pwm: Add support for the Berlin PWM controller
authorAntoine Ténart <antoine.tenart@free-electrons.com>
Fri, 2 Oct 2015 14:59:47 +0000 (16:59 +0200)
committerThierry Reding <thierry.reding@gmail.com>
Tue, 6 Oct 2015 07:40:44 +0000 (09:40 +0200)
Add a PWM controller driver for the Marvell Berlin SoCs. This PWM
controller has 4 channels.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
drivers/pwm/Kconfig
drivers/pwm/Makefile
drivers/pwm/pwm-berlin.c [new file with mode: 0644]

index 062630ab742451c8d4d06b61262d0a4753bb4711..afe6573b025342cb80a4b6c65cb1c379fc29341c 100644 (file)
@@ -92,6 +92,15 @@ config PWM_BCM2835
          To compile this driver as a module, choose M here: the module
          will be called pwm-bcm2835.
 
+config PWM_BERLIN
+       tristate "Marvell Berlin PWM support"
+       depends on ARCH_BERLIN
+       help
+         PWM framework driver for Marvell Berlin SoCs.
+
+         To compile this driver as a module, choose M here: the module
+         will be called pwm-berlin.
+
 config PWM_BFIN
        tristate "Blackfin PWM support"
        depends on BFIN_GPTIMERS
index a0e00c09ead3d05e6fb92c68f4744cfcf5177f17..601833d82da57599f3900e4b35d7ce6016344ff4 100644 (file)
@@ -6,6 +6,7 @@ obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)       += pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)    += pwm-atmel-tcb.o
 obj-$(CONFIG_PWM_BCM_KONA)     += pwm-bcm-kona.o
 obj-$(CONFIG_PWM_BCM2835)      += pwm-bcm2835.o
+obj-$(CONFIG_PWM_BERLIN)       += pwm-berlin.o
 obj-$(CONFIG_PWM_BFIN)         += pwm-bfin.o
 obj-$(CONFIG_PWM_CLPS711X)     += pwm-clps711x.o
 obj-$(CONFIG_PWM_CRC)          += pwm-crc.o
diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
new file mode 100644 (file)
index 0000000..6510812
--- /dev/null
@@ -0,0 +1,219 @@
+/*
+ * Marvell Berlin PWM driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define BERLIN_PWM_EN                  0x0
+#define  BERLIN_PWM_ENABLE             BIT(0)
+#define BERLIN_PWM_CONTROL             0x4
+#define  BERLIN_PWM_PRESCALE_MASK      0x7
+#define  BERLIN_PWM_PRESCALE_MAX       4096
+#define  BERLIN_PWM_INVERT_POLARITY    BIT(3)
+#define BERLIN_PWM_DUTY                        0x8
+#define BERLIN_PWM_TCNT                        0xc
+#define  BERLIN_PWM_MAX_TCNT           65535
+
+struct berlin_pwm_chip {
+       struct pwm_chip chip;
+       struct clk *clk;
+       void __iomem *base;
+};
+
+static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
+{
+       return container_of(chip, struct berlin_pwm_chip, chip);
+}
+
+static const u32 prescaler_table[] = {
+       1, 4, 8, 16, 64, 256, 1024, 4096
+};
+
+static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
+                                  unsigned int channel, unsigned long offset)
+{
+       return readl_relaxed(chip->base + channel * 0x10 + offset);
+}
+
+static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
+                                    unsigned int channel, u32 value,
+                                    unsigned long offset)
+{
+       writel_relaxed(value, chip->base + channel * 0x10 + offset);
+}
+
+static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
+                            int duty_ns, int period_ns)
+{
+       struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+       unsigned int prescale;
+       u32 value, duty, period;
+       u64 cycles, tmp;
+
+       cycles = clk_get_rate(pwm->clk);
+       cycles *= period_ns;
+       do_div(cycles, NSEC_PER_SEC);
+
+       for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
+               tmp = cycles;
+               do_div(tmp, prescaler_table[prescale]);
+
+               if (tmp <= BERLIN_PWM_MAX_TCNT)
+                       break;
+       }
+
+       if (tmp > BERLIN_PWM_MAX_TCNT)
+               return -ERANGE;
+
+       period = tmp;
+       cycles = tmp * duty_ns;
+       do_div(cycles, period_ns);
+       duty = cycles;
+
+       value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+       value &= ~BERLIN_PWM_PRESCALE_MASK;
+       value |= prescale;
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);
+
+       return 0;
+}
+
+static int berlin_pwm_set_polarity(struct pwm_chip *chip,
+                                  struct pwm_device *pwm_dev,
+                                  enum pwm_polarity polarity)
+{
+       struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+       u32 value;
+
+       value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+
+       if (polarity == PWM_POLARITY_NORMAL)
+               value &= ~BERLIN_PWM_INVERT_POLARITY;
+       else
+               value |= BERLIN_PWM_INVERT_POLARITY;
+
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+       return 0;
+}
+
+static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
+{
+       struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+       u32 value;
+
+       value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+       value |= BERLIN_PWM_ENABLE;
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+
+       return 0;
+}
+
+static void berlin_pwm_disable(struct pwm_chip *chip,
+                              struct pwm_device *pwm_dev)
+{
+       struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+       u32 value;
+
+       value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+       value &= ~BERLIN_PWM_ENABLE;
+       berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+}
+
+static const struct pwm_ops berlin_pwm_ops = {
+       .config = berlin_pwm_config,
+       .set_polarity = berlin_pwm_set_polarity,
+       .enable = berlin_pwm_enable,
+       .disable = berlin_pwm_disable,
+       .owner = THIS_MODULE,
+};
+
+static const struct of_device_id berlin_pwm_match[] = {
+       { .compatible = "marvell,berlin-pwm" },
+       { },
+};
+MODULE_DEVICE_TABLE(of, berlin_pwm_match);
+
+static int berlin_pwm_probe(struct platform_device *pdev)
+{
+       struct berlin_pwm_chip *pwm;
+       struct resource *res;
+       int ret;
+
+       pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+       if (!pwm)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       pwm->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(pwm->base))
+               return PTR_ERR(pwm->base);
+
+       pwm->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(pwm->clk))
+               return PTR_ERR(pwm->clk);
+
+       ret = clk_prepare_enable(pwm->clk);
+       if (ret)
+               return ret;
+
+       pwm->chip.dev = &pdev->dev;
+       pwm->chip.ops = &berlin_pwm_ops;
+       pwm->chip.base = -1;
+       pwm->chip.npwm = 4;
+       pwm->chip.can_sleep = true;
+       pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+       pwm->chip.of_pwm_n_cells = 3;
+
+       ret = pwmchip_add(&pwm->chip);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+               clk_disable_unprepare(pwm->clk);
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, pwm);
+
+       return 0;
+}
+
+static int berlin_pwm_remove(struct platform_device *pdev)
+{
+       struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
+       int ret;
+
+       ret = pwmchip_remove(&pwm->chip);
+       clk_disable_unprepare(pwm->clk);
+
+       return ret;
+}
+
+static struct platform_driver berlin_pwm_driver = {
+       .probe = berlin_pwm_probe,
+       .remove = berlin_pwm_remove,
+       .driver = {
+               .name = "berlin-pwm",
+               .of_match_table = berlin_pwm_match,
+       },
+};
+module_platform_driver(berlin_pwm_driver);
+
+MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin PWM driver");
+MODULE_LICENSE("GPL v2");