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