[PATCHv3 1/7] pwm: Add Allwinner SoC support

Alexandre Belloni
2014-04-28T16:17:58Z

This adds a generic PWM framework driver for the PWM controller
found on Allwinner SoCs.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/pwm/Kconfig | 9 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-sunxi.c | 345 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 355 insertions(+)
create mode 100644 drivers/pwm/pwm-sunxi.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 5b34ff29ea38..178b017be827 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -217,6 +217,15 @@ config PWM_SPEAR
To compile this driver as a module, choose M here: the module
will be called pwm-spear.

+config PWM_SUNXI
+ tristate "Allwinner PWM support"
+ depends on ARCH_SUNXI || COMPILE_TEST
+ help
+ Generic PWM framework driver for Allwinner SoCs.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-sunxi.
+
config PWM_TEGRA
tristate "NVIDIA Tegra PWM support"
depends on ARCH_TEGRA
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index e57d2c38a794..39997ea2e276 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
+obj-$(CONFIG_PWM_SUNXI) += pwm-sunxi.o
obj-$(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-sunxi.c b/drivers/pwm/pwm-sunxi.c
new file mode 100644
index 000000000000..0f2d65e8976b
--- /dev/null
+++ b/drivers/pwm/pwm-sunxi.c
@@ -0,0 +1,345 @@
+/*
+ * Driver for Allwinner Pulse Width Modulation Controller
+ *
+ * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com>
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#define PWM_CTRL_REG 0x0
+
+#define PWM_CH_PRD_BASE 0x4
+#define PWM_CH_PRD_OFF 0x4
+#define PWM_CH_PRD(x) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFF * (x))
+
+#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_OFF 1
+#define PWM_RDY(x) BIT(PWM_RDY_BASE + PWM_RDY_OFF * (x))
+
+#define PWM_PRD_ACT_MASK 0xFF
+#define PWM_PRD(x) ((x - 1) << 16)
+#define PWM_PRD_MASK 0xFF
+
+#define BIT_CH(bit, chan) (bit << (chan * PWMCH_OFFSET))
+
+u32 prescal_table[] = { 120, 180, 240, 360, 480, 0, 0, 0,
+ 12000, 24000, 36000, 48000, 72000,
+ 0, 0, 1 };
+
+struct sunxi_pwm_data {
+ bool has_rdy;
+};
+
+struct sunxi_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+ struct mutex ctrl_lock;
+ const struct sunxi_pwm_data *data;
+};
+
+#define to_sunxi_pwm_chip(chip) container_of(chip, struct sunxi_pwm_chip, chip)
+
+static inline u32 sunxi_pwm_readl(struct sunxi_pwm_chip *chip,
+ unsigned long offset)
+{
+ return readl_relaxed(chip->base + offset);
+}
+
+static inline void sunxi_pwm_writel(struct sunxi_pwm_chip *chip,
+ unsigned long offset, unsigned long val)
+{
+ writel_relaxed(val, chip->base + offset);
+}
+
+static int sunxi_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct sunxi_pwm_chip *sunxi_pwm = to_sunxi_pwm_chip(chip);
+ u32 clk_rate, prd, dty;
+ u64 div;
+ u32 val, clk_gate;
+ int i, ret;
+
+ clk_rate = clk_get_rate(sunxi_pwm->clk);
+
+ /* First, test without any divider */
+ i = PWM_PRESCAL_MASK;
+ div = clk_rate * period_ns;
+ do_div(div, 1000000000);
+ if (div > PWM_PRD_MASK) {
+ /* Then go up from the first divider */
+ for (i = 0; i < PWM_PRESCAL_MASK; i++) {
+ if (!prescal_table[i])
+ continue;
+ div = clk_rate / prescal_table[i];
+ div = div * period_ns;
+ do_div(div, 1000000000);
+ if (div <= PWM_PRD_MASK)
+ break;
+ }
+ }
+
+ if (div > PWM_PRD_MASK) {
+ dev_err(chip->dev, "prescaler exceeds the maximum value\n");
+ return -EINVAL;
+ }
+
+ prd = div;
+ div *= duty_ns;
+ do_div(div, period_ns);
+ dty = div;
+
+ ret = clk_enable(sunxi_pwm->clk);
+ if (ret) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return ret;
+ }
+
+ mutex_lock(&sunxi_pwm->ctrl_lock);
+ val = sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG);
+
+ if (sunxi_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) {
+ mutex_unlock(&sunxi_pwm->ctrl_lock);
+ clk_disable(sunxi_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);
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+ }
+
+ val = sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG);
+ val &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm);
+ val |= i;
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+
+ sunxi_pwm_writel(sunxi_pwm, PWM_CH_PRD(pwm->hwpwm), dty | PWM_PRD(prd));
+
+ if (clk_gate) {
+ val = sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG);
+ val |= clk_gate;
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+ }
+
+ mutex_unlock(&sunxi_pwm->ctrl_lock);
+ clk_disable(sunxi_pwm->clk);
+
+ return 0;
+}
+
+static int sunxi_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct sunxi_pwm_chip *sunxi_pwm = to_sunxi_pwm_chip(chip);
+ u32 val;
+ int ret;
+
+ ret = clk_enable(sunxi_pwm->clk);
+ if (ret) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return ret;
+ }
+
+ mutex_lock(&sunxi_pwm->ctrl_lock);
+ val = sunxi_pwm_readl(sunxi_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);
+
+
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+
+ mutex_unlock(&sunxi_pwm->ctrl_lock);
+ clk_disable(sunxi_pwm->clk);
+
+ return 0;
+}
+
+static int sunxi_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct sunxi_pwm_chip *sunxi_pwm = to_sunxi_pwm_chip(chip);
+ u32 val;
+ int ret;
+
+ ret = clk_enable(sunxi_pwm->clk);
+ if (ret) {
+ dev_err(chip->dev, "failed to enable PWM clock\n");
+ return ret;
+ }
+
+ mutex_lock(&sunxi_pwm->ctrl_lock);
+ val = sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG);
+ val |= BIT_CH(PWM_EN, pwm->hwpwm);
+ val |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+ mutex_unlock(&sunxi_pwm->ctrl_lock);
+
+ return 0;
+}
+
+static void sunxi_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct sunxi_pwm_chip *sunxi_pwm = to_sunxi_pwm_chip(chip);
+ u32 val;
+
+ mutex_lock(&sunxi_pwm->ctrl_lock);
+ val = sunxi_pwm_readl(sunxi_pwm, PWM_CTRL_REG);
+ val &= ~BIT_CH(PWM_EN, pwm->hwpwm);
+ val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG, val);
+ mutex_unlock(&sunxi_pwm->ctrl_lock);
+
+ clk_disable(sunxi_pwm->clk);
+}
+
+static const struct pwm_ops sunxi_pwm_ops = {
+ .config = sunxi_pwm_config,
+ .set_polarity = sunxi_pwm_set_polarity,
+ .enable = sunxi_pwm_enable,
+ .disable = sunxi_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static const struct sunxi_pwm_data sunxi_pwm_data_a10 = {
+ .has_rdy = false,
+};
+
+static const struct sunxi_pwm_data sunxi_pwm_data_a20 = {
+ .has_rdy = true,
+};
+
+static const struct of_device_id sunxi_pwm_dt_ids[] = {
+ {
+ .compatible = "allwinner,sun4i-a10-pwm",
+ .data = &sunxi_pwm_data_a10,
+ }, {
+ .compatible = "allwinner,sun7i-a20-pwm",
+ .data = &sunxi_pwm_data_a20,
+ }, {
+ /* sentinel */
+ },
+};
+MODULE_DEVICE_TABLE(of, sunxi_pwm_dt_ids);
+
+static int sunxi_pwm_probe(struct platform_device *pdev)
+{
+ struct sunxi_pwm_chip *sunxi_pwm;
+ struct resource *res;
+ int ret;
+
+ const struct of_device_id *match;
+
+ match = of_match_device(sunxi_pwm_dt_ids, &pdev->dev);
+ if (!match || !match->data)
+ return -ENODEV;
+
+ sunxi_pwm = devm_kzalloc(&pdev->dev, sizeof(*sunxi_pwm), GFP_KERNEL);
+ if (!sunxi_pwm)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ sunxi_pwm->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(sunxi_pwm->base))
+ return PTR_ERR(sunxi_pwm->base);
+
+ sunxi_pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(sunxi_pwm->clk))
+ return PTR_ERR(sunxi_pwm->clk);
+
+ ret = clk_prepare(sunxi_pwm->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to prepare PWM clock\n");
+ return ret;
+ }
+
+ sunxi_pwm->chip.dev = &pdev->dev;
+ sunxi_pwm->chip.ops = &sunxi_pwm_ops;
+
+ sunxi_pwm->chip.base = -1;
+ sunxi_pwm->chip.npwm = 2;
+ sunxi_pwm->chip.can_sleep = true;
+ sunxi_pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+ sunxi_pwm->chip.of_pwm_n_cells = 3;
+ sunxi_pwm->data = match->data;
+
+ mutex_init(&sunxi_pwm->ctrl_lock);
+
+ ret = clk_enable(sunxi_pwm->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable PWM clock\n");
+ goto error;
+ }
+
+ /* By default, the polarity is inversed, set it to normal */
+ sunxi_pwm_writel(sunxi_pwm, PWM_CTRL_REG,
+ BIT_CH(PWM_ACT_STATE, 0) |
+ BIT_CH(PWM_ACT_STATE, 1));
+ clk_disable(sunxi_pwm->clk);
+
+ ret = pwmchip_add(&sunxi_pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret);
+ goto error;
+ }
+
+ platform_set_drvdata(pdev, sunxi_pwm);
+
+ return ret;
+
+error:
+ mutex_destroy(&sunxi_pwm->ctrl_lock);
+ clk_unprepare(sunxi_pwm->clk);
+ return ret;
+}
+
+static int sunxi_pwm_remove(struct platform_device *pdev)
+{
+ struct sunxi_pwm_chip *sunxi_pwm = platform_get_drvdata(pdev);
+
+ mutex_destroy(&sunxi_pwm->ctrl_lock);
+ clk_unprepare(sunxi_pwm->clk);
+
+ return pwmchip_remove(&sunxi_pwm->chip);
+}
+
+static struct platform_driver sunxi_pwm_driver = {
+ .driver = {
+ .name = "sunxi-pwm",
+ .of_match_table = sunxi_pwm_dt_ids,
+ },
+ .probe = sunxi_pwm_probe,
+ .remove = sunxi_pwm_remove,
+};
+module_platform_driver(sunxi_pwm_driver);
+
+MODULE_ALIAS("platform:sunxi-pwm");
+MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner PWM driver");
+MODULE_LICENSE("GPL v2");
--
1.9.1