linux-stable/drivers/pwm/pwm-samsung.c
Linus Torvalds 74779e2226 pwm: Changes for v3.8-rc1
A new driver has been added for the SPEAr platform and the TWL4030/6030
 driver has been replaced by two drivers that control the regular PWMs
 and the PWM driven LEDs provided by the chips.
 
 The vt8500, tiecap, tiehrpwm, i.MX, LPC32xx and Samsung drivers have all
 been improved and the device tree bindings now support the PWM signal
 polarity.
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Merge tag 'for-3.8-rc1' of git://gitorious.org/linux-pwm/linux-pwm

Pull pwm changes from Thierry Reding:
 "A new driver has been added for the SPEAr platform and the
  TWL4030/6030 driver has been replaced by two drivers that control the
  regular PWMs and the PWM driven LEDs provided by the chips.

  The vt8500, tiecap, tiehrpwm, i.MX, LPC32xx and Samsung drivers have
  all been improved and the device tree bindings now support the PWM
  signal polarity."

Fix up trivial conflicts due to __devinit/exit removal.

* tag 'for-3.8-rc1' of git://gitorious.org/linux-pwm/linux-pwm: (21 commits)
  pwm: samsung: add missing s3c->pwm_id assignment
  pwm: lpc32xx: Set the chip base for dynamic allocation
  pwm: lpc32xx: Properly disable the clock on device removal
  pwm: lpc32xx: Fix the PWM polarity
  pwm: i.MX: eliminate build warning
  pwm: Export of_pwm_xlate_with_flags()
  pwm: Remove pwm-twl6030 driver
  pwm: New driver to support PWM driven LEDs on TWL4030/6030 series of PMICs
  pwm: New driver to support PWMs on TWL4030/6030 series of PMICs
  pwm: pwm-tiehrpwm: pinctrl support
  pwm: tiehrpwm: Add device-tree binding
  pwm: pwm-tiehrpwm: Adding TBCLK gating support.
  pwm: pwm-tiecap: pinctrl support
  pwm: tiecap: Add device-tree binding
  pwm: Add TI PWM subsystem driver
  pwm: Device tree support for PWM polarity
  pwm: vt8500: Ensure PWM clock is enabled during pwm_config
  pwm: vt8500: Fix build error
  pwm: spear: Staticize spear_pwm_config()
  pwm: Add SPEAr PWM chip driver support
  ...
2012-12-19 08:19:07 -08:00

355 lines
7.9 KiB
C

/* drivers/pwm/pwm-samsung.c
*
* Copyright (c) 2007 Ben Dooks
* Copyright (c) 2008 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
*
* S3C series PWM device core
*
* 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.
*/
#define pr_fmt(fmt) "pwm-samsung: " fmt
#include <linux/export.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 <mach/map.h>
#include <plat/regs-timer.h>
struct s3c_chip {
struct platform_device *pdev;
struct clk *clk_div;
struct clk *clk;
const char *label;
unsigned int period_ns;
unsigned int duty_ns;
unsigned char tcon_base;
unsigned char pwm_id;
struct pwm_chip chip;
};
#define to_s3c_chip(chip) container_of(chip, struct s3c_chip, chip)
#define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
static struct clk *clk_scaler[2];
static inline int pwm_is_tdiv(struct s3c_chip *chip)
{
return clk_get_parent(chip->clk) == chip->clk_div;
}
#define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
#define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
#define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
#define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))
static int s3c_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct s3c_chip *s3c = to_s3c_chip(chip);
unsigned long flags;
unsigned long tcon;
local_irq_save(flags);
tcon = __raw_readl(S3C2410_TCON);
tcon |= pwm_tcon_start(s3c);
__raw_writel(tcon, S3C2410_TCON);
local_irq_restore(flags);
return 0;
}
static void s3c_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct s3c_chip *s3c = to_s3c_chip(chip);
unsigned long flags;
unsigned long tcon;
local_irq_save(flags);
tcon = __raw_readl(S3C2410_TCON);
tcon &= ~pwm_tcon_start(s3c);
__raw_writel(tcon, S3C2410_TCON);
local_irq_restore(flags);
}
static unsigned long pwm_calc_tin(struct s3c_chip *s3c, unsigned long freq)
{
unsigned long tin_parent_rate;
unsigned int div;
tin_parent_rate = clk_get_rate(clk_get_parent(s3c->clk_div));
pwm_dbg(s3c, "tin parent at %lu\n", tin_parent_rate);
for (div = 2; div <= 16; div *= 2) {
if ((tin_parent_rate / (div << 16)) < freq)
return tin_parent_rate / div;
}
return tin_parent_rate / 16;
}
#define NS_IN_HZ (1000000000UL)
static int s3c_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct s3c_chip *s3c = to_s3c_chip(chip);
unsigned long tin_rate;
unsigned long tin_ns;
unsigned long period;
unsigned long flags;
unsigned long tcon;
unsigned long tcnt;
long tcmp;
/* We currently avoid using 64bit arithmetic by using the
* fact that anything faster than 1Hz is easily representable
* by 32bits. */
if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
return -ERANGE;
if (period_ns == s3c->period_ns &&
duty_ns == s3c->duty_ns)
return 0;
/* The TCMP and TCNT can be read without a lock, they're not
* shared between the timers. */
tcmp = __raw_readl(S3C2410_TCMPB(s3c->pwm_id));
tcnt = __raw_readl(S3C2410_TCNTB(s3c->pwm_id));
period = NS_IN_HZ / period_ns;
pwm_dbg(s3c, "duty_ns=%d, period_ns=%d (%lu)\n",
duty_ns, period_ns, period);
/* Check to see if we are changing the clock rate of the PWM */
if (s3c->period_ns != period_ns) {
if (pwm_is_tdiv(s3c)) {
tin_rate = pwm_calc_tin(s3c, period);
clk_set_rate(s3c->clk_div, tin_rate);
} else
tin_rate = clk_get_rate(s3c->clk);
s3c->period_ns = period_ns;
pwm_dbg(s3c, "tin_rate=%lu\n", tin_rate);
tin_ns = NS_IN_HZ / tin_rate;
tcnt = period_ns / tin_ns;
} else
tin_ns = NS_IN_HZ / clk_get_rate(s3c->clk);
/* Note, counters count down */
tcmp = duty_ns / tin_ns;
tcmp = tcnt - tcmp;
/* the pwm hw only checks the compare register after a decrement,
so the pin never toggles if tcmp = tcnt */
if (tcmp == tcnt)
tcmp--;
pwm_dbg(s3c, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt);
if (tcmp < 0)
tcmp = 0;
/* Update the PWM register block. */
local_irq_save(flags);
__raw_writel(tcmp, S3C2410_TCMPB(s3c->pwm_id));
__raw_writel(tcnt, S3C2410_TCNTB(s3c->pwm_id));
tcon = __raw_readl(S3C2410_TCON);
tcon |= pwm_tcon_manulupdate(s3c);
tcon |= pwm_tcon_autoreload(s3c);
__raw_writel(tcon, S3C2410_TCON);
tcon &= ~pwm_tcon_manulupdate(s3c);
__raw_writel(tcon, S3C2410_TCON);
local_irq_restore(flags);
return 0;
}
static struct pwm_ops s3c_pwm_ops = {
.enable = s3c_pwm_enable,
.disable = s3c_pwm_disable,
.config = s3c_pwm_config,
.owner = THIS_MODULE,
};
static int s3c_pwm_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct s3c_chip *s3c;
unsigned long flags;
unsigned long tcon;
unsigned int id = pdev->id;
int ret;
if (id == 4) {
dev_err(dev, "TIMER4 is currently not supported\n");
return -ENXIO;
}
s3c = devm_kzalloc(&pdev->dev, sizeof(*s3c), GFP_KERNEL);
if (s3c == NULL) {
dev_err(dev, "failed to allocate pwm_device\n");
return -ENOMEM;
}
/* calculate base of control bits in TCON */
s3c->tcon_base = id == 0 ? 0 : (id * 4) + 4;
s3c->pwm_id = id;
s3c->chip.dev = &pdev->dev;
s3c->chip.ops = &s3c_pwm_ops;
s3c->chip.base = -1;
s3c->chip.npwm = 1;
s3c->clk = devm_clk_get(dev, "pwm-tin");
if (IS_ERR(s3c->clk)) {
dev_err(dev, "failed to get pwm tin clk\n");
return PTR_ERR(s3c->clk);
}
s3c->clk_div = devm_clk_get(dev, "pwm-tdiv");
if (IS_ERR(s3c->clk_div)) {
dev_err(dev, "failed to get pwm tdiv clk\n");
return PTR_ERR(s3c->clk_div);
}
clk_enable(s3c->clk);
clk_enable(s3c->clk_div);
local_irq_save(flags);
tcon = __raw_readl(S3C2410_TCON);
tcon |= pwm_tcon_invert(s3c);
__raw_writel(tcon, S3C2410_TCON);
local_irq_restore(flags);
ret = pwmchip_add(&s3c->chip);
if (ret < 0) {
dev_err(dev, "failed to register pwm\n");
goto err_clk_tdiv;
}
pwm_dbg(s3c, "config bits %02x\n",
(__raw_readl(S3C2410_TCON) >> s3c->tcon_base) & 0x0f);
dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
clk_get_rate(s3c->clk),
clk_get_rate(s3c->clk_div),
pwm_is_tdiv(s3c) ? "div" : "ext", s3c->tcon_base);
platform_set_drvdata(pdev, s3c);
return 0;
err_clk_tdiv:
clk_disable(s3c->clk_div);
clk_disable(s3c->clk);
return ret;
}
static int s3c_pwm_remove(struct platform_device *pdev)
{
struct s3c_chip *s3c = platform_get_drvdata(pdev);
int err;
err = pwmchip_remove(&s3c->chip);
if (err < 0)
return err;
clk_disable(s3c->clk_div);
clk_disable(s3c->clk);
return 0;
}
#ifdef CONFIG_PM
static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state)
{
struct s3c_chip *s3c = platform_get_drvdata(pdev);
/* No one preserve these values during suspend so reset them
* Otherwise driver leaves PWM unconfigured if same values
* passed to pwm_config
*/
s3c->period_ns = 0;
s3c->duty_ns = 0;
return 0;
}
static int s3c_pwm_resume(struct platform_device *pdev)
{
struct s3c_chip *s3c = platform_get_drvdata(pdev);
unsigned long tcon;
/* Restore invertion */
tcon = __raw_readl(S3C2410_TCON);
tcon |= pwm_tcon_invert(s3c);
__raw_writel(tcon, S3C2410_TCON);
return 0;
}
#else
#define s3c_pwm_suspend NULL
#define s3c_pwm_resume NULL
#endif
static struct platform_driver s3c_pwm_driver = {
.driver = {
.name = "s3c24xx-pwm",
.owner = THIS_MODULE,
},
.probe = s3c_pwm_probe,
.remove = s3c_pwm_remove,
.suspend = s3c_pwm_suspend,
.resume = s3c_pwm_resume,
};
static int __init pwm_init(void)
{
int ret;
clk_scaler[0] = clk_get(NULL, "pwm-scaler0");
clk_scaler[1] = clk_get(NULL, "pwm-scaler1");
if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) {
pr_err("failed to get scaler clocks\n");
return -EINVAL;
}
ret = platform_driver_register(&s3c_pwm_driver);
if (ret)
pr_err("failed to add pwm driver\n");
return ret;
}
arch_initcall(pwm_init);