[PATCH v2 1/5] pwm: add the Berlin pwm controller driver
Antoine Tenart
antoine.tenart at free-electrons.com
Thu Jul 30 02:23:17 PDT 2015
Add a PWM controller driver for the Marvell Berlin SoCs. This PWM
controller has 4 channels.
Signed-off-by: Antoine Tenart <antoine.tenart at free-electrons.com>
---
drivers/pwm/Kconfig | 9 +++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-berlin.c | 207 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 217 insertions(+)
create mode 100644 drivers/pwm/pwm-berlin.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index b1541f40fd8d..1773da8145b8 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -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 "Berlin PWM support"
+ depends on ARCH_BERLIN
+ help
+ PWM framework driver for Berlin.
+
+ 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
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index ec50eb5b5a8f..670c5fce8bbb 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -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_EP93XX) += pwm-ep93xx.o
diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
new file mode 100644
index 000000000000..786990c1c750
--- /dev/null
+++ b/drivers/pwm/pwm-berlin.c
@@ -0,0 +1,207 @@
+/*
+ * Marvell Berlin PWM driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Antoine Tenart <antoine.tenart at 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/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/spinlock.h>
+
+#define BERLIN_PWM_EN 0x0
+#define BERLIN_PWM_CONTROL 0x4
+#define BERLIN_PWM_DUTY 0x8
+#define BERLIN_PWM_TCNT 0xc
+
+#define BERLIN_PWM_CLK_RATE 100000000
+#define BERLIN_PWM_PRESCALE_MASK 0x7
+#define BERLIN_PWM_PRESCALE_MAX 4096
+
+struct berlin_pwm_chip {
+ struct pwm_chip chip;
+ void __iomem *base;
+ spinlock_t lock;
+};
+
+#define to_berlin_pwm_chip(chip) \
+ container_of((chip), struct berlin_pwm_chip, chip)
+
+#define berlin_pwm_readl(chip, channel, offset) \
+ readl((chip)->base + (channel) * 0x10 + offset)
+#define berlin_pwm_writel(val, chip, channel, offset) \
+ writel(val, (chip)->base + (channel) * 0x10 + offset)
+
+static const u32 prescaler_table[] = {
+ 1,
+ 4,
+ 8,
+ 16,
+ 64,
+ 256,
+ 1024,
+ 4096,
+};
+
+static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct berlin_pwm_chip *berlin_chip = to_berlin_pwm_chip(chip);
+ int prescale;
+ u32 val, duty, period;
+ u64 tmp;
+
+ for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
+ tmp = BERLIN_PWM_CLK_RATE;
+ do_div(tmp, prescaler_table[prescale]);
+ tmp *= period_ns;
+ do_div(tmp, NSEC_PER_SEC);
+
+ if (tmp - 1 <= BERLIN_PWM_PRESCALE_MAX)
+ break;
+ }
+
+ if (tmp - 1 > BERLIN_PWM_PRESCALE_MAX)
+ return -EINVAL;
+
+ period = tmp;
+ tmp *= duty_ns;
+ do_div(tmp, period_ns);
+ duty = tmp;
+
+ spin_lock(&berlin_chip->lock);
+
+ val = berlin_pwm_readl(berlin_chip, pwm->hwpwm, BERLIN_PWM_CONTROL);
+ val &= ~BERLIN_PWM_PRESCALE_MASK;
+ val |= prescale;
+ berlin_pwm_writel(val, berlin_chip, pwm->hwpwm, BERLIN_PWM_CONTROL);
+
+ berlin_pwm_writel(duty, berlin_chip, pwm->hwpwm, BERLIN_PWM_DUTY);
+ berlin_pwm_writel(period, berlin_chip, pwm->hwpwm, BERLIN_PWM_TCNT);
+
+ spin_unlock(&berlin_chip->lock);
+
+ return 0;
+}
+
+static int berlin_pwm_set_polarity(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct berlin_pwm_chip *berlin_chip = to_berlin_pwm_chip(chip);
+ u32 val;
+
+ spin_lock(&berlin_chip->lock);
+
+ val = berlin_pwm_readl(berlin_chip, pwm->hwpwm, BERLIN_PWM_CONTROL);
+
+ if (polarity == PWM_POLARITY_NORMAL)
+ val &= ~BIT(3);
+ else
+ val |= BIT(3);
+
+ berlin_pwm_writel(val, berlin_chip, pwm->hwpwm, BERLIN_PWM_CONTROL);
+
+ spin_unlock(&berlin_chip->lock);
+
+ return 0;
+}
+
+static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct berlin_pwm_chip *berlin_chip = to_berlin_pwm_chip(chip);
+
+ spin_lock(&berlin_chip->lock);
+ berlin_pwm_writel(0x1, berlin_chip, pwm->hwpwm, BERLIN_PWM_EN);
+ spin_unlock(&berlin_chip->lock);
+
+ return 0;
+}
+
+static void berlin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct berlin_pwm_chip *berlin_chip = to_berlin_pwm_chip(chip);
+
+ spin_lock(&berlin_chip->lock);
+ berlin_pwm_writel(0x0, berlin_chip, pwm->hwpwm, BERLIN_PWM_EN);
+ spin_unlock(&berlin_chip->lock);
+}
+
+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->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;
+
+ spin_lock_init(&pwm->lock);
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to add PWM chip: %d\n", ret);
+ 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);
+
+ return pwmchip_remove(&pwm->chip);
+}
+
+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 at free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin PWM driver");
+MODULE_LICENSE("GPL v2");
--
2.5.0
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