1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright 2012 Freescale Semiconductor, Inc. 4 */ 5 6 #include <linux/clk.h> 7 #include <linux/err.h> 8 #include <linux/io.h> 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/of_address.h> 13 #include <linux/platform_device.h> 14 #include <linux/pwm.h> 15 #include <linux/slab.h> 16 #include <linux/stmp_device.h> 17 18 #define SET 0x4 19 #define CLR 0x8 20 #define TOG 0xc 21 22 #define PWM_CTRL 0x0 23 #define PWM_ACTIVE0 0x10 24 #define PWM_PERIOD0 0x20 25 #define PERIOD_PERIOD(p) ((p) & 0xffff) 26 #define PERIOD_PERIOD_MAX 0x10000 27 #define PERIOD_ACTIVE_HIGH (3 << 16) 28 #define PERIOD_INACTIVE_LOW (2 << 18) 29 #define PERIOD_CDIV(div) (((div) & 0x7) << 20) 30 #define PERIOD_CDIV_MAX 8 31 32 static const unsigned int cdiv[PERIOD_CDIV_MAX] = { 33 1, 2, 4, 8, 16, 64, 256, 1024 34 }; 35 36 struct mxs_pwm_chip { 37 struct pwm_chip chip; 38 struct clk *clk; 39 void __iomem *base; 40 }; 41 42 #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip) 43 44 static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 45 int duty_ns, int period_ns) 46 { 47 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); 48 int ret, div = 0; 49 unsigned int period_cycles, duty_cycles; 50 unsigned long rate; 51 unsigned long long c; 52 53 rate = clk_get_rate(mxs->clk); 54 while (1) { 55 c = rate / cdiv[div]; 56 c = c * period_ns; 57 do_div(c, 1000000000); 58 if (c < PERIOD_PERIOD_MAX) 59 break; 60 div++; 61 if (div >= PERIOD_CDIV_MAX) 62 return -EINVAL; 63 } 64 65 period_cycles = c; 66 c *= duty_ns; 67 do_div(c, period_ns); 68 duty_cycles = c; 69 70 /* 71 * If the PWM channel is disabled, make sure to turn on the clock 72 * before writing the register. Otherwise, keep it enabled. 73 */ 74 if (!pwm_is_enabled(pwm)) { 75 ret = clk_prepare_enable(mxs->clk); 76 if (ret) 77 return ret; 78 } 79 80 writel(duty_cycles << 16, 81 mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); 82 writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH | 83 PERIOD_INACTIVE_LOW | PERIOD_CDIV(div), 84 mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); 85 86 /* 87 * If the PWM is not enabled, turn the clock off again to save power. 88 */ 89 if (!pwm_is_enabled(pwm)) 90 clk_disable_unprepare(mxs->clk); 91 92 return 0; 93 } 94 95 static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 96 { 97 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); 98 int ret; 99 100 ret = clk_prepare_enable(mxs->clk); 101 if (ret) 102 return ret; 103 104 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET); 105 106 return 0; 107 } 108 109 static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 110 { 111 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); 112 113 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR); 114 115 clk_disable_unprepare(mxs->clk); 116 } 117 118 static const struct pwm_ops mxs_pwm_ops = { 119 .config = mxs_pwm_config, 120 .enable = mxs_pwm_enable, 121 .disable = mxs_pwm_disable, 122 .owner = THIS_MODULE, 123 }; 124 125 static int mxs_pwm_probe(struct platform_device *pdev) 126 { 127 struct device_node *np = pdev->dev.of_node; 128 struct mxs_pwm_chip *mxs; 129 int ret; 130 131 mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL); 132 if (!mxs) 133 return -ENOMEM; 134 135 mxs->base = devm_platform_ioremap_resource(pdev, 0); 136 if (IS_ERR(mxs->base)) 137 return PTR_ERR(mxs->base); 138 139 mxs->clk = devm_clk_get(&pdev->dev, NULL); 140 if (IS_ERR(mxs->clk)) 141 return PTR_ERR(mxs->clk); 142 143 mxs->chip.dev = &pdev->dev; 144 mxs->chip.ops = &mxs_pwm_ops; 145 mxs->chip.base = -1; 146 147 ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm); 148 if (ret < 0) { 149 dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret); 150 return ret; 151 } 152 153 ret = pwmchip_add(&mxs->chip); 154 if (ret < 0) { 155 dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret); 156 return ret; 157 } 158 159 platform_set_drvdata(pdev, mxs); 160 161 ret = stmp_reset_block(mxs->base); 162 if (ret) 163 goto pwm_remove; 164 165 return 0; 166 167 pwm_remove: 168 pwmchip_remove(&mxs->chip); 169 return ret; 170 } 171 172 static int mxs_pwm_remove(struct platform_device *pdev) 173 { 174 struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev); 175 176 return pwmchip_remove(&mxs->chip); 177 } 178 179 static const struct of_device_id mxs_pwm_dt_ids[] = { 180 { .compatible = "fsl,imx23-pwm", }, 181 { /* sentinel */ } 182 }; 183 MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids); 184 185 static struct platform_driver mxs_pwm_driver = { 186 .driver = { 187 .name = "mxs-pwm", 188 .of_match_table = mxs_pwm_dt_ids, 189 }, 190 .probe = mxs_pwm_probe, 191 .remove = mxs_pwm_remove, 192 }; 193 module_platform_driver(mxs_pwm_driver); 194 195 MODULE_ALIAS("platform:mxs-pwm"); 196 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); 197 MODULE_DESCRIPTION("Freescale MXS PWM Driver"); 198 MODULE_LICENSE("GPL v2"); 199