[PATCH V3] pwm: lpc32xx - Add a driver for the motor PWM

From: Alban Bedel
Date: Tue Sep 09 2014 - 11:43:19 EST

The LPC32xx motor PWMs have two output pin, A and B, with B = !A.
The driver can switch the polarity to allow use either output pin A
or output pin B.

Signed-off-by: Alban Bedel <alban.bedel@xxxxxxxxxxxxxxxxx>
---
V3: * Updated to current mainline API
* Fixed LPC32xx vs. LPC32XX
* Various coding style fix
V2: * Splitted the DTS to its own patch
---
.../devicetree/bindings/pwm/lpc32xx-motor-pwm.txt | 24 +++
drivers/pwm/Kconfig | 10 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-lpc32xx-motor.c | 210 +++++++++++++++++++++
4 files changed, 245 insertions(+)
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..decc27c
--- /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.
+By default, output A should be used, if 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 properties:
+- 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
+ pin A or output pin B has the correct polarity.
+
+Examples:
+
+mpwm@400e8000 {
+ compatible = "nxp,lpc3220-motor-pwm";
+ reg = <0x400E8000 0x78>;
+ linux,polarity = <0x5>; /* Use outputs B0, A1 and B2 */
+ #pwm-cells = <2>;
+};
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index b800783..1143348 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -147,6 +147,16 @@ 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-lpc32xx-motor.
+
config PWM_LPSS
tristate "Intel LPSS PWM support"
depends on ACPI
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index f8c577d..3eb5dd9 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
obj-$(CONFIG_PWM_LP3943) += pwm-lp3943.o
obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
+obj-$(CONFIG_PWM_LPC32XX_MOTOR) += pwm-lpc32xx-motor.o
obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o
diff --git a/drivers/pwm/pwm-lpc32xx-motor.c b/drivers/pwm/pwm-lpc32xx-motor.c
new file mode 100644
index 0000000..01cac53
--- /dev/null
+++ b/drivers/pwm/pwm-lpc32xx-motor.c
@@ -0,0 +1,210 @@
+/*
+ * Copyright 2012 Alban Bedel <alban.bedel@xxxxxxxxxxxxxxxxx>
+ *
+ * Based on pwm-lpc32xx.c from Alexandre Pereira da Silva
+ * <aletes.xgr@xxxxxxxxx>
+ *
+ * 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;
+ unsigned int pins;
+ void __iomem *base;
+};
+
+#define to_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_config(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx = to_motor_pwm_chip(chip);
+ u64 rate, period, duty;
+ int err = 0;
+
+ /* The clock is needed to access the registers */
+ err = clk_enable(lpc32xx->clk);
+ if (err)
+ return err;
+
+ /* Calculate period */
+ rate = clk_get_rate(lpc32xx->clk);
+ period = (u64)period_ns * rate;
+ duty = (u64)duty_ns * rate;
+ do_div(period, 1000000000);
+ do_div(duty, 1000000000);
+
+ /* Write to limit register -> period */
+ __raw_writel(period, lpc32xx->base + MCLIM_REG_OFFSET(pwm));
+
+ /* Write to match register -> duty */
+ __raw_writel(period - duty, lpc32xx->base + MCMAT_REG_OFFSET(pwm));
+
+ /* Disable the clock now that we are done */
+ clk_disable(lpc32xx->clk);
+ return 0;
+}
+
+static int lpc32xx_motor_pwm_enable(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx = to_motor_pwm_chip(chip);
+ int err;
+
+ err = clk_enable(lpc32xx->clk);
+ 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_motor_pwm_chip(chip);
+
+ __raw_writel(PWM_EN_MASK(pwm), lpc32xx->base + LPC32XX_MCPWM_MCCON_CLR);
+
+ clk_disable(lpc32xx->clk);
+}
+
+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_ioremap_resource(&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);
+
+ /* 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++)
+ if (lpc32xx->pins & BIT(i))
+ set |= BIT(2 + i * 8);
+ else
+ clr |= BIT(2 + i * 8);
+
+ ret = clk_enable(lpc32xx->clk);
+ if (ret)
+ return ret;
+
+ __raw_writel(set, lpc32xx->base + LPC32XX_MCPWM_MCCON_SET);
+ __raw_writel(clr, lpc32xx->base + LPC32XX_MCPWM_MCCON_CLR);
+
+ clk_disable(lpc32xx->clk);
+ }
+
+ 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 lpc32xx_motor_pwm_remove(struct platform_device *pdev)
+{
+ struct lpc32xx_motor_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < lpc32xx->chip.npwm; i++)
+ pwm_disable(&lpc32xx->chip.pwms[i]);
+
+ return pwmchip_remove(&lpc32xx->chip);
+}
+
+static const struct of_device_id lpc32xx_motor_pwm_dt_ids[] = {
+ { .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 = lpc32xx_motor_pwm_remove,
+};
+module_platform_driver(lpc32xx_motor_pwm_driver);
+
+MODULE_ALIAS("platform:lpc32xx-motor-pwm");
+MODULE_AUTHOR("Alban Bedel <alban.bedel@xxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("LPC32xx Motor PWM Driver");
+MODULE_LICENSE("GPL v2");
--
2.1.0

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