[PATCH] pwm: add pwm-mxs support
Shawn Guo
shawn.guo at linaro.org
Tue Apr 3 22:33:42 EDT 2012
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>
---
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 at linaro.org>");
+MODULE_DESCRIPTION("Freescale MXS PWM Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.5.4
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