[PATCH V1 2/2] pwm: pwm-qti-lpg: Add PWM driver for QTI LPG module

[fenglinw@codeaurora.org]

From: Fenglin Wu <fenglinw@codeaurora.org>

Add pwm_chip to support QTI LPG module and export LPG channels as
PWM devices for consumer drivers' usage.

Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>
---
 .../devicetree/bindings/pwm/pwm-qti-lpg.txt        |  39 ++
 drivers/pwm/Kconfig                                |  10 +
 drivers/pwm/Makefile                               |   1 +
 drivers/pwm/pwm-qti-lpg.c                          | 578 +++++++++++++++++++++
 4 files changed, 628 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/pwm-qti-lpg.txt
 create mode 100644 drivers/pwm/pwm-qti-lpg.c

diff --git a/Documentation/devicetree/bindings/pwm/pwm-qti-lpg.txt b/Documentation/devicetree/bindings/pwm/pwm-qti-lpg.txt
new file mode 100644
index 0000000..df81f5f
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-qti-lpg.txt
@@ -0,0 +1,39 @@
+Qualcomm Technologies, Inc. LPG driver specific bindings
+
+This binding document describes the properties of LPG (Light Pulse Generator)
+device module in Qualcomm Technologies, Inc. PMIC chips.
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: Must be "qcom,pwm-lpg".
+
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: Register base and length for LPG modules. The length
+		      varies based on the number of channels available in
+		      the PMIC chips.
+
+- reg-names:
+	Usage: required
+	Value type: <string>
+	Definition: The name of the register defined in the reg property.
+		      It must be "lpg-base".
+
+- #pwm-cells:
+	Usage: required
+	Value type: <u32>
+	Definition: The number of cells in "pwms" property specified in
+		      PWM user nodes. It should be 2. The first cell is
+		      the PWM channel ID indexed from 0, and the second
+		      cell is the PWM default period in nanoseconds.
+
+Example:
+
+	pmi8998_lpg: lpg@b100 {
+		compatible = "qcom,pwm-lpg";
+		reg = <0xb100 0x600>;
+		reg-names = "lpg-base";
+		#pwm-cells = <2>;
+	};
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 313c107..711104f 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -349,6 +349,16 @@ config PWM_PXA
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-pxa.
 
+config PWM_QTI_LPG
+	tristate "Qualcomm Technologies, Inc. LPG driver"
+	depends on  MFD_SPMI_PMIC && OF
+	help
+	  This driver supports the LPG (Light Pulse Generator) module found in
+	  Qualcomm Technologies, Inc. PMIC chips. Each LPG channel can be
+	  configured to operate in PWM mode to output a fixed amplitude with
+	  variable duty cycle or in LUT (Look up table) mode to output PWM
+	  signal with a modulated amplitude.
+
 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 93da1f7..16958be 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PUV3)		+= pwm-puv3.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
+obj-$(CONFIG_PWM_QTI_LPG)	+= pwm-qti-lpg.o
 obj-$(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-qti-lpg.c b/drivers/pwm/pwm-qti-lpg.c
new file mode 100644
index 0000000..929b6a4
--- /dev/null
+++ b/drivers/pwm/pwm-qti-lpg.c
@@ -0,0 +1,578 @@
+/* Copyright (c) 2017, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#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/types.h>
+
+#define REG_SIZE_PER_LPG	0x100
+
+#define REG_LPG_PWM_SIZE_CLK		0x41
+#define REG_LPG_PWM_FREQ_PREDIV_CLK	0x42
+#define REG_LPG_PWM_TYPE_CONFIG		0x43
+#define REG_LPG_PWM_VALUE_LSB		0x44
+#define REG_LPG_PWM_VALUE_MSB		0x45
+#define REG_LPG_ENABLE_CONTROL		0x46
+#define REG_LPG_PWM_SYNC		0x47
+
+/* REG_LPG_PWM_SIZE_CLK */
+#define LPG_PWM_SIZE_MASK		BIT(4)
+#define LPG_PWM_SIZE_SHIFT		4
+#define LPG_PWM_CLK_FREQ_SEL_MASK	GENMASK(1, 0)
+
+/* REG_LPG_PWM_FREQ_PREDIV_CLK */
+#define LPG_PWM_FREQ_PREDIV_MASK	GENMASK(6, 5)
+#define LPG_PWM_FREQ_PREDIV_SHIFT	5
+#define LPG_PWM_FREQ_EXPONENT_MASK	GENMASK(2, 0)
+
+/* REG_LPG_PWM_TYPE_CONFIG */
+#define LPG_PWM_EN_GLITCH_REMOVAL_MASK	BIT(5)
+
+/* REG_LPG_PWM_VALUE_LSB */
+#define LPG_PWM_VALUE_LSB_MASK		GENMASK(7, 0)
+
+/* REG_LPG_PWM_VALUE_MSB */
+#define LPG_PWM_VALUE_MSB_MASK		BIT(0)
+
+/* REG_LPG_ENABLE_CONTROL */
+#define LPG_EN_LPG_OUT_BIT		BIT(7)
+#define LPG_PWM_SRC_SELECT_MASK		BIT(2)
+#define LPG_PWM_SRC_SELECT_SHIFT	2
+#define LPG_EN_RAMP_GEN_MASK		BIT(1)
+#define LPG_EN_RAMP_GEN_SHIFT		1
+
+/* REG_LPG_PWM_SYNC */
+#define LPG_PWM_VALUE_SYNC		BIT(0)
+
+#define NUM_PWM_SIZE			2
+#define NUM_PWM_CLK			3
+#define NUM_CLK_PREDIV			4
+#define NUM_PWM_EXP			8
+
+enum {
+	LUT_PATTERN = 0,
+	PWM_OUTPUT,
+};
+
+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 lpg_pwm_config {
+	u32	pwm_size;
+	u32	pwm_clk;
+	u32	prediv;
+	u32	clk_exp;
+	u16	pwm_value;
+	u32	best_period_ns;
+};
+
+struct qti_lpg_channel {
+	struct qti_lpg_chip		*chip;
+	struct lpg_pwm_config		pwm_config;
+	u32				lpg_idx;
+	u32				reg_base;
+	u8				src_sel;
+	int				current_period_ns;
+	int				current_duty_ns;
+};
+
+struct qti_lpg_chip {
+	struct pwm_chip		pwm_chip;
+	struct regmap		*regmap;
+	struct device		*dev;
+	struct qti_lpg_channel	*lpgs;
+	struct mutex		bus_lock;
+	u32			lpg_nums;
+};
+
+static int qti_lpg_write(struct qti_lpg_channel *lpg, u16 addr, u8 val)
+{
+	int rc;
+
+	mutex_lock(&lpg->chip->bus_lock);
+	rc = regmap_write(lpg->chip->regmap, lpg->reg_base + addr, val);
+	if (rc < 0)
+		dev_err(lpg->chip->dev, "Write addr 0x%x with value %d failed, rc=%d\n",
+				lpg->reg_base + addr, val, rc);
+	mutex_unlock(&lpg->chip->bus_lock);
+
+	return rc;
+}
+
+static int qti_lpg_masked_write(struct qti_lpg_channel *lpg,
+				u16 addr, u8 mask, u8 val)
+{
+	int rc;
+
+	mutex_lock(&lpg->chip->bus_lock);
+	rc = regmap_update_bits(lpg->chip->regmap, lpg->reg_base + addr,
+							mask, val);
+	if (rc < 0)
+		dev_err(lpg->chip->dev, "Update addr 0x%x to val 0x%x with mask 0x%x failed, rc=%d\n",
+				lpg->reg_base + addr, val, mask, rc);
+	mutex_unlock(&lpg->chip->bus_lock);
+
+	return rc;
+}
+
+static struct qti_lpg_channel *pwm_dev_to_qti_lpg(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm) {
+
+	struct qti_lpg_chip *chip = container_of(pwm_chip,
+			struct qti_lpg_chip, pwm_chip);
+	u32 hw_idx = pwm->hwpwm;
+
+	if (hw_idx >= chip->lpg_nums) {
+		dev_err(chip->dev, "hw index %d out of range [0-%d]\n",
+				hw_idx, chip->lpg_nums - 1);
+		return NULL;
+	}
+
+	return &chip->lpgs[hw_idx];
+}
+
+static int __find_index_in_array(int member, const int array[], int length)
+{
+	int i;
+
+	for (i = 0; i < length; i++) {
+		if (member == array[i])
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int qti_lpg_set_pwm_config(struct qti_lpg_channel *lpg)
+{
+	int rc;
+	u8 val, mask;
+	int pwm_size_idx, pwm_clk_idx, prediv_idx, clk_exp_idx;
+
+	pwm_size_idx = __find_index_in_array(lpg->pwm_config.pwm_size,
+			pwm_size, ARRAY_SIZE(pwm_size));
+	pwm_clk_idx = __find_index_in_array(lpg->pwm_config.pwm_clk,
+			clk_freq_hz, ARRAY_SIZE(clk_freq_hz));
+	prediv_idx = __find_index_in_array(lpg->pwm_config.prediv,
+			clk_prediv, ARRAY_SIZE(clk_prediv));
+	clk_exp_idx = __find_index_in_array(lpg->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 += 1;
+	val = pwm_size_idx << LPG_PWM_SIZE_SHIFT | pwm_clk_idx;
+	mask = LPG_PWM_SIZE_MASK | LPG_PWM_CLK_FREQ_SEL_MASK;
+	rc = qti_lpg_masked_write(lpg, REG_LPG_PWM_SIZE_CLK, mask, val);
+	if (rc < 0) {
+		dev_err(lpg->chip->dev, "Write LPG_PWM_SIZE_CLK failed, rc=%d\n",
+							rc);
+		return rc;
+	}
+
+	val = prediv_idx << LPG_PWM_FREQ_PREDIV_SHIFT | clk_exp_idx;
+	mask = LPG_PWM_FREQ_PREDIV_MASK | LPG_PWM_FREQ_EXPONENT_MASK;
+	rc = qti_lpg_masked_write(lpg, REG_LPG_PWM_FREQ_PREDIV_CLK, mask, val);
+	if (rc < 0) {
+		dev_err(lpg->chip->dev, "Write LPG_PWM_FREQ_PREDIV_CLK failed, rc=%d\n",
+							rc);
+		return rc;
+	}
+
+	val = lpg->pwm_config.pwm_value & LPG_PWM_VALUE_LSB_MASK;
+	rc = qti_lpg_write(lpg, REG_LPG_PWM_VALUE_LSB, val);
+	if (rc < 0) {
+		dev_err(lpg->chip->dev, "Write LPG_PWM_VALUE_LSB failed, rc=%d\n",
+							rc);
+		return rc;
+	}
+
+	val = lpg->pwm_config.pwm_value >> 8;
+	mask = LPG_PWM_VALUE_MSB_MASK;
+	rc = qti_lpg_masked_write(lpg, REG_LPG_PWM_VALUE_MSB, mask, val);
+	if (rc < 0) {
+		dev_err(lpg->chip->dev, "Write LPG_PWM_VALUE_MSB failed, rc=%d\n",
+							rc);
+		return rc;
+	}
+
+	val = LPG_PWM_VALUE_SYNC;
+	rc = qti_lpg_write(lpg, REG_LPG_PWM_SYNC, val);
+	if (rc < 0) {
+		dev_err(lpg->chip->dev, "Write LPG_PWM_SYNC failed, rc=%d\n",
+							rc);
+		return rc;
+	}
+
+	return rc;
+}
+
+static void __qti_lpg_calc_pwm_period(int period_ns,
+			struct lpg_pwm_config *pwm_config)
+{
+	struct lpg_pwm_config configs[NUM_PWM_SIZE];
+	int i, j, m, n;
+	int tmp1, tmp2;
+	int clk_period_ns = 0, pwm_clk_period_ns;
+	int clk_delta_ns = INT_MAX, min_clk_delta_ns = INT_MAX;
+	int pwm_period_delta = INT_MAX, min_pwm_period_delta = INT_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 / clk_freq_hz[i];
+
+					clk_period_ns = tmp1 * tmp2;
+
+					clk_delta_ns = abs(pwm_clk_period_ns
+						- clk_period_ns);
+					/*
+					 * Find the closet 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 closet 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 lpg_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 %d: 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: %dns\n", pwm_config->best_period_ns);
+}
+
+static void __qti_lpg_calc_pwm_duty(int period_ns, int duty_ns,
+			struct lpg_pwm_config *pwm_config)
+{
+	u16 pwm_value, max_pwm_value;
+
+	if ((1 << pwm_config->pwm_size) > (INT_MAX / duty_ns))
+		pwm_value = duty_ns / (period_ns >> pwm_config->pwm_size);
+	else
+		pwm_value = (duty_ns << pwm_config->pwm_size) / 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 qti_lpg_pwm_config(struct pwm_chip *pwm_chip,
+		struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+	struct qti_lpg_channel *lpg;
+	int rc = 0;
+
+	lpg = pwm_dev_to_qti_lpg(pwm_chip, pwm);
+	if (lpg == NULL) {
+		dev_err(pwm_chip->dev, "lpg not found\n");
+		return -ENODEV;
+	}
+
+	if (duty_ns > period_ns) {
+		dev_err(pwm_chip->dev, "Duty %dns is larger than period %dns\n",
+						duty_ns, period_ns);
+		return -EINVAL;
+	}
+
+	if (period_ns != lpg->current_period_ns)
+		__qti_lpg_calc_pwm_period(period_ns, &lpg->pwm_config);
+
+	if (period_ns != lpg->current_period_ns ||
+			duty_ns != lpg->current_duty_ns)
+		__qti_lpg_calc_pwm_duty(period_ns, duty_ns, &lpg->pwm_config);
+
+	rc = qti_lpg_set_pwm_config(lpg);
+	if (rc < 0)
+		dev_err(pwm_chip->dev, "Config PWM failed for channel %d, rc=%d\n",
+						lpg->lpg_idx, rc);
+
+	return rc;
+}
+
+static int qti_lpg_pwm_enable(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm)
+{
+	struct qti_lpg_channel *lpg;
+	int rc = 0;
+	u8 mask, val;
+
+	lpg = pwm_dev_to_qti_lpg(pwm_chip, pwm);
+	if (lpg == NULL) {
+		dev_err(pwm_chip->dev, "lpg not found\n");
+		return -ENODEV;
+	}
+
+	mask = LPG_PWM_SRC_SELECT_MASK | LPG_EN_LPG_OUT_BIT;
+
+	val = lpg->src_sel << LPG_PWM_SRC_SELECT_SHIFT | LPG_EN_LPG_OUT_BIT;
+
+	rc = qti_lpg_masked_write(lpg, REG_LPG_ENABLE_CONTROL, mask, val);
+	if (rc < 0)
+		dev_err(pwm_chip->dev, "Enable PWM output failed for channel %d, rc=%d\n",
+						lpg->lpg_idx, rc);
+
+	return rc;
+}
+
+static void qti_lpg_pwm_disable(struct pwm_chip *pwm_chip,
+				struct pwm_device *pwm)
+{
+	struct qti_lpg_channel *lpg;
+	int rc;
+	u8 mask, val;
+
+	lpg = pwm_dev_to_qti_lpg(pwm_chip, pwm);
+	if (lpg == NULL) {
+		dev_err(pwm_chip->dev, "lpg not found\n");
+		return;
+	}
+
+	mask = LPG_PWM_SRC_SELECT_MASK | LPG_EN_LPG_OUT_BIT;
+
+	val = lpg->src_sel << LPG_PWM_SRC_SELECT_SHIFT;
+
+	rc = qti_lpg_masked_write(lpg, REG_LPG_ENABLE_CONTROL, mask, val);
+	if (rc < 0)
+		dev_err(pwm_chip->dev, "Disable PWM output failed for channel %d, rc=%d\n",
+						lpg->lpg_idx, rc);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void qti_lpg_pwm_dbg_show(struct pwm_chip *pwm_chip, struct seq_file *s)
+{
+	struct qti_lpg_channel *lpg;
+	struct lpg_pwm_config *cfg;
+	struct pwm_device *pwm;
+	int i;
+
+	for (i = 0; i < pwm_chip->npwm; i++) {
+		pwm = &pwm_chip->pwms[i];
+
+		lpg = pwm_dev_to_qti_lpg(pwm_chip, pwm);
+		if (lpg == NULL) {
+			dev_err(pwm_chip->dev, "lpg not found\n");
+			return;
+		}
+
+		if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
+			seq_printf(s, "LPG %d is requested by %s\n",
+					lpg->lpg_idx + 1, pwm->label);
+		} else {
+			seq_printf(s, "LPG %d is free\n",
+					lpg->lpg_idx + 1);
+			continue;
+		}
+
+		if (pwm_is_enabled(pwm)) {
+			seq_puts(s, "  enabled\n");
+		} else {
+			seq_puts(s, "  disabled\n");
+			continue;
+		}
+
+		cfg = &lpg->pwm_config;
+		seq_printf(s, "     clk = %dHz\n", cfg->pwm_clk);
+		seq_printf(s, "     pwm_size = %d\n", cfg->pwm_size);
+		seq_printf(s, "     prediv = %d\n", cfg->prediv);
+		seq_printf(s, "     exponent = %d\n", cfg->clk_exp);
+		seq_printf(s, "     pwm_value = %d\n", cfg->pwm_value);
+		seq_printf(s, "  Requested period: %dns, best period = %dns\n",
+				pwm_get_period(pwm), cfg->best_period_ns);
+	}
+}
+#endif
+
+static const struct pwm_ops qti_lpg_pwm_ops = {
+	.config = qti_lpg_pwm_config,
+	.enable = qti_lpg_pwm_enable,
+	.disable = qti_lpg_pwm_disable,
+#ifdef CONFIG_DEBUG_FS
+	.dbg_show = qti_lpg_pwm_dbg_show,
+#endif
+	.owner = THIS_MODULE,
+};
+
+static int qti_lpg_add_pwmchip(struct qti_lpg_chip *chip)
+{
+	int rc;
+
+	chip->pwm_chip.dev = chip->dev;
+	chip->pwm_chip.base = -1;
+	chip->pwm_chip.npwm = chip->lpg_nums;
+	chip->pwm_chip.ops = &qti_lpg_pwm_ops;
+
+	rc = pwmchip_add(&chip->pwm_chip);
+	if (rc < 0)
+		dev_err(chip->dev, "Add pwmchip failed, rc=%d\n", rc);
+
+	return rc;
+}
+
+static int qti_lpg_parse_dt(struct qti_lpg_chip *chip)
+{
+	int rc = 0, i;
+	u64 base, length;
+	const __be32 *addr;
+
+	addr = of_get_address(chip->dev->of_node, 0, NULL, NULL);
+	if (!addr) {
+		dev_err(chip->dev, "Getting address failed\n");
+		return -EINVAL;
+	}
+	base = be32_to_cpu(addr[0]);
+	length = be32_to_cpu(addr[1]);
+
+	chip->lpg_nums = length / REG_SIZE_PER_LPG;
+	chip->lpgs = devm_kcalloc(chip->dev, chip->lpg_nums,
+			sizeof(*chip->lpgs), GFP_KERNEL);
+	if (!chip->lpgs)
+		return -ENOMEM;
+
+	for (i = 0; i < chip->lpg_nums; i++) {
+		chip->lpgs[i].chip = chip;
+		chip->lpgs[i].lpg_idx = i;
+		chip->lpgs[i].reg_base = base + i * REG_SIZE_PER_LPG;
+		chip->lpgs[i].src_sel = PWM_OUTPUT;
+	}
+
+	return rc;
+}
+
+static int qti_lpg_probe(struct platform_device *pdev)
+{
+	int rc;
+	struct qti_lpg_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 = qti_lpg_parse_dt(chip);
+	if (rc < 0) {
+		dev_err(chip->dev, "Devicetree properties parsing failed, rc=%d\n",
+				rc);
+		return rc;
+	}
+
+	dev_set_drvdata(chip->dev, chip);
+
+	mutex_init(&chip->bus_lock);
+	rc = qti_lpg_add_pwmchip(chip);
+	if (rc < 0) {
+		dev_err(chip->dev, "Add pwmchip failed, rc=%d\n", rc);
+		mutex_destroy(&chip->bus_lock);
+	}
+
+	return rc;
+}
+
+static int qti_lpg_remove(struct platform_device *pdev)
+{
+	struct qti_lpg_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->bus_lock);
+	dev_set_drvdata(chip->dev, NULL);
+
+	return rc;
+}
+
+static const struct of_device_id qti_lpg_of_match[] = {
+	{ .compatible = "qcom,pwm-lpg",},
+	{ },
+};
+
+static struct platform_driver qti_lpg_driver = {
+	.driver		= {
+		.name		= "qcom,pwm-lpg",
+		.of_match_table	= qti_lpg_of_match,
+	},
+	.probe		= qti_lpg_probe,
+	.remove		= qti_lpg_remove,
+};
+module_platform_driver(qti_lpg_driver);
+
+MODULE_DESCRIPTION("QTI LPG driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("pwm:pwm-lpg");
-- 
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.