diff options
Diffstat (limited to 'kernel/drivers/pwm/pwm-clps711x.c')
| -rw-r--r-- | kernel/drivers/pwm/pwm-clps711x.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/pwm-clps711x.c b/kernel/drivers/pwm/pwm-clps711x.c new file mode 100644 index 000000000..a80c10803 --- /dev/null +++ b/kernel/drivers/pwm/pwm-clps711x.c @@ -0,0 +1,175 @@ +/* + * Cirrus Logic CLPS711X PWM driver + * + * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru> + * + * 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; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +struct clps711x_chip { + struct pwm_chip chip; + void __iomem *pmpcon; + struct clk *clk; + spinlock_t lock; +}; + +static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct clps711x_chip, chip); +} + +static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v) +{ + /* PWM0 - bits 4..7, PWM1 - bits 8..11 */ + u32 shift = (n + 1) * 4; + unsigned long flags; + u32 tmp; + + spin_lock_irqsave(&priv->lock, flags); + + tmp = readl(priv->pmpcon); + tmp &= ~(0xf << shift); + tmp |= v << shift; + writel(tmp, priv->pmpcon); + + spin_unlock_irqrestore(&priv->lock, flags); +} + +static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v) +{ + /* Duty cycle 0..15 max */ + return DIV_ROUND_CLOSEST(v * 0xf, pwm_get_period(pwm)); +} + +static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int freq = clk_get_rate(priv->clk); + + if (!freq) + return -EINVAL; + + /* Store constant period value */ + pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq)); + + return 0; +} + +static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int duty; + + if (period_ns != pwm_get_period(pwm)) + return -EINVAL; + + duty = clps711x_get_duty(pwm, duty_ns); + clps711x_pwm_update_val(priv, pwm->hwpwm, duty); + + return 0; +} + +static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + unsigned int duty; + + duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm)); + clps711x_pwm_update_val(priv, pwm->hwpwm, duty); + + return 0; +} + +static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct clps711x_chip *priv = to_clps711x_chip(chip); + + clps711x_pwm_update_val(priv, pwm->hwpwm, 0); +} + +static const struct pwm_ops clps711x_pwm_ops = { + .request = clps711x_pwm_request, + .config = clps711x_pwm_config, + .enable = clps711x_pwm_enable, + .disable = clps711x_pwm_disable, + .owner = THIS_MODULE, +}; + +static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip, + const struct of_phandle_args *args) +{ + if (args->args[0] >= chip->npwm) + return ERR_PTR(-EINVAL); + + return pwm_request_from_chip(chip, args->args[0], NULL); +} + +static int clps711x_pwm_probe(struct platform_device *pdev) +{ + struct clps711x_chip *priv; + struct resource *res; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->pmpcon = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(priv->pmpcon)) + return PTR_ERR(priv->pmpcon); + + priv->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(priv->clk)) + return PTR_ERR(priv->clk); + + priv->chip.ops = &clps711x_pwm_ops; + priv->chip.dev = &pdev->dev; + priv->chip.base = -1; + priv->chip.npwm = 2; + priv->chip.of_xlate = clps711x_pwm_xlate; + priv->chip.of_pwm_n_cells = 1; + + spin_lock_init(&priv->lock); + + platform_set_drvdata(pdev, priv); + + return pwmchip_add(&priv->chip); +} + +static int clps711x_pwm_remove(struct platform_device *pdev) +{ + struct clps711x_chip *priv = platform_get_drvdata(pdev); + + return pwmchip_remove(&priv->chip); +} + +static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = { + { .compatible = "cirrus,clps711x-pwm", }, + { } +}; +MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids); + +static struct platform_driver clps711x_pwm_driver = { + .driver = { + .name = "clps711x-pwm", + .of_match_table = of_match_ptr(clps711x_pwm_dt_ids), + }, + .probe = clps711x_pwm_probe, + .remove = clps711x_pwm_remove, +}; +module_platform_driver(clps711x_pwm_driver); + +MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); +MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver"); +MODULE_LICENSE("GPL"); |