[PATCH v6 2/4] pwm: opencores: Add PWM driver support

[William Qiu]

Add Pulse Width Modulation driver support for OpenCores.

Co-developed-by: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
Signed-off-by: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
Signed-off-by: William Qiu <william.qiu@xxxxxxxxxxxxxxxx>
---
 MAINTAINERS              |   7 ++
 drivers/pwm/Kconfig      |  11 ++
 drivers/pwm/Makefile     |   1 +
 drivers/pwm/pwm-ocores.c | 211 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 230 insertions(+)
 create mode 100644 drivers/pwm/pwm-ocores.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6c4cce45a09d..321af8fa7aad 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16003,6 +16003,13 @@ F:	Documentation/i2c/busses/i2c-ocores.rst
 F:	drivers/i2c/busses/i2c-ocores.c
 F:	include/linux/platform_data/i2c-ocores.h

+OPENCORES PWM DRIVER
+M:	William Qiu <william.qiu@xxxxxxxxxxxxxxxx>
+M:	Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
+S:	Supported
+F:	Documentation/devicetree/bindings/pwm/opencores,pwm-ocores.yaml
+F:	drivers/pwm/pwm-ocores.c
+
 OPENRISC ARCHITECTURE
 M:	Jonas Bonn <jonas@xxxxxxxxxxxx>
 M:	Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 8ebcddf91f7b..cbfbf227d957 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -434,6 +434,17 @@ config PWM_NTXEC
 	  controller found in certain e-book readers designed by the original
 	  design manufacturer Netronix.

+config PWM_OCORES
+	tristate "Opencores PWM support"
+	depends on HAS_IOMEM && OF
+	depends on COMMON_CLK && RESET_CONTROLLER
+	help
+	  If you say yes to this option, support will be included for the
+	  OpenCores PWM. For details see https://opencores.org/projects/ptc.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-ocores.
+
 config PWM_OMAP_DMTIMER
 	tristate "OMAP Dual-Mode Timer PWM support"
 	depends on OF
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c822389c2a24..542b98202153 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_PWM_MICROCHIP_CORE)	+= pwm-microchip-core.o
 obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_NTXEC)		+= pwm-ntxec.o
+obj-$(CONFIG_PWM_OCORES)	+= pwm-ocores.o
 obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
diff --git a/drivers/pwm/pwm-ocores.c b/drivers/pwm/pwm-ocores.c
new file mode 100644
index 000000000000..7a510de4e063
--- /dev/null
+++ b/drivers/pwm/pwm-ocores.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OpenCores PWM Driver
+ *
+ * https://opencores.org/projects/ptc
+ *
+ * Copyright (C) 2018-2023 StarFive Technology Co., Ltd.
+ */
+
+#include <linux/clk.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/reset.h>
+#include <linux/slab.h>
+
+#define REG_OCPWM_CNTR(base)	((base))
+#define REG_OCPWM_HRC(base)	((base) + 0x4)
+#define REG_OCPWM_LRC(base)	((base) + 0x8)
+#define REG_OCPWM_CTRL(base)	((base) + 0xC)
+
+/* OCPWM_CTRL register bits*/
+#define OCPWM_EN      BIT(0)
+#define OCPWM_ECLK    BIT(1)
+#define OCPWM_NEC     BIT(2)
+#define OCPWM_OE      BIT(3)
+#define OCPWM_SIGNLE  BIT(4)
+#define OCPWM_INTE    BIT(5)
+#define OCPWM_INT     BIT(6)
+#define OCPWM_CNTRRST BIT(7)
+#define OCPWM_CAPTE   BIT(8)
+
+struct ocores_pwm_device {
+	struct pwm_chip chip;
+	struct clk *clk;
+	struct reset_control *rst;
+	const struct ocores_pwm_data *data;
+	void __iomem *regs;
+	u32 clk_rate; /* PWM APB clock frequency */
+};
+
+struct ocores_pwm_data {
+	void __iomem *(*get_ch_base)(void __iomem *base, unsigned int channel);
+};
+
+static inline struct ocores_pwm_device *
+chip_to_ocores(struct pwm_chip *chip)
+
+{
+	return container_of(chip, struct ocores_pwm_device, chip);
+}
+
+void __iomem *starfive_jh71x0_get_ch_base(void __iomem *base,
+					  unsigned int channel)
+{
+	return base + (channel > 3 ? channel % 4 * 0x10 + (1 << 15) : channel * 0x10);
+}
+
+static int ocores_pwm_get_state(struct pwm_chip *chip,
+				struct pwm_device *dev,
+				struct pwm_state *state)
+{
+	struct ocores_pwm_device *pwm = chip_to_ocores(chip);
+	void __iomem *base = pwm->data->get_ch_base ?
+			     pwm->data->get_ch_base(pwm->regs, dev->hwpwm) : pwm->regs;
+	u32 period_data, duty_data, ctrl_data;
+
+	period_data = readl(REG_OCPWM_LRC(base));
+	duty_data = readl(REG_OCPWM_HRC(base));
+	ctrl_data = readl(REG_OCPWM_CTRL(base));
+
+	state->period = DIV_ROUND_CLOSEST_ULL((u64)period_data * NSEC_PER_SEC, pwm->clk_rate);
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_data * NSEC_PER_SEC, pwm->clk_rate);
+	state->polarity = PWM_POLARITY_INVERSED;
+	state->enabled = (ctrl_data & OCPWM_EN) ? true : false;
+
+	return 0;
+}
+
+static int ocores_pwm_apply(struct pwm_chip *chip,
+			    struct pwm_device *dev,
+			    const struct pwm_state *state)
+{
+	struct ocores_pwm_device *pwm = chip_to_ocores(chip);
+	void __iomem *base = pwm->data->get_ch_base ?
+			     pwm->data->get_ch_base(pwm->regs, dev->hwpwm) : pwm->regs;
+	u32 period_data, duty_data, ctrl_data = 0;
+
+	if (state->polarity != PWM_POLARITY_INVERSED)
+		return -EINVAL;
+
+	period_data = DIV_ROUND_CLOSEST_ULL(state->period * pwm->clk_rate,
+					    NSEC_PER_SEC);
+	duty_data = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * pwm->clk_rate,
+					  NSEC_PER_SEC);
+
+	writel(period_data, REG_OCPWM_LRC(base));
+	writel(duty_data, REG_OCPWM_HRC(base));
+	writel(0,  REG_OCPWM_CNTR(base));
+
+	ctrl_data = readl(REG_OCPWM_CTRL(base));
+	if (state->enabled)
+		writel(ctrl_data | OCPWM_EN | OCPWM_OE, REG_OCPWM_CTRL(base));
+	else
+		writel(ctrl_data & ~(OCPWM_EN | OCPWM_OE), REG_OCPWM_CTRL(base));
+
+	return 0;
+}
+
+static const struct pwm_ops ocores_pwm_ops = {
+	.get_state	= ocores_pwm_get_state,
+	.apply		= ocores_pwm_apply,
+	.owner		= THIS_MODULE,
+};
+
+static const struct ocores_pwm_data jh71x0_pwm_data = {
+	.get_ch_base = starfive_jh71x0_get_ch_base,
+};
+
+static const struct of_device_id ocores_pwm_of_match[] = {
+	{ .compatible = "opencores,pwm-ocores" },
+	{ .compatible = "starfive,jh71x0-pwm", .data = &jh71x0_pwm_data},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ocores_pwm_of_match);
+
+static int ocores_pwm_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *id;
+	struct device *dev = &pdev->dev;
+	struct ocores_pwm_device *pwm;
+	struct pwm_chip *chip;
+	int ret;
+
+	id = of_match_device(ocores_pwm_of_match, dev);
+	if (!id)
+		return -EINVAL;
+
+	pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->data = id->data;
+	chip = &pwm->chip;
+	chip->dev = dev;
+	chip->ops = &ocores_pwm_ops;
+	chip->npwm = 8;
+	chip->of_pwm_n_cells = 3;
+
+	pwm->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pwm->regs))
+		return dev_err_probe(dev, PTR_ERR(pwm->regs),
+				     "Unable to map IO resources\n");
+
+	pwm->clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(pwm->clk))
+		return dev_err_probe(dev, PTR_ERR(pwm->clk),
+				     "Unable to get pwm's clock\n");
+
+	pwm->rst = devm_reset_control_get_optional_exclusive(dev, NULL);
+	reset_control_deassert(pwm->rst);
+
+	pwm->clk_rate = clk_get_rate(pwm->clk);
+	if (pwm->clk_rate <= 0) {
+		dev_warn(dev, "Failed to get APB clock rate\n");
+		return -EINVAL;
+	}
+
+	ret = devm_pwmchip_add(dev, chip);
+	if (ret < 0) {
+		dev_err(dev, "Cannot register PTC: %d\n", ret);
+		clk_disable_unprepare(pwm->clk);
+		reset_control_assert(pwm->rst);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+
+	return 0;
+}
+
+static int ocores_pwm_remove(struct platform_device *dev)
+{
+	struct ocores_pwm_device *pwm = platform_get_drvdata(dev);
+
+	reset_control_assert(pwm->rst);
+	clk_disable_unprepare(pwm->clk);
+
+	return 0;
+}
+
+static struct platform_driver ocores_pwm_driver = {
+	.probe = ocores_pwm_probe,
+	.remove = ocores_pwm_remove,
+	.driver = {
+		.name = "ocores-pwm",
+		.of_match_table = ocores_pwm_of_match,
+	},
+};
+module_platform_driver(ocores_pwm_driver);
+
+MODULE_AUTHOR("Jieqin Chen");
+MODULE_AUTHOR("Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("OpenCores PWM PTC driver");
+MODULE_LICENSE("GPL");
--
2.34.1