[v7,2/4] pwm: driver for qualcomm ipq6018 pwm block

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c76adedd58c9..08add845596f 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -260,6 +260,18 @@  config PWM_INTEL_LGM
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-intel-lgm.
 
+config PWM_IPQ
+	tristate "IPQ PWM support"
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on HAVE_CLK && HAS_IOMEM
+	help
+	  Generic PWM framework driver for IPQ PWM block which supports
+	  4 pwm channels. Each of the these channels can be configured
+	  independent of each other.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-ipq.
+
 config PWM_IQS620A
 	tristate "Azoteq IQS620A PWM support"
 	depends on MFD_IQS62X || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 708840b7fba8..7402feae4b36 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -22,6 +22,7 @@  obj-$(CONFIG_PWM_IMX1)		+= pwm-imx1.o
 obj-$(CONFIG_PWM_IMX27)		+= pwm-imx27.o
 obj-$(CONFIG_PWM_IMX_TPM)	+= pwm-imx-tpm.o
 obj-$(CONFIG_PWM_INTEL_LGM)	+= pwm-intel-lgm.o
+obj-$(CONFIG_PWM_IPQ)		+= pwm-ipq.o
 obj-$(CONFIG_PWM_IQS620A)	+= pwm-iqs620a.o
 obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o
 obj-$(CONFIG_PWM_KEEMBAY)	+= pwm-keembay.o
diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c
new file mode 100644
index 000000000000..8405d0554951
--- /dev/null
+++ b/drivers/pwm/pwm-ipq.c
@@ -0,0 +1,275 @@ 
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/*
+ * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/math64.h>
+#include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/bitfield.h>
+
+/* The frequency range supported is 1 Hz to clock rate */
+#define IPQ_PWM_MAX_PERIOD_NS	((u64)NSEC_PER_SEC)
+
+/*
+ * The max value specified for each field is based on the number of bits
+ * in the pwm control register for that field
+ */
+#define IPQ_PWM_MAX_DIV		0xFFFF
+
+/*
+ * Two 32-bit registers for each PWM: REG0, and REG1.
+ * Base offset for PWM #i is at 8 * #i.
+ */
+#define IPQ_PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/
+#define IPQ_PWM_REG0_PWM_DIV		GENMASK(15, 0)
+#define IPQ_PWM_REG0_HI_DURATION	GENMASK(31, 16)
+
+#define IPQ_PWM_CFG_REG1 4 /*ENABLE UPDATE PWM_PRE_DIV*/
+#define IPQ_PWM_REG1_PRE_DIV		GENMASK(15, 0)
+/*
+ * Enable bit is set to enable output toggling in pwm device.
+ * Update bit is set to reflect the changed divider and high duration
+ * values in register.
+ */
+#define IPQ_PWM_REG1_UPDATE		BIT(30)
+#define IPQ_PWM_REG1_ENABLE		BIT(31)
+
+
+struct ipq_pwm_chip {
+	struct pwm_chip chip;
+	struct clk *clk;
+	struct regmap *regmap;
+	u32 regmap_off;
+};
+
+static struct ipq_pwm_chip *to_ipq_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct ipq_pwm_chip, chip);
+}
+
+static unsigned int ipq_pwm_reg_read(struct pwm_device *pwm, unsigned reg)
+{
+	struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip);
+	unsigned int off = ipq_chip->regmap_off + 8 * pwm->hwpwm + reg;
+	unsigned int val;
+
+	regmap_read(ipq_chip->regmap, off, &val);
+
+	return val;
+}
+
+static void ipq_pwm_reg_write(struct pwm_device *pwm, unsigned reg,
+		unsigned val)
+{
+	struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip);
+	unsigned int off = ipq_chip->regmap_off + 8 * pwm->hwpwm + reg;
+
+	regmap_write(ipq_chip->regmap, off, val);
+}
+
+static void config_div_and_duty(struct pwm_device *pwm, unsigned int pre_div,
+			unsigned int pwm_div, unsigned long rate, u64 duty_ns,
+			bool enable)
+{
+	unsigned long hi_dur;
+	unsigned long val = 0;
+
+	/*
+	 * high duration = pwm duty * (pwm div + 1)
+	 * pwm duty = duty_ns / period_ns
+	 */
+	hi_dur = div64_u64(duty_ns * rate, (pre_div + 1) * NSEC_PER_SEC);
+
+	val = FIELD_PREP(IPQ_PWM_REG0_HI_DURATION, hi_dur) |
+		FIELD_PREP(IPQ_PWM_REG0_PWM_DIV, pwm_div);
+	ipq_pwm_reg_write(pwm, IPQ_PWM_CFG_REG0, val);
+
+	val = FIELD_PREP(IPQ_PWM_REG1_PRE_DIV, pre_div);
+	ipq_pwm_reg_write(pwm, IPQ_PWM_CFG_REG1, val);
+
+	/* Enable needs a separate write to REG1 */
+	val |= IPQ_PWM_REG1_UPDATE;
+	if (enable)
+		val |= IPQ_PWM_REG1_ENABLE;
+	ipq_pwm_reg_write(pwm, IPQ_PWM_CFG_REG1, val);
+}
+
+static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
+{
+	struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip);
+	unsigned long freq;
+	unsigned int pre_div, pwm_div, best_pre_div, best_pwm_div;
+	long long diff;
+	unsigned long rate = clk_get_rate(ipq_chip->clk);
+	unsigned long min_diff = rate;
+	u64 period_ns, duty_ns;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (state->period < div64_u64(NSEC_PER_SEC, rate))
+		return -ERANGE;
+
+	period_ns = min(state->period, IPQ_PWM_MAX_PERIOD_NS);
+	duty_ns = min(state->duty_cycle, period_ns);
+
+	/* freq in Hz for period in nano second */
+	freq = div64_u64(NSEC_PER_SEC, period_ns);
+	best_pre_div = IPQ_PWM_MAX_DIV;
+	best_pwm_div = IPQ_PWM_MAX_DIV;
+	/* Initial pre_div value such that pwm_div < IPQ_PWM_MAX_DIV */
+	pre_div = DIV64_U64_ROUND_UP(period_ns * rate,
+			(u64)NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1));
+
+	for (; pre_div <= IPQ_PWM_MAX_DIV; pre_div++) {
+		pwm_div = DIV64_U64_ROUND_UP(period_ns * rate,
+				(u64)NSEC_PER_SEC * (pre_div + 1));
+		pwm_div--;
+
+		if (pre_div > pwm_div)
+			break;
+
+		/*
+		 * Make sure we can do 100% duty cycle where
+		 * hi_dur == pwm_div + 1
+		 */
+		if (pwm_div > IPQ_PWM_MAX_DIV - 1)
+			continue;
+
+		diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1))
+			- (uint64_t)rate;
+
+		if (diff < 0) /* period larger than requested */
+			continue;
+		if (diff == 0) { /* bingo */
+			best_pre_div = pre_div;
+			best_pwm_div = pwm_div;
+			break;
+		}
+		if (diff < min_diff) {
+			min_diff = diff;
+			best_pre_div = pre_div;
+			best_pwm_div = pwm_div;
+		}
+	}
+
+	/* config divider values for the closest possible frequency */
+	config_div_and_duty(pwm, best_pre_div, best_pwm_div,
+			    rate, duty_ns, state->enabled);
+
+	return 0;
+}
+
+static void ipq_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			      struct pwm_state *state)
+{
+	struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip);
+	unsigned long rate = clk_get_rate(ipq_chip->clk);
+	unsigned int pre_div, pwm_div, hi_dur;
+	u64 effective_div, hi_div;
+	u32 reg0, reg1;
+
+	reg0 = ipq_pwm_reg_read(pwm, IPQ_PWM_CFG_REG0);
+	reg1 = ipq_pwm_reg_read(pwm, IPQ_PWM_CFG_REG1);
+
+	state->polarity = PWM_POLARITY_NORMAL;
+	state->enabled = reg1 & IPQ_PWM_REG1_ENABLE;
+
+	pwm_div = FIELD_GET(IPQ_PWM_REG0_PWM_DIV, reg0);
+	hi_dur = FIELD_GET(IPQ_PWM_REG0_HI_DURATION, reg0);
+	pre_div = FIELD_GET(IPQ_PWM_REG1_PRE_DIV, reg1);
+
+	/* No overflow here, both pre_div and pwm_div <= 0xffff */
+	effective_div = (u64)(pre_div + 1) * (pwm_div + 1);
+	state->period = div64_u64(effective_div * NSEC_PER_SEC, rate);
+
+	hi_div = hi_dur * (pre_div + 1);
+	state->duty_cycle = div64_u64(hi_div * NSEC_PER_SEC, rate);
+}
+
+static const struct pwm_ops ipq_pwm_ops = {
+	.apply = ipq_pwm_apply,
+	.get_state = ipq_pwm_get_state,
+	.owner = THIS_MODULE,
+};
+
+static int ipq_pwm_probe(struct platform_device *pdev)
+{
+	struct ipq_pwm_chip *pwm;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, pwm);
+
+	pwm->regmap = syscon_node_to_regmap(dev->parent->of_node);
+	if (IS_ERR(pwm->regmap))
+		return dev_err_probe(dev, PTR_ERR(pwm->regmap),
+				"regs map failed");
+
+	ret = of_property_read_u32(dev->of_node, "reg", &pwm->regmap_off);
+	if (ret)
+		return dev_err_probe(dev, ret, "error reading 'reg'");
+
+	pwm->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(pwm->clk))
+		return dev_err_probe(dev, PTR_ERR(pwm->clk),
+				"failed to get clock");
+
+	ret = clk_prepare_enable(pwm->clk);
+	if (ret)
+		return dev_err_probe(dev, ret, "clock enable failed");
+
+	pwm->chip.dev = dev;
+	pwm->chip.ops = &ipq_pwm_ops;
+	pwm->chip.npwm = 4;
+
+	ret = pwmchip_add(&pwm->chip);
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "pwmchip_add() failed\n");
+		clk_disable_unprepare(pwm->clk);
+	}
+
+	return ret;
+}
+
+static int ipq_pwm_remove(struct platform_device *pdev)
+{
+	struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev);
+
+	pwmchip_remove(&pwm->chip);
+	clk_disable_unprepare(pwm->clk);
+
+	return 0;
+}
+
+static const struct of_device_id pwm_ipq_dt_match[] = {
+	{ .compatible = "qcom,ipq6018-pwm", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match);
+
+static struct platform_driver ipq_pwm_driver = {
+	.driver = {
+		.name = "ipq-pwm",
+		.of_match_table = pwm_ipq_dt_match,
+	},
+	.probe = ipq_pwm_probe,
+	.remove = ipq_pwm_remove,
+};
+
+module_platform_driver(ipq_pwm_driver);
+
+MODULE_LICENSE("Dual BSD/GPL");