--- /dev/null
+/*
+ * Marvell Berlin PWM driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define BERLIN_PWM_EN 0x0
+#define BERLIN_PWM_ENABLE BIT(0)
+#define BERLIN_PWM_CONTROL 0x4
+#define BERLIN_PWM_PRESCALE_MASK 0x7
+#define BERLIN_PWM_PRESCALE_MAX 4096
+#define BERLIN_PWM_INVERT_POLARITY BIT(3)
+#define BERLIN_PWM_DUTY 0x8
+#define BERLIN_PWM_TCNT 0xc
+#define BERLIN_PWM_MAX_TCNT 65535
+
+struct berlin_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+};
+
+static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct berlin_pwm_chip, chip);
+}
+
+static const u32 prescaler_table[] = {
+ 1, 4, 8, 16, 64, 256, 1024, 4096
+};
+
+static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
+ unsigned int channel, unsigned long offset)
+{
+ return readl_relaxed(chip->base + channel * 0x10 + offset);
+}
+
+static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
+ unsigned int channel, u32 value,
+ unsigned long offset)
+{
+ writel_relaxed(value, chip->base + channel * 0x10 + offset);
+}
+
+static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
+ int duty_ns, int period_ns)
+{
+ struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+ unsigned int prescale;
+ u32 value, duty, period;
+ u64 cycles, tmp;
+
+ cycles = clk_get_rate(pwm->clk);
+ cycles *= period_ns;
+ do_div(cycles, NSEC_PER_SEC);
+
+ for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
+ tmp = cycles;
+ do_div(tmp, prescaler_table[prescale]);
+
+ if (tmp <= BERLIN_PWM_MAX_TCNT)
+ break;
+ }
+
+ if (tmp > BERLIN_PWM_MAX_TCNT)
+ return -ERANGE;
+
+ period = tmp;
+ cycles = tmp * duty_ns;
+ do_div(cycles, period_ns);
+ duty = cycles;
+
+ value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+ value &= ~BERLIN_PWM_PRESCALE_MASK;
+ value |= prescale;
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);
+
+ return 0;
+}
+
+static int berlin_pwm_set_polarity(struct pwm_chip *chip,
+ struct pwm_device *pwm_dev,
+ enum pwm_polarity polarity)
+{
+ struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+ u32 value;
+
+ value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+
+ if (polarity == PWM_POLARITY_NORMAL)
+ value &= ~BERLIN_PWM_INVERT_POLARITY;
+ else
+ value |= BERLIN_PWM_INVERT_POLARITY;
+
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+ return 0;
+}
+
+static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
+{
+ struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+ u32 value;
+
+ value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+ value |= BERLIN_PWM_ENABLE;
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+
+ return 0;
+}
+
+static void berlin_pwm_disable(struct pwm_chip *chip,
+ struct pwm_device *pwm_dev)
+{
+ struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+ u32 value;
+
+ value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+ value &= ~BERLIN_PWM_ENABLE;
+ berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+}
+
+static const struct pwm_ops berlin_pwm_ops = {
+ .config = berlin_pwm_config,
+ .set_polarity = berlin_pwm_set_polarity,
+ .enable = berlin_pwm_enable,
+ .disable = berlin_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static const struct of_device_id berlin_pwm_match[] = {
+ { .compatible = "marvell,berlin-pwm" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, berlin_pwm_match);
+
+static int berlin_pwm_probe(struct platform_device *pdev)
+{
+ struct berlin_pwm_chip *pwm;
+ struct resource *res;
+ int ret;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pwm->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(pwm->base))
+ return PTR_ERR(pwm->base);
+
+ pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk))
+ return PTR_ERR(pwm->clk);
+
+ ret = clk_prepare_enable(pwm->clk);
+ if (ret)
+ return ret;
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &berlin_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = 4;
+ pwm->chip.can_sleep = true;
+ pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+ pwm->chip.of_pwm_n_cells = 3;
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+ clk_disable_unprepare(pwm->clk);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+
+ return 0;
+}
+
+static int berlin_pwm_remove(struct platform_device *pdev)
+{
+ struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = pwmchip_remove(&pwm->chip);
+ clk_disable_unprepare(pwm->clk);
+
+ return ret;
+}
+
+static struct platform_driver berlin_pwm_driver = {
+ .probe = berlin_pwm_probe,
+ .remove = berlin_pwm_remove,
+ .driver = {
+ .name = "berlin-pwm",
+ .of_match_table = berlin_pwm_match,
+ },
+};
+module_platform_driver(berlin_pwm_driver);
+
+MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin PWM driver");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff