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path: root/drivers/pwm
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-rw-r--r--drivers/pwm/Kconfig31
-rw-r--r--drivers/pwm/core.c12
-rw-r--r--drivers/pwm/pwm-samsung.c1
-rw-r--r--drivers/pwm/pwm-tegra.c4
-rw-r--r--drivers/pwm/pwm-tiecap.c11
-rw-r--r--drivers/pwm/pwm-tiehrpwm.c33
-rw-r--r--drivers/pwm/pwm-vt8500.c2
7 files changed, 72 insertions, 22 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c7500dcdc65e..d7c6b83097c1 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -1,12 +1,31 @@
menuconfig PWM
- bool "PWM Support"
+ bool "Pulse-Width Modulation (PWM) Support"
depends on !MACH_JZ4740 && !PUV3_PWM
help
- This enables PWM support through the generic PWM framework.
- You only need to enable this, if you also want to enable
- one or more of the PWM drivers below.
-
- If unsure, say N.
+ Generic Pulse-Width Modulation (PWM) support.
+
+ In Pulse-Width Modulation, a variation of the width of pulses
+ in a rectangular pulse signal is used as a means to alter the
+ average power of the signal. Applications include efficient
+ power delivery and voltage regulation. In computer systems,
+ PWMs are commonly used to control fans or the brightness of
+ display backlights.
+
+ This framework provides a generic interface to PWM devices
+ within the Linux kernel. On the driver side it provides an API
+ to register and unregister a PWM chip, an abstraction of a PWM
+ controller, that supports one or more PWM devices. Client
+ drivers can request PWM devices and use the generic framework
+ to configure as well as enable and disable them.
+
+ This generic framework replaces the legacy PWM framework which
+ allows only a single driver implementing the required API. Not
+ all legacy implementations have been ported to the framework
+ yet. The framework provides an API that is backward compatible
+ with the legacy framework so that existing client drivers
+ continue to work as expected.
+
+ If unsure, say no.
if PWM
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ecb76909e946..c6e05078d3ad 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -129,8 +129,8 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
return 0;
}
-static struct pwm_device *of_pwm_simple_xlate(struct pwm_chip *pc,
- const struct of_phandle_args *args)
+static struct pwm_device *
+of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;
@@ -149,7 +149,7 @@ static struct pwm_device *of_pwm_simple_xlate(struct pwm_chip *pc,
return pwm;
}
-void of_pwmchip_add(struct pwm_chip *chip)
+static void of_pwmchip_add(struct pwm_chip *chip)
{
if (!chip->dev || !chip->dev->of_node)
return;
@@ -162,7 +162,7 @@ void of_pwmchip_add(struct pwm_chip *chip)
of_node_get(chip->dev->of_node);
}
-void of_pwmchip_remove(struct pwm_chip *chip)
+static void of_pwmchip_remove(struct pwm_chip *chip)
{
if (chip->dev && chip->dev->of_node)
of_node_put(chip->dev->of_node);
@@ -527,7 +527,7 @@ void __init pwm_add_table(struct pwm_lookup *table, size_t num)
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
- const char *dev_id = dev ? dev_name(dev): NULL;
+ const char *dev_id = dev ? dev_name(dev) : NULL;
struct pwm_chip *chip = NULL;
unsigned int index = 0;
unsigned int best = 0;
@@ -609,7 +609,7 @@ void pwm_put(struct pwm_device *pwm)
mutex_lock(&pwm_lock);
if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
- pr_warning("PWM device already freed\n");
+ pr_warn("PWM device already freed\n");
goto out;
}
diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
index d10386528c9c..e5187c0ade9f 100644
--- a/drivers/pwm/pwm-samsung.c
+++ b/drivers/pwm/pwm-samsung.c
@@ -225,6 +225,7 @@ static int s3c_pwm_probe(struct platform_device *pdev)
/* calculate base of control bits in TCON */
s3c->tcon_base = id == 0 ? 0 : (id * 4) + 4;
+ s3c->chip.dev = &pdev->dev;
s3c->chip.ops = &s3c_pwm_ops;
s3c->chip.base = -1;
s3c->chip.npwm = 1;
diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
index 02ce18d5e49a..057465e0553c 100644
--- a/drivers/pwm/pwm-tegra.c
+++ b/drivers/pwm/pwm-tegra.c
@@ -187,10 +187,8 @@ static int tegra_pwm_probe(struct platform_device *pdev)
}
pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
- if (!pwm->mmio_base) {
- dev_err(&pdev->dev, "failed to ioremap() region\n");
+ if (!pwm->mmio_base)
return -EADDRNOTAVAIL;
- }
platform_set_drvdata(pdev, pwm);
diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
index 3c2ad284ee3e..4b6688909fee 100644
--- a/drivers/pwm/pwm-tiecap.c
+++ b/drivers/pwm/pwm-tiecap.c
@@ -100,6 +100,13 @@ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
writel(period_cycles, pc->mmio_base + CAP3);
}
+ if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ /* Disable APWM mode to put APWM output Low */
+ reg_val &= ~ECCTL2_APWM_MODE;
+ writew(reg_val, pc->mmio_base + ECCTL2);
+ }
+
pm_runtime_put_sync(pc->chip.dev);
return 0;
}
@@ -192,10 +199,8 @@ static int __devinit ecap_pwm_probe(struct platform_device *pdev)
}
pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
- if (!pc->mmio_base) {
- dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ if (!pc->mmio_base)
return -EADDRNOTAVAIL;
- }
ret = pwmchip_add(&pc->chip);
if (ret < 0) {
diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c
index 010d232cb0c8..b1996bcd5b78 100644
--- a/drivers/pwm/pwm-tiehrpwm.c
+++ b/drivers/pwm/pwm-tiehrpwm.c
@@ -104,6 +104,7 @@ struct ehrpwm_pwm_chip {
struct pwm_chip chip;
unsigned int clk_rate;
void __iomem *mmio_base;
+ unsigned long period_cycles[NUM_PWM_CHANNEL];
};
static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
@@ -210,6 +211,7 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
unsigned long long c;
unsigned long period_cycles, duty_cycles;
unsigned short ps_divval, tb_divval;
+ int i;
if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC)
return -ERANGE;
@@ -229,6 +231,28 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
duty_cycles = (unsigned long)c;
}
+ /*
+ * Period values should be same for multiple PWM channels as IP uses
+ * same period register for multiple channels.
+ */
+ for (i = 0; i < NUM_PWM_CHANNEL; i++) {
+ if (pc->period_cycles[i] &&
+ (pc->period_cycles[i] != period_cycles)) {
+ /*
+ * Allow channel to reconfigure period if no other
+ * channels being configured.
+ */
+ if (i == pwm->hwpwm)
+ continue;
+
+ dev_err(chip->dev, "Period value conflicts with channel %d\n",
+ i);
+ return -EINVAL;
+ }
+ }
+
+ pc->period_cycles[pwm->hwpwm] = period_cycles;
+
/* Configure clock prescaler to support Low frequency PWM wave */
if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
&tb_divval)) {
@@ -320,10 +344,15 @@ static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
+ struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
+
if (test_bit(PWMF_ENABLED, &pwm->flags)) {
dev_warn(chip->dev, "Removing PWM device without disabling\n");
pm_runtime_put_sync(chip->dev);
}
+
+ /* set period value to zero on free */
+ pc->period_cycles[pwm->hwpwm] = 0;
}
static const struct pwm_ops ehrpwm_pwm_ops = {
@@ -371,10 +400,8 @@ static int __devinit ehrpwm_pwm_probe(struct platform_device *pdev)
}
pc->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
- if (!pc->mmio_base) {
- dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ if (!pc->mmio_base)
return -EADDRNOTAVAIL;
- }
ret = pwmchip_add(&pc->chip);
if (ret < 0) {
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
index 548021439f0c..ad14389b7144 100644
--- a/drivers/pwm/pwm-vt8500.c
+++ b/drivers/pwm/pwm-vt8500.c
@@ -41,7 +41,7 @@ static inline void pwm_busy_wait(void __iomem *reg, u8 bitmask)
cpu_relax();
if (unlikely(!loops))
- pr_warning("Waiting for status bits 0x%x to clear timed out\n",
+ pr_warn("Waiting for status bits 0x%x to clear timed out\n",
bitmask);
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-23 16:34:47 +0300