1 // SPDX-License-Identifier: GPL-2.0
3  * DesignWare PWM Controller driver core
5  * Copyright (C) 2018-2020 Intel Corporation
20 #include <linux/pwm.h>
22 #include "pwm-dwc.h"
24 static void __dwc_pwm_set_enable(struct dwc_pwm *dwc, int pwm, int enabled)  in __dwc_pwm_set_enable()  argument
28 	reg = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm));  in __dwc_pwm_set_enable()
35 	dwc_pwm_writel(dwc, reg, DWC_TIM_CTRL(pwm));  in __dwc_pwm_set_enable()
39 				     struct pwm_device *pwm,  in __dwc_pwm_configure_timer()  argument
52 	tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, dwc->clk_ns);  in __dwc_pwm_configure_timer()
54 		return -ERANGE;  in __dwc_pwm_configure_timer()
55 	low = tmp - 1;  in __dwc_pwm_configure_timer()
57 	tmp = DIV_ROUND_CLOSEST_ULL(state->period - state->duty_cycle,  in __dwc_pwm_configure_timer()
58 				    dwc->clk_ns);  in __dwc_pwm_configure_timer()
60 		return -ERANGE;  in __dwc_pwm_configure_timer()
61 	high = tmp - 1;  in __dwc_pwm_configure_timer()
64 	 * Specification says timer usage flow is to disable timer, then  in __dwc_pwm_configure_timer()
66 	 * into timer after it is enabled - either after a disable or  in __dwc_pwm_configure_timer()
70 	__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);  in __dwc_pwm_configure_timer()
78 	dwc_pwm_writel(dwc, low, DWC_TIM_LD_CNT(pwm->hwpwm));  in __dwc_pwm_configure_timer()
79 	dwc_pwm_writel(dwc, high, DWC_TIM_LD_CNT2(pwm->hwpwm));  in __dwc_pwm_configure_timer()
82 	 * Set user-defined mode, timer reloads from Load Count registers  in __dwc_pwm_configure_timer()
84 	 * Set PWM mode, it makes output to toggle and width of low and high  in __dwc_pwm_configure_timer()
88 	dwc_pwm_writel(dwc, ctrl, DWC_TIM_CTRL(pwm->hwpwm));  in __dwc_pwm_configure_timer()
91 	 * Enable timer. Output starts from low period.  in __dwc_pwm_configure_timer()
93 	__dwc_pwm_set_enable(dwc, pwm->hwpwm, state->enabled);  in __dwc_pwm_configure_timer()
98 static int dwc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in dwc_pwm_apply()  argument
103 	if (state->polarity != PWM_POLARITY_INVERSED)  in dwc_pwm_apply()
104 		return -EINVAL;  in dwc_pwm_apply()
106 	if (state->enabled) {  in dwc_pwm_apply()
107 		if (!pwm->state.enabled)  in dwc_pwm_apply()
109 		return __dwc_pwm_configure_timer(dwc, pwm, state);  in dwc_pwm_apply()
111 		if (pwm->state.enabled) {  in dwc_pwm_apply()
112 			__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);  in dwc_pwm_apply()
120 static int dwc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,  in dwc_pwm_get_state()  argument
129 	ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm->hwpwm));  in dwc_pwm_get_state()
130 	ld = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(pwm->hwpwm));  in dwc_pwm_get_state()
131 	ld2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(pwm->hwpwm));  in dwc_pwm_get_state()
133 	state->enabled = !!(ctrl & DWC_TIM_CTRL_EN);  in dwc_pwm_get_state()
136 	 * If we're not in PWM, technically the output is a 50-50  in dwc_pwm_get_state()
137 	 * based on the timer load-count only.  in dwc_pwm_get_state()
140 		duty = (ld + 1) * dwc->clk_ns;  in dwc_pwm_get_state()
141 		period = (ld2 + 1)  * dwc->clk_ns;  in dwc_pwm_get_state()
144 		duty = (ld + 1) * dwc->clk_ns;  in dwc_pwm_get_state()
148 	state->polarity = PWM_POLARITY_INVERSED;  in dwc_pwm_get_state()
149 	state->period = period;  in dwc_pwm_get_state()
150 	state->duty_cycle = duty;  in dwc_pwm_get_state()
172 	dwc->clk_ns = 10;  in dwc_pwm_alloc()
173 	chip->ops = &dwc_pwm_ops;  in dwc_pwm_alloc()
182 MODULE_DESCRIPTION("DesignWare PWM Controller");