1 // SPDX-License-Identifier: GPL-2.0-only
13 #include <linux/pwm.h>
18  * The Kona PWM has some unusual characteristics.  Here are the main points.
34  * 5) When the external clock that feeds the PWM is disabled, output is pegged
74 	unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_prepare_for_settings()
78 	writel(value, kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_prepare_for_settings()
82 	 * it. Failing to do this may result in no PWM signal.  in kona_pwmc_prepare_for_settings()
89 	unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_apply_settings()
94 	writel(value, kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_apply_settings()
100 static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,  in kona_pwmc_config()  argument
106 	unsigned int value, chan = pwm->hwpwm;  in kona_pwmc_config()
119 	rate = clk_get_rate(kp->clk);  in kona_pwmc_config()
129 			return -EINVAL;  in kona_pwmc_config()
137 			return -EINVAL;  in kona_pwmc_config()
142 	value = readl(kp->base + PRESCALE_OFFSET);  in kona_pwmc_config()
145 	writel(value, kp->base + PRESCALE_OFFSET);  in kona_pwmc_config()
147 	writel(pc, kp->base + PERIOD_COUNT_OFFSET(chan));  in kona_pwmc_config()
149 	writel(dc, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan));  in kona_pwmc_config()
156 static int kona_pwmc_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,  in kona_pwmc_set_polarity()  argument
160 	unsigned int chan = pwm->hwpwm;  in kona_pwmc_set_polarity()
164 	ret = clk_prepare_enable(kp->clk);  in kona_pwmc_set_polarity()
172 	value = readl(kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_set_polarity()
179 	writel(value, kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_set_polarity()
183 	clk_disable_unprepare(kp->clk);  in kona_pwmc_set_polarity()
188 static int kona_pwmc_enable(struct pwm_chip *chip, struct pwm_device *pwm)  in kona_pwmc_enable()  argument
193 	ret = clk_prepare_enable(kp->clk);  in kona_pwmc_enable()
202 static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)  in kona_pwmc_disable()  argument
205 	unsigned int chan = pwm->hwpwm;  in kona_pwmc_disable()
211 	writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan));  in kona_pwmc_disable()
212 	writel(0, kp->base + PERIOD_COUNT_OFFSET(chan));  in kona_pwmc_disable()
215 	value = readl(kp->base + PRESCALE_OFFSET);  in kona_pwmc_disable()
217 	writel(value, kp->base + PRESCALE_OFFSET);  in kona_pwmc_disable()
221 	clk_disable_unprepare(kp->clk);  in kona_pwmc_disable()
224 static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in kona_pwmc_apply()  argument
229 	bool enabled = pwm->state.enabled;  in kona_pwmc_apply()
231 	if (state->polarity != pwm->state.polarity) {  in kona_pwmc_apply()
233 			kona_pwmc_disable(chip, pwm);  in kona_pwmc_apply()
237 		err = kona_pwmc_set_polarity(chip, pwm, state->polarity);  in kona_pwmc_apply()
241 		pwm->state.polarity = state->polarity;  in kona_pwmc_apply()
244 	if (!state->enabled) {  in kona_pwmc_apply()
246 			kona_pwmc_disable(chip, pwm);  in kona_pwmc_apply()
250 		 * This is a bit special here, usually the PWM should only be  in kona_pwmc_apply()
257 		err = kona_pwmc_enable(chip, pwm);  in kona_pwmc_apply()
262 	err = kona_pwmc_config(chip, pwm, state->duty_cycle, state->period);  in kona_pwmc_apply()
263 	if (err && !pwm->state.enabled)  in kona_pwmc_apply()
264 		clk_disable_unprepare(kp->clk);  in kona_pwmc_apply()
281 	chip = devm_pwmchip_alloc(&pdev->dev, 6, sizeof(*kp));  in kona_pwmc_probe()
286 	chip->ops = &kona_pwm_ops;  in kona_pwmc_probe()
288 	kp->base = devm_platform_ioremap_resource(pdev, 0);  in kona_pwmc_probe()
289 	if (IS_ERR(kp->base))  in kona_pwmc_probe()
290 		return PTR_ERR(kp->base);  in kona_pwmc_probe()
292 	kp->clk = devm_clk_get(&pdev->dev, NULL);  in kona_pwmc_probe()
293 	if (IS_ERR(kp->clk)) {  in kona_pwmc_probe()
294 		dev_err(&pdev->dev, "failed to get clock: %ld\n",  in kona_pwmc_probe()
295 			PTR_ERR(kp->clk));  in kona_pwmc_probe()
296 		return PTR_ERR(kp->clk);  in kona_pwmc_probe()
299 	ret = clk_prepare_enable(kp->clk);  in kona_pwmc_probe()
301 		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);  in kona_pwmc_probe()
306 	for (chan = 0; chan < chip->npwm; chan++)  in kona_pwmc_probe()
309 	writel(value, kp->base + PWM_CONTROL_OFFSET);  in kona_pwmc_probe()
311 	clk_disable_unprepare(kp->clk);  in kona_pwmc_probe()
313 	ret = devm_pwmchip_add(&pdev->dev, chip);  in kona_pwmc_probe()
315 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);  in kona_pwmc_probe()
321 	{ .compatible = "brcm,kona-pwm" },
328 		.name = "bcm-kona-pwm",
335 MODULE_AUTHOR("Broadcom Corporation <bcm-kernel-feedback-list@broadcom.com>");
337 MODULE_DESCRIPTION("Broadcom Kona PWM driver");