[PATCHv10 1/2] pwm: Add Allwinner SoC support
Alexandre Belloni
alexandre.belloni at free-electrons.com
Wed Dec 17 13:15:39 PST 2014
This adds a generic PWM framework driver for the PWM controller
found on Allwinner SoCs.
Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard at free-electrons.com>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-sun4i.c | 366 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 377 insertions(+)
create mode 100644 drivers/pwm/pwm-sun4i.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index ef2dd2e4754b..07f533d2b5be 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -263,6 +263,16 @@ config PWM_STI
To compile this driver as a module, choose M here: the module
will be called pwm-sti.
+config PWM_SUN4I
+ tristate "Allwinner PWM support"
+ depends on ARCH_SUNXI || COMPILE_TEST
+ depends on HAS_IOMEM && COMMON_CLK
+ help
+ Generic PWM framework driver for Allwinner SoCs.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-sun4i.
+
config PWM_TEGRA
tristate "NVIDIA Tegra PWM support"
depends on ARCH_TEGRA
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c458606c3755..d607804deea1 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_STI) += pwm-sti.o
+obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
new file mode 100644
index 000000000000..cd9dde563018
--- /dev/null
+++ b/drivers/pwm/pwm-sun4i.c
@@ -0,0 +1,366 @@
+/*
+ * Driver for Allwinner sun4i Pulse Width Modulation Controller
+ *
+ * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni at free-electrons.com>
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
+
+#define PWM_CTRL_REG 0x0
+
+#define PWM_CH_PRD_BASE 0x4
+#define PWM_CH_PRD_OFFSET 0x4
+#define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch))
+
+#define PWMCH_OFFSET 15
+#define PWM_PRESCAL_MASK GENMASK(3, 0)
+#define PWM_PRESCAL_OFF 0
+#define PWM_EN BIT(4)
+#define PWM_ACT_STATE BIT(5)
+#define PWM_CLK_GATING BIT(6)
+#define PWM_MODE BIT(7)
+#define PWM_PULSE BIT(8)
+#define PWM_BYPASS BIT(9)
+
+#define PWM_RDY_BASE 28
+#define PWM_RDY_OFFSET 1
+#define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch))
+
+#define PWM_PRD(prd) (((prd) - 1) << 16)
+#define PWM_PRD_MASK GENMASK(15, 0)
+
+#define PWM_DTY_MASK GENMASK(15, 0)
+
+#define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET))
+
+static const u32 prescaler_table[] = {
+ 120,
+ 180,
+ 240,
+ 360,
+ 480,
+ 0,
+ 0,
+ 0,
+ 12000,
+ 24000,
+ 36000,
+ 48000,
+ 72000,
+ 0,
+ 0,
+ 0, /* Actually 1 but tested separately */
+};
+
+struct sun4i_pwm_data {
+ bool has_prescaler_bypass;
+ bool has_rdy;
+};
+
+struct sun4i_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+ spinlock_t ctrl_lock;
+ const struct sun4i_pwm_data *data;
+};
+
+static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct sun4i_pwm_chip, chip);
+}
+
+static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip,
+ unsigned long offset)
+{
+ return readl(chip->base + offset);
+}
+
+static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip,
+ u32 val, unsigned long offset)
+{
+ writel(val, chip->base + offset);
+}
+
+static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
+ u32 prd, dty, val, clk_gate;
+ u64 clk_rate, div = 0;
+ unsigned int prescaler = 0;
+ int err;
+
+ clk_rate = clk_get_rate(sun4i_pwm->clk);
+
+ if (sun4i_pwm->data->has_prescaler_bypass) {
+ /* First, test without any prescaler when available */
+ prescaler = PWM_PRESCAL_MASK;
+ /*
+ * When not using any prescaler, the clock period in nanoseconds
+ * is not an integer so round it half up instead of
+ * truncating to get less surprising values.
+ */
+ div = clk_rate * period_ns + NSEC_PER_SEC/2;
+ do_div(div, NSEC_PER_SEC);
+ if (div - 1 > PWM_PRD_MASK)
+ prescaler = 0;
+ }
+
+ if (prescaler == 0) {
+ /* Go up from the first divider */
+ for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) {
+ if (!prescaler_table[prescaler])
+ continue;
+ div = clk_rate;
+ do_div(div, prescaler_table[prescaler]);
+ div = div * period_ns;
+ do_div(div, NSEC_PER_SEC);
+ if (div - 1 <= PWM_PRD_MASK)
+ break;
+ }
+
+ if (div - 1 > PWM_PRD_MASK) {
+ dev_err(chip->dev, "period exceeds the maximum value\n");
+ return -EINVAL;
+ }
+ }
+
+ prd = div;
+ div *= duty_ns;
+ do_div(div, period_ns);
+ dty = div;
+
+ err = clk_prepare_enable(sun4i_pwm->clk);
+ if (err) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return err;
+ }
+
+ spin_lock(&sun4i_pwm->ctrl_lock);
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+
+ if (sun4i_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) {
+ spin_unlock(&sun4i_pwm->ctrl_lock);
+ clk_disable_unprepare(sun4i_pwm->clk);
+ return -EBUSY;
+ }
+
+ clk_gate = val & BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ if (clk_gate) {
+ val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+ }
+
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+ val &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
+ val |= BIT_CH(prescaler, pwm->hwpwm);
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+
+ val = (dty & PWM_DTY_MASK) | PWM_PRD(prd);
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
+
+ if (clk_gate) {
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+ val |= clk_gate;
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+ }
+
+ spin_unlock(&sun4i_pwm->ctrl_lock);
+ clk_disable_unprepare(sun4i_pwm->clk);
+
+ return 0;
+}
+
+static int sun4i_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
+ u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(sun4i_pwm->clk);
+ if (ret) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return ret;
+ }
+
+ spin_lock(&sun4i_pwm->ctrl_lock);
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+
+ if (polarity != PWM_POLARITY_NORMAL)
+ val &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
+ else
+ val |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
+
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+
+ spin_unlock(&sun4i_pwm->ctrl_lock);
+ clk_disable_unprepare(sun4i_pwm->clk);
+
+ return 0;
+}
+
+static int sun4i_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
+ u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(sun4i_pwm->clk);
+ if (ret) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return ret;
+ }
+
+ spin_lock(&sun4i_pwm->ctrl_lock);
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+ val |= BIT_CH(PWM_EN, pwm->hwpwm);
+ val |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+ spin_unlock(&sun4i_pwm->ctrl_lock);
+
+ return 0;
+}
+
+static void sun4i_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
+ u32 val;
+
+ spin_lock(&sun4i_pwm->ctrl_lock);
+ val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+ val &= ~BIT_CH(PWM_EN, pwm->hwpwm);
+ val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG);
+ spin_unlock(&sun4i_pwm->ctrl_lock);
+
+ clk_disable_unprepare(sun4i_pwm->clk);
+}
+
+static const struct pwm_ops sun4i_pwm_ops = {
+ .config = sun4i_pwm_config,
+ .set_polarity = sun4i_pwm_set_polarity,
+ .enable = sun4i_pwm_enable,
+ .disable = sun4i_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static const struct sun4i_pwm_data sun4i_pwm_data_a10 = {
+ .has_prescaler_bypass = false,
+ .has_rdy = false,
+};
+
+static const struct sun4i_pwm_data sun4i_pwm_data_a20 = {
+ .has_prescaler_bypass = true,
+ .has_rdy = true,
+};
+
+static const struct of_device_id sun4i_pwm_dt_ids[] = {
+ {
+ .compatible = "allwinner,sun4i-a10-pwm",
+ .data = &sun4i_pwm_data_a10,
+ }, {
+ .compatible = "allwinner,sun7i-a20-pwm",
+ .data = &sun4i_pwm_data_a20,
+ }, {
+ /* sentinel */
+ },
+};
+MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids);
+
+static int sun4i_pwm_probe(struct platform_device *pdev)
+{
+ struct sun4i_pwm_chip *pwm;
+ struct resource *res;
+ u32 val;
+ int i, ret;
+ const struct of_device_id *match;
+
+ match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev);
+
+ 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);
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &sun4i_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = 2;
+ pwm->chip.can_sleep = true;
+ pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+ pwm->chip.of_pwm_n_cells = 3;
+ pwm->data = match->data;
+
+ spin_lock_init(&pwm->ctrl_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);
+
+ ret = clk_prepare_enable(pwm->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable PWM clock\n");
+ goto clk_error;
+ }
+
+ val = sun4i_pwm_readl(pwm, PWM_CTRL_REG);
+ for (i = 0; i < pwm->chip.npwm; i++)
+ if (!(val & BIT_CH(PWM_ACT_STATE, i)))
+ pwm->chip.pwms[i].polarity = PWM_POLARITY_INVERSED;
+ clk_disable_unprepare(pwm->clk);
+
+ return 0;
+
+clk_error:
+ pwmchip_remove(&pwm->chip);
+ return ret;
+}
+
+static int sun4i_pwm_remove(struct platform_device *pdev)
+{
+ struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&pwm->chip);
+}
+
+static struct platform_driver sun4i_pwm_driver = {
+ .driver = {
+ .name = "sun4i-pwm",
+ .of_match_table = sun4i_pwm_dt_ids,
+ },
+ .probe = sun4i_pwm_probe,
+ .remove = sun4i_pwm_remove,
+};
+module_platform_driver(sun4i_pwm_driver);
+
+MODULE_ALIAS("platform:sun4i-pwm");
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni at free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner sun4i PWM driver");
+MODULE_LICENSE("GPL v2");
--
2.1.0
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