diff options
Diffstat (limited to 'drivers/pwm/pwm-puv3.c')
| -rw-r--r-- | drivers/pwm/pwm-puv3.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-puv3.c b/drivers/pwm/pwm-puv3.c new file mode 100644 index 000000000000..2a93f37c46ad --- /dev/null +++ b/drivers/pwm/pwm-puv3.c @@ -0,0 +1,161 @@ +/* + * linux/arch/unicore32/kernel/pwm.c + * + * Code specific to PKUnity SoC and UniCore ISA + * + * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> + * Copyright (C) 2001-2010 Guan Xuetao + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/pwm.h> + +#include <asm/div64.h> +#include <mach/hardware.h> + +struct puv3_pwm_chip { + struct pwm_chip chip; + void __iomem *base; + struct clk *clk; + bool enabled; +}; + +static inline struct puv3_pwm_chip *to_puv3(struct pwm_chip *chip) +{ + return container_of(chip, struct puv3_pwm_chip, chip); +} + +/* + * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE + * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE + */ +static int puv3_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + unsigned long period_cycles, prescale, pv, dc; + struct puv3_pwm_chip *puv3 = to_puv3(chip); + unsigned long long c; + + c = clk_get_rate(puv3->clk); + c = c * period_ns; + do_div(c, 1000000000); + period_cycles = c; + + if (period_cycles < 1) + period_cycles = 1; + + prescale = (period_cycles - 1) / 1024; + pv = period_cycles / (prescale + 1) - 1; + + if (prescale > 63) + return -EINVAL; + + if (duty_ns == period_ns) + dc = OST_PWMDCCR_FDCYCLE; + else + dc = (pv + 1) * duty_ns / period_ns; + + /* + * NOTE: the clock to PWM has to be enabled first + * before writing to the registers + */ + clk_prepare_enable(puv3->clk); + + writel(prescale, puv3->base + OST_PWM_PWCR); + writel(pv - dc, puv3->base + OST_PWM_DCCR); + writel(pv, puv3->base + OST_PWM_PCR); + + clk_disable_unprepare(puv3->clk); + + return 0; +} + +static int puv3_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct puv3_pwm_chip *puv3 = to_puv3(chip); + + return clk_prepare_enable(puv3->clk); +} + +static void puv3_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct puv3_pwm_chip *puv3 = to_puv3(chip); + + clk_disable_unprepare(puv3->clk); +} + +static const struct pwm_ops puv3_pwm_ops = { + .config = puv3_pwm_config, + .enable = puv3_pwm_enable, + .disable = puv3_pwm_disable, + .owner = THIS_MODULE, +}; + +static int __devinit pwm_probe(struct platform_device *pdev) +{ + struct puv3_pwm_chip *puv3; + struct resource *r; + int ret; + + puv3 = devm_kzalloc(&pdev->dev, sizeof(*puv3), GFP_KERNEL); + if (puv3 == NULL) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + puv3->clk = devm_clk_get(&pdev->dev, "OST_CLK"); + if (IS_ERR(puv3->clk)) + return PTR_ERR(puv3->clk); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + dev_err(&pdev->dev, "no memory resource defined\n"); + return -ENODEV; + } + + puv3->base = devm_request_and_ioremap(&pdev->dev, r); + if (puv3->base == NULL) + return -EADDRNOTAVAIL; + + puv3->chip.dev = &pdev->dev; + puv3->chip.ops = &puv3_pwm_ops; + puv3->chip.base = -1; + puv3->chip.npwm = 1; + + ret = pwmchip_add(&puv3->chip); + if (ret < 0) { + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, puv3); + return 0; +} + +static int __devexit pwm_remove(struct platform_device *pdev) +{ + struct puv3_pwm_chip *puv3 = platform_get_drvdata(pdev); + + return pwmchip_remove(&puv3->chip); +} + +static struct platform_driver puv3_pwm_driver = { + .driver = { + .name = "PKUnity-v3-PWM", + }, + .probe = pwm_probe, + .remove = __devexit_p(pwm_remove), +}; +module_platform_driver(puv3_pwm_driver); + +MODULE_LICENSE("GPL v2"); |