1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * PWM framework driver for Cirrus Logic EP93xx
9  *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
12  *   platform device ep93xx-pwm.0 - PWMOUT
15  *   platform device ep93xx-pwm.0 - PWMOUT
16  *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
22 #include <linux/clk.h>
25 #include <linux/pwm.h>
38 	struct clk *clk;  member
47 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)  in ep93xx_pwm_request()  argument
49 	struct platform_device *pdev = to_platform_device(chip->dev);  in ep93xx_pwm_request()
54 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)  in ep93xx_pwm_free()  argument
56 	struct platform_device *pdev = to_platform_device(chip->dev);  in ep93xx_pwm_free()
61 static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in ep93xx_pwm_apply()  argument
66 	bool enabled = state->enabled;  in ep93xx_pwm_apply()
67 	void __iomem *base = ep93xx_pwm->base;  in ep93xx_pwm_apply()
73 	if (state->polarity != pwm->state.polarity) {  in ep93xx_pwm_apply()
75 			writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);  in ep93xx_pwm_apply()
76 			clk_disable_unprepare(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
81 		 * The clock needs to be enabled to access the PWM registers.  in ep93xx_pwm_apply()
82 		 * Polarity can only be changed when the PWM is disabled.  in ep93xx_pwm_apply()
84 		ret = clk_prepare_enable(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
88 		if (state->polarity == PWM_POLARITY_INVERSED)  in ep93xx_pwm_apply()
89 			writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);  in ep93xx_pwm_apply()
91 			writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);  in ep93xx_pwm_apply()
93 		clk_disable_unprepare(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
96 	if (!state->enabled) {  in ep93xx_pwm_apply()
98 			writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);  in ep93xx_pwm_apply()
99 			clk_disable_unprepare(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
106 	 * The clock needs to be enabled to access the PWM registers.  in ep93xx_pwm_apply()
109 	if (!pwm_is_enabled(pwm)) {  in ep93xx_pwm_apply()
110 		ret = clk_prepare_enable(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
115 	c = clk_get_rate(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
116 	c *= state->period;  in ep93xx_pwm_apply()
121 	c *= state->duty_cycle;  in ep93xx_pwm_apply()
122 	do_div(c, state->period);  in ep93xx_pwm_apply()
128 		/* Order is important if PWM is running */  in ep93xx_pwm_apply()
138 		ret = -EINVAL;  in ep93xx_pwm_apply()
141 	if (!pwm_is_enabled(pwm))  in ep93xx_pwm_apply()
142 		clk_disable_unprepare(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
148 		ret = clk_prepare_enable(ep93xx_pwm->clk);  in ep93xx_pwm_apply()
152 		writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);  in ep93xx_pwm_apply()
170 	ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);  in ep93xx_pwm_probe()
172 		return -ENOMEM;  in ep93xx_pwm_probe()
174 	ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);  in ep93xx_pwm_probe()
175 	if (IS_ERR(ep93xx_pwm->base))  in ep93xx_pwm_probe()
176 		return PTR_ERR(ep93xx_pwm->base);  in ep93xx_pwm_probe()
178 	ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");  in ep93xx_pwm_probe()
179 	if (IS_ERR(ep93xx_pwm->clk))  in ep93xx_pwm_probe()
180 		return PTR_ERR(ep93xx_pwm->clk);  in ep93xx_pwm_probe()
182 	ep93xx_pwm->chip.dev = &pdev->dev;  in ep93xx_pwm_probe()
183 	ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;  in ep93xx_pwm_probe()
184 	ep93xx_pwm->chip.npwm = 1;  in ep93xx_pwm_probe()
186 	ret = devm_pwmchip_add(&pdev->dev, &ep93xx_pwm->chip);  in ep93xx_pwm_probe()
195 		.name = "ep93xx-pwm",
201 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
204 MODULE_ALIAS("platform:ep93xx-pwm");