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authorAlexander Shiyan <shc_work@mail.ru>2014-03-12 19:53:05 +0400
committerThierry Reding <thierry.reding@gmail.com>2014-03-19 00:15:16 +0400
commit7eb3f6ffb5c3635e8cc5df7b19741b4bfc5894f5 (patch)
tree1fc37173d371c507c996ad8fb984c7ac81585171 /drivers/pwm/pwm-clps711x.c
parent916030db4399f9237beef480fee6b11dd83cacd5 (diff)
downloadlinux-7eb3f6ffb5c3635e8cc5df7b19741b4bfc5894f5.tar.xz
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>
Diffstat (limited to 'drivers/pwm/pwm-clps711x.c')
-rw-r--r--drivers/pwm/pwm-clps711x.c176
1 files changed, 176 insertions, 0 deletions
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");