pwm: Add CLPS711X PWM support

Add a new driver for the ARM CLPS711X Pulse Width Modulator (PWM) interface.
This CPU contain two 4-bit PWM outputs with constant period, based on CPU
PLL frequency. PWM polarity is determined by hardware by power on reset.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

3 files changed, 186 insertions, 0 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 17935628383a..1445ba176574 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -71,6 +71,15 @@ config PWM_BFIN
           To compile this driver as a module, choose M here: the module
           will be called pwm-bfin.
 
+config PWM_CLPS711X
+        tristate "CLPS711X PWM support"
+        depends on ARCH_CLPS711X || COMPILE_TEST
+        help
+          Generic PWM framework driver for Cirrus Logic CLPS711X.
+
+          To compile this driver as a module, choose M here: the module
+          will be called pwm-clps711x.
+
 config PWM_EP93XX
         tristate "Cirrus Logic EP93xx PWM support"
         depends on ARCH_EP93XX
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 7a10e05acb48..82f294e67079 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
 obj-$(CONFIG_PWM_ATMEL)         += pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_TCB)     += pwm-atmel-tcb.o
 obj-$(CONFIG_PWM_BFIN)          += pwm-bfin.o
+obj-$(CONFIG_PWM_CLPS711X)      += pwm-clps711x.o
 obj-$(CONFIG_PWM_EP93XX)        += pwm-ep93xx.o
 obj-$(CONFIG_PWM_FSL_FTM)       += pwm-fsl-ftm.o
 obj-$(CONFIG_PWM_IMX)           += pwm-imx.o
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
new file mode 100644
index 000000000000..fafb6a0111b0
--- /dev/null
+++ b/drivers/pwm/pwm-clps711x.c
@@ -0,0 +1,176 @@
+/*
+ * Cirrus Logic CLPS711X PWM driver
+ *
+ * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+struct clps711x_chip {
+        struct pwm_chip chip;
+        void __iomem *pmpcon;
+        struct clk *clk;
+        spinlock_t lock;
+};
+
+static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
+{
+        return container_of(chip, struct clps711x_chip, chip);
+}
+
+static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
+{
+        /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
+        u32 shift = (n + 1) * 4;
+        unsigned long flags;
+        u32 tmp;
+
+        spin_lock_irqsave(&priv->lock, flags);
+
+        tmp = readl(priv->pmpcon);
+        tmp &= ~(0xf << shift);
+        tmp |= v << shift;
+        writel(tmp, priv->pmpcon);
+
+        spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
+{
+        /* Duty cycle 0..15 max */
+        return DIV_ROUND_CLOSEST(v * 0xf, pwm_get_period(pwm));
+}
+
+static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct clps711x_chip *priv = to_clps711x_chip(chip);
+        unsigned int freq = clk_get_rate(priv->clk);
+
+        if (!freq)
+                return -EINVAL;
+
+        /* Store constant period value */
+        pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq));
+
+        return 0;
+}
+
+static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+                               int duty_ns, int period_ns)
+{
+        struct clps711x_chip *priv = to_clps711x_chip(chip);
+        unsigned int duty;
+
+        if (period_ns != pwm_get_period(pwm))
+                return -EINVAL;
+
+        duty = clps711x_get_duty(pwm, duty_ns);
+        clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
+
+        return 0;
+}
+
+static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct clps711x_chip *priv = to_clps711x_chip(chip);
+        unsigned int duty;
+
+        duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm));
+        clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
+
+        return 0;
+}
+
+static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct clps711x_chip *priv = to_clps711x_chip(chip);
+
+        clps711x_pwm_update_val(priv, pwm->hwpwm, 0);
+}
+
+static const struct pwm_ops clps711x_pwm_ops = {
+        .request = clps711x_pwm_request,
+        .config = clps711x_pwm_config,
+        .enable = clps711x_pwm_enable,
+        .disable = clps711x_pwm_disable,
+        .owner = THIS_MODULE,
+};
+
+static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
+                                             const struct of_phandle_args *args)
+{
+        if (args->args[0] >= chip->npwm)
+                return ERR_PTR(-EINVAL);
+
+        return pwm_request_from_chip(chip, args->args[0], NULL);
+}
+
+static int clps711x_pwm_probe(struct platform_device *pdev)
+{
+        struct clps711x_chip *priv;
+        struct resource *res;
+
+        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        priv->pmpcon = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(priv->pmpcon))
+                return PTR_ERR(priv->pmpcon);
+
+        priv->clk = devm_clk_get(&pdev->dev, NULL);
+        if (IS_ERR(priv->clk))
+                return PTR_ERR(priv->clk);
+
+        priv->chip.ops = &clps711x_pwm_ops;
+        priv->chip.dev = &pdev->dev;
+        priv->chip.base = -1;
+        priv->chip.npwm = 2;
+        priv->chip.of_xlate = clps711x_pwm_xlate;
+        priv->chip.of_pwm_n_cells = 1;
+
+        spin_lock_init(&priv->lock);
+
+        platform_set_drvdata(pdev, priv);
+
+        return pwmchip_add(&priv->chip);
+}
+
+static int clps711x_pwm_remove(struct platform_device *pdev)
+{
+        struct clps711x_chip *priv = platform_get_drvdata(pdev);
+
+        return pwmchip_remove(&priv->chip);
+}
+
+static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
+        { .compatible = "cirrus,clps711x-pwm", },
+        { }
+};
+MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
+
+static struct platform_driver clps711x_pwm_driver = {
+        .driver = {
+                .name = "clps711x-pwm",
+                .owner = THIS_MODULE,
+                .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
+        },
+        .probe = clps711x_pwm_probe,
+        .remove = clps711x_pwm_remove,
+};
+module_platform_driver(clps711x_pwm_driver);
+
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
+MODULE_LICENSE("GPL");