Lines Matching +full:pwm +full:- +full:period
1 // SPDX-License-Identifier: GPL-2.0
12 #include <linux/pwm.h>
17 #define PWM_MODE 0x80 /* set timer in PWM mode */
21 #define PERIOD(x) (((x) * 0x10) + 0x10) macro
38 static int bcm2835_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) in bcm2835_pwm_request() argument
43 value = readl(pc->base + PWM_CONTROL); in bcm2835_pwm_request()
44 value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm)); in bcm2835_pwm_request()
45 value |= (PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm)); in bcm2835_pwm_request()
46 writel(value, pc->base + PWM_CONTROL); in bcm2835_pwm_request()
51 static void bcm2835_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) in bcm2835_pwm_free() argument
56 value = readl(pc->base + PWM_CONTROL); in bcm2835_pwm_free()
57 value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm)); in bcm2835_pwm_free()
58 writel(value, pc->base + PWM_CONTROL); in bcm2835_pwm_free()
61 static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, in bcm2835_pwm_apply() argument
66 unsigned long rate = clk_get_rate(pc->clk); in bcm2835_pwm_apply()
73 dev_err(pc->dev, "failed to get clock rate\n"); in bcm2835_pwm_apply()
74 return -EINVAL; in bcm2835_pwm_apply()
78 * period_cycles must be a 32 bit value, so period * rate / NSEC_PER_SEC in bcm2835_pwm_apply()
80 * multiplication period * rate doesn't overflow. in bcm2835_pwm_apply()
81 * To calculate the maximal possible period that guarantees the in bcm2835_pwm_apply()
84 * round(period * rate / NSEC_PER_SEC) <= U32_MAX in bcm2835_pwm_apply()
85 * <=> period * rate / NSEC_PER_SEC < U32_MAX + 0.5 in bcm2835_pwm_apply()
86 * <=> period * rate < (U32_MAX + 0.5) * NSEC_PER_SEC in bcm2835_pwm_apply()
87 * <=> period < ((U32_MAX + 0.5) * NSEC_PER_SEC) / rate in bcm2835_pwm_apply()
88 * <=> period < ((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate in bcm2835_pwm_apply()
89 * <=> period <= ceil((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate) - 1 in bcm2835_pwm_apply()
91 max_period = DIV_ROUND_UP_ULL((u64)U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC / 2, rate) - 1; in bcm2835_pwm_apply()
93 if (state->period > max_period) in bcm2835_pwm_apply()
94 return -EINVAL; in bcm2835_pwm_apply()
96 /* set period */ in bcm2835_pwm_apply()
97 period_cycles = DIV_ROUND_CLOSEST_ULL(state->period * rate, NSEC_PER_SEC); in bcm2835_pwm_apply()
99 /* don't accept a period that is too small */ in bcm2835_pwm_apply()
101 return -EINVAL; in bcm2835_pwm_apply()
103 writel(period_cycles, pc->base + PERIOD(pwm->hwpwm)); in bcm2835_pwm_apply()
106 val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * rate, NSEC_PER_SEC); in bcm2835_pwm_apply()
107 writel(val, pc->base + DUTY(pwm->hwpwm)); in bcm2835_pwm_apply()
110 val = readl(pc->base + PWM_CONTROL); in bcm2835_pwm_apply()
112 if (state->polarity == PWM_POLARITY_NORMAL) in bcm2835_pwm_apply()
113 val &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm)); in bcm2835_pwm_apply()
115 val |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm); in bcm2835_pwm_apply()
118 if (state->enabled) in bcm2835_pwm_apply()
119 val |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm); in bcm2835_pwm_apply()
121 val &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm)); in bcm2835_pwm_apply()
123 writel(val, pc->base + PWM_CONTROL); in bcm2835_pwm_apply()
140 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); in bcm2835_pwm_probe()
142 return -ENOMEM; in bcm2835_pwm_probe()
144 pc->dev = &pdev->dev; in bcm2835_pwm_probe()
146 pc->base = devm_platform_ioremap_resource(pdev, 0); in bcm2835_pwm_probe()
147 if (IS_ERR(pc->base)) in bcm2835_pwm_probe()
148 return PTR_ERR(pc->base); in bcm2835_pwm_probe()
150 pc->clk = devm_clk_get(&pdev->dev, NULL); in bcm2835_pwm_probe()
151 if (IS_ERR(pc->clk)) in bcm2835_pwm_probe()
152 return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk), in bcm2835_pwm_probe()
155 ret = clk_prepare_enable(pc->clk); in bcm2835_pwm_probe()
159 pc->chip.dev = &pdev->dev; in bcm2835_pwm_probe()
160 pc->chip.ops = &bcm2835_pwm_ops; in bcm2835_pwm_probe()
161 pc->chip.npwm = 2; in bcm2835_pwm_probe()
165 ret = pwmchip_add(&pc->chip); in bcm2835_pwm_probe()
172 clk_disable_unprepare(pc->clk); in bcm2835_pwm_probe()
180 pwmchip_remove(&pc->chip); in bcm2835_pwm_remove()
182 clk_disable_unprepare(pc->clk); in bcm2835_pwm_remove()
186 { .compatible = "brcm,bcm2835-pwm", },
193 .name = "bcm2835-pwm",
202 MODULE_DESCRIPTION("Broadcom BCM2835 PWM driver");