mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 12:43:55 +08:00
abeaf75527
If the pwmchip_remove() call fails, propagate the error to the driver's remove callback. This is required to prevent the module from being unloaded if a PWM provided by the driver is still in use. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
219 lines
4.7 KiB
C
219 lines
4.7 KiB
C
/*
|
|
* drivers/pwm/pwm-pxa.c
|
|
*
|
|
* simple driver for PWM (Pulse Width Modulator) controller
|
|
*
|
|
* 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.
|
|
*
|
|
* 2008-02-13 initial version
|
|
* eric miao <eric.miao@marvell.com>
|
|
*/
|
|
|
|
#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>
|
|
|
|
#define HAS_SECONDARY_PWM 0x10
|
|
#define PWM_ID_BASE(d) ((d) & 0xf)
|
|
|
|
static const struct platform_device_id pwm_id_table[] = {
|
|
/* PWM has_secondary_pwm? */
|
|
{ "pxa25x-pwm", 0 },
|
|
{ "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
|
|
{ "pxa168-pwm", 1 },
|
|
{ "pxa910-pwm", 1 },
|
|
{ },
|
|
};
|
|
MODULE_DEVICE_TABLE(platform, pwm_id_table);
|
|
|
|
/* PWM registers and bits definitions */
|
|
#define PWMCR (0x00)
|
|
#define PWMDCR (0x04)
|
|
#define PWMPCR (0x08)
|
|
|
|
#define PWMCR_SD (1 << 6)
|
|
#define PWMDCR_FD (1 << 10)
|
|
|
|
struct pxa_pwm_chip {
|
|
struct pwm_chip chip;
|
|
struct device *dev;
|
|
|
|
struct clk *clk;
|
|
int clk_enabled;
|
|
void __iomem *mmio_base;
|
|
};
|
|
|
|
static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
|
|
{
|
|
return container_of(chip, struct pxa_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 pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
|
|
int duty_ns, int period_ns)
|
|
{
|
|
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
|
|
unsigned long long c;
|
|
unsigned long period_cycles, prescale, pv, dc;
|
|
unsigned long offset;
|
|
int rc;
|
|
|
|
if (period_ns == 0 || duty_ns > period_ns)
|
|
return -EINVAL;
|
|
|
|
offset = pwm->hwpwm ? 0x10 : 0;
|
|
|
|
c = clk_get_rate(pc->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 = PWMDCR_FD;
|
|
else
|
|
dc = (pv + 1) * duty_ns / period_ns;
|
|
|
|
/* NOTE: the clock to PWM has to be enabled first
|
|
* before writing to the registers
|
|
*/
|
|
rc = clk_prepare_enable(pc->clk);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
writel(prescale, pc->mmio_base + offset + PWMCR);
|
|
writel(dc, pc->mmio_base + offset + PWMDCR);
|
|
writel(pv, pc->mmio_base + offset + PWMPCR);
|
|
|
|
clk_disable_unprepare(pc->clk);
|
|
return 0;
|
|
}
|
|
|
|
static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
|
|
{
|
|
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
|
|
int rc = 0;
|
|
|
|
if (!pc->clk_enabled) {
|
|
rc = clk_prepare_enable(pc->clk);
|
|
if (!rc)
|
|
pc->clk_enabled++;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
|
|
{
|
|
struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
|
|
|
|
if (pc->clk_enabled) {
|
|
clk_disable_unprepare(pc->clk);
|
|
pc->clk_enabled--;
|
|
}
|
|
}
|
|
|
|
static struct pwm_ops pxa_pwm_ops = {
|
|
.config = pxa_pwm_config,
|
|
.enable = pxa_pwm_enable,
|
|
.disable = pxa_pwm_disable,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int __devinit pwm_probe(struct platform_device *pdev)
|
|
{
|
|
const struct platform_device_id *id = platform_get_device_id(pdev);
|
|
struct pxa_pwm_chip *pwm;
|
|
struct resource *r;
|
|
int ret = 0;
|
|
|
|
pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
|
|
if (pwm == NULL) {
|
|
dev_err(&pdev->dev, "failed to allocate memory\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pwm->clk = devm_clk_get(&pdev->dev, NULL);
|
|
if (IS_ERR(pwm->clk))
|
|
return PTR_ERR(pwm->clk);
|
|
|
|
pwm->clk_enabled = 0;
|
|
|
|
pwm->chip.dev = &pdev->dev;
|
|
pwm->chip.ops = &pxa_pwm_ops;
|
|
pwm->chip.base = -1;
|
|
pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
|
|
|
|
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (r == NULL) {
|
|
dev_err(&pdev->dev, "no memory resource defined\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
|
|
if (pwm->mmio_base == NULL)
|
|
return -EADDRNOTAVAIL;
|
|
|
|
ret = pwmchip_add(&pwm->chip);
|
|
if (ret < 0) {
|
|
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
platform_set_drvdata(pdev, pwm);
|
|
return 0;
|
|
}
|
|
|
|
static int __devexit pwm_remove(struct platform_device *pdev)
|
|
{
|
|
struct pxa_pwm_chip *chip;
|
|
|
|
chip = platform_get_drvdata(pdev);
|
|
if (chip == NULL)
|
|
return -ENODEV;
|
|
|
|
return pwmchip_remove(&chip->chip);
|
|
}
|
|
|
|
static struct platform_driver pwm_driver = {
|
|
.driver = {
|
|
.name = "pxa25x-pwm",
|
|
.owner = THIS_MODULE,
|
|
},
|
|
.probe = pwm_probe,
|
|
.remove = __devexit_p(pwm_remove),
|
|
.id_table = pwm_id_table,
|
|
};
|
|
|
|
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 v2");
|