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pwm: tegra: Add support for reset control 

Add reset control of the PWM controller to reset it before
accessing the PWM register.

Signed-off-by: Rohith Seelaboyina <rseelaboyina@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Rohith Seelaboyina 2016-06-22 17:17:19 +05:30 committed by Thierry Reding
parent 4f57f5a01f
commit 5dfbd2bd54
1 changed files with 20 additions and 0 deletions
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20
drivers/pwm/pwm-tegra.c
View File

@ -29,6 +29,7 @@
#include <linux/pwm.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/reset.h>
#define PWM_ENABLE (1 << 31)
#define PWM_DUTY_WIDTH 8
@ -41,6 +42,7 @@ struct tegra_pwm_chip {
struct device *dev;
struct clk *clk;
struct reset_control*rst;
void __iomem *regs;
};
@ -187,6 +189,15 @@ static int tegra_pwm_probe(struct platform_device *pdev)
if (IS_ERR(pwm->clk))
return PTR_ERR(pwm->clk);
pwm->rst = devm_reset_control_get(&pdev->dev, "pwm");
if (IS_ERR(pwm->rst)) {
ret = PTR_ERR(pwm->rst);
dev_err(&pdev->dev, "Reset control is not found: %d\n", ret);
return ret;
}
reset_control_deassert(pwm->rst);
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &tegra_pwm_ops;
pwm->chip.base = -1;
@ -195,6 +206,7 @@ static int tegra_pwm_probe(struct platform_device *pdev)
ret = pwmchip_add(&pwm->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
reset_control_assert(pwm->rst);
return ret;
}
@ -205,10 +217,15 @@ static int tegra_pwm_remove(struct platform_device *pdev)
{
struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
unsigned int i;
int err;
if (WARN_ON(!pc))
return -ENODEV;
err = clk_prepare_enable(pc->clk);
if (err < 0)
return err;
for (i = 0; i < pc->chip.npwm; i++) {
struct pwm_device *pwm = &pc->chip.pwms[i];
@ -221,6 +238,9 @@ static int tegra_pwm_remove(struct platform_device *pdev)
clk_disable_unprepare(pc->clk);
}
reset_control_assert(pc->rst);
clk_disable_unprepare(pc->clk);
return pwmchip_remove(&pc->chip);
}