[PATCH v6 15/17] pwm: add pwm-mxs support
Thierry Reding
thierry.reding at avionic-design.de
Tue Apr 10 11:06:38 EDT 2012
From: Shawn Guo <shawn.guo at linaro.org>
Add generic PWM framework driver (DT only) for Freescale MXS.
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
---
Changes in v6:
- adopt patch by Shawn Guo
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(+)
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 at linaro.org>");
+MODULE_DESCRIPTION("Freescale MXS PWM Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.6
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