[PATCH] pwm: add pwm-mxs support

[PATCH] pwm: add pwm-mxs support

[Shawn Guo]

Add generic PWM framework driver (DT only) for Freescale MXS.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---

Hi Thierry,

This patch is based on your "Add PWM framework and device tree
support" series v5.  Could you consider to fold it into your series
if it looks good to you?

Regards,
Shawn

 drivers/pwm/Kconfig   |    9 ++
 drivers/pwm/Makefile  |    1 +
 drivers/pwm/pwm-mxs.c |  207 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 217 insertions(+), 0 deletions(-)
 create mode 100644 drivers/pwm/pwm-mxs.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index a93feff..39bdebc 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -27,6 +27,15 @@ config PWM_IMX
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-imx.
 
+config PWM_MXS
+	tristate "Freescale MXS PWM support"
+	depends on ARCH_MXS && OF
+	help
+	  Generic PWM framework driver for Freescale MXS.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-mxs.
+
 config PWM_PXA
 	tristate "PXA PWM support"
 	depends on ARCH_PXA
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index b7c0fcf..cec2500 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
+obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o
diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c
new file mode 100644
index 0000000..ebf91da
--- /dev/null
+++ b/drivers/pwm/pwm-mxs.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <mach/common.h>
+
+#define SET	0x4
+#define CLR	0x8
+#define TOG	0xc
+
+#define PWM_CTRL		0x0
+#define PWM_ACTIVE0		0x10
+#define PWM_PERIOD0		0x20
+#define  PERIOD_PERIOD(p)	((p) & 0xffff)
+#define  PERIOD_PERIOD_MAX	0x10000
+#define  PERIOD_ACTIVE_HIGH	(3 << 16)
+#define  PERIOD_INACTIVE_LOW	(2 << 18)
+#define  PERIOD_CDIV(div)	(((div) & 0x7) << 20)
+#define  PERIOD_CDIV_MAX	8
+
+struct mxs_pwm_chip {
+	struct pwm_chip chip;
+	struct device *dev;
+	struct clk *clk;
+	void __iomem *base;
+};
+
+#define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
+
+static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  int duty_ns, int period_ns)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+	int ret, div = 0;
+	unsigned int period_cycles, duty_cycles;
+	unsigned long rate;
+	unsigned long long c;
+
+	rate = clk_get_rate(mxs->clk);
+	while (1) {
+		c = rate / (1 << div);
+		c = c * period_ns;
+		do_div(c, 1000000000);
+		if (c < PERIOD_PERIOD_MAX)
+			break;
+		div++;
+		if (div > PERIOD_CDIV_MAX)
+			return -EINVAL;
+	}
+
+	period_cycles = c;
+	c *= duty_ns;
+	do_div(c, period_ns);
+	duty_cycles = c;
+
+	/*
+	 * If the PWM channel is disabled, make sure to turn on the clock
+	 * before writing the register. Otherwise, keep it enabled.
+	 */
+	if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+		ret = clk_prepare_enable(mxs->clk);
+		if (ret)
+			return ret;
+	}
+
+	writel(duty_cycles << 16,
+			mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
+	writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
+	       PERIOD_INACTIVE_LOW | PERIOD_CDIV(div),
+			mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
+
+	/*
+	 * If the PWM is not enabled, turn the clock off again to save power.
+	 */
+	if (!test_bit(PWMF_ENABLED, &pwm->flags))
+		clk_disable_unprepare(mxs->clk);
+
+	return 0;
+}
+
+static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+	int ret;
+
+	ret = clk_prepare_enable(mxs->clk);
+	if (ret)
+		return ret;
+
+	writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
+
+	return 0;
+}
+
+static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+
+	writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
+
+	clk_disable_unprepare(mxs->clk);
+}
+
+static const struct pwm_ops mxs_pwm_ops = {
+	.config = mxs_pwm_config,
+	.enable = mxs_pwm_enable,
+	.disable = mxs_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mxs_pwm_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct mxs_pwm_chip *mxs;
+	int ret;
+
+	mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
+	if (!mxs)
+		return -ENOMEM;
+
+	mxs->base = of_iomap(np, 0);
+	if (!mxs->base)
+		return -EADDRNOTAVAIL;
+
+	mxs->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mxs->clk)) {
+		ret = PTR_ERR(mxs->clk);
+		goto iounmap;
+	}
+
+	mxs->chip.dev = &pdev->dev;
+	mxs->chip.ops = &mxs_pwm_ops;
+	mxs->chip.base = -1;
+	ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
+		goto clk_put;
+	}
+
+	ret = pwmchip_add(&mxs->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
+		goto clk_put;
+	}
+
+	mxs->dev = &pdev->dev;
+	platform_set_drvdata(pdev, mxs);
+
+	mxs_reset_block(mxs->base);
+
+	return 0;
+
+clk_put:
+	clk_put(mxs->clk);
+iounmap:
+	iounmap(mxs->base);
+	return ret;
+}
+
+static int __devexit mxs_pwm_remove(struct platform_device *pdev)
+{
+	struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
+
+	pwmchip_remove(&mxs->chip);
+	clk_put(mxs->clk);
+	iounmap(mxs->base);
+
+	return 0;
+}
+
+static struct of_device_id mxs_pwm_dt_ids[] = {
+	{ .compatible = "fsl,mxs-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_pwm_of_match);
+
+static struct platform_driver mxs_pwm_driver = {
+	.driver = {
+		.name = "mxs-pwm",
+		.of_match_table = of_match_ptr(mxs_pwm_dt_ids),
+	},
+	.probe = mxs_pwm_probe,
+	.remove = __devexit_p(mxs_pwm_remove),
+};
+module_platform_driver(mxs_pwm_driver);
+
+MODULE_ALIAS("platform:mxs-pwm");
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Freescale MXS PWM Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.5.4

[PATCH RESEND] pwm: add pwm-mxs support

[Shawn Guo]

Add generic PWM framework driver (DT only) for Freescale MXS.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
---

Resend to add binding document.

 Documentation/devicetree/bindings/pwm/mxs-pwm.txt |   17 ++
 drivers/pwm/Kconfig                               |    9 +
 drivers/pwm/Makefile                              |    1 +
 drivers/pwm/pwm-mxs.c                             |  207 +++++++++++++++++++++
 4 files changed, 234 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/pwm/mxs-pwm.txt
 create mode 100644 drivers/pwm/pwm-mxs.c

diff --git a/Documentation/devicetree/bindings/pwm/mxs-pwm.txt b/Documentation/devicetree/bindings/pwm/mxs-pwm.txt
new file mode 100644
index 0000000..48ead0d
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/mxs-pwm.txt
@@ -0,0 +1,17 @@
+Freescale MXS PWM controller
+
+Required properties:
+- compatible: should be "fsl,mxs-pwm"
+- reg: physical base address and length of the controller's registers
+- #pwm-cells: should be 2.  The first cell specifies the per-chip index
+  of the PWM to use and the second cell is the duty cycle in nanoseconds.
+- fsl,pwm-number: the number of PWM devices
+
+Example:
+
+pwm: pwm at 80064000 {
+	compatible = "fsl,imx28-pwm", "fsl,mxs-pwm";
+	reg = <0x80064000 2000>;
+	#pwm-cells = <2>;
+	fsl,pwm-number = <8>;
+};
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index a93feff..39bdebc 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -27,6 +27,15 @@ config PWM_IMX
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-imx.
 
+config PWM_MXS
+	tristate "Freescale MXS PWM support"
+	depends on ARCH_MXS && OF
+	help
+	  Generic PWM framework driver for Freescale MXS.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-mxs.
+
 config PWM_PXA
 	tristate "PXA PWM support"
 	depends on ARCH_PXA
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index b7c0fcf..cec2500 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
+obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o
diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c
new file mode 100644
index 0000000..ebf91da
--- /dev/null
+++ b/drivers/pwm/pwm-mxs.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <mach/common.h>
+
+#define SET	0x4
+#define CLR	0x8
+#define TOG	0xc
+
+#define PWM_CTRL		0x0
+#define PWM_ACTIVE0		0x10
+#define PWM_PERIOD0		0x20
+#define  PERIOD_PERIOD(p)	((p) & 0xffff)
+#define  PERIOD_PERIOD_MAX	0x10000
+#define  PERIOD_ACTIVE_HIGH	(3 << 16)
+#define  PERIOD_INACTIVE_LOW	(2 << 18)
+#define  PERIOD_CDIV(div)	(((div) & 0x7) << 20)
+#define  PERIOD_CDIV_MAX	8
+
+struct mxs_pwm_chip {
+	struct pwm_chip chip;
+	struct device *dev;
+	struct clk *clk;
+	void __iomem *base;
+};
+
+#define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
+
+static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  int duty_ns, int period_ns)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+	int ret, div = 0;
+	unsigned int period_cycles, duty_cycles;
+	unsigned long rate;
+	unsigned long long c;
+
+	rate = clk_get_rate(mxs->clk);
+	while (1) {
+		c = rate / (1 << div);
+		c = c * period_ns;
+		do_div(c, 1000000000);
+		if (c < PERIOD_PERIOD_MAX)
+			break;
+		div++;
+		if (div > PERIOD_CDIV_MAX)
+			return -EINVAL;
+	}
+
+	period_cycles = c;
+	c *= duty_ns;
+	do_div(c, period_ns);
+	duty_cycles = c;
+
+	/*
+	 * If the PWM channel is disabled, make sure to turn on the clock
+	 * before writing the register. Otherwise, keep it enabled.
+	 */
+	if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+		ret = clk_prepare_enable(mxs->clk);
+		if (ret)
+			return ret;
+	}
+
+	writel(duty_cycles << 16,
+			mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
+	writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
+	       PERIOD_INACTIVE_LOW | PERIOD_CDIV(div),
+			mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
+
+	/*
+	 * If the PWM is not enabled, turn the clock off again to save power.
+	 */
+	if (!test_bit(PWMF_ENABLED, &pwm->flags))
+		clk_disable_unprepare(mxs->clk);
+
+	return 0;
+}
+
+static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+	int ret;
+
+	ret = clk_prepare_enable(mxs->clk);
+	if (ret)
+		return ret;
+
+	writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
+
+	return 0;
+}
+
+static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
+
+	writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
+
+	clk_disable_unprepare(mxs->clk);
+}
+
+static const struct pwm_ops mxs_pwm_ops = {
+	.config = mxs_pwm_config,
+	.enable = mxs_pwm_enable,
+	.disable = mxs_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mxs_pwm_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct mxs_pwm_chip *mxs;
+	int ret;
+
+	mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
+	if (!mxs)
+		return -ENOMEM;
+
+	mxs->base = of_iomap(np, 0);
+	if (!mxs->base)
+		return -EADDRNOTAVAIL;
+
+	mxs->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mxs->clk)) {
+		ret = PTR_ERR(mxs->clk);
+		goto iounmap;
+	}
+
+	mxs->chip.dev = &pdev->dev;
+	mxs->chip.ops = &mxs_pwm_ops;
+	mxs->chip.base = -1;
+	ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
+		goto clk_put;
+	}
+
+	ret = pwmchip_add(&mxs->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
+		goto clk_put;
+	}
+
+	mxs->dev = &pdev->dev;
+	platform_set_drvdata(pdev, mxs);
+
+	mxs_reset_block(mxs->base);
+
+	return 0;
+
+clk_put:
+	clk_put(mxs->clk);
+iounmap:
+	iounmap(mxs->base);
+	return ret;
+}
+
+static int __devexit mxs_pwm_remove(struct platform_device *pdev)
+{
+	struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
+
+	pwmchip_remove(&mxs->chip);
+	clk_put(mxs->clk);
+	iounmap(mxs->base);
+
+	return 0;
+}
+
+static struct of_device_id mxs_pwm_dt_ids[] = {
+	{ .compatible = "fsl,mxs-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_pwm_of_match);
+
+static struct platform_driver mxs_pwm_driver = {
+	.driver = {
+		.name = "mxs-pwm",
+		.of_match_table = of_match_ptr(mxs_pwm_dt_ids),
+	},
+	.probe = mxs_pwm_probe,
+	.remove = __devexit_p(mxs_pwm_remove),
+};
+module_platform_driver(mxs_pwm_driver);
+
+MODULE_ALIAS("platform:mxs-pwm");
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Freescale MXS PWM Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.5.4

[PATCH RESEND] pwm: add pwm-mxs support

[Thierry Reding]

* Shawn Guo wrote:
> Add generic PWM framework driver (DT only) for Freescale MXS.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> ---
> 
> Resend to add binding document.
> 
>  Documentation/devicetree/bindings/pwm/mxs-pwm.txt |   17 ++
>  drivers/pwm/Kconfig                               |    9 +
>  drivers/pwm/Makefile                              |    1 +
>  drivers/pwm/pwm-mxs.c                             |  207 +++++++++++++++++++++
>  4 files changed, 234 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/pwm/mxs-pwm.txt
>  create mode 100644 drivers/pwm/pwm-mxs.c

This looks great. I'll take it into the next round. I'm still waiting for one
comment from Stephen Warren but otherwise I should have v6 ready before the
weekend.

Thierry
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