Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; version 2. |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | #include <linux/clk.h> |
| 11 | #include <linux/err.h> |
| 12 | #include <linux/io.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/of.h> |
| 16 | #include <linux/of_address.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/pwm.h> |
| 19 | #include <linux/slab.h> |
| 20 | |
| 21 | struct lpc32xx_pwm_chip { |
| 22 | struct pwm_chip chip; |
| 23 | struct clk *clk; |
| 24 | void __iomem *base; |
| 25 | }; |
| 26 | |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 27 | #define PWM_ENABLE BIT(31) |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 28 | |
| 29 | #define to_lpc32xx_pwm_chip(_chip) \ |
| 30 | container_of(_chip, struct lpc32xx_pwm_chip, chip) |
| 31 | |
| 32 | static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 33 | int duty_ns, int period_ns) |
| 34 | { |
| 35 | struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); |
| 36 | unsigned long long c; |
| 37 | int period_cycles, duty_cycles; |
Axel Lin | affb923 | 2013-04-23 14:02:49 +0800 | [diff] [blame] | 38 | u32 val; |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 39 | c = clk_get_rate(lpc32xx->clk); |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 40 | |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 41 | /* The highest acceptable divisor is 256, which is represented by 0 */ |
| 42 | period_cycles = div64_u64(c * period_ns, |
| 43 | (unsigned long long)NSEC_PER_SEC * 256); |
Vladimir Zapolskiy | d6dbdf0 | 2015-12-06 13:32:02 +0200 | [diff] [blame^] | 44 | if (!period_cycles || period_cycles > 256) |
| 45 | return -ERANGE; |
| 46 | if (period_cycles == 256) |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 47 | period_cycles = 0; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 48 | |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 49 | /* Compute 256 x #duty/period value and care for corner cases */ |
| 50 | duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256, |
| 51 | period_ns); |
| 52 | if (!duty_cycles) |
| 53 | duty_cycles = 1; |
| 54 | if (duty_cycles > 255) |
| 55 | duty_cycles = 255; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 56 | |
Axel Lin | affb923 | 2013-04-23 14:02:49 +0800 | [diff] [blame] | 57 | val = readl(lpc32xx->base + (pwm->hwpwm << 2)); |
| 58 | val &= ~0xFFFF; |
Vladimir Zapolskiy | 5a9fc9c | 2015-12-06 13:32:01 +0200 | [diff] [blame] | 59 | val |= (period_cycles << 8) | duty_cycles; |
Axel Lin | affb923 | 2013-04-23 14:02:49 +0800 | [diff] [blame] | 60 | writel(val, lpc32xx->base + (pwm->hwpwm << 2)); |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 61 | |
| 62 | return 0; |
| 63 | } |
| 64 | |
| 65 | static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 66 | { |
| 67 | struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); |
Axel Lin | 08ee77b | 2013-04-23 14:01:31 +0800 | [diff] [blame] | 68 | u32 val; |
| 69 | int ret; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 70 | |
Vladimir Zapolskiy | 82aff04 | 2015-12-06 13:32:00 +0200 | [diff] [blame] | 71 | ret = clk_prepare_enable(lpc32xx->clk); |
Axel Lin | 08ee77b | 2013-04-23 14:01:31 +0800 | [diff] [blame] | 72 | if (ret) |
| 73 | return ret; |
| 74 | |
| 75 | val = readl(lpc32xx->base + (pwm->hwpwm << 2)); |
| 76 | val |= PWM_ENABLE; |
| 77 | writel(val, lpc32xx->base + (pwm->hwpwm << 2)); |
| 78 | |
| 79 | return 0; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 83 | { |
| 84 | struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); |
Axel Lin | 08ee77b | 2013-04-23 14:01:31 +0800 | [diff] [blame] | 85 | u32 val; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 86 | |
Axel Lin | 08ee77b | 2013-04-23 14:01:31 +0800 | [diff] [blame] | 87 | val = readl(lpc32xx->base + (pwm->hwpwm << 2)); |
| 88 | val &= ~PWM_ENABLE; |
| 89 | writel(val, lpc32xx->base + (pwm->hwpwm << 2)); |
| 90 | |
Vladimir Zapolskiy | 82aff04 | 2015-12-06 13:32:00 +0200 | [diff] [blame] | 91 | clk_disable_unprepare(lpc32xx->clk); |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 92 | } |
| 93 | |
| 94 | static const struct pwm_ops lpc32xx_pwm_ops = { |
| 95 | .config = lpc32xx_pwm_config, |
| 96 | .enable = lpc32xx_pwm_enable, |
| 97 | .disable = lpc32xx_pwm_disable, |
| 98 | .owner = THIS_MODULE, |
| 99 | }; |
| 100 | |
| 101 | static int lpc32xx_pwm_probe(struct platform_device *pdev) |
| 102 | { |
| 103 | struct lpc32xx_pwm_chip *lpc32xx; |
| 104 | struct resource *res; |
| 105 | int ret; |
| 106 | |
| 107 | lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL); |
| 108 | if (!lpc32xx) |
| 109 | return -ENOMEM; |
| 110 | |
| 111 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
Thierry Reding | 6d4294d | 2013-01-21 11:09:16 +0100 | [diff] [blame] | 112 | lpc32xx->base = devm_ioremap_resource(&pdev->dev, res); |
| 113 | if (IS_ERR(lpc32xx->base)) |
| 114 | return PTR_ERR(lpc32xx->base); |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 115 | |
| 116 | lpc32xx->clk = devm_clk_get(&pdev->dev, NULL); |
| 117 | if (IS_ERR(lpc32xx->clk)) |
| 118 | return PTR_ERR(lpc32xx->clk); |
| 119 | |
| 120 | lpc32xx->chip.dev = &pdev->dev; |
| 121 | lpc32xx->chip.ops = &lpc32xx_pwm_ops; |
Vladimir Zapolskiy | ebe1fca | 2015-12-06 13:31:59 +0200 | [diff] [blame] | 122 | lpc32xx->chip.npwm = 1; |
Alban Bedel | 8fc6d09 | 2012-11-14 12:58:15 +0100 | [diff] [blame] | 123 | lpc32xx->chip.base = -1; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 124 | |
| 125 | ret = pwmchip_add(&lpc32xx->chip); |
| 126 | if (ret < 0) { |
| 127 | dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret); |
| 128 | return ret; |
| 129 | } |
| 130 | |
| 131 | platform_set_drvdata(pdev, lpc32xx); |
| 132 | |
| 133 | return 0; |
| 134 | } |
| 135 | |
Bill Pemberton | 77f3791 | 2012-11-19 13:26:09 -0500 | [diff] [blame] | 136 | static int lpc32xx_pwm_remove(struct platform_device *pdev) |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 137 | { |
| 138 | struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev); |
Alban Bedel | 54b2a99 | 2012-11-14 12:58:14 +0100 | [diff] [blame] | 139 | unsigned int i; |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 140 | |
Alban Bedel | 54b2a99 | 2012-11-14 12:58:14 +0100 | [diff] [blame] | 141 | for (i = 0; i < lpc32xx->chip.npwm; i++) |
| 142 | pwm_disable(&lpc32xx->chip.pwms[i]); |
| 143 | |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 144 | return pwmchip_remove(&lpc32xx->chip); |
| 145 | } |
| 146 | |
Thierry Reding | f1a8870 | 2013-04-18 10:04:14 +0200 | [diff] [blame] | 147 | static const struct of_device_id lpc32xx_pwm_dt_ids[] = { |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 148 | { .compatible = "nxp,lpc3220-pwm", }, |
| 149 | { /* sentinel */ } |
| 150 | }; |
| 151 | MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids); |
| 152 | |
| 153 | static struct platform_driver lpc32xx_pwm_driver = { |
| 154 | .driver = { |
| 155 | .name = "lpc32xx-pwm", |
Sachin Kamat | 3cb3b2b | 2013-09-30 08:56:40 +0530 | [diff] [blame] | 156 | .of_match_table = lpc32xx_pwm_dt_ids, |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 157 | }, |
| 158 | .probe = lpc32xx_pwm_probe, |
Bill Pemberton | fd10911 | 2012-11-19 13:21:28 -0500 | [diff] [blame] | 159 | .remove = lpc32xx_pwm_remove, |
Alexandre Pereira da Silva | 2132fa8 | 2012-07-10 11:38:10 -0300 | [diff] [blame] | 160 | }; |
| 161 | module_platform_driver(lpc32xx_pwm_driver); |
| 162 | |
| 163 | MODULE_ALIAS("platform:lpc32xx-pwm"); |
| 164 | MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>"); |
| 165 | MODULE_DESCRIPTION("LPC32XX PWM Driver"); |
| 166 | MODULE_LICENSE("GPL v2"); |