diff options
Diffstat (limited to 'drivers/pwm/pwm-vt8500.c')
| -rw-r--r-- | drivers/pwm/pwm-vt8500.c | 98 |
1 files changed, 74 insertions, 24 deletions
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c index ad14389b714..b0ba2d40343 100644 --- a/drivers/pwm/pwm-vt8500.c +++ b/drivers/pwm/pwm-vt8500.c @@ -1,7 +1,8 @@ /* * drivers/pwm/pwm-vt8500.c * - * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com> + * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz> + * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com> * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and @@ -21,14 +22,24 @@ #include <linux/io.h> #include <linux/pwm.h> #include <linux/delay.h> +#include <linux/clk.h> #include <asm/div64.h> -#define VT8500_NR_PWMS 4 +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_address.h> + +/* + * SoC architecture allocates register space for 4 PWMs but only + * 2 are currently implemented. + */ +#define VT8500_NR_PWMS 2 struct vt8500_chip { struct pwm_chip chip; void __iomem *base; + struct clk *clk; }; #define to_vt8500_chip(chip) container_of(chip, struct vt8500_chip, chip) @@ -51,8 +62,15 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, struct vt8500_chip *vt8500 = to_vt8500_chip(chip); unsigned long long c; unsigned long period_cycles, prescale, pv, dc; + int err; - c = 25000000/2; /* wild guess --- need to implement clocks */ + err = clk_enable(vt8500->clk); + if (err < 0) { + dev_err(chip->dev, "failed to enable clock\n"); + return err; + } + + c = clk_get_rate(vt8500->clk); c = c * period_ns; do_div(c, 1000000000); period_cycles = c; @@ -64,8 +82,10 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, if (pv > 4095) pv = 4095; - if (prescale > 1023) + if (prescale > 1023) { + clk_disable(vt8500->clk); return -EINVAL; + } c = (unsigned long long)pv * duty_ns; do_div(c, period_ns); @@ -80,13 +100,21 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3)); writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4)); + clk_disable(vt8500->clk); return 0; } static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { + int err; struct vt8500_chip *vt8500 = to_vt8500_chip(chip); + err = clk_enable(vt8500->clk); + if (err < 0) { + dev_err(chip->dev, "failed to enable clock\n"); + return err; + } + pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0)); writel(5, vt8500->base + (pwm->hwpwm << 4)); return 0; @@ -98,6 +126,8 @@ static void vt8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0)); writel(0, vt8500->base + (pwm->hwpwm << 4)); + + clk_disable(vt8500->clk); } static struct pwm_ops vt8500_pwm_ops = { @@ -107,12 +137,24 @@ static struct pwm_ops vt8500_pwm_ops = { .owner = THIS_MODULE, }; -static int __devinit pwm_probe(struct platform_device *pdev) +static const struct of_device_id vt8500_pwm_dt_ids[] = { + { .compatible = "via,vt8500-pwm", }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(of, vt8500_pwm_dt_ids); + +static int vt8500_pwm_probe(struct platform_device *pdev) { struct vt8500_chip *chip; struct resource *r; + struct device_node *np = pdev->dev.of_node; int ret; + if (!np) { + dev_err(&pdev->dev, "invalid devicetree node\n"); + return -EINVAL; + } + chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); if (chip == NULL) { dev_err(&pdev->dev, "failed to allocate memory\n"); @@ -124,6 +166,12 @@ static int __devinit pwm_probe(struct platform_device *pdev) chip->chip.base = -1; chip->chip.npwm = VT8500_NR_PWMS; + chip->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(chip->clk)) { + dev_err(&pdev->dev, "clock source not specified\n"); + return PTR_ERR(chip->clk); + } + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (r == NULL) { dev_err(&pdev->dev, "no memory resource defined\n"); @@ -131,18 +179,26 @@ static int __devinit pwm_probe(struct platform_device *pdev) } chip->base = devm_request_and_ioremap(&pdev->dev, r); - if (chip->base == NULL) + if (!chip->base) return -EADDRNOTAVAIL; + ret = clk_prepare(chip->clk); + if (ret < 0) { + dev_err(&pdev->dev, "failed to prepare clock\n"); + return ret; + } + ret = pwmchip_add(&chip->chip); - if (ret < 0) + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip\n"); return ret; + } platform_set_drvdata(pdev, chip); return ret; } -static int __devexit pwm_remove(struct platform_device *pdev) +static int vt8500_pwm_remove(struct platform_device *pdev) { struct vt8500_chip *chip; @@ -150,28 +206,22 @@ static int __devexit pwm_remove(struct platform_device *pdev) if (chip == NULL) return -ENODEV; + clk_unprepare(chip->clk); + return pwmchip_remove(&chip->chip); } -static struct platform_driver pwm_driver = { +static struct platform_driver vt8500_pwm_driver = { + .probe = vt8500_pwm_probe, + .remove = vt8500_pwm_remove, .driver = { .name = "vt8500-pwm", .owner = THIS_MODULE, + .of_match_table = vt8500_pwm_dt_ids, }, - .probe = pwm_probe, - .remove = __devexit_p(pwm_remove), }; +module_platform_driver(vt8500_pwm_driver); -static int __init pwm_init(void) -{ - return platform_driver_register(&pwm_driver); -} -arch_initcall(pwm_init); - -static void __exit pwm_exit(void) -{ - platform_driver_unregister(&pwm_driver); -} -module_exit(pwm_exit); - -MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("VT8500 PWM Driver"); +MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>"); +MODULE_LICENSE("GPL v2"); |