1 /* 2 * Copyright (C) 2016 Broadcom 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License as 6 * published by the Free Software Foundation version 2. 7 * 8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 9 * kind, whether express or implied; without even the implied warranty 10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #include <linux/clk.h> 15 #include <linux/delay.h> 16 #include <linux/err.h> 17 #include <linux/io.h> 18 #include <linux/math64.h> 19 #include <linux/module.h> 20 #include <linux/of.h> 21 #include <linux/platform_device.h> 22 #include <linux/pwm.h> 23 24 #define IPROC_PWM_CTRL_OFFSET 0x00 25 #define IPROC_PWM_CTRL_TYPE_SHIFT(ch) (15 + (ch)) 26 #define IPROC_PWM_CTRL_POLARITY_SHIFT(ch) (8 + (ch)) 27 #define IPROC_PWM_CTRL_EN_SHIFT(ch) (ch) 28 29 #define IPROC_PWM_PERIOD_OFFSET(ch) (0x04 + ((ch) << 3)) 30 #define IPROC_PWM_PERIOD_MIN 0x02 31 #define IPROC_PWM_PERIOD_MAX 0xffff 32 33 #define IPROC_PWM_DUTY_CYCLE_OFFSET(ch) (0x08 + ((ch) << 3)) 34 #define IPROC_PWM_DUTY_CYCLE_MIN 0x00 35 #define IPROC_PWM_DUTY_CYCLE_MAX 0xffff 36 37 #define IPROC_PWM_PRESCALE_OFFSET 0x24 38 #define IPROC_PWM_PRESCALE_BITS 0x06 39 #define IPROC_PWM_PRESCALE_SHIFT(ch) ((3 - (ch)) * \ 40 IPROC_PWM_PRESCALE_BITS) 41 #define IPROC_PWM_PRESCALE_MASK(ch) (IPROC_PWM_PRESCALE_MAX << \ 42 IPROC_PWM_PRESCALE_SHIFT(ch)) 43 #define IPROC_PWM_PRESCALE_MIN 0x00 44 #define IPROC_PWM_PRESCALE_MAX 0x3f 45 46 struct iproc_pwmc { 47 struct pwm_chip chip; 48 void __iomem *base; 49 struct clk *clk; 50 }; 51 52 static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip) 53 { 54 return container_of(chip, struct iproc_pwmc, chip); 55 } 56 57 static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel) 58 { 59 u32 value; 60 61 value = readl(ip->base + IPROC_PWM_CTRL_OFFSET); 62 value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel); 63 writel(value, ip->base + IPROC_PWM_CTRL_OFFSET); 64 65 /* must be a 400 ns delay between clearing and setting enable bit */ 66 ndelay(400); 67 } 68 69 static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel) 70 { 71 u32 value; 72 73 value = readl(ip->base + IPROC_PWM_CTRL_OFFSET); 74 value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel)); 75 writel(value, ip->base + IPROC_PWM_CTRL_OFFSET); 76 77 /* must be a 400 ns delay between clearing and setting enable bit */ 78 ndelay(400); 79 } 80 81 static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 82 struct pwm_state *state) 83 { 84 struct iproc_pwmc *ip = to_iproc_pwmc(chip); 85 u64 tmp, multi, rate; 86 u32 value, prescale; 87 88 rate = clk_get_rate(ip->clk); 89 90 value = readl(ip->base + IPROC_PWM_CTRL_OFFSET); 91 92 if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm))) 93 state->enabled = true; 94 else 95 state->enabled = false; 96 97 if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm))) 98 state->polarity = PWM_POLARITY_NORMAL; 99 else 100 state->polarity = PWM_POLARITY_INVERSED; 101 102 value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET); 103 prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm); 104 prescale &= IPROC_PWM_PRESCALE_MAX; 105 106 multi = NSEC_PER_SEC * (prescale + 1); 107 108 value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm)); 109 tmp = (value & IPROC_PWM_PERIOD_MAX) * multi; 110 state->period = div64_u64(tmp, rate); 111 112 value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm)); 113 tmp = (value & IPROC_PWM_PERIOD_MAX) * multi; 114 state->duty_cycle = div64_u64(tmp, rate); 115 } 116 117 static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm, 118 struct pwm_state *state) 119 { 120 unsigned long prescale = IPROC_PWM_PRESCALE_MIN; 121 struct iproc_pwmc *ip = to_iproc_pwmc(chip); 122 u32 value, period, duty; 123 u64 rate; 124 125 rate = clk_get_rate(ip->clk); 126 127 /* 128 * Find period count, duty count and prescale to suit duty_cycle and 129 * period. This is done according to formulas described below: 130 * 131 * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE 132 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE 133 * 134 * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1)) 135 * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1)) 136 */ 137 while (1) { 138 u64 value, div; 139 140 div = NSEC_PER_SEC * (prescale + 1); 141 value = rate * state->period; 142 period = div64_u64(value, div); 143 value = rate * state->duty_cycle; 144 duty = div64_u64(value, div); 145 146 if (period < IPROC_PWM_PERIOD_MIN || 147 duty < IPROC_PWM_DUTY_CYCLE_MIN) 148 return -EINVAL; 149 150 if (period <= IPROC_PWM_PERIOD_MAX && 151 duty <= IPROC_PWM_DUTY_CYCLE_MAX) 152 break; 153 154 /* Otherwise, increase prescale and recalculate counts */ 155 if (++prescale > IPROC_PWM_PRESCALE_MAX) 156 return -EINVAL; 157 } 158 159 iproc_pwmc_disable(ip, pwm->hwpwm); 160 161 /* Set prescale */ 162 value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET); 163 value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm); 164 value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm); 165 writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET); 166 167 /* set period and duty cycle */ 168 writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm)); 169 writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm)); 170 171 /* set polarity */ 172 value = readl(ip->base + IPROC_PWM_CTRL_OFFSET); 173 174 if (state->polarity == PWM_POLARITY_NORMAL) 175 value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm); 176 else 177 value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)); 178 179 writel(value, ip->base + IPROC_PWM_CTRL_OFFSET); 180 181 if (state->enabled) 182 iproc_pwmc_enable(ip, pwm->hwpwm); 183 184 return 0; 185 } 186 187 static const struct pwm_ops iproc_pwm_ops = { 188 .apply = iproc_pwmc_apply, 189 .get_state = iproc_pwmc_get_state, 190 }; 191 192 static int iproc_pwmc_probe(struct platform_device *pdev) 193 { 194 struct iproc_pwmc *ip; 195 struct resource *res; 196 unsigned int i; 197 u32 value; 198 int ret; 199 200 ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL); 201 if (!ip) 202 return -ENOMEM; 203 204 platform_set_drvdata(pdev, ip); 205 206 ip->chip.dev = &pdev->dev; 207 ip->chip.ops = &iproc_pwm_ops; 208 ip->chip.base = -1; 209 ip->chip.npwm = 4; 210 ip->chip.of_xlate = of_pwm_xlate_with_flags; 211 ip->chip.of_pwm_n_cells = 3; 212 213 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 214 ip->base = devm_ioremap_resource(&pdev->dev, res); 215 if (IS_ERR(ip->base)) 216 return PTR_ERR(ip->base); 217 218 ip->clk = devm_clk_get(&pdev->dev, NULL); 219 if (IS_ERR(ip->clk)) { 220 dev_err(&pdev->dev, "failed to get clock: %ld\n", 221 PTR_ERR(ip->clk)); 222 return PTR_ERR(ip->clk); 223 } 224 225 ret = clk_prepare_enable(ip->clk); 226 if (ret < 0) { 227 dev_err(&pdev->dev, "failed to enable clock: %d\n", ret); 228 return ret; 229 } 230 231 /* Set full drive and normal polarity for all channels */ 232 value = readl(ip->base + IPROC_PWM_CTRL_OFFSET); 233 234 for (i = 0; i < ip->chip.npwm; i++) { 235 value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i)); 236 value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i); 237 } 238 239 writel(value, ip->base + IPROC_PWM_CTRL_OFFSET); 240 241 ret = pwmchip_add(&ip->chip); 242 if (ret < 0) { 243 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); 244 clk_disable_unprepare(ip->clk); 245 } 246 247 return ret; 248 } 249 250 static int iproc_pwmc_remove(struct platform_device *pdev) 251 { 252 struct iproc_pwmc *ip = platform_get_drvdata(pdev); 253 254 clk_disable_unprepare(ip->clk); 255 256 return pwmchip_remove(&ip->chip); 257 } 258 259 static const struct of_device_id bcm_iproc_pwmc_dt[] = { 260 { .compatible = "brcm,iproc-pwm" }, 261 { }, 262 }; 263 MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt); 264 265 static struct platform_driver iproc_pwmc_driver = { 266 .driver = { 267 .name = "bcm-iproc-pwm", 268 .of_match_table = bcm_iproc_pwmc_dt, 269 }, 270 .probe = iproc_pwmc_probe, 271 .remove = iproc_pwmc_remove, 272 }; 273 module_platform_driver(iproc_pwmc_driver); 274 275 MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>"); 276 MODULE_DESCRIPTION("Broadcom iProc PWM driver"); 277 MODULE_LICENSE("GPL v2"); 278