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 27 #define PWM_ENABLE (1 << 31) 28 #define PWM_RELOADV(x) (((x) & 0xFF) << 8) 29 #define PWM_DUTY(x) ((x) & 0xFF) 30 31 #define to_lpc32xx_pwm_chip(_chip) \ 32 container_of(_chip, struct lpc32xx_pwm_chip, chip) 33 34 static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 35 int duty_ns, int period_ns) 36 { 37 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); 38 unsigned long long c; 39 int period_cycles, duty_cycles; 40 41 c = clk_get_rate(lpc32xx->clk) / 256; 42 c = c * period_ns; 43 do_div(c, NSEC_PER_SEC); 44 45 /* Handle high and low extremes */ 46 if (c == 0) 47 c = 1; 48 if (c > 255) 49 c = 0; /* 0 set division by 256 */ 50 period_cycles = c; 51 52 c = 256 * duty_ns; 53 do_div(c, period_ns); 54 duty_cycles = c; 55 56 writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles), 57 lpc32xx->base + (pwm->hwpwm << 2)); 58 59 return 0; 60 } 61 62 static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 63 { 64 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); 65 66 return clk_enable(lpc32xx->clk); 67 } 68 69 static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 70 { 71 struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip); 72 73 writel(0, lpc32xx->base + (pwm->hwpwm << 2)); 74 clk_disable(lpc32xx->clk); 75 } 76 77 static const struct pwm_ops lpc32xx_pwm_ops = { 78 .config = lpc32xx_pwm_config, 79 .enable = lpc32xx_pwm_enable, 80 .disable = lpc32xx_pwm_disable, 81 .owner = THIS_MODULE, 82 }; 83 84 static int lpc32xx_pwm_probe(struct platform_device *pdev) 85 { 86 struct lpc32xx_pwm_chip *lpc32xx; 87 struct resource *res; 88 int ret; 89 90 lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL); 91 if (!lpc32xx) 92 return -ENOMEM; 93 94 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 95 if (!res) 96 return -EINVAL; 97 98 lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res); 99 if (!lpc32xx->base) 100 return -EADDRNOTAVAIL; 101 102 lpc32xx->clk = devm_clk_get(&pdev->dev, NULL); 103 if (IS_ERR(lpc32xx->clk)) 104 return PTR_ERR(lpc32xx->clk); 105 106 lpc32xx->chip.dev = &pdev->dev; 107 lpc32xx->chip.ops = &lpc32xx_pwm_ops; 108 lpc32xx->chip.npwm = 2; 109 110 ret = pwmchip_add(&lpc32xx->chip); 111 if (ret < 0) { 112 dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret); 113 return ret; 114 } 115 116 platform_set_drvdata(pdev, lpc32xx); 117 118 return 0; 119 } 120 121 static int __devexit lpc32xx_pwm_remove(struct platform_device *pdev) 122 { 123 struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev); 124 125 clk_disable(lpc32xx->clk); 126 return pwmchip_remove(&lpc32xx->chip); 127 } 128 129 static struct of_device_id lpc32xx_pwm_dt_ids[] = { 130 { .compatible = "nxp,lpc3220-pwm", }, 131 { /* sentinel */ } 132 }; 133 MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids); 134 135 static struct platform_driver lpc32xx_pwm_driver = { 136 .driver = { 137 .name = "lpc32xx-pwm", 138 .of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids), 139 }, 140 .probe = lpc32xx_pwm_probe, 141 .remove = __devexit_p(lpc32xx_pwm_remove), 142 }; 143 module_platform_driver(lpc32xx_pwm_driver); 144 145 MODULE_ALIAS("platform:lpc32xx-pwm"); 146 MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>"); 147 MODULE_DESCRIPTION("LPC32XX PWM Driver"); 148 MODULE_LICENSE("GPL v2"); 149