--- /dev/null
+/*
+ * TI/National Semiconductor LP3943 PWM driver
+ *
+ * Copyright 2013 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mfd/lp3943.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define LP3943_MAX_DUTY 255
+#define LP3943_MIN_PERIOD 6250
+#define LP3943_MAX_PERIOD 1600000
+
+struct lp3943_pwm {
+ struct pwm_chip chip;
+ struct lp3943 *lp3943;
+ struct lp3943_platform_data *pdata;
+};
+
+static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
+{
+ return container_of(_chip, struct lp3943_pwm, chip);
+}
+
+static struct lp3943_pwm_map *
+lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
+{
+ struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
+ struct lp3943 *lp3943 = lp3943_pwm->lp3943;
+ struct lp3943_pwm_map *pwm_map;
+ int i, offset;
+
+ pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
+ if (!pwm_map)
+ return ERR_PTR(-ENOMEM);
+
+ pwm_map->output = pdata->pwms[hwpwm]->output;
+ pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
+
+ for (i = 0; i < pwm_map->num_outputs; i++) {
+ offset = pwm_map->output[i];
+
+ /* Return an error if the pin is already assigned */
+ if (test_and_set_bit(offset, &lp3943->pin_used)) {
+ kfree(pwm_map);
+ return ERR_PTR(-EBUSY);
+ }
+ }
+
+ return pwm_map;
+}
+
+static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
+ struct lp3943_pwm_map *pwm_map;
+
+ pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
+ if (IS_ERR(pwm_map))
+ return PTR_ERR(pwm_map);
+
+ return pwm_set_chip_data(pwm, pwm_map);
+}
+
+static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
+ struct lp3943_pwm_map *pwm_map)
+{
+ struct lp3943 *lp3943 = lp3943_pwm->lp3943;
+ int i, offset;
+
+ for (i = 0; i < pwm_map->num_outputs; i++) {
+ offset = pwm_map->output[i];
+ clear_bit(offset, &lp3943->pin_used);
+ }
+
+ kfree(pwm_map);
+}
+
+static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
+ struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
+
+ lp3943_pwm_free_map(lp3943_pwm, pwm_map);
+}
+
+static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
+ struct lp3943 *lp3943 = lp3943_pwm->lp3943;
+ u8 val, reg_duty, reg_prescale;
+ int err;
+
+ /*
+ * How to configure the LP3943 PWMs
+ *
+ * 1) Period = 6250 ~ 1600000
+ * 2) Prescale = period / 6250 -1
+ * 3) Duty = input duty
+ *
+ * Prescale and duty are register values
+ */
+
+ if (pwm->hwpwm == 0) {
+ reg_prescale = LP3943_REG_PRESCALE0;
+ reg_duty = LP3943_REG_PWM0;
+ } else {
+ reg_prescale = LP3943_REG_PRESCALE1;
+ reg_duty = LP3943_REG_PWM1;
+ }
+
+ period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
+ val = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
+
+ err = lp3943_write_byte(lp3943, reg_prescale, val);
+ if (err)
+ return err;
+
+ val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
+
+ return lp3943_write_byte(lp3943, reg_duty, val);
+}
+
+static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
+ struct lp3943_pwm_map *pwm_map,
+ u8 val)
+{
+ struct lp3943 *lp3943 = lp3943_pwm->lp3943;
+ const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
+ int i, index, err;
+
+ for (i = 0; i < pwm_map->num_outputs; i++) {
+ index = pwm_map->output[i];
+ err = lp3943_update_bits(lp3943, mux[index].reg,
+ mux[index].mask,
+ val << mux[index].shift);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
+ struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
+ u8 val;
+
+ if (pwm->hwpwm == 0)
+ val = LP3943_DIM_PWM0;
+ else
+ val = LP3943_DIM_PWM1;
+
+ /*
+ * Each PWM generator is set to control any of outputs of LP3943.
+ * To enable/disable the PWM, these output pins should be configured.
+ */
+
+ return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
+}
+
+static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
+ struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
+
+ /*
+ * LP3943 outputs are open-drain, so the pin should be configured
+ * when the PWM is disabled.
+ */
+
+ lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
+}
+
+static const struct pwm_ops lp3943_pwm_ops = {
+ .request = lp3943_pwm_request,
+ .free = lp3943_pwm_free,
+ .config = lp3943_pwm_config,
+ .enable = lp3943_pwm_enable,
+ .disable = lp3943_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int lp3943_pwm_parse_dt(struct device *dev,
+ struct lp3943_pwm *lp3943_pwm)
+{
+ static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
+ struct device_node *node = dev->of_node;
+ struct lp3943_platform_data *pdata;
+ struct lp3943_pwm_map *pwm_map;
+ enum lp3943_pwm_output *output;
+ int i, err, proplen, count = 0;
+ u32 num_outputs;
+
+ if (!node)
+ return -EINVAL;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ /*
+ * Read the output map configuration from the device tree.
+ * Each of the two PWM generators can drive zero or more outputs.
+ */
+
+ for (i = 0; i < LP3943_NUM_PWMS; i++) {
+ if (!of_get_property(node, name[i], &proplen))
+ continue;
+
+ num_outputs = proplen / sizeof(u32);
+ if (num_outputs == 0)
+ continue;
+
+ output = devm_kzalloc(dev, sizeof(*output) * num_outputs,
+ GFP_KERNEL);
+ if (!output)
+ return -ENOMEM;
+
+ err = of_property_read_u32_array(node, name[i], output,
+ num_outputs);
+ if (err)
+ return err;
+
+ pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
+ if (!pwm_map)
+ return -ENOMEM;
+
+ pwm_map->output = output;
+ pwm_map->num_outputs = num_outputs;
+ pdata->pwms[i] = pwm_map;
+
+ count++;
+ }
+
+ if (count == 0)
+ return -ENODATA;
+
+ lp3943_pwm->pdata = pdata;
+ return 0;
+}
+
+static int lp3943_pwm_probe(struct platform_device *pdev)
+{
+ struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
+ struct lp3943_pwm *lp3943_pwm;
+ int ret;
+
+ lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
+ if (!lp3943_pwm)
+ return -ENOMEM;
+
+ lp3943_pwm->pdata = lp3943->pdata;
+ if (!lp3943_pwm->pdata) {
+ if (IS_ENABLED(CONFIG_OF))
+ ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
+ else
+ ret = -ENODEV;
+
+ if (ret)
+ return ret;
+ }
+
+ lp3943_pwm->lp3943 = lp3943;
+ lp3943_pwm->chip.dev = &pdev->dev;
+ lp3943_pwm->chip.ops = &lp3943_pwm_ops;
+ lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
+ lp3943_pwm->chip.can_sleep = true;
+
+ platform_set_drvdata(pdev, lp3943_pwm);
+
+ return pwmchip_add(&lp3943_pwm->chip);
+}
+
+static int lp3943_pwm_remove(struct platform_device *pdev)
+{
+ struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&lp3943_pwm->chip);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id lp3943_pwm_of_match[] = {
+ { .compatible = "ti,lp3943-pwm", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
+#endif
+
+static struct platform_driver lp3943_pwm_driver = {
+ .probe = lp3943_pwm_probe,
+ .remove = lp3943_pwm_remove,
+ .driver = {
+ .name = "lp3943-pwm",
+ .of_match_table = of_match_ptr(lp3943_pwm_of_match),
+ },
+};
+module_platform_driver(lp3943_pwm_driver);
+
+MODULE_DESCRIPTION("LP3943 PWM driver");
+MODULE_ALIAS("platform:lp3943-pwm");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff