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mfd: pm8xxx-pwm: add pm8xxx PWM driver

From:  Willie Ruan <wruan@codeaurora.org>
To:  sameo@linux.intel.com
Subject:  [PATCH 1/2] mfd: pm8xxx-pwm: add pm8xxx PWM driver
Date:  Thu, 21 Apr 2011 23:15:51 -0700
Message-ID:  <1303452952-20499-1-git-send-email-wruan@codeaurora.org>
Cc:  Willie Ruan <wruan@codeaurora.org>, David Brown <davidb@codeaurora.org>, Daniel Walker <dwalker@fifo99.com>, Bryan Huntsman <bryanh@codeaurora.org>, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
Archive-link:  Article

Qualcomm PM8xxx chips, such as PM8058 and PM8921, have 8 channels of
PWM, also called LPG (Light Pulse Generator) in HW specs. All PWM
channels can be used as simple PWM machine or as a more advanced PWM
pattern generator using programmed lookup table.

This patch supports all APIs listed in <linux/pwm.h> with a small
difference. The two parameters (duty_ns and period_ns) in pwm_config()
are used as values in microseconds instead of nanoseconds. Otherwise a
32-bit integer can't fit for a range of 7 us to 300+ seconds.

Signed-off-by: Willie Ruan <wruan@codeaurora.org>
---
 drivers/mfd/Kconfig            |   10 +
 drivers/mfd/Makefile           |    1 +
 drivers/mfd/pm8xxx-pwm.c       |  819 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/pm8xxx/pwm.h |   88 +++++
 4 files changed, 918 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mfd/pm8xxx-pwm.c
 create mode 100644 include/linux/mfd/pm8xxx/pwm.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 38320e2..8d97996 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -699,6 +699,16 @@ config MFD_PM8XXX_IRQ
 	  This is required to use certain other PM 8xxx features, such as GPIO
 	  and MPP.
 
+config MFD_PM8XXX_PWM
+	tristate "Support for Qualcomm PM8xxx PWM feature"
+	depends on MFD_PM8XXX
+	default y if MFD_PM8XXX
+	help
+	  This is the Pulse Width Modulation (PWM) driver for Qualcomm
+	  PM 8xxx PMIC chips. It can driver 8 channels of PWM output, and
+	  has a lookup table with size of 64 to be shared by any of the
+	  8 channels.
+
 endif # MFD_SUPPORT
 
 menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f4afcc8..7975466 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -90,3 +90,4 @@ obj-$(CONFIG_MFD_CS5535)	+= cs5535-mfd.o
 obj-$(CONFIG_MFD_OMAP_USB_HOST)	+= omap-usb-host.o
 obj-$(CONFIG_MFD_PM8921_CORE) 	+= pm8921-core.o
 obj-$(CONFIG_MFD_PM8XXX_IRQ) 	+= pm8xxx-irq.o
+obj-$(CONFIG_MFD_PM8XXX_PWM)	+= pm8xxx-pwm.o
diff --git a/drivers/mfd/pm8xxx-pwm.c b/drivers/mfd/pm8xxx-pwm.c
new file mode 100644
index 0000000..277f81a
--- /dev/null
+++ b/drivers/mfd/pm8xxx-pwm.c
@@ -0,0 +1,819 @@
+/* Copyright (c) 2011, Code Aurora Forum. 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.
+ */
+/*
+ * Qualcomm PM8XXX Pulse Width Modulation (PWM) driver
+ *
+ * The HW module is also called LPG (Light Pulse Generator).
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/mfd/pm8xxx/core.h>
+#include <linux/mfd/pm8xxx/pwm.h>
+
+#define PM8XXX_LPG_BANKS		8
+#define PM8XXX_PWM_CHANNELS		PM8XXX_LPG_BANKS
+
+#define PM8XXX_LPG_CTL_REGS		7
+
+/* PM8XXX PWM */
+#define SSBI_REG_ADDR_LPG_CTL_BASE	0x13C
+#define SSBI_REG_ADDR_LPG_CTL(n)	(SSBI_REG_ADDR_LPG_CTL_BASE + (n))
+#define SSBI_REG_ADDR_LPG_BANK_SEL	0x143
+#define SSBI_REG_ADDR_LPG_BANK_EN	0x144
+#define SSBI_REG_ADDR_LPG_LUT_CFG0	0x145
+#define SSBI_REG_ADDR_LPG_LUT_CFG1	0x146
+
+/* Control 0 */
+#define PM8XXX_PWM_1KHZ_COUNT_MASK	0xF0
+#define PM8XXX_PWM_1KHZ_COUNT_SHIFT	4
+
+#define PM8XXX_PWM_1KHZ_COUNT_MAX	15
+
+#define PM8XXX_PWM_OUTPUT_EN		0x08
+#define PM8XXX_PWM_PWM_EN		0x04
+#define PM8XXX_PWM_RAMP_GEN_EN		0x02
+#define PM8XXX_PWM_RAMP_START		0x01
+
+#define PM8XXX_PWM_PWM_START		(PM8XXX_PWM_OUTPUT_EN \
+					| PM8XXX_PWM_PWM_EN)
+#define PM8XXX_PWM_RAMP_GEN_START	(PM8XXX_PWM_RAMP_GEN_EN \
+					| PM8XXX_PWM_RAMP_START)
+
+/* Control 1 */
+#define PM8XXX_PWM_REVERSE_EN		0x80
+#define PM8XXX_PWM_BYPASS_LUT		0x40
+#define PM8XXX_PWM_HIGH_INDEX_MASK	0x3F
+
+/* Control 2 */
+#define PM8XXX_PWM_LOOP_EN		0x80
+#define PM8XXX_PWM_RAMP_UP		0x40
+#define PM8XXX_PWM_LOW_INDEX_MASK	0x3F
+
+/* Control 3 */
+#define PM8XXX_PWM_VALUE_BIT7_0		0xFF
+#define PM8XXX_PWM_VALUE_BIT5_0		0x3F
+
+/* Control 4 */
+#define PM8XXX_PWM_VALUE_BIT8		0x80
+
+#define PM8XXX_PWM_CLK_SEL_MASK		0x60
+#define PM8XXX_PWM_CLK_SEL_SHIFT	5
+
+#define PM8XXX_PWM_CLK_SEL_NO		0
+#define PM8XXX_PWM_CLK_SEL_1KHZ		1
+#define PM8XXX_PWM_CLK_SEL_32KHZ	2
+#define PM8XXX_PWM_CLK_SEL_19P2MHZ	3
+
+#define PM8XXX_PWM_PREDIVIDE_MASK	0x18
+#define PM8XXX_PWM_PREDIVIDE_SHIFT	3
+
+#define PM8XXX_PWM_PREDIVIDE_2		0
+#define PM8XXX_PWM_PREDIVIDE_3		1
+#define PM8XXX_PWM_PREDIVIDE_5		2
+#define PM8XXX_PWM_PREDIVIDE_6		3
+
+#define PM8XXX_PWM_M_MASK		0x07
+#define PM8XXX_PWM_M_MIN		0
+#define PM8XXX_PWM_M_MAX		7
+
+/* Control 5 */
+#define PM8XXX_PWM_PAUSE_COUNT_HI_MASK		0xFC
+#define PM8XXX_PWM_PAUSE_COUNT_HI_SHIFT		2
+
+#define PM8XXX_PWM_PAUSE_ENABLE_HIGH		0x02
+#define PM8XXX_PWM_SIZE_9_BIT			0x01
+
+/* Control 6 */
+#define PM8XXX_PWM_PAUSE_COUNT_LO_MASK		0xFC
+#define PM8XXX_PWM_PAUSE_COUNT_LO_SHIFT		2
+
+#define PM8XXX_PWM_PAUSE_ENABLE_LOW		0x02
+#define PM8XXX_PWM_RESERVED			0x01
+
+#define PM8XXX_PWM_PAUSE_COUNT_MAX		56 /* < 2^6 = 64 */
+
+/* LUT_CFG1 */
+#define PM8XXX_PWM_LUT_READ			0x40
+
+/*
+ * PWM Frequency = Clock Frequency / (N * T)
+ *	or
+ * PWM Period = Clock Period * (N * T)
+ *	where
+ * N = 2^9 or 2^6 for 9-bit or 6-bit PWM size
+ * T = Pre-divide * 2^m, where m = 0..7 (exponent)
+ *
+ * This is the formula to figure out m for the best pre-divide and clock:
+ * (PWM Period / N) / 2^m = (Pre-divide * Clock Period)
+ */
+#define NUM_CLOCKS	3
+
+#define NSEC_1000HZ	(NSEC_PER_SEC / 1000)
+#define NSEC_32768HZ	(NSEC_PER_SEC / 32768)
+#define NSEC_19P2MHZ	(NSEC_PER_SEC / 19200000)
+
+#define CLK_PERIOD_MIN	NSEC_19P2MHZ
+#define CLK_PERIOD_MAX	NSEC_1000HZ
+
+#define NUM_PRE_DIVIDE	3	/* No default support for pre-divide = 6 */
+
+#define PRE_DIVIDE_0		2
+#define PRE_DIVIDE_1		3
+#define PRE_DIVIDE_2		5
+
+#define PRE_DIVIDE_MIN		PRE_DIVIDE_0
+#define PRE_DIVIDE_MAX		PRE_DIVIDE_2
+
+static unsigned int pt_t[NUM_PRE_DIVIDE][NUM_CLOCKS] = {
+	{	PRE_DIVIDE_0 * NSEC_1000HZ,
+		PRE_DIVIDE_0 * NSEC_32768HZ,
+		PRE_DIVIDE_0 * NSEC_19P2MHZ,
+	},
+	{	PRE_DIVIDE_1 * NSEC_1000HZ,
+		PRE_DIVIDE_1 * NSEC_32768HZ,
+		PRE_DIVIDE_1 * NSEC_19P2MHZ,
+	},
+	{	PRE_DIVIDE_2 * NSEC_1000HZ,
+		PRE_DIVIDE_2 * NSEC_32768HZ,
+		PRE_DIVIDE_2 * NSEC_19P2MHZ,
+	},
+};
+
+#define MIN_MPT	((PRE_DIVIDE_MIN * CLK_PERIOD_MIN) << PM8XXX_PWM_M_MIN)
+#define MAX_MPT	((PRE_DIVIDE_MAX * CLK_PERIOD_MAX) << PM8XXX_PWM_M_MAX)
+
+/* Private data */
+struct pm8xxx_pwm_chip;
+
+struct pwm_device {
+	int			pwm_id;		/* = bank/channel id */
+	int			in_use;
+	const char		*label;
+	int			pwm_period;
+	int			pwm_duty;
+	u8			pwm_ctl[PM8XXX_LPG_CTL_REGS];
+	int			irq;
+	struct pm8xxx_pwm_chip	*chip;
+};
+
+struct pm8xxx_pwm_chip {
+	struct pwm_device		pwm_dev[PM8XXX_PWM_CHANNELS];
+	u8				bank_mask;
+	struct mutex			pwm_mutex;
+	struct device			*dev;
+};
+
+static struct pm8xxx_pwm_chip	*pwm_chip;
+
+struct pm8xxx_pwm_config {
+	int	pwm_size;	/* round up to 6 or 9 for 6/9-bit PWM SIZE */
+	int	clk;
+	int	pre_div;
+	int	pre_div_exp;
+	int	pwm_value;
+	int	bypass_lut;
+
+	/* LUT parameters when bypass_lut is 0 */
+	int	lut_duty_ms;
+	int	lut_lo_index;
+	int	lut_hi_index;
+	int	lut_pause_hi;
+	int	lut_pause_lo;
+	int	flags;
+};
+
+static const u16 duty_msec[PM8XXX_PWM_1KHZ_COUNT_MAX + 1] = {
+	0, 1, 2, 3, 4, 6, 8, 16, 18, 24, 32, 36, 64, 128, 256, 512
+};
+
+static const u16 pause_count[PM8XXX_PWM_PAUSE_COUNT_MAX + 1] = {
+	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+	23, 28, 31, 42, 47, 56, 63, 83, 94, 111, 125, 167, 188, 222, 250, 333,
+	375, 500, 667, 750, 800, 900, 1000, 1100,
+	1200, 1300, 1400, 1500, 1600, 1800, 2000, 2500,
+	3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500,
+	7000
+};
+
+/* Internal functions */
+static int pm8xxx_pwm_bank_enable(struct pwm_device *pwm, int enable)
+{
+	int	rc;
+	u8	reg;
+	struct pm8xxx_pwm_chip	*chip;
+
+	chip = pwm->chip;
+
+	if (enable)
+		reg = chip->bank_mask | (1 << pwm->pwm_id);
+	else
+		reg = chip->bank_mask & ~(1 << pwm->pwm_id);
+
+	rc = pm8xxx_writeb(chip->dev->parent, SSBI_REG_ADDR_LPG_BANK_EN, reg);
+	if (rc) {
+		pr_err("pm8xxx_write(): rc=%d (Enable LPG Bank)\n", rc);
+		return rc;
+	}
+	chip->bank_mask = reg;
+
+	return 0;
+}
+
+static int pm8xxx_pwm_bank_sel(struct pwm_device *pwm)
+{
+	int	rc;
+
+	rc = pm8xxx_writeb(pwm->chip->dev->parent, SSBI_REG_ADDR_LPG_BANK_SEL,
+			   pwm->pwm_id);
+	if (rc)
+		pr_err("pm8xxx_write(): rc=%d (Select PWM Bank)\n", rc);
+	return rc;
+}
+
+static int pm8xxx_pwm_start(struct pwm_device *pwm, int start, int ramp_start)
+{
+	int	rc;
+	u8	reg;
+
+	if (start) {
+		reg = pwm->pwm_ctl[0] | PM8XXX_PWM_PWM_START;
+		if (ramp_start)
+			reg |= PM8XXX_PWM_RAMP_GEN_START;
+		else
+			reg &= ~PM8XXX_PWM_RAMP_GEN_START;
+	} else {
+		reg = pwm->pwm_ctl[0] & ~PM8XXX_PWM_PWM_START;
+		reg &= ~PM8XXX_PWM_RAMP_GEN_START;
+	}
+
+	rc = pm8xxx_writeb(pwm->chip->dev->parent, SSBI_REG_ADDR_LPG_CTL(0),
+			   reg);
+	if (rc)
+		pr_err("pm8xxx_write(): rc=%d (Enable PWM Ctl 0)\n", rc);
+	else
+		pwm->pwm_ctl[0] = reg;
+	return rc;
+}
+
+static void pm8xxx_pwm_calc_period(unsigned int period_us,
+					   struct pm8xxx_pwm_config *pwm_conf)
+{
+	int	n, m, clk, div;
+	int	best_m, best_div, best_clk;
+	int	last_err, cur_err, better_err, better_m;
+	unsigned int	tmp_p, last_p, min_err, period_n;
+
+	/* PWM Period / N */
+	if (period_us < (40 * USEC_PER_SEC)) {  /* ~6-bit max */
+		period_n = (period_us * NSEC_PER_USEC) >> 6;
+		n = 6;
+	} else if (period_us < (274 * USEC_PER_SEC)) { /* overflow threshold */
+		period_n = (period_us >> 6) * NSEC_PER_USEC;
+		if (period_n >= MAX_MPT) {
+			n = 9;
+			period_n >>= 3;
+		} else
+			n = 6;
+	} else {
+		period_n = (period_us >> 9) * NSEC_PER_USEC;
+		n = 9;
+	}
+
+	min_err = MAX_MPT;
+	best_m = 0;
+	best_clk = 0;
+	best_div = 0;
+	for (clk = 0; clk < NUM_CLOCKS; clk++) {
+		for (div = 0; div < NUM_PRE_DIVIDE; div++) {
+			tmp_p = period_n;
+			last_p = tmp_p;
+			for (m = 0; m <= PM8XXX_PWM_M_MAX; m++) {
+				if (tmp_p <= pt_t[div][clk]) {
+					/* Found local best */
+					if (!m) {
+						better_err = pt_t[div][clk] -
+							tmp_p;
+						better_m = m;
+					} else {
+						last_err = last_p -
+							pt_t[div][clk];
+						cur_err = pt_t[div][clk] -
+							tmp_p;
+
+						if (cur_err < last_err) {
+							better_err = cur_err;
+							better_m = m;
+						} else {
+							better_err = last_err;
+							better_m = m - 1;
+						}
+					}
+
+					if (better_err < min_err) {
+						min_err = better_err;
+						best_m = better_m;
+						best_clk = clk;
+						best_div = div;
+					}
+					break;
+				} else {
+					last_p = tmp_p;
+					tmp_p >>= 1;
+				}
+			}
+		}
+	}
+
+	pwm_conf->pwm_size = n;
+	pwm_conf->clk = best_clk;
+	pwm_conf->pre_div = best_div;
+	pwm_conf->pre_div_exp = best_m;
+}
+
+static int pm8xxx_pwm_configure(struct pwm_device *pwm,
+			 struct pm8xxx_pwm_config *pwm_conf)
+{
+	int	i, rc, len;
+	u8	reg, ramp_enabled = 0;
+
+	reg = (pwm_conf->pwm_size > 6) ? PM8XXX_PWM_SIZE_9_BIT : 0;
+	pwm->pwm_ctl[5] = reg;
+
+	reg = ((pwm_conf->clk + 1) << PM8XXX_PWM_CLK_SEL_SHIFT)
+		& PM8XXX_PWM_CLK_SEL_MASK;
+	reg |= (pwm_conf->pre_div << PM8XXX_PWM_PREDIVIDE_SHIFT)
+		& PM8XXX_PWM_PREDIVIDE_MASK;
+	reg |= pwm_conf->pre_div_exp & PM8XXX_PWM_M_MASK;
+	pwm->pwm_ctl[4] = reg;
+
+	if (pwm_conf->bypass_lut) {
+		pwm->pwm_ctl[0] &= PM8XXX_PWM_PWM_START; /* keep enabled */
+		pwm->pwm_ctl[1] = PM8XXX_PWM_BYPASS_LUT;
+		pwm->pwm_ctl[2] = 0;
+
+		if (pwm_conf->pwm_size > 6) {
+			pwm->pwm_ctl[3] = pwm_conf->pwm_value
+						& PM8XXX_PWM_VALUE_BIT7_0;
+			pwm->pwm_ctl[4] |= (pwm_conf->pwm_value >> 1)
+						& PM8XXX_PWM_VALUE_BIT8;
+		} else {
+			pwm->pwm_ctl[3] = pwm_conf->pwm_value
+						& PM8XXX_PWM_VALUE_BIT5_0;
+		}
+
+		len = 6;
+	} else {
+		int	pause_cnt, j;
+
+		/* Linear search for duty time */
+		for (i = 0; i < PM8XXX_PWM_1KHZ_COUNT_MAX; i++) {
+			if (duty_msec[i] >= pwm_conf->lut_duty_ms)
+				break;
+		}
+
+		ramp_enabled = pwm->pwm_ctl[0] & PM8XXX_PWM_RAMP_GEN_START;
+		pwm->pwm_ctl[0] &= PM8XXX_PWM_PWM_START; /* keep enabled */
+		pwm->pwm_ctl[0] |= (i << PM8XXX_PWM_1KHZ_COUNT_SHIFT) &
+					PM8XXX_PWM_1KHZ_COUNT_MASK;
+		pwm->pwm_ctl[1] = pwm_conf->lut_hi_index &
+					PM8XXX_PWM_HIGH_INDEX_MASK;
+		pwm->pwm_ctl[2] = pwm_conf->lut_lo_index &
+					PM8XXX_PWM_LOW_INDEX_MASK;
+
+		if (pwm_conf->flags & PM_PWM_LUT_REVERSE)
+			pwm->pwm_ctl[1] |= PM8XXX_PWM_REVERSE_EN;
+		if (pwm_conf->flags & PM_PWM_LUT_RAMP_UP)
+			pwm->pwm_ctl[2] |= PM8XXX_PWM_RAMP_UP;
+		if (pwm_conf->flags & PM_PWM_LUT_LOOP)
+			pwm->pwm_ctl[2] |= PM8XXX_PWM_LOOP_EN;
+
+		/* Pause time */
+		if (pwm_conf->flags & PM_PWM_LUT_PAUSE_HI_EN) {
+			/* Linear search for pause time */
+			pause_cnt = (pwm_conf->lut_pause_hi + duty_msec[i] / 2)
+					/ duty_msec[i];
+			for (j = 0; j < PM8XXX_PWM_PAUSE_COUNT_MAX; j++) {
+				if (pause_count[j] >= pause_cnt)
+					break;
+			}
+			pwm->pwm_ctl[5] = (j <<
+					   PM8XXX_PWM_PAUSE_COUNT_HI_SHIFT) &
+						PM8XXX_PWM_PAUSE_COUNT_HI_MASK;
+			pwm->pwm_ctl[5] |= PM8XXX_PWM_PAUSE_ENABLE_HIGH;
+		} else
+			pwm->pwm_ctl[5] = 0;
+
+		if (pwm_conf->flags & PM_PWM_LUT_PAUSE_LO_EN) {
+			/* Linear search for pause time */
+			pause_cnt = (pwm_conf->lut_pause_lo + duty_msec[i] / 2)
+					/ duty_msec[i];
+			for (j = 0; j < PM8XXX_PWM_PAUSE_COUNT_MAX; j++) {
+				if (pause_count[j] >= pause_cnt)
+					break;
+			}
+			pwm->pwm_ctl[6] = (j <<
+					   PM8XXX_PWM_PAUSE_COUNT_LO_SHIFT) &
+						PM8XXX_PWM_PAUSE_COUNT_LO_MASK;
+			pwm->pwm_ctl[6] |= PM8XXX_PWM_PAUSE_ENABLE_LOW;
+		} else
+			pwm->pwm_ctl[6] = 0;
+
+		len = 7;
+	}
+
+	pm8xxx_pwm_bank_sel(pwm);
+
+	for (i = 0; i < len; i++) {
+		rc = pm8xxx_writeb(pwm->chip->dev->parent,
+				   SSBI_REG_ADDR_LPG_CTL(i),
+				   pwm->pwm_ctl[i]);
+		if (rc) {
+			pr_err("pm8xxx_write(): rc=%d (PWM Ctl[%d])\n", rc, i);
+			break;
+		}
+	}
+
+	if (ramp_enabled) {
+		pwm->pwm_ctl[0] |= ramp_enabled;
+		pm8xxx_writeb(pwm->chip->dev->parent,
+			      SSBI_REG_ADDR_LPG_CTL(0),
+			      pwm->pwm_ctl[0]);
+	}
+
+	return rc;
+}
+
+/* APIs */
+/**
+ * pwm_request - request a PWM device
+ * @pwm_id: PWM id or channel
+ * @label: the label to identify the user
+ */
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+	struct pwm_device	*pwm;
+
+	if (pwm_id > PM8XXX_PWM_CHANNELS || pwm_id < 0) {
+		pr_err("Invalid pwm_id: %d with %s\n",
+		       pwm_id, label ? label : ".");
+		return ERR_PTR(-EINVAL);
+	}
+	if (pwm_chip == NULL) {
+		pr_err("No pwm_chip\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	mutex_lock(&pwm_chip->pwm_mutex);
+	pwm = &pwm_chip->pwm_dev[pwm_id];
+	if (!pwm->in_use) {
+		pwm->in_use = 1;
+		pwm->label = label;
+	} else
+		pwm = ERR_PTR(-EBUSY);
+	mutex_unlock(&pwm_chip->pwm_mutex);
+
+	return pwm;
+}
+EXPORT_SYMBOL_GPL(pwm_request);
+
+/**
+ * pwm_free - free a PWM device
+ * @pwm: the PWM device
+ */
+void pwm_free(struct pwm_device *pwm)
+{
+	if (pwm == NULL || IS_ERR(pwm) || pwm->chip == NULL) {
+		pr_err("Invalid pwm handle\n");
+		return;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+	if (pwm->in_use) {
+		pm8xxx_pwm_bank_sel(pwm);
+		pm8xxx_pwm_start(pwm, 0, 0);
+
+		pwm->in_use = 0;
+		pwm->label = NULL;
+	}
+	pm8xxx_pwm_bank_enable(pwm, 0);
+	mutex_unlock(&pwm->chip->pwm_mutex);
+}
+EXPORT_SYMBOL_GPL(pwm_free);
+
+/**
+ * pwm_config - change a PWM device configuration
+ * @pwm: the PWM device
+ * @period_us: period in microseconds
+ * @duty_us: duty cycle in microseconds
+ */
+int pwm_config(struct pwm_device *pwm, int duty_us, int period_us)
+{
+	struct pm8xxx_pwm_config	pwm_conf;
+	unsigned int max_pwm_value, tmp;
+	int	rc;
+
+	if (pwm == NULL || IS_ERR(pwm) ||
+		(unsigned)duty_us > (unsigned)period_us ||
+		(unsigned)period_us > PM8XXX_PWM_PERIOD_MAX ||
+		(unsigned)period_us < PM8XXX_PWM_PERIOD_MIN) {
+		pr_err("Invalid pwm handle or parameters\n");
+		return -EINVAL;
+	}
+	if (pwm->chip == NULL) {
+		pr_err("No pwm_chip\n");
+		return -ENODEV;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+
+	if (!pwm->in_use) {
+		pr_err("pwm_id: %d: stale handle?\n", pwm->pwm_id);
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+
+	pm8xxx_pwm_calc_period(period_us, &pwm_conf);
+
+	/* Figure out pwm_value with overflow handling */
+	if ((unsigned)period_us > (1 << pwm_conf.pwm_size)) {
+		tmp = period_us;
+		tmp >>= pwm_conf.pwm_size;
+		pwm_conf.pwm_value = (unsigned)duty_us / tmp;
+	} else {
+		tmp = duty_us;
+		tmp <<= pwm_conf.pwm_size;
+		pwm_conf.pwm_value = tmp / (unsigned)period_us;
+	}
+	max_pwm_value = (1 << pwm_conf.pwm_size) - 1;
+	if (pwm_conf.pwm_value > max_pwm_value)
+		pwm_conf.pwm_value = max_pwm_value;
+
+	pwm_conf.bypass_lut = 1;
+
+	rc = pm8xxx_pwm_configure(pwm, &pwm_conf);
+
+out_unlock:
+	mutex_unlock(&pwm->chip->pwm_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pwm_config);
+
+/**
+ * pwm_enable - start a PWM output toggling
+ * @pwm: the PWM device
+ */
+int pwm_enable(struct pwm_device *pwm)
+{
+	int	rc;
+
+	if (pwm == NULL || IS_ERR(pwm)) {
+		pr_err("Invalid pwm handle\n");
+		return -EINVAL;
+	}
+	if (pwm->chip == NULL) {
+		pr_err("No pwm_chip\n");
+		return -ENODEV;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+	if (!pwm->in_use) {
+		pr_err("pwm_id: %d: stale handle?\n", pwm->pwm_id);
+		rc = -EINVAL;
+	} else {
+		rc = pm8xxx_pwm_bank_enable(pwm, 1);
+
+		pm8xxx_pwm_bank_sel(pwm);
+		pm8xxx_pwm_start(pwm, 1, 0);
+	}
+	mutex_unlock(&pwm->chip->pwm_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pwm_enable);
+
+/**
+ * pwm_disable - stop a PWM output toggling
+ * @pwm: the PWM device
+ */
+void pwm_disable(struct pwm_device *pwm)
+{
+	if (pwm == NULL || IS_ERR(pwm) || pwm->chip == NULL) {
+		pr_err("Invalid pwm handle or no pwm_chip\n");
+		return;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+	if (pwm->in_use) {
+		pm8xxx_pwm_bank_sel(pwm);
+		pm8xxx_pwm_start(pwm, 0, 0);
+
+		pm8xxx_pwm_bank_enable(pwm, 0);
+	}
+	mutex_unlock(&pwm->chip->pwm_mutex);
+}
+EXPORT_SYMBOL_GPL(pwm_disable);
+
+/**
+ * pm8xxx_pwm_lut_config - change a PWM device configuration to use LUT
+ * @pwm: the PWM device
+ * @period_us: period in microseconds
+ * @duty_pct: arrary of duty cycles in percent, like 20, 50.
+ * @duty_time_ms: time for each duty cycle in milliseconds
+ * @start_idx: start index in lookup table from 0 to MAX-1
+ * @idx_len: number of index
+ * @pause_lo: pause time in milliseconds at low index
+ * @pause_hi: pause time in milliseconds at high index
+ * @flags: control flags
+ */
+int pm8xxx_pwm_lut_config(struct pwm_device *pwm, int period_us,
+			  int duty_pct[], int duty_time_ms, int start_idx,
+			  int idx_len, int pause_lo, int pause_hi, int flags)
+{
+	struct pm8xxx_pwm_config	pwm_conf;
+	unsigned int pwm_value, max_pwm_value;
+	u8	cfg0, cfg1;
+	int	i, len;
+	int	rc;
+
+	if (pwm == NULL || IS_ERR(pwm) || !idx_len) {
+		pr_err("Invalid pwm handle or idx_len=0\n");
+		return -EINVAL;
+	}
+	if (duty_pct == NULL && !(flags & PM_PWM_LUT_NO_TABLE)) {
+		pr_err("Invalid duty_pct with flag\n");
+		return -EINVAL;
+	}
+	if (pwm->chip == NULL) {
+		pr_err("No pwm_chip\n");
+		return -ENODEV;
+	}
+	if (idx_len >= PM_PWM_LUT_SIZE && start_idx) {
+		pr_err("Wrong LUT size or index\n");
+		return -EINVAL;
+	}
+	if ((start_idx + idx_len) > PM_PWM_LUT_SIZE) {
+		pr_err("Exceed LUT limit\n");
+		return -EINVAL;
+	}
+	if ((unsigned)period_us > PM8XXX_PWM_PERIOD_MAX ||
+		(unsigned)period_us < PM8XXX_PWM_PERIOD_MIN) {
+		pr_err("Period out of range\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+
+	if (!pwm->in_use) {
+		pr_err("pwm_id: %d: stale handle?\n", pwm->pwm_id);
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+
+	pm8xxx_pwm_calc_period(period_us, &pwm_conf);
+
+	len = (idx_len > PM_PWM_LUT_SIZE) ? PM_PWM_LUT_SIZE : idx_len;
+
+	if (flags & PM_PWM_LUT_NO_TABLE)
+		goto after_table_write;
+
+	max_pwm_value = (1 << pwm_conf.pwm_size) - 1;
+	for (i = 0; i < len; i++) {
+		pwm_value = (duty_pct[i] << pwm_conf.pwm_size) / 100;
+		/* Avoid overflow */
+		if (pwm_value > max_pwm_value)
+			pwm_value = max_pwm_value;
+		cfg0 = pwm_value & 0xff;
+		cfg1 = (pwm_value >> 1) & 0x80;
+		cfg1 |= start_idx + i;
+
+		pm8xxx_writeb(pwm->chip->dev->parent,
+			      SSBI_REG_ADDR_LPG_LUT_CFG0, cfg0);
+		pm8xxx_writeb(pwm->chip->dev->parent,
+			      SSBI_REG_ADDR_LPG_LUT_CFG1, cfg1);
+	}
+
+after_table_write:
+	pwm_conf.lut_duty_ms = duty_time_ms;
+	pwm_conf.lut_lo_index = start_idx;
+	pwm_conf.lut_hi_index = start_idx + len - 1;
+	pwm_conf.lut_pause_lo = pause_lo;
+	pwm_conf.lut_pause_hi = pause_hi;
+	pwm_conf.flags = flags;
+	pwm_conf.bypass_lut = 0;
+
+	rc = pm8xxx_pwm_configure(pwm, &pwm_conf);
+
+out_unlock:
+	mutex_unlock(&pwm->chip->pwm_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pm8xxx_pwm_lut_config);
+
+/**
+ * pm8xxx_pwm_lut_enable - control a PWM device to start/stop LUT ramp
+ * @pwm: the PWM device
+ * @start: to start (1), or stop (0)
+ */
+int pm8xxx_pwm_lut_enable(struct pwm_device *pwm, int start)
+{
+	if (pwm == NULL || IS_ERR(pwm)) {
+		pr_err("Invalid pwm handle\n");
+		return -EINVAL;
+	}
+	if (pwm->chip == NULL) {
+		pr_err("No pwm_chip\n");
+		return -ENODEV;
+	}
+
+	mutex_lock(&pwm->chip->pwm_mutex);
+	if (start) {
+		pm8xxx_pwm_bank_enable(pwm, 1);
+
+		pm8xxx_pwm_bank_sel(pwm);
+		pm8xxx_pwm_start(pwm, 1, 1);
+	} else {
+		pm8xxx_pwm_bank_sel(pwm);
+		pm8xxx_pwm_start(pwm, 0, 0);
+
+		pm8xxx_pwm_bank_enable(pwm, 0);
+	}
+	mutex_unlock(&pwm->chip->pwm_mutex);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm8xxx_pwm_lut_enable);
+
+static int __devinit pm8xxx_pwm_probe(struct platform_device *pdev)
+{
+	struct pm8xxx_pwm_chip	*chip;
+	int	i;
+
+	chip = kzalloc(sizeof *chip, GFP_KERNEL);
+	if (chip == NULL) {
+		pr_err("kzalloc() failed.\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < PM8XXX_PWM_CHANNELS; i++) {
+		chip->pwm_dev[i].pwm_id = i;
+		chip->pwm_dev[i].chip = chip;
+	}
+
+	mutex_init(&chip->pwm_mutex);
+
+	chip->dev = &pdev->dev;
+	pwm_chip = chip;
+	platform_set_drvdata(pdev, chip);
+
+	pr_notice("OK\n");
+	return 0;
+}
+
+static int __devexit pm8xxx_pwm_remove(struct platform_device *pdev)
+{
+	struct pm8xxx_pwm_chip	*chip = platform_get_drvdata(pdev);
+
+	mutex_destroy(&chip->pwm_mutex);
+	platform_set_drvdata(pdev, NULL);
+	kfree(chip);
+	return 0;
+}
+
+static struct platform_driver pm8xxx_pwm_driver = {
+	.probe		= pm8xxx_pwm_probe,
+	.remove		= __devexit_p(pm8xxx_pwm_remove),
+	.driver		= {
+		.name = PM8XXX_PWM_DEV_NAME,
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init pm8xxx_pwm_init(void)
+{
+	return platform_driver_register(&pm8xxx_pwm_driver);
+}
+
+static void __exit pm8xxx_pwm_exit(void)
+{
+	platform_driver_unregister(&pm8xxx_pwm_driver);
+}
+
+subsys_initcall(pm8xxx_pwm_init);
+module_exit(pm8xxx_pwm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("PM8XXX PWM driver");
+MODULE_VERSION("1.0");
+MODULE_ALIAS("platform:" PM8XXX_PWM_DEV_NAME);
diff --git a/include/linux/mfd/pm8xxx/pwm.h b/include/linux/mfd/pm8xxx/pwm.h
new file mode 100644
index 0000000..d85eae0
--- /dev/null
+++ b/include/linux/mfd/pm8xxx/pwm.h
@@ -0,0 +1,88 @@
+/* Copyright (c) 2011, Code Aurora Forum. 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.
+ */
+
+#ifndef __PM8XXX_PWM_H__
+#define __PM8XXX_PWM_H__
+
+#include <linux/pwm.h>
+
+#define PM8XXX_PWM_DEV_NAME	"pm8xxx-pwm"
+
+#define PM8XXX_PWM_PERIOD_MAX		(327 * USEC_PER_SEC)
+#define PM8XXX_PWM_PERIOD_MIN		7 /* micro seconds */
+
+#define PM_PWM_LUT_SIZE			64
+#define PM_PWM_LUT_DUTY_TIME_MAX	512	/* ms */
+#define PM_PWM_LUT_PAUSE_MAX		(7000 * PM_PWM_LUT_DUTY_TIME_MAX)
+
+/* Flags for Look Up Table */
+#define PM_PWM_LUT_LOOP		0x01
+#define PM_PWM_LUT_RAMP_UP	0x02
+#define PM_PWM_LUT_REVERSE	0x04
+#define PM_PWM_LUT_PAUSE_HI_EN	0x10
+#define PM_PWM_LUT_PAUSE_LO_EN	0x20
+
+#define PM_PWM_LUT_NO_TABLE	0x100
+
+/**
+ * pm8xxx_pwm_lut_config - change a PWM device configuration to use LUT
+ * @pwm: the PWM device
+ * @period_us: period in micro second
+ * @duty_pct: arrary of duty cycles in percent, like 20, 50.
+ * @duty_time_ms: time for each duty cycle in millisecond
+ * @start_idx: start index in lookup table from 0 to MAX-1
+ * @idx_len: number of index
+ * @pause_lo: pause time in millisecond at low index
+ * @pause_hi: pause time in millisecond at high index
+ * @flags: control flags
+ */
+int pm8xxx_pwm_lut_config(struct pwm_device *pwm, int period_us,
+			  int duty_pct[], int duty_time_ms, int start_idx,
+			  int len, int pause_lo, int pause_hi, int flags);
+
+/**
+ * pm8xxx_pwm_lut_enable - control a PWM device to start/stop LUT ramp
+ * @pwm: the PWM device
+ * @start: to start (1), or stop (0)
+ */
+int pm8xxx_pwm_lut_enable(struct pwm_device *pwm, int start);
+
+/* Standard APIs supported */
+/**
+ * pwm_request - request a PWM device
+ * @pwm_id: PWM id or channel
+ * @label: the label to identify the user
+ */
+
+/**
+ * pwm_free - free a PWM device
+ * @pwm: the PWM device
+ */
+
+/**
+ * pwm_config - change a PWM device configuration
+ * @pwm: the PWM device
+ * @period_us: period in microsecond
+ * @duty_us: duty cycle in microsecond
+ */
+
+/**
+ * pwm_enable - start a PWM output toggling
+ * @pwm: the PWM device
+ */
+
+/**
+ * pwm_disable - stop a PWM output toggling
+ * @pwm: the PWM device
+ */
+
+#endif /* __PM8XXX_PWM_H__ */
-- 
1.6.5.2

--
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