1 files changed, 114 insertions, 68 deletions

diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c
index bd0ebd04856a..98ee5cdbd0ba 100644
--- a/drivers/pwm/pwm-crc.c
+++ b/drivers/pwm/pwm-crc.c
@@ -1,15 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2015 Intel Corporation. All rights reserved.
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License version
- * 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
  * Author: Shobhit Kumar <shobhit.kumar@intel.com>
  */
 
@@ -29,115 +21,169 @@
 
 #define PWM_MAX_LEVEL		0xFF
 
-#define PWM_BASE_CLK		6000000  /* 6 MHz */
-#define PWM_MAX_PERIOD_NS	21333    /* 46.875KHz */
+#define PWM_BASE_CLK_MHZ	6	/* 6 MHz */
+#define PWM_MAX_PERIOD_NS	5461334	/* 183 Hz */
 
 /**
  * struct crystalcove_pwm - Crystal Cove PWM controller
- * @chip: the abstract pwm_chip structure.
  * @regmap: the regmap from the parent device.
  */
 struct crystalcove_pwm {
-	struct pwm_chip chip;
 	struct regmap *regmap;
 };
 
-static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
+static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *chip)
 {
-	return container_of(pc, struct crystalcove_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
-static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
+static int crc_pwm_calc_clk_div(int period_ns)
 {
-	struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
-
-	regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
-
-	return 0;
-}
+	int clk_div;
 
-static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
-{
-	struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
+	clk_div = PWM_BASE_CLK_MHZ * period_ns / (256 * NSEC_PER_USEC);
+	/* clk_div 1 - 128, maps to register values 0-127 */
+	if (clk_div > 0)
+		clk_div--;
 
-	regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
+	return clk_div;
 }
 
-static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
-			  int duty_ns, int period_ns)
+static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
 {
-	struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
-	struct device *dev = crc_pwm->chip.dev;
-	int level;
+	struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
+	struct device *dev = pwmchip_parent(chip);
+	int err;
 
-	if (period_ns > PWM_MAX_PERIOD_NS) {
+	if (state->period > PWM_MAX_PERIOD_NS) {
 		dev_err(dev, "un-supported period_ns\n");
 		return -EINVAL;
 	}
 
-	if (pwm_get_period(pwm) != period_ns) {
-		int clk_div;
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (pwm_is_enabled(pwm) && !state->enabled) {
+		err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
+		if (err) {
+			dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
+			return err;
+		}
+	}
+
+	if (pwm_get_duty_cycle(pwm) != state->duty_cycle ||
+	    pwm_get_period(pwm) != state->period) {
+		u64 level = state->duty_cycle * PWM_MAX_LEVEL;
+
+		do_div(level, state->period);
+
+		err = regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
+		if (err) {
+			dev_err(dev, "Error writing PWM0_DUTY_CYCLE %d\n", err);
+			return err;
+		}
+	}
+
+	if (pwm_is_enabled(pwm) && state->enabled &&
+	    pwm_get_period(pwm) != state->period) {
+		/* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */
+		err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0);
+		if (err) {
+			dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
+			return err;
+		}
+	}
+
+	if (pwm_get_period(pwm) != state->period ||
+	    pwm_is_enabled(pwm) != state->enabled) {
+		int clk_div = crc_pwm_calc_clk_div(state->period);
+		int pwm_output_enable = state->enabled ? PWM_OUTPUT_ENABLE : 0;
+
+		err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
+				   clk_div | pwm_output_enable);
+		if (err) {
+			dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
+			return err;
+		}
+	}
 
-		/* changing the clk divisor, need to disable fisrt */
-		crc_pwm_disable(c, pwm);
-		clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
+	if (!pwm_is_enabled(pwm) && state->enabled) {
+		err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
+		if (err) {
+			dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
+			return err;
+		}
+	}
 
-		regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
-					clk_div | PWM_OUTPUT_ENABLE);
+	return 0;
+}
 
-		/* enable back */
-		crc_pwm_enable(c, pwm);
+static int crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			     struct pwm_state *state)
+{
+	struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
+	struct device *dev = pwmchip_parent(chip);
+	unsigned int clk_div, clk_div_reg, duty_cycle_reg;
+	int error;
+
+	error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
+	if (error) {
+		dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
+		return error;
 	}
 
-	/* change the pwm duty cycle */
-	level = duty_ns * PWM_MAX_LEVEL / period_ns;
-	regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
+	error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
+	if (error) {
+		dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
+		return error;
+	}
+
+	clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
+
+	state->period =
+		DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ);
+	state->duty_cycle =
+		DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
+	state->polarity = PWM_POLARITY_NORMAL;
+	state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
 
 	return 0;
 }
 
 static const struct pwm_ops crc_pwm_ops = {
-	.config = crc_pwm_config,
-	.enable = crc_pwm_enable,
-	.disable = crc_pwm_disable,
+	.apply = crc_pwm_apply,
+	.get_state = crc_pwm_get_state,
 };
 
 static int crystalcove_pwm_probe(struct platform_device *pdev)
 {
-	struct crystalcove_pwm *pwm;
+	struct pwm_chip *chip;
+	struct crystalcove_pwm *crc_pwm;
 	struct device *dev = pdev->dev.parent;
 	struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
 
-	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
-	if (!pwm)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*crc_pwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	crc_pwm = to_crc_pwm(chip);
 
-	pwm->chip.dev = &pdev->dev;
-	pwm->chip.ops = &crc_pwm_ops;
-	pwm->chip.base = -1;
-	pwm->chip.npwm = 1;
+	chip->ops = &crc_pwm_ops;
 
 	/* get the PMIC regmap */
-	pwm->regmap = pmic->regmap;
-
-	platform_set_drvdata(pdev, pwm);
-
-	return pwmchip_add(&pwm->chip);
-}
-
-static int crystalcove_pwm_remove(struct platform_device *pdev)
-{
-	struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
+	crc_pwm->regmap = pmic->regmap;
 
-	return pwmchip_remove(&pwm->chip);
+	return devm_pwmchip_add(&pdev->dev, chip);
 }
 
 static struct platform_driver crystalcove_pwm_driver = {
 	.probe = crystalcove_pwm_probe,
-	.remove = crystalcove_pwm_remove,
 	.driver = {
 		.name = "crystal_cove_pwm",
 	},
 };
+module_platform_driver(crystalcove_pwm_driver);
 
-builtin_platform_driver(crystalcove_pwm_driver);
+MODULE_ALIAS("platform:crystal_cove_pwm");
+MODULE_DESCRIPTION("Intel Crystalcove (CRC) PWM support");
+MODULE_LICENSE("GPL");