pwm: Add PWM driver for HiSilicon BVT SOCs

Add PWM driver for the PWM controller found on HiSilicon BVT SoCs such
as Hi3519V100, Hi3516CV300, etc. The PWM controller is primarily in
charge of controlling the P-Iris lens.

Reviewed-by: Jiancheng Xue <xuejiancheng@hisilicon.com>
Signed-off-by: Jian Yuan <yuanjian12@hisilicon.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Documentation/devicetree/bindings/pwm/pwm-hibvt.txt

@@ -0,0 +1,21 @@
+Hisilicon PWM controller
+
+Required properties:
+-compatible: should contain one SoC specific compatible string
+ The SoC specific strings supported including:
+	"hisilicon,hi3516cv300-pwm"
+	"hisilicon,hi3519v100-pwm"
+- reg: physical base address and length of the controller's registers.
+- clocks: phandle and clock specifier of the PWM reference clock.
+- resets: phandle and reset specifier for the PWM controller reset.
+- #pwm-cells: Should be 3. See pwm.txt in this directory for a description of
+  the cells format.
+
+Example:
+	pwm: pwm@12130000 {
+		compatible = "hisilicon,hi3516cv300-pwm";
+		reg = <0x12130000 0x10000>;
+		clocks = <&crg_ctrl HI3516CV300_PWM_CLK>;
+		resets = <&crg_ctrl 0x38 0>;
+		#pwm-cells = <3>;
+	};

drivers/pwm/Kconfig

@@ -175,6 +175,15 @@ config PWM_FSL_FTM
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-fsl-ftm.
 
+config PWM_HIBVT
+	tristate "HiSilicon BVT PWM support"
+	depends on ARCH_HISI || COMPILE_TEST
+	help
+	  Generic PWM framework driver for HiSilicon BVT SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-hibvt.
+
 config PWM_IMG
 	tristate "Imagination Technologies PWM driver"
 	depends on HAS_IOMEM

drivers/pwm/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
 obj-$(CONFIG_PWM_CROS_EC)	+= pwm-cros-ec.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
 obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
+obj-$(CONFIG_PWM_HIBVT)		+= pwm-hibvt.o
 obj-$(CONFIG_PWM_IMG)		+= pwm-img.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
 obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o

drivers/pwm/pwm-hibvt.c

@@ -0,0 +1,271 @@
+/*
+ * PWM Controller Driver for HiSilicon BVT SoCs
+ *
+ * Copyright (c) 2016 HiSilicon Technologies Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+
+#define PWM_CFG0_ADDR(x)    (((x) * 0x20) + 0x0)
+#define PWM_CFG1_ADDR(x)    (((x) * 0x20) + 0x4)
+#define PWM_CFG2_ADDR(x)    (((x) * 0x20) + 0x8)
+#define PWM_CTRL_ADDR(x)    (((x) * 0x20) + 0xC)
+
+#define PWM_ENABLE_SHIFT    0
+#define PWM_ENABLE_MASK     BIT(0)
+
+#define PWM_POLARITY_SHIFT  1
+#define PWM_POLARITY_MASK   BIT(1)
+
+#define PWM_KEEP_SHIFT      2
+#define PWM_KEEP_MASK       BIT(2)
+
+#define PWM_PERIOD_MASK     GENMASK(31, 0)
+#define PWM_DUTY_MASK       GENMASK(31, 0)
+
+struct hibvt_pwm_chip {
+	struct pwm_chip	chip;
+	struct clk *clk;
+	void __iomem *base;
+	struct reset_control *rstc;
+};
+
+struct hibvt_pwm_soc {
+	u32 num_pwms;
+};
+
+static const struct hibvt_pwm_soc pwm_soc[2] = {
+	{ .num_pwms = 4 },
+	{ .num_pwms = 8 },
+};
+
+static inline struct hibvt_pwm_chip *to_hibvt_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct hibvt_pwm_chip, chip);
+}
+
+static void hibvt_pwm_set_bits(void __iomem *base, u32 offset,
+					u32 mask, u32 data)
+{
+	void __iomem *address = base + offset;
+	u32 value;
+
+	value = readl(address);
+	value &= ~mask;
+	value |= (data & mask);
+	writel(value, address);
+}
+
+static void hibvt_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
+
+	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
+			PWM_ENABLE_MASK, 0x1);
+}
+
+static void hibvt_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
+
+	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
+			PWM_ENABLE_MASK, 0x0);
+}
+
+static void hibvt_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+					int duty_cycle_ns, int period_ns)
+{
+	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
+	u32 freq, period, duty;
+
+	freq = div_u64(clk_get_rate(hi_pwm_chip->clk), 1000000);
+
+	period = div_u64(freq * period_ns, 1000);
+	duty = div_u64(period * duty_cycle_ns, period_ns);
+
+	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CFG0_ADDR(pwm->hwpwm),
+			PWM_PERIOD_MASK, period);
+
+	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CFG1_ADDR(pwm->hwpwm),
+			PWM_DUTY_MASK, duty);
+}
+
+static void hibvt_pwm_set_polarity(struct pwm_chip *chip,
+					struct pwm_device *pwm,
+					enum pwm_polarity polarity)
+{
+	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
+
+	if (polarity == PWM_POLARITY_INVERSED)
+		hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
+				PWM_POLARITY_MASK, (0x1 << PWM_POLARITY_SHIFT));
+	else
+		hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
+				PWM_POLARITY_MASK, (0x0 << PWM_POLARITY_SHIFT));
+}
+
+static void hibvt_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
+	void __iomem *base;
+	u32 freq, value;
+
+	freq = div_u64(clk_get_rate(hi_pwm_chip->clk), 1000000);
+	base = hi_pwm_chip->base;
+
+	value = readl(base + PWM_CFG0_ADDR(pwm->hwpwm));
+	state->period = div_u64(value * 1000, freq);
+
+	value = readl(base + PWM_CFG1_ADDR(pwm->hwpwm));
+	state->duty_cycle = div_u64(value * 1000, freq);
+
+	value = readl(base + PWM_CTRL_ADDR(pwm->hwpwm));
+	state->enabled = (PWM_ENABLE_MASK & value);
+}
+
+static int hibvt_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+				struct pwm_state *state)
+{
+	if (state->polarity != pwm->state.polarity)
+		hibvt_pwm_set_polarity(chip, pwm, state->polarity);
+
+	if (state->period != pwm->state.period ||
+		state->duty_cycle != pwm->state.duty_cycle)
+		hibvt_pwm_config(chip, pwm, state->duty_cycle, state->period);
+
+	if (state->enabled != pwm->state.enabled) {
+		if (state->enabled)
+			hibvt_pwm_enable(chip, pwm);
+		else
+			hibvt_pwm_disable(chip, pwm);
+	}
+
+	return 0;
+}
+
+static struct pwm_ops hibvt_pwm_ops = {
+	.get_state = hibvt_pwm_get_state,
+	.apply = hibvt_pwm_apply,
+
+	.owner = THIS_MODULE,
+};
+
+static int hibvt_pwm_probe(struct platform_device *pdev)
+{
+	const struct hibvt_pwm_soc *soc =
+				of_device_get_match_data(&pdev->dev);
+	struct hibvt_pwm_chip *pwm_chip;
+	struct resource *res;
+	int ret;
+	int i;
+
+	pwm_chip = devm_kzalloc(&pdev->dev, sizeof(*pwm_chip), GFP_KERNEL);
+	if (pwm_chip == NULL)
+		return -ENOMEM;
+
+	pwm_chip->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pwm_chip->clk)) {
+		dev_err(&pdev->dev, "getting clock failed with %ld\n",
+				PTR_ERR(pwm_chip->clk));
+		return PTR_ERR(pwm_chip->clk);
+	}
+
+	pwm_chip->chip.ops = &hibvt_pwm_ops;
+	pwm_chip->chip.dev = &pdev->dev;
+	pwm_chip->chip.base = -1;
+	pwm_chip->chip.npwm = soc->num_pwms;
+	pwm_chip->chip.of_xlate = of_pwm_xlate_with_flags;
+	pwm_chip->chip.of_pwm_n_cells = 3;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pwm_chip->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pwm_chip->base))
+		return PTR_ERR(pwm_chip->base);
+
+	ret = clk_prepare_enable(pwm_chip->clk);
+	if (ret < 0)
+		return ret;
+
+	pwm_chip->rstc = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(pwm_chip->rstc)) {
+		clk_disable_unprepare(pwm_chip->clk);
+		return PTR_ERR(pwm_chip->rstc);
+	}
+
+	reset_control_assert(pwm_chip->rstc);
+	msleep(30);
+	reset_control_deassert(pwm_chip->rstc);
+
+	ret = pwmchip_add(&pwm_chip->chip);
+	if (ret < 0) {
+		clk_disable_unprepare(pwm_chip->clk);
+		return ret;
+	}
+
+	for (i = 0; i < pwm_chip->chip.npwm; i++) {
+		hibvt_pwm_set_bits(pwm_chip->base, PWM_CTRL_ADDR(i),
+				PWM_KEEP_MASK, (0x1 << PWM_KEEP_SHIFT));
+	}
+
+	platform_set_drvdata(pdev, pwm_chip);
+
+	return 0;
+}
+
+static int hibvt_pwm_remove(struct platform_device *pdev)
+{
+	struct hibvt_pwm_chip *pwm_chip;
+
+	pwm_chip = platform_get_drvdata(pdev);
+
+	reset_control_assert(pwm_chip->rstc);
+	msleep(30);
+	reset_control_deassert(pwm_chip->rstc);
+
+	clk_disable_unprepare(pwm_chip->clk);
+
+	return pwmchip_remove(&pwm_chip->chip);
+}
+
+static const struct of_device_id hibvt_pwm_of_match[] = {
+	{ .compatible = "hisilicon,hi3516cv300-pwm", .data = &pwm_soc[0] },
+	{ .compatible = "hisilicon,hi3519v100-pwm", .data = &pwm_soc[1] },
+	{  }
+};
+MODULE_DEVICE_TABLE(of, hibvt_pwm_of_match);
+
+static struct platform_driver hibvt_pwm_driver = {
+	.driver = {
+		.name = "hibvt-pwm",
+		.of_match_table = hibvt_pwm_of_match,
+	},
+	.probe = hibvt_pwm_probe,
+	.remove	= hibvt_pwm_remove,
+};
+module_platform_driver(hibvt_pwm_driver);
+
+MODULE_AUTHOR("Jian Yuan");
+MODULE_DESCRIPTION("HiSilicon BVT SoCs PWM driver");
+MODULE_LICENSE("GPL");