xFFFFFFFF; off_cycles = mul_u64_u64_div_u64(fpwm->clkrate, state->period, NSEC_PER_SEC) - on_cycles; if (off_cycles > 0xFFFFFFFF) off_cycles = 0xFFFFFFFF; writel(on_cycles, fpwm->base + APPLE_PWM_ON_CYCLES); writel(off_cycles, fpwm->base + APPLE_PWM_OFF_CYCLES); writel(APPLE_PWM_CTRL_ENABLE | APPLE_PWM_CTRL_OUTPUT_ENABLE | APPLE_PWM_CTRL_UPDATE, fpwm->base + APPLE_PWM_CTRL); } else { writel(0, fpwm->base + APPLE_PWM_CTRL); } return 0; } static int apple_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { struct apple_pwm *fpwm; u32 on_cycles, off_cycles, ctrl; fpwm = to_apple_pwm(chip); ctrl = readl(fpwm->base + APPLE_PWM_CTRL); on_cycles = readl(fpwm->base + APPLE_PWM_ON_CYCLES); off_cycles = readl(fpwm->base + APPLE_PWM_OFF_CYCLES); state->enabled = (ctrl & APPLE_PWM_CTRL_ENABLE) && (ctrl & APPLE_PWM_CTRL_OUTPUT_ENABLE); state->polarity = PWM_POLARITY_NORMAL; // on_cycles + off_cycles is 33 bits, NSEC_PER_SEC is 30, there is no overflow state->duty_cycle = DIV64_U64_ROUND_UP((u64)on_cycles * NSEC_PER_SEC, fpwm->clkrate); state->period = DIV64_U64_ROUND_UP(((u64)off_cycles + (u64)on_cycles) * NSEC_PER_SEC, fpwm->clkrate); return 0; } static const struct pwm_ops apple_pwm_ops = { .apply = apple_pwm_apply, .get_state = apple_pwm_get_state, .owner = THIS_MODULE, }; static int apple_pwm_probe(struct platform_device *pdev) { struct apple_pwm *fpwm; struct clk *clk; int ret; fpwm = devm_kzalloc(&pdev->dev, sizeof(*fpwm), GFP_KERNEL); if (!fpwm) return -ENOMEM; fpwm->base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(fpwm->base)) return PTR_ERR(fpwm->base); clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(clk)) return dev_err_probe(&pdev->dev, PTR_ERR(clk), "unable to get the clock"); /* * Uses the 24MHz system clock on all existing devices, can only * happen if the device tree is broken * * This check is done to prevent an overflow in .apply */ fpwm->clkrate = clk_get_rate(clk); if (fpwm->clkrate > NSEC_PER_SEC) return dev_err_probe(&pdev->dev, -EINVAL, "pwm clock out of range"); fpwm->chip.dev = &pdev->dev; fpwm->chip.npwm = 1; fpwm->chip.ops = &apple_pwm_ops; ret = devm_pwmchip_add(&pdev->dev, &fpwm->chip); if (ret < 0) return dev_err_probe(&pdev->dev, ret, "unable to add pwm chip"); return 0; } static const struct of_device_id apple_pwm_of_match[] = { { .compatible = "apple,s5l-fpwm" }, {} }; MODULE_DEVICE_TABLE(of, apple_pwm_of_match); static struct platform_driver apple_pwm_driver = { .probe = apple_pwm_probe, .driver = { .name = "apple-pwm", .of_match_table = apple_pwm_of_match, }, }; module_platform_driver(apple_pwm_driver); MODULE_DESCRIPTION("Apple SoC PWM driver"); MODULE_LICENSE("Dual MIT/GPL"); |