[PATCH 2/2] pwm: pwm-qcom: add driver for PWM modules in QCOM PMICs

[Fenglin Wu]

PWM modules present in QCOM PMICs are controlled through SPMI bus.
Normally, it would have several PWM modules together with adjacent
register space and each PWM module can be controlled independently.

Signed-off-by: Fenglin Wu <fenglinw@xxxxxxxxxxxxxx>
---
 drivers/pwm/Kconfig    |   9 +
 drivers/pwm/Makefile   |   1 +
 drivers/pwm/pwm-qcom.c | 585 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 595 insertions(+)
 create mode 100644 drivers/pwm/pwm-qcom.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 8ae68d6..324ab5d 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -423,6 +423,15 @@ config PWM_PXA
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-pxa.
 
+config PWM_QCOM
+	tristate "Qcom PMIC PWM support"
+	depends on MFD_SPMI_PMIC && OF
+	help
+	  Generic PWM framework driver for PWM module in QCOM PMIC chips
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-qcom.
+
 config PWM_RCAR
 	tristate "Renesas R-Car PWM support"
 	depends on ARCH_RENESAS || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index d43b1e1..78316e9 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
+obj-$(CONFIG_PWM_QCOM)		+= pwm-qcom.o
 obj-$(CONFIG_PWM_RCAR)		+= pwm-rcar.o
 obj-$(CONFIG_PWM_RENESAS_TPU)	+= pwm-renesas-tpu.o
 obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
diff --git a/drivers/pwm/pwm-qcom.c b/drivers/pwm/pwm-qcom.c
new file mode 100644
index 0000000..48bd823
--- /dev/null
+++ b/drivers/pwm/pwm-qcom.c
@@ -0,0 +1,585 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/* PWM module registers */
+#define REG_PERPH_SUBTYPE		0x05
+#define REG_PWM_SIZE_CLK		0x41
+#define REG_PWM_FREQ_PREDIV_CLK		0x42
+#define REG_PWM_TYPE_CONFIG		0x43
+#define REG_PWM_VALUE_LSB		0x44
+#define REG_PWM_VALUE_MSB		0x45
+#define REG_ENABLE_CONTROL		0x46
+#define REG_PWM_SYNC			0x47
+
+/* REG_PERPH_SUBTYPE */
+#define SUBTYPE_PWM			0x0b
+#define SUBTYPE_PWM_LITE		0x11
+
+/* REG_PWM_SIZE_CLK */
+#define PWM_LITE_PWM_SIZE_MASK		BIT(4)
+#define PWM_LITE_PWM_SIZE_SHIFT		4
+#define PWM_SIZE_MASK			BIT(2)
+#define PWM_SIZE_SHIFT			2
+#define PWM_CLK_FREQ_SEL_MASK		GENMASK(1, 0)
+
+/* REG_PWM_FREQ_PREDIV_CLK */
+#define PWM_FREQ_PREDIV_MASK		GENMASK(6, 5)
+#define PWM_FREQ_PREDIV_SHIFT		5
+#define PWM_FREQ_EXPONENT_MASK		GENMASK(2, 0)
+
+/* REG_PWM_TYPE_CONFIG */
+#define PWM_EN_GLITCH_REMOVAL_MASK	BIT(5)
+
+/* REG_PWM_VALUE */
+#define PWM_VALUE_LSB_MASK		GENMASK(7, 0)
+#define PWM_VALUE_MSB_MASK		BIT(0)
+
+/* REG_ENABLE_CONTROL */
+#define EN_MODULE_BIT			BIT(7)
+
+/* REG_PWM_SYNC */
+#define PWM_VALUE_SYNC			BIT(0)
+
+/* constant definitions */
+#define REG_SIZE_PER_CHANN		0x100
+#define NUM_PWM_SIZE			2
+#define NUM_PWM_CLK			3
+#define NUM_CLK_PREDIV			4
+#define NUM_PWM_EXP			8
+
+static const int pwm_size[NUM_PWM_SIZE] = {6, 9};
+static const int clk_freq_hz[NUM_PWM_CLK] = {1024, 32768, 19200000};
+static const int clk_prediv[NUM_CLK_PREDIV] = {1, 3, 5, 6};
+static const int pwm_exponent[NUM_PWM_EXP] = {0, 1, 2, 3, 4, 5, 6, 7};
+
+struct qcom_pwm_config {
+	u32	pwm_size;
+	u32	pwm_clk;
+	u32	prediv;
+	u32	clk_exp;
+	u16	pwm_value;
+	u64	best_period_ns;
+};
+
+struct qcom_pwm_channel {
+	struct qcom_pwm_chip	*chip;
+	struct qcom_pwm_config	pwm_config;
+	u32			chan_idx;
+	u32			reg_base;
+	u8			subtype;
+	u64			current_period_ns;
+	u64			current_duty_ns;
+};
+
+struct qcom_pwm_chip {
+	struct pwm_chip		pwm_chip;
+	struct regmap		*regmap;
+	struct device		*dev;
+	struct qcom_pwm_channel	*pwms;
+	struct mutex		rw_lock;
+	u32			num_channels;
+};
+
+static int qcom_pwm_channel_read(struct qcom_pwm_channel *pwm,
+					u16 addr, u8 *val)
+{
+	int rc;
+	unsigned int tmp;
+
+	mutex_lock(&pwm->chip->rw_lock);
+	rc = regmap_read(pwm->chip->regmap, pwm->reg_base + addr, &tmp);
+	if (rc < 0)
+		dev_err(pwm->chip->dev, "Read addr %#x failed, rc=%d\n",
+				pwm->reg_base + addr, rc);
+	else
+		*val = (u8)tmp;
+	mutex_unlock(&pwm->chip->rw_lock);
+
+	return rc;
+}
+
+static int qcom_pwm_channel_write(struct qcom_pwm_channel *pwm, u16 addr, u8 val)
+{
+	int rc;
+
+	mutex_lock(&pwm->chip->rw_lock);
+	rc = regmap_write(pwm->chip->regmap, pwm->reg_base + addr, val);
+	if (rc < 0)
+		dev_err(pwm->chip->dev, "Write addr %#x with value %#x failed, rc=%d\n",
+				pwm->reg_base + addr, val, rc);
+	mutex_unlock(&pwm->chip->rw_lock);
+
+	return rc;
+}
+
+static int qcom_pwm_channel_masked_write(struct qcom_pwm_channel *pwm,
+				u16 addr, u8 mask, u8 val)
+{
+	int rc;
+
+	mutex_lock(&pwm->chip->rw_lock);
+	rc = regmap_update_bits(pwm->chip->regmap, pwm->reg_base + addr,
+							mask, val);
+	if (rc < 0)
+		dev_err(pwm->chip->dev, "Update addr %#x to val %#x with mask %#x failed, rc=%d\n",
+				pwm->reg_base + addr, val, mask, rc);
+	mutex_unlock(&pwm->chip->rw_lock);
+
+	return rc;
+}
+
+static struct qcom_pwm_channel *pwm_dev_to_pwm_channel(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm_dev)
+{
+
+	struct qcom_pwm_chip *chip = container_of(pwm_chip,
+			struct qcom_pwm_chip, pwm_chip);
+	u32 chan_idx = pwm_dev->hwpwm;
+
+	if (chan_idx >= chip->num_channels) {
+		dev_err(chip->dev, "hw index %u out of range [0-%u]\n",
+				chan_idx, chip->num_channels - 1);
+		return NULL;
+	}
+
+	return &chip->pwms[chan_idx];
+}
+
+static int __find_index_in_array(int data, const int array[], int length)
+{
+	int i;
+
+	for (i = 0; i < length; i++) {
+		if (data == array[i])
+			return i;
+	}
+
+	return -ENOENT;
+}
+
+static int qcom_pwm_channel_set_glitch_removal(
+		struct qcom_pwm_channel *pwm, bool en)
+{
+	u8 mask, val;
+
+	val = en ? PWM_EN_GLITCH_REMOVAL_MASK : 0;
+	mask = PWM_EN_GLITCH_REMOVAL_MASK;
+	return qcom_pwm_channel_masked_write(pwm,
+			REG_PWM_TYPE_CONFIG, mask, val);
+}
+
+static int qcom_pwm_channel_config(struct qcom_pwm_channel *pwm)
+{
+	int rc;
+	u8 val, mask, shift;
+	int pwm_size_idx, pwm_clk_idx, prediv_idx, clk_exp_idx;
+
+	pwm_size_idx = __find_index_in_array(pwm->pwm_config.pwm_size,
+			pwm_size, ARRAY_SIZE(pwm_size));
+	pwm_clk_idx = __find_index_in_array(pwm->pwm_config.pwm_clk,
+			clk_freq_hz, ARRAY_SIZE(clk_freq_hz));
+	prediv_idx = __find_index_in_array(pwm->pwm_config.prediv,
+			clk_prediv, ARRAY_SIZE(clk_prediv));
+	clk_exp_idx = __find_index_in_array(pwm->pwm_config.clk_exp,
+			pwm_exponent, ARRAY_SIZE(pwm_exponent));
+
+	if (pwm_size_idx < 0 || pwm_clk_idx < 0
+			|| prediv_idx < 0 || clk_exp_idx < 0)
+		return -EINVAL;
+
+	/* pwm_clk_idx is 1 bit lower than the register value */
+	pwm_clk_idx += 1;
+	shift = PWM_SIZE_SHIFT;
+	mask = PWM_SIZE_MASK;
+	if (pwm->subtype == SUBTYPE_PWM_LITE) {
+		shift = PWM_LITE_PWM_SIZE_SHIFT;
+		mask = PWM_LITE_PWM_SIZE_MASK;
+	}
+
+	val = pwm_size_idx << shift | pwm_clk_idx;
+	mask |= PWM_CLK_FREQ_SEL_MASK;
+	rc = qcom_pwm_channel_masked_write(pwm, REG_PWM_SIZE_CLK, mask, val);
+	if (rc < 0)
+		return rc;
+
+	val = prediv_idx << PWM_FREQ_PREDIV_SHIFT | clk_exp_idx;
+	mask = PWM_FREQ_PREDIV_MASK | PWM_FREQ_EXPONENT_MASK;
+	rc = qcom_pwm_channel_masked_write(pwm, REG_PWM_FREQ_PREDIV_CLK, mask, val);
+	if (rc < 0)
+		return rc;
+
+	val = pwm->pwm_config.pwm_value >> 8;
+	mask = PWM_VALUE_MSB_MASK;
+	rc = qcom_pwm_channel_masked_write(pwm, REG_PWM_VALUE_MSB, mask, val);
+	if (rc < 0)
+		return rc;
+
+	val = pwm->pwm_config.pwm_value & PWM_VALUE_LSB_MASK;
+	rc = qcom_pwm_channel_write(pwm, REG_PWM_VALUE_LSB, val);
+	if (rc < 0)
+		return rc;
+
+	val = PWM_VALUE_SYNC;
+	return qcom_pwm_channel_write(pwm, REG_PWM_SYNC, val);
+}
+
+static int qcom_pwm_channel_enable(struct qcom_pwm_channel *pwm, bool en)
+{
+	u8 mask, val;
+
+	mask = EN_MODULE_BIT;
+	val = en ? EN_MODULE_BIT : 0;
+	return qcom_pwm_channel_masked_write(pwm,
+			REG_ENABLE_CONTROL, mask, val);
+}
+
+static void __qcom_pwm_calc_pwm_period(u64 period_ns,
+			struct qcom_pwm_config *pwm_config)
+{
+	struct qcom_pwm_config configs[NUM_PWM_SIZE];
+	int i, j, m, n;
+	u64 tmp1, tmp2;
+	u64 clk_period_ns = 0, pwm_clk_period_ns;
+	u64 clk_delta_ns = U64_MAX, min_clk_delta_ns = U64_MAX;
+	u64 pwm_period_delta = U64_MAX, min_pwm_period_delta = U64_MAX;
+	int pwm_size_step;
+
+	/*
+	 *              (2^pwm_size) * (2^pwm_exp) * prediv * NSEC_PER_SEC
+	 * pwm_period = ---------------------------------------------------
+	 *                               clk_freq_hz
+	 *
+	 * Searching the closest settings for the requested PWM period.
+	 */
+
+	for (n = 0; n < ARRAY_SIZE(pwm_size); n++) {
+		pwm_clk_period_ns = period_ns >> pwm_size[n];
+		for (i = ARRAY_SIZE(clk_freq_hz) - 1; i >= 0; i--) {
+			for (j = 0; j < ARRAY_SIZE(clk_prediv); j++) {
+				for (m = 0; m < ARRAY_SIZE(pwm_exponent); m++) {
+					tmp1 = 1 << pwm_exponent[m];
+					tmp1 *= clk_prediv[j];
+					tmp2 = NSEC_PER_SEC;
+					do_div(tmp2, clk_freq_hz[i]);
+
+					clk_period_ns = tmp1 * tmp2;
+
+					clk_delta_ns = abs(pwm_clk_period_ns
+						- clk_period_ns);
+					/*
+					 * Find the closest setting for
+					 * PWM frequency predivide value
+					 */
+					if (clk_delta_ns < min_clk_delta_ns) {
+						min_clk_delta_ns
+							= clk_delta_ns;
+						configs[n].pwm_clk
+							= clk_freq_hz[i];
+						configs[n].prediv
+							= clk_prediv[j];
+						configs[n].clk_exp
+							= pwm_exponent[m];
+						configs[n].pwm_size
+							= pwm_size[n];
+						configs[n].best_period_ns
+							= clk_period_ns;
+					}
+				}
+			}
+		}
+
+		configs[n].best_period_ns *= 1 << pwm_size[n];
+		/* Find the closest setting for PWM period */
+		pwm_period_delta = min_clk_delta_ns << pwm_size[n];
+		if (pwm_period_delta < min_pwm_period_delta) {
+			min_pwm_period_delta = pwm_period_delta;
+			memcpy(pwm_config, &configs[n],
+					sizeof(struct qcom_pwm_config));
+		}
+	}
+
+	/* Larger PWM size can achieve better resolution for PWM duty */
+	for (n = ARRAY_SIZE(pwm_size) - 1; n > 0; n--) {
+		if (pwm_config->pwm_size >= pwm_size[n])
+			break;
+		pwm_size_step = pwm_size[n] - pwm_config->pwm_size;
+		if (pwm_config->clk_exp >= pwm_size_step) {
+			pwm_config->pwm_size = pwm_size[n];
+			pwm_config->clk_exp -= pwm_size_step;
+		}
+	}
+
+	pr_debug("PWM setting for period_ns %llu: pwm_clk = %dHZ, prediv = %d, exponent = %d, pwm_size = %d\n",
+			period_ns, pwm_config->pwm_clk, pwm_config->prediv,
+			pwm_config->clk_exp, pwm_config->pwm_size);
+	pr_debug("Actual period: %lluns\n", pwm_config->best_period_ns);
+}
+
+static void __qcom_pwm_calc_pwm_duty(u64 period_ns, u64 duty_ns,
+			struct qcom_pwm_config *pwm_config)
+{
+	u16 pwm_value, max_pwm_value;
+	u64 tmp;
+
+	tmp = (u64)duty_ns << pwm_config->pwm_size;
+	pwm_value = (u16)div64_u64(tmp, period_ns);
+
+	max_pwm_value = (1 << pwm_config->pwm_size) - 1;
+	if (pwm_value > max_pwm_value)
+		pwm_value = max_pwm_value;
+
+	pwm_config->pwm_value = pwm_value;
+}
+
+static int qcom_pwm_config(struct pwm_chip *pwm_chip,
+		struct pwm_device *pwm_dev, u64 duty_ns, u64 period_ns)
+{
+	struct qcom_pwm_channel *pwm;
+	int rc;
+
+	pwm = pwm_dev_to_pwm_channel(pwm_chip, pwm_dev);
+	if (pwm == NULL) {
+		dev_err(pwm_chip->dev, "PWM channel not found\n");
+		return -ENODEV;
+	}
+
+	if (duty_ns > period_ns) {
+		dev_err(pwm_chip->dev, "Duty %llu ns is larger than period %llu ns\n",
+						duty_ns, period_ns);
+		return -EINVAL;
+	}
+
+	if (period_ns != pwm->current_period_ns)
+		__qcom_pwm_calc_pwm_period(period_ns, &pwm->pwm_config);
+
+	if (period_ns != pwm->current_period_ns ||
+			duty_ns != pwm->current_duty_ns)
+		__qcom_pwm_calc_pwm_duty(period_ns, duty_ns, &pwm->pwm_config);
+
+	rc = qcom_pwm_channel_config(pwm);
+	if (rc < 0) {
+		dev_err(pwm_chip->dev, "Config PWM channel %u failed, rc=%d\n",
+						pwm->chan_idx, rc);
+		return rc;
+	}
+
+	pwm->current_period_ns = period_ns;
+	pwm->current_duty_ns = duty_ns;
+	return 0;
+}
+
+static int qcom_pwm_enable(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm_dev)
+{
+	struct qcom_pwm_channel *pwm;
+	int rc = 0;
+
+	pwm = pwm_dev_to_pwm_channel(pwm_chip, pwm_dev);
+	if (pwm == NULL) {
+		dev_err(pwm_chip->dev, "PWM channel not found\n");
+		return -ENODEV;
+	}
+
+	rc = qcom_pwm_channel_write(pwm, REG_PWM_SYNC, PWM_VALUE_SYNC);
+	if (rc < 0)
+		return rc;
+
+	rc = qcom_pwm_channel_set_glitch_removal(pwm, true);
+	if (rc < 0)
+		return rc;
+
+	return qcom_pwm_channel_enable(pwm, true);
+}
+
+static int qcom_pwm_disable(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm_dev)
+{
+	struct qcom_pwm_channel *pwm;
+	int rc;
+
+	pwm = pwm_dev_to_pwm_channel(pwm_chip, pwm_dev);
+	if (pwm == NULL) {
+		dev_err(pwm_chip->dev, "PWM channel not found\n");
+		return -ENODEV;
+	}
+
+	rc = qcom_pwm_channel_enable(pwm, false);
+	if (rc < 0)
+		return rc;
+
+	return qcom_pwm_channel_set_glitch_removal(pwm, false);
+}
+
+static int qcom_pwm_apply(struct pwm_chip *pwm_chip,
+		struct pwm_device *pwm_dev, const struct pwm_state *state)
+{
+	int rc;
+
+	if (state->period != pwm_dev->state.period ||
+			state->duty_cycle != pwm_dev->state.duty_cycle) {
+		rc = qcom_pwm_config(pwm_chip, pwm_dev,
+				state->duty_cycle, state->period);
+		if (rc < 0)
+			return rc;
+
+		pwm_dev->state.duty_cycle = state->duty_cycle;
+		pwm_dev->state.period = state->period;
+	}
+
+	if (state->enabled != pwm_dev->state.enabled) {
+		if (state->enabled)
+			rc = qcom_pwm_enable(pwm_chip, pwm_dev);
+		else
+			rc = qcom_pwm_disable(pwm_chip, pwm_dev);
+		if (rc < 0)
+			return rc;
+
+		pwm_dev->state.enabled = state->enabled;
+	}
+
+	return 0;
+}
+
+static const struct pwm_ops qcom_pwm_ops = {
+	.apply = qcom_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+static int qcom_pwm_parse_dt(struct qcom_pwm_chip *chip)
+{
+	int rc = 0, i;
+	const __be32 *addr;
+	u32 base;
+
+	addr = of_get_address(chip->dev->of_node, 0, NULL, NULL);
+	if (!addr) {
+		dev_err(chip->dev, "Get PWM device address failed, rc=%d\n",
+				rc);
+		return -EINVAL;
+	}
+
+	base = be32_to_cpu(*addr);
+	rc = of_property_read_u32(chip->dev->of_node, "qcom,num-channels",
+			&chip->num_channels);
+	if (rc < 0) {
+		dev_err(chip->dev, "Failed to get qcom,num-channels, rc=%d\n",
+				rc);
+		return rc;
+	}
+
+	if (chip->num_channels == 0) {
+		dev_err(chip->dev, "No PWM channel specified\n");
+		return rc;
+	}
+
+	chip->pwms = devm_kcalloc(chip->dev, chip->num_channels,
+			sizeof(*chip->pwms), GFP_KERNEL);
+	if (!chip->pwms)
+		return -ENOMEM;
+
+	for (i = 0; i < chip->num_channels; i++) {
+		chip->pwms[i].chip = chip;
+		chip->pwms[i].chan_idx = i;
+		chip->pwms[i].reg_base = base + i * REG_SIZE_PER_CHANN;
+		rc = qcom_pwm_channel_read(&chip->pwms[i], REG_PERPH_SUBTYPE,
+				&chip->pwms[i].subtype);
+		if (rc < 0) {
+			dev_err(chip->dev, "Read PWM channel %d subtype failed, rc=%d\n",
+					i, rc);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int qcom_pwm_probe(struct platform_device *pdev)
+{
+	int rc;
+	struct qcom_pwm_chip *chip;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = &pdev->dev;
+	chip->regmap = dev_get_regmap(chip->dev->parent, NULL);
+	if (!chip->regmap) {
+		dev_err(chip->dev, "Getting regmap failed\n");
+		return -EINVAL;
+	}
+
+	rc = qcom_pwm_parse_dt(chip);
+	if (rc < 0)
+		return rc;
+
+	mutex_init(&chip->rw_lock);
+	dev_set_drvdata(chip->dev, chip);
+	chip->pwm_chip.dev = chip->dev;
+	chip->pwm_chip.base = -1;
+	chip->pwm_chip.npwm = chip->num_channels;
+	chip->pwm_chip.ops = &qcom_pwm_ops;
+
+	rc = pwmchip_add(&chip->pwm_chip);
+	if (rc < 0) {
+		dev_err(chip->dev, "Add pwmchip failed, rc=%d\n", rc);
+		goto err_out;
+	}
+
+	return 0;
+err_out:
+	mutex_destroy(&chip->rw_lock);
+	dev_set_drvdata(chip->dev, NULL);
+	return rc;
+}
+
+static int qcom_pwm_remove(struct platform_device *pdev)
+{
+	struct qcom_pwm_chip *chip = dev_get_drvdata(&pdev->dev);
+	int rc = 0;
+
+	rc = pwmchip_remove(&chip->pwm_chip);
+	if (rc < 0)
+		dev_err(chip->dev, "Remove pwmchip failed, rc=%d\n", rc);
+
+	mutex_destroy(&chip->rw_lock);
+	dev_set_drvdata(chip->dev, NULL);
+
+	return rc;
+}
+
+static const struct of_device_id qcom_pwm_of_match[] = {
+	{ .compatible = "qcom,pwm"},
+	{ },
+};
+
+static struct platform_driver qcom_pwm_driver = {
+	.driver		= {
+		.name		= "qcom,pwm",
+		.of_match_table	= qcom_pwm_of_match,
+	},
+	.probe		= qcom_pwm_probe,
+	.remove		= qcom_pwm_remove,
+};
+module_platform_driver(qcom_pwm_driver);
+
+MODULE_DESCRIPTION("QCOM PWM driver");
+MODULE_LICENSE("GPL v2");
-- 
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a Linux Foundation Collaborative Project.