[PATCH] pwm: lpc32xx - Add a driver for the motor PWM
Alban Bedel
alban.bedel at avionic-design.de
Wed Nov 7 11:30:28 EST 2012
Signed-off-by: Alban Bedel <alban.bedel at avionic-design.de>
---
.../devicetree/bindings/pwm/lpc32xx-motor-pwm.txt | 24 ++
arch/arm/boot/dts/lpc32xx.dtsi | 7 +
drivers/pwm/Kconfig | 10 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-lpc32xx-motor.c | 230 ++++++++++++++++++++
5 files changed, 272 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/pwm/lpc32xx-motor-pwm.txt
create mode 100644 drivers/pwm/pwm-lpc32xx-motor.c
diff --git a/Documentation/devicetree/bindings/pwm/lpc32xx-motor-pwm.txt b/Documentation/devicetree/bindings/pwm/lpc32xx-motor-pwm.txt
new file mode 100644
index 0000000..e19b0a4
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/lpc32xx-motor-pwm.txt
@@ -0,0 +1,24 @@
+LPC32XX Motor PWM controller
+
+The LPC32xx motor PWMs have two output pin, A and B, with B=!A.
+Per default the output A should be used, if the output B is used the
+PWM polarity should be inverted using the linux,polarity property.
+
+Required properties:
+- compatible: should be "nxp,lpc3220-motor-pwm"
+- reg: physical base address and length of the controller's registers
+
+Optional properites:
+- linux,polarity: Bit mask of the polarity to use for each output,
+ a bit set to 0 indicate the default polarity, a bit set to 1
+ indicate an inverted polarity. In other word this set if output
+ A or output B has the correct polarity.
+
+Examples:
+
+mpwm at 400e8000 {
+ compatible = "nxp,lpc3220-motor-pwm";
+ reg = <0x400E8000 0x78>;
+ linux,polarity = 5; /* Use outputs B0, A1 and B2 */
+ #pwm-cells = <2>;
+};
diff --git a/arch/arm/boot/dts/lpc32xx.dtsi b/arch/arm/boot/dts/lpc32xx.dtsi
index ef0fdc7..a1e6a9b 100644
--- a/arch/arm/boot/dts/lpc32xx.dtsi
+++ b/arch/arm/boot/dts/lpc32xx.dtsi
@@ -182,6 +182,13 @@
pnx,timeout = <0x64>;
};
+ mpwm: mpwm at 400E8000 {
+ compatible = "nxp,lpc3220-motor-pwm";
+ reg = <0x400E8000 0x78>;
+ status = "disabled";
+ #pwm-cells = <2>;
+ };
+
i2cusb: i2c at 31020300 {
compatible = "nxp,pnx-i2c";
reg = <0x31020300 0x100>;
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 90c5c73..90fc167 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -57,6 +57,16 @@ config PWM_LPC32XX
To compile this driver as a module, choose M here: the module
will be called pwm-lpc32xx.
+config PWM_LPC32XX_MOTOR
+ tristate "LPC32XX Motor PWM support"
+ depends on ARCH_LPC32XX
+ help
+ Generic PWM framework driver for LPC32XX motor PWM. The LPC32XX SOC
+ has one motor PWM controllers.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-motor-lpc32xx.
+
config PWM_MXS
tristate "Freescale MXS PWM support"
depends on ARCH_MXS && OF
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index e4b2c89..510bad8 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
+obj-$(CONFIG_PWM_LPC32XX_MOTOR) += pwm-lpc32xx-motor.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
diff --git a/drivers/pwm/pwm-lpc32xx-motor.c b/drivers/pwm/pwm-lpc32xx-motor.c
new file mode 100644
index 0000000..e1b4d46
--- /dev/null
+++ b/drivers/pwm/pwm-lpc32xx-motor.c
@@ -0,0 +1,230 @@
+/*
+ * Copyright 2012 Alban Bedel <alban.bedel at avionic-design.de>
+ *
+ * Based on pwm-lpc32xx.c from Alexandre Pereira da Silva
+ * <aletes.xgr at gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2.
+ *
+ */
+
+#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>
+
+struct lpc32xx_motor_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ spinlock_t lock;
+ unsigned int clk_enabled;
+ unsigned int pins;
+ void __iomem *base;
+};
+
+#define to_lpc32xx_motor_pwm_chip(_chip) \
+ container_of(_chip, struct lpc32xx_motor_pwm_chip, chip)
+
+/* Register mapping for MCPWM modules */
+#define LPC32XX_MCPWM_MCCON 0x00
+#define LPC32XX_MCPWM_MCCON_SET 0x04
+#define LPC32XX_MCPWM_MCCON_CLR 0x08
+#define LPC32XX_MCPWM_MCCAPCON 0x0C
+#define LPC32XX_MCPWM_MCCAPCON_SET 0x10
+#define LPC32XX_MCPWM_MCCAPCON_CLR 0x14
+#define LPC32XX_MCPWM_MCLIM0 0x24
+#define LPC32XX_MCPWM_MCLIM1 0x28
+#define LPC32XX_MCPWM_MCLIM2 0x2C
+#define LPC32XX_MCPWM_MCMAT0 0x30
+#define LPC32XX_MCPWM_MCMAT1 0x34
+#define LPC32XX_MCPWM_MCMAT2 0x38
+#define LPC32XX_MCPWM_MCINTEN_CLR 0x58
+
+#define LPC32XX_MCPWM_COUNT 3
+
+#define PWM_EN_MASK(pwm) BIT(0 + (pwm)->hwpwm*8)
+#define MCLIM_REG_OFFSET(pwm) (LPC32XX_MCPWM_MCLIM0 + (pwm)->hwpwm*4)
+#define MCMAT_REG_OFFSET(pwm) (LPC32XX_MCPWM_MCMAT0 + (pwm)->hwpwm*4)
+
+static int lpc32xx_motor_pwm_enable_clock(
+ struct lpc32xx_motor_pwm_chip *lpc32xx)
+{
+ int err = 0;
+ spin_lock(&lpc32xx->lock);
+ if (lpc32xx->clk_enabled == 0)
+ err = clk_enable(lpc32xx->clk);
+ lpc32xx->clk_enabled += 1;
+ spin_unlock(&lpc32xx->lock);
+ return err;
+}
+
+static void lpc32xx_motor_pwm_disable_clock(
+ struct lpc32xx_motor_pwm_chip *lpc32xx)
+{
+ spin_lock(&lpc32xx->lock);
+ if (lpc32xx->clk_enabled > 0) {
+ lpc32xx->clk_enabled -= 1;
+ if (lpc32xx->clk_enabled == 0)
+ clk_disable(lpc32xx->clk);
+ }
+ spin_unlock(&lpc32xx->lock);
+}
+
+static int lpc32xx_motor_pwm_config(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx =
+ to_lpc32xx_motor_pwm_chip(chip);
+ u64 rate, per, duty;
+ int err = 0;
+
+ /* The clock is needed to access the registers */
+ err = lpc32xx_motor_pwm_enable_clock(lpc32xx);
+ if (err)
+ return err;
+
+ /* Calculate period */
+ rate = clk_get_rate(lpc32xx->clk);
+ per = (u64)period_ns * rate;
+ duty = (u64)duty_ns * rate;
+ do_div(per, 1000000000);
+ do_div(duty, 1000000000);
+
+ /* Write to limit register -> period */
+ __raw_writel(per, lpc32xx->base + MCLIM_REG_OFFSET(pwm));
+
+ /* Write to match register -> duty */
+ __raw_writel(per - duty, lpc32xx->base + MCMAT_REG_OFFSET(pwm));
+
+ /* Disable the clock now that we are done */
+ lpc32xx_motor_pwm_disable_clock(lpc32xx);
+ return 0;
+}
+
+static int lpc32xx_motor_pwm_enable(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx =
+ to_lpc32xx_motor_pwm_chip(chip);
+ int err;
+
+ err = lpc32xx_motor_pwm_enable_clock(lpc32xx);
+ if (err)
+ return err;
+
+ __raw_writel(PWM_EN_MASK(pwm), lpc32xx->base + LPC32XX_MCPWM_MCCON_SET);
+
+ return 0;
+}
+
+static void lpc32xx_motor_pwm_disable(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx =
+ to_lpc32xx_motor_pwm_chip(chip);
+
+ __raw_writel(PWM_EN_MASK(pwm), lpc32xx->base + LPC32XX_MCPWM_MCCON_CLR);
+
+ lpc32xx_motor_pwm_disable_clock(lpc32xx);
+}
+
+static const struct pwm_ops lpc32xx_motor_pwm_ops = {
+ .config = lpc32xx_motor_pwm_config,
+ .enable = lpc32xx_motor_pwm_enable,
+ .disable = lpc32xx_motor_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static int lpc32xx_motor_pwm_probe(struct platform_device *pdev)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx;
+ struct resource *res;
+ int ret;
+
+ lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
+ if (!lpc32xx)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -EINVAL;
+
+ lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);
+ if (!lpc32xx->base)
+ return -EADDRNOTAVAIL;
+
+ lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(lpc32xx->clk))
+ return PTR_ERR(lpc32xx->clk);
+
+ spin_lock_init(&lpc32xx->lock);
+
+ /* Configure the pins polarity */
+ ret = of_property_read_u32(pdev->dev.of_node, "linux,polarity",
+ &lpc32xx->pins);
+ if (!ret) {
+ u32 set = 0, clr = 0;
+ int i;
+ for (i = 0 ; i < LPC32XX_MCPWM_COUNT ; i += 1)
+ if (lpc32xx->pins & BIT(i))
+ set |= BIT(2 + i*8);
+ else
+ clr |= BIT(2 + i*8);
+ __raw_writel(set, lpc32xx->base + LPC32XX_MCPWM_MCCON_SET);
+ __raw_writel(clr, lpc32xx->base + LPC32XX_MCPWM_MCCON_CLR);
+ }
+
+ lpc32xx->chip.dev = &pdev->dev;
+ lpc32xx->chip.ops = &lpc32xx_motor_pwm_ops;
+ lpc32xx->chip.npwm = LPC32XX_MCPWM_COUNT;
+ lpc32xx->chip.base = -1;
+
+ ret = pwmchip_add(&lpc32xx->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, lpc32xx);
+
+ return 0;
+}
+
+static int __devexit lpc32xx_motor_pwm_remove(struct platform_device *pdev)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
+
+ clk_disable(lpc32xx->clk);
+ return pwmchip_remove(&lpc32xx->chip);
+}
+
+static const struct of_device_id lpc32xx_motor_pwm_dt_ids[] __devinitconst = {
+ { .compatible = "nxp,lpc3220-motor-pwm", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc32xx_motor_pwm_dt_ids);
+
+static struct platform_driver lpc32xx_motor_pwm_driver = {
+ .driver = {
+ .name = "lpc32xx-motor-pwm",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(lpc32xx_motor_pwm_dt_ids),
+ },
+ .probe = lpc32xx_motor_pwm_probe,
+ .remove = __devexit_p(lpc32xx_motor_pwm_remove),
+};
+module_platform_driver(lpc32xx_motor_pwm_driver);
+
+MODULE_ALIAS("platform:lpc32xx-motor-pwm");
+MODULE_AUTHOR("Alban Bedel <alban.bedel at avionic-design.de>");
+MODULE_DESCRIPTION("LPC32XX Motor PWM Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.0.4
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