pwm: add ep93xx PWM support

Remove the non-standard EP93xx PWM driver in drivers/misc and add
a new driver for the PWM controllers on the EP93xx platform based
on the PWM framework.

These PWM controllers each support 1 PWM channel with programmable
duty cycle, frequency, and polarity inversion.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ryan Mallon <rmallon@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

3 files changed, 240 insertions, 0 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 75840b5cea6d..eece329d7872 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -62,6 +62,15 @@ config PWM_BFIN
           To compile this driver as a module, choose M here: the module
           will be called pwm-bfin.
 
+config PWM_EP93XX
+        tristate "Cirrus Logic EP93xx PWM support"
+        depends on ARCH_EP93XX
+        help
+          Generic PWM framework driver for Cirrus Logic EP93xx.
+
+          To compile this driver as a module, choose M here: the module
+          will be called pwm-ep93xx.
+
 config PWM_IMX
         tristate "i.MX PWM support"
         depends on ARCH_MXC
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 77a8c185c5b2..8b754e4dba4a 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_PWM_SYSFS)		+= sysfs.o
 obj-$(CONFIG_PWM_AB8500)        += pwm-ab8500.o
 obj-$(CONFIG_PWM_ATMEL_TCB)     += pwm-atmel-tcb.o
 obj-$(CONFIG_PWM_BFIN)          += pwm-bfin.o
+obj-$(CONFIG_PWM_EP93XX)        += pwm-ep93xx.o
 obj-$(CONFIG_PWM_IMX)           += pwm-imx.o
 obj-$(CONFIG_PWM_JZ4740)        += pwm-jz4740.o
 obj-$(CONFIG_PWM_LPC32XX)       += pwm-lpc32xx.o
diff --git a/drivers/pwm/pwm-ep93xx.c b/drivers/pwm/pwm-ep93xx.c
new file mode 100644
index 000000000000..33aa4461e1ce
--- /dev/null
+++ b/drivers/pwm/pwm-ep93xx.c
@@ -0,0 +1,230 @@
+/*
+ * PWM framework driver for Cirrus Logic EP93xx
+ *
+ * Copyright (c) 2009        Matthieu Crapet <mcrapet@gmail.com>
+ * Copyright (c) 2009, 2013  H Hartley Sweeten <hsweeten@visionengravers.com>
+ *
+ * EP9301/02 have only one channel:
+ *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
+ *
+ * EP9307 has only one channel:
+ *   platform device ep93xx-pwm.0 - PWMOUT
+ *
+ * EP9312/15 have two channels:
+ *   platform device ep93xx-pwm.0 - PWMOUT
+ *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+
+#include <asm/div64.h>
+
+#include <mach/platform.h>      /* for ep93xx_pwm_{acquire,release}_gpio() */
+
+#define EP93XX_PWMx_TERM_COUNT  0x00
+#define EP93XX_PWMx_DUTY_CYCLE  0x04
+#define EP93XX_PWMx_ENABLE      0x08
+#define EP93XX_PWMx_INVERT      0x0c
+
+struct ep93xx_pwm {
+        void __iomem *base;
+        struct clk *clk;
+        struct pwm_chip chip;
+};
+
+static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
+{
+        return container_of(chip, struct ep93xx_pwm, chip);
+}
+
+static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct platform_device *pdev = to_platform_device(chip->dev);
+
+        return ep93xx_pwm_acquire_gpio(pdev);
+}
+
+static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct platform_device *pdev = to_platform_device(chip->dev);
+
+        ep93xx_pwm_release_gpio(pdev);
+}
+
+static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+                             int duty_ns, int period_ns)
+{
+        struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
+        void __iomem *base = ep93xx_pwm->base;
+        unsigned long long c;
+        unsigned long period_cycles;
+        unsigned long duty_cycles;
+        unsigned long term;
+        int ret = 0;
+
+        /*
+         * The clock needs to be enabled to access the PWM registers.
+         * Configuration can be changed at any time.
+         */
+        if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+                ret = clk_enable(ep93xx_pwm->clk);
+                if (ret)
+                        return ret;
+        }
+
+        c = clk_get_rate(ep93xx_pwm->clk);
+        c *= period_ns;
+        do_div(c, 1000000000);
+        period_cycles = c;
+
+        c = period_cycles;
+        c *= duty_ns;
+        do_div(c, period_ns);
+        duty_cycles = c;
+
+        if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
+                term = readw(base + EP93XX_PWMx_TERM_COUNT);
+
+                /* Order is important if PWM is running */
+                if (period_cycles > term) {
+                        writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
+                        writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
+                } else {
+                        writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
+                        writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
+                }
+        } else {
+                ret = -EINVAL;
+        }
+
+        if (!test_bit(PWMF_ENABLED, &pwm->flags))
+                clk_disable(ep93xx_pwm->clk);
+
+        return ret;
+}
+
+static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+                               enum pwm_polarity polarity)
+{
+        struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
+        int ret;
+
+        /*
+         * The clock needs to be enabled to access the PWM registers.
+         * Polarity can only be changed when the PWM is disabled.
+         */
+        ret = clk_enable(ep93xx_pwm->clk);
+        if (ret)
+                return ret;
+
+        if (polarity == PWM_POLARITY_INVERSED)
+                writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
+        else
+                writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
+
+        clk_disable(ep93xx_pwm->clk);
+
+        return 0;
+}
+
+static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
+        int ret;
+
+        ret = clk_enable(ep93xx_pwm->clk);
+        if (ret)
+                return ret;
+
+        writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
+
+        return 0;
+}
+
+static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
+
+        writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
+        clk_disable(ep93xx_pwm->clk);
+}
+
+static const struct pwm_ops ep93xx_pwm_ops = {
+        .request = ep93xx_pwm_request,
+        .free = ep93xx_pwm_free,
+        .config = ep93xx_pwm_config,
+        .set_polarity = ep93xx_pwm_polarity,
+        .enable = ep93xx_pwm_enable,
+        .disable = ep93xx_pwm_disable,
+        .owner = THIS_MODULE,
+};
+
+static int ep93xx_pwm_probe(struct platform_device *pdev)
+{
+        struct ep93xx_pwm *ep93xx_pwm;
+        struct resource *res;
+        int ret;
+
+        ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);
+        if (!ep93xx_pwm)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(ep93xx_pwm->base))
+                return PTR_ERR(ep93xx_pwm->base);
+
+        ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
+        if (IS_ERR(ep93xx_pwm->clk))
+                return PTR_ERR(ep93xx_pwm->clk);
+
+        ep93xx_pwm->chip.dev = &pdev->dev;
+        ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;
+        ep93xx_pwm->chip.base = -1;
+        ep93xx_pwm->chip.npwm = 1;
+
+        ret = pwmchip_add(&ep93xx_pwm->chip);
+        if (ret < 0)
+                return ret;
+
+        platform_set_drvdata(pdev, ep93xx_pwm);
+        return 0;
+}
+
+static int ep93xx_pwm_remove(struct platform_device *pdev)
+{
+        struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev);
+
+        return pwmchip_remove(&ep93xx_pwm->chip);
+}
+
+static struct platform_driver ep93xx_pwm_driver = {
+        .driver = {
+                .name = "ep93xx-pwm",
+        },
+        .probe = ep93xx_pwm_probe,
+        .remove = ep93xx_pwm_remove,
+};
+module_platform_driver(ep93xx_pwm_driver);
+
+MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
+MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
+              "H Hartley Sweeten <hsweeten@visionengravers.com>");
+MODULE_ALIAS("platform:ep93xx-pwm");
+MODULE_LICENSE("GPL");