diff options
Diffstat (limited to 'drivers/pwm/pwm-berlin.c')
| -rw-r--r-- | drivers/pwm/pwm-berlin.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c new file mode 100644 index 000000000..65108129d --- /dev/null +++ b/drivers/pwm/pwm-berlin.c @@ -0,0 +1,219 @@ +/* + * 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"); |