Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/unicore32/kernel/pwm.c |
| 3 | * |
| 4 | * Code specific to PKUnity SoC and UniCore ISA |
| 5 | * |
| 6 | * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> |
| 7 | * Copyright (C) 2001-2010 Guan Xuetao |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/platform_device.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/err.h> |
| 19 | #include <linux/clk.h> |
| 20 | #include <linux/io.h> |
| 21 | #include <linux/pwm.h> |
| 22 | |
| 23 | #include <asm/div64.h> |
| 24 | #include <mach/hardware.h> |
| 25 | |
| 26 | struct puv3_pwm_chip { |
| 27 | struct pwm_chip chip; |
| 28 | void __iomem *base; |
| 29 | struct clk *clk; |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 30 | }; |
| 31 | |
| 32 | static inline struct puv3_pwm_chip *to_puv3(struct pwm_chip *chip) |
| 33 | { |
| 34 | return container_of(chip, struct puv3_pwm_chip, chip); |
| 35 | } |
| 36 | |
| 37 | /* |
| 38 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE |
| 39 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE |
| 40 | */ |
| 41 | static int puv3_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 42 | int duty_ns, int period_ns) |
| 43 | { |
| 44 | unsigned long period_cycles, prescale, pv, dc; |
| 45 | struct puv3_pwm_chip *puv3 = to_puv3(chip); |
| 46 | unsigned long long c; |
| 47 | |
| 48 | c = clk_get_rate(puv3->clk); |
| 49 | c = c * period_ns; |
| 50 | do_div(c, 1000000000); |
| 51 | period_cycles = c; |
| 52 | |
| 53 | if (period_cycles < 1) |
| 54 | period_cycles = 1; |
| 55 | |
| 56 | prescale = (period_cycles - 1) / 1024; |
| 57 | pv = period_cycles / (prescale + 1) - 1; |
| 58 | |
| 59 | if (prescale > 63) |
| 60 | return -EINVAL; |
| 61 | |
| 62 | if (duty_ns == period_ns) |
| 63 | dc = OST_PWMDCCR_FDCYCLE; |
| 64 | else |
| 65 | dc = (pv + 1) * duty_ns / period_ns; |
| 66 | |
| 67 | /* |
| 68 | * NOTE: the clock to PWM has to be enabled first |
| 69 | * before writing to the registers |
| 70 | */ |
| 71 | clk_prepare_enable(puv3->clk); |
| 72 | |
| 73 | writel(prescale, puv3->base + OST_PWM_PWCR); |
| 74 | writel(pv - dc, puv3->base + OST_PWM_DCCR); |
| 75 | writel(pv, puv3->base + OST_PWM_PCR); |
| 76 | |
| 77 | clk_disable_unprepare(puv3->clk); |
| 78 | |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | static int puv3_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 83 | { |
| 84 | struct puv3_pwm_chip *puv3 = to_puv3(chip); |
| 85 | |
| 86 | return clk_prepare_enable(puv3->clk); |
| 87 | } |
| 88 | |
| 89 | static void puv3_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 90 | { |
| 91 | struct puv3_pwm_chip *puv3 = to_puv3(chip); |
| 92 | |
| 93 | clk_disable_unprepare(puv3->clk); |
| 94 | } |
| 95 | |
| 96 | static const struct pwm_ops puv3_pwm_ops = { |
| 97 | .config = puv3_pwm_config, |
| 98 | .enable = puv3_pwm_enable, |
| 99 | .disable = puv3_pwm_disable, |
| 100 | .owner = THIS_MODULE, |
| 101 | }; |
| 102 | |
Bill Pemberton | 3e9fe83 | 2012-11-19 13:23:14 -0500 | [diff] [blame] | 103 | static int pwm_probe(struct platform_device *pdev) |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 104 | { |
| 105 | struct puv3_pwm_chip *puv3; |
| 106 | struct resource *r; |
| 107 | int ret; |
| 108 | |
| 109 | puv3 = devm_kzalloc(&pdev->dev, sizeof(*puv3), GFP_KERNEL); |
Markus Elfring | 6106d88 | 2017-12-15 18:29:49 +0100 | [diff] [blame] | 110 | if (!puv3) |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 111 | return -ENOMEM; |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 112 | |
| 113 | puv3->clk = devm_clk_get(&pdev->dev, "OST_CLK"); |
| 114 | if (IS_ERR(puv3->clk)) |
| 115 | return PTR_ERR(puv3->clk); |
| 116 | |
| 117 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
Thierry Reding | 6d4294d | 2013-01-21 11:09:16 +0100 | [diff] [blame] | 118 | puv3->base = devm_ioremap_resource(&pdev->dev, r); |
| 119 | if (IS_ERR(puv3->base)) |
| 120 | return PTR_ERR(puv3->base); |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 121 | |
| 122 | puv3->chip.dev = &pdev->dev; |
| 123 | puv3->chip.ops = &puv3_pwm_ops; |
| 124 | puv3->chip.base = -1; |
| 125 | puv3->chip.npwm = 1; |
| 126 | |
| 127 | ret = pwmchip_add(&puv3->chip); |
| 128 | if (ret < 0) { |
| 129 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); |
| 130 | return ret; |
| 131 | } |
| 132 | |
| 133 | platform_set_drvdata(pdev, puv3); |
| 134 | return 0; |
| 135 | } |
| 136 | |
Bill Pemberton | 77f3791 | 2012-11-19 13:26:09 -0500 | [diff] [blame] | 137 | static int pwm_remove(struct platform_device *pdev) |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 138 | { |
| 139 | struct puv3_pwm_chip *puv3 = platform_get_drvdata(pdev); |
| 140 | |
| 141 | return pwmchip_remove(&puv3->chip); |
| 142 | } |
| 143 | |
| 144 | static struct platform_driver puv3_pwm_driver = { |
| 145 | .driver = { |
| 146 | .name = "PKUnity-v3-PWM", |
| 147 | }, |
| 148 | .probe = pwm_probe, |
Bill Pemberton | fd10911 | 2012-11-19 13:21:28 -0500 | [diff] [blame] | 149 | .remove = pwm_remove, |
Thierry Reding | 79c11b6 | 2012-08-31 08:29:24 +0200 | [diff] [blame] | 150 | }; |
| 151 | module_platform_driver(puv3_pwm_driver); |
| 152 | |
| 153 | MODULE_LICENSE("GPL v2"); |