[PATCH v6 08/10] pwm: dwc: add of/platform support

[Ben Dooks]

The dwc pwm controller can be used in non-PCI systems, so allow
either platform or OF based probing.

Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxx>
---
v5:
 - fix missing " in kconfig
 - remove .remove method, devm already sorts this.
 - merge pwm-number code
 - split the of code out of the core
 - get bus clock
v4:
 - moved the compile test code earlier
 - fixed review comments
  - used NS_PER_SEC
  - use devm_clk_get_enabled
  - ensure we get the bus clock
v3:
 - changed compatible name

fixup add pwm/Kconfig
---
 drivers/pwm/Kconfig      |  9 +++++
 drivers/pwm/Makefile     |  1 +
 drivers/pwm/pwm-dwc-of.c | 76 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 drivers/pwm/pwm-dwc-of.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index a9f1c554db2b..c734f58a8bfc 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -192,6 +192,15 @@ config PWM_DWC_PCI
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-dwc-pci.
 
+config PWM_DWC_OF
+	tristate "DesignWare PWM Controller (OF bus)"
+	depends on PWM_DWC && OF
+	help
+	  PWM driver for Synopsys DWC PWM Controller on an OF bus.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-dwc-of.
+
 config PWM_EP93XX
 	tristate "Cirrus Logic EP93xx PWM support"
 	depends on ARCH_EP93XX || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index a70d36623129..d1fd1641f077 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
 obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
 obj-$(CONFIG_PWM_CROS_EC)	+= pwm-cros-ec.o
 obj-$(CONFIG_PWM_DWC)		+= pwm-dwc.o
+obj-$(CONFIG_PWM_DWC_OF)	+= pwm-dwc-of.o
 obj-$(CONFIG_PWM_DWC_PCI)	+= pwm-dwc-pci.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
 obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
diff --git a/drivers/pwm/pwm-dwc-of.c b/drivers/pwm/pwm-dwc-of.c
new file mode 100644
index 000000000000..c5b4351cc7b0
--- /dev/null
+++ b/drivers/pwm/pwm-dwc-of.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DesignWare PWM Controller driver OF
+ *
+ * Copyright (C) 2022 SiFive, Inc.
+ */
+
+#include <linux/bitops.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/io.h>
+
+#include "pwm-dwc.h"
+
+static int dwc_pwm_plat_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dwc_pwm *dwc;
+	struct clk *bus;
+	u32 nr_pwm;
+
+	dwc = dwc_pwm_alloc(dev);
+	if (!dwc)
+		return -ENOMEM;
+
+	if (!device_property_read_u32(dev, "snps,pwm-number", &nr_pwm)) {
+		if (nr_pwm > DWC_TIMERS_TOTAL)
+			dev_err(dev, "too many PWMs (%d) specified, capping at %d\n",
+				nr_pwm, dwc->chip.npwm);
+		else
+			dwc->chip.npwm = nr_pwm;
+	}
+
+	dwc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dwc->base))
+		return PTR_ERR(dwc->base);
+
+	bus = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(bus))
+		return dev_err_probe(dev, PTR_ERR(bus),
+				     "failed to get clock\n");
+
+	dwc->clk = devm_clk_get_enabled(dev, "timer");
+	if (IS_ERR(dwc->clk))
+		return dev_err_probe(dev, PTR_ERR(dwc->clk),
+				     "failed to get timer clock\n");
+
+	dwc->clk_ns = NSEC_PER_SEC / clk_get_rate(dwc->clk);
+	return devm_pwmchip_add(dev, &dwc->chip);
+}
+
+static const struct of_device_id dwc_pwm_dt_ids[] = {
+	{ .compatible = "snps,dw-apb-timers-pwm2" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, dwc_pwm_dt_ids);
+
+static struct platform_driver dwc_pwm_plat_driver = {
+	.driver = {
+		.name		= "dwc-pwm",
+		.of_match_table  = dwc_pwm_dt_ids,
+	},
+	.probe	= dwc_pwm_plat_probe,
+};
+
+module_platform_driver(dwc_pwm_plat_driver);
+
+MODULE_ALIAS("platform:dwc-pwm-of");
+MODULE_AUTHOR("Ben Dooks <ben.dooks@xxxxxxxxxx>");
+MODULE_DESCRIPTION("DesignWare PWM Controller");
+MODULE_LICENSE("GPL");
-- 
2.35.1