Add AXI PWM generator driver to mainline

Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml

@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/adi,axi-pwmgen.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AXI PWM generator
+
+maintainers:
+  - Michael Hennerich <[email protected]>
+  - Nuno Sá <[email protected]>
+
+description:
+  The Analog Devices AXI PWM generator can generate PWM signals
+  with variable pulse width and period.
+
+  https://wiki.analog.com/resources/fpga/docs/axi_pwm_gen
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    const: adi,axi-pwmgen-v1
+
+  reg:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 2
+
+  clocks:
+    maxItems: 1
+
+unevaluatedProperties: false
+
+required:
+  - reg
+  - clocks
+
+examples:
+  - |
+    pwm@44b00000 {
+       compatible = "adi,axi-pwmgen";
+       reg = <0x44b00000 0x1000>;
+       clocks = <&spi_clk>;
+       #pwm-cells = <2>;
+    };

MAINTAINERS

@@ -3415,6 +3415,15 @@ W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/hwmon/adi,axi-fan-control.yaml
 F:	drivers/hwmon/axi-fan-control.c
 
+AXI PWM GENERATOR
+M:	Michael Hennerich <[email protected]>
+M:	Nuno Sá <[email protected]>
+L:	[email protected]
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml
+F:	drivers/pwm/pwm-axi-pwmgen.c
+
 AXI SPI ENGINE
 M:	Michael Hennerich <[email protected]>
 M:	Nuno Sá <[email protected]>

drivers/pwm/Kconfig

@@ -98,6 +98,18 @@ config PWM_ATMEL_TCB
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-atmel-tcb.
 
+config PWM_AXI_PWMGEN
+	tristate "Analog Devices AXI PWM generator"
+	depends on HAS_IOMEM
+	help
+	  This enables support for the Analog Devices AXI PWM generator.
+
+	  This is a single output configurable PWM generator with variable
+	  pulse width and period.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called pwm-axi-pwmgen.
+
 config PWM_BCM_IPROC
 	tristate "iProc PWM support"
 	depends on ARCH_BCM_IPROC || COMPILE_TEST

drivers/pwm/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_PWM_APPLE)		+= pwm-apple.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
+obj-$(CONFIG_PWM_AXI_PWMGEN)	+= pwm-axi-pwmgen.o
 obj-$(CONFIG_PWM_BCM_IPROC)	+= pwm-bcm-iproc.o
 obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o
 obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o

drivers/pwm/pwm-axi-pwmgen.c

@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices AXI PWM generator
+ *
+ * Copyright 2023 Analog Devices Inc.
+ */
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define AXI_PWMGEN_NPWM			4
+#define AXI_PWMGEN_REG_CORE_VERSION	0x00
+#define AXI_PWMGEN_REG_ID		0x04
+#define AXI_PWMGEN_REG_SCRATCHPAD	0x08
+#define AXI_PWMGEN_REG_CORE_MAGIC	0x0C
+#define AXI_PWMGEN_REG_CONFIG		0x10
+#define AXI_PWMGEN_REG_NPWM		0x14
+#define AXI_PWMGEN_CH_PERIOD_BASE	0x40
+#define AXI_PWMGEN_CH_DUTY_BASE		0x44
+#define AXI_PWMGEN_CH_OFFSET_BASE	0x48
+#define AXI_PWMGEN_CHX_PERIOD(ch)	(AXI_PWMGEN_CH_PERIOD_BASE + (12 * (ch)))
+#define AXI_PWMGEN_CHX_DUTY(ch)		(AXI_PWMGEN_CH_DUTY_BASE + (12 * (ch)))
+#define AXI_PWMGEN_CHX_OFFSET(ch)	(AXI_PWMGEN_CH_OFFSET_BASE + (12 * (ch)))
+#define AXI_PWMGEN_TEST_DATA		0x5A0F0081
+#define AXI_PWMGEN_LOAD_CONIG		BIT(1)
+#define AXI_PWMGEN_RESET		BIT(0)
+
+struct axi_pwmgen {
+	struct pwm_chip		chip;
+	struct clk		*clk;
+	void __iomem		*base;
+
+	/* Used to store the period when the channel is disabled */
+	unsigned int		ch_period[AXI_PWMGEN_NPWM];
+	bool			ch_enabled[AXI_PWMGEN_NPWM];
+};
+
+static inline unsigned int axi_pwmgen_read(struct axi_pwmgen *pwm,
+					   unsigned int reg)
+{
+	return readl(pwm->base + reg);
+}
+
+static inline void axi_pwmgen_write(struct axi_pwmgen *pwm,
+				    unsigned int reg,
+				    unsigned int value)
+{
+	writel(value, pwm->base + reg);
+}
+
+static void axi_pwmgen_write_mask(struct axi_pwmgen *pwm,
+				  unsigned int reg,
+				  unsigned int mask,
+				  unsigned int value)
+{
+	unsigned int temp;
+
+	temp = axi_pwmgen_read(pwm, reg);
+	axi_pwmgen_write(pwm, reg, (temp & ~mask) | value);
+}
+
+static struct axi_pwmgen *to_axi_pwmgen(struct pwm_chip *chip)
+{
+	return container_of(chip, struct axi_pwmgen, chip);
+}
+
+static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *device,
+			    const struct pwm_state *state)
+{
+	struct axi_pwmgen *pwm = to_axi_pwmgen(chip);
+	unsigned long clk_rate = clk_get_rate(pwm->clk);
+	unsigned int ch = device->hwpwm;
+	u64 period_cnt, duty_cnt;
+
+	period_cnt = DIV_ROUND_UP_ULL(state->period * clk_rate, NSEC_PER_SEC);
+	if (period_cnt > UINT_MAX)
+		return -EINVAL;
+
+	pwm->ch_period[ch] = period_cnt;
+	pwm->ch_enabled[ch] = state->enabled;
+	axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_PERIOD(ch),
+			 state->enabled ? period_cnt : 0);
+
+	duty_cnt = DIV_ROUND_UP_ULL(state->duty_cycle * clk_rate, NSEC_PER_SEC);
+	axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_DUTY(ch), duty_cnt);
+
+	axi_pwmgen_write(pwm, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_LOAD_CONIG);
+
+	return 0;
+}
+
+static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	struct axi_pwmgen *pwmgen = to_axi_pwmgen(chip);
+	unsigned long rate = clk_get_rate(pwmgen->clk);
+	size_t ch = pwm->hwpwm;
+	unsigned int cnt;
+
+	state->enabled = pwmgen->ch_enabled[ch];
+
+	if (state->enabled)
+		cnt = axi_pwmgen_read(pwmgen, AXI_PWMGEN_CHX_PERIOD(ch));
+	else
+		cnt = pwmgen->ch_period[ch];
+
+	state->period = DIV_ROUND_CLOSEST_ULL((u64)cnt * NSEC_PER_SEC, rate);
+
+	cnt = axi_pwmgen_read(pwmgen, AXI_PWMGEN_CHX_DUTY(ch));
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)cnt * NSEC_PER_SEC, rate);
+
+	return 0;
+}
+
+static const struct pwm_ops axi_pwmgen_pwm_ops = {
+	.apply = axi_pwmgen_apply,
+	.get_state = axi_pwmgen_get_state,
+};
+
+static int axi_pwmgen_setup(struct pwm_chip *chip)
+{
+	struct axi_pwmgen *pwm;
+	unsigned int reg;
+	int idx;
+
+	pwm = to_axi_pwmgen(chip);
+	axi_pwmgen_write(pwm, AXI_PWMGEN_REG_SCRATCHPAD, AXI_PWMGEN_TEST_DATA);
+	reg = axi_pwmgen_read(pwm, AXI_PWMGEN_REG_SCRATCHPAD);
+	if (reg != AXI_PWMGEN_TEST_DATA)
+		return dev_err_probe(chip->dev, -EIO,
+				     "failed to access the device registers\n");
+
+	pwm->chip.npwm = axi_pwmgen_read(pwm, AXI_PWMGEN_REG_NPWM);
+	if (pwm->chip.npwm > AXI_PWMGEN_NPWM)
+		return -EINVAL;
+
+	/* Disable all the outputs */
+	for (idx = 0; idx < pwm->chip.npwm; idx++) {
+		axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_PERIOD(idx), 0);
+		axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_DUTY(idx), 0);
+		axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_OFFSET(idx), 0);
+	}
+
+	/* Enable the core */
+	axi_pwmgen_write_mask(pwm, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_RESET, 0);
+
+	return 0;
+}
+
+static int axi_pwmgen_probe(struct platform_device *pdev)
+{
+	struct axi_pwmgen *pwm;
+	int ret;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pwm->base))
+		return PTR_ERR(pwm->base);
+
+	pwm->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(pwm->clk))
+		return PTR_ERR(pwm->clk);
+
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.ops = &axi_pwmgen_pwm_ops;
+	pwm->chip.base = -1;
+
+	ret = axi_pwmgen_setup(&pwm->chip);
+	if (ret < 0)
+		return ret;
+
+	return devm_pwmchip_add(&pdev->dev, &pwm->chip);
+}
+
+static const struct of_device_id axi_pwmgen_ids[] = {
+	{ .compatible = "adi,axi-pwmgen" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, axi_pwmgen_ids);
+
+static struct platform_driver axi_pwmgen_driver = {
+	.driver = {
+		.name = "axi-pwmgen",
+		.of_match_table = axi_pwmgen_ids,
+	},
+	.probe = axi_pwmgen_probe,
+};
+
+module_platform_driver(axi_pwmgen_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sergiu Cuciurean <[email protected]>");
+MODULE_DESCRIPTION("Driver for the Analog Devices AXI PWM generator");