[PATCH] Add support for TWL6030 PWM

[Hemanth V]

TWL6030 supports PWM (Pulse Width Modulator) which is used
to control charging LED. PWM allows for controlling brightness.
This patch implements the APIs required by leds-pwm driver.

Signed-off-by: Hemanth V <hemanthv@xxxxxx>
---
 drivers/mfd/Kconfig       |    9 +++
 drivers/mfd/Makefile      |    3 +-
 drivers/mfd/twl6030-pwm.c |  163 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 174 insertions(+), 1 deletions(-)
 create mode 100644 drivers/mfd/twl6030-pwm.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index c7c11ef..4459fe5 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -162,6 +162,15 @@ config TWL6030_GPADC
 	  Say yes here if you want support for the TWL6030 General Purpose
 	  A/D Convertor.

+config TWL6030_PWM
+	tristate "TWL6030 PWM (Pulse Width Modulator) Support"
+	depends on TWL4030_CORE
+	select HAVE_PWM
+	default n
+	help
+	  Say yes here if you want support for TWL6030 PWM.
+	  This is used to control charging LED brightness.
+
 config MFD_TMIO
 	bool
 	default n
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 204a974..e697101 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_TWL4030_CORE)	+= twl-core.o twl4030-irq.o twl6030-irq.o
 obj-$(CONFIG_TWL4030_POWER)    += twl4030-power.o
 obj-$(CONFIG_TWL4030_CODEC)	+= twl4030-codec.o
 obj-$(CONFIG_TWL6030_GPADC)	+= twl6030-gpadc.o
+obj-$(CONFIG_TWL6030_PWM)	+= twl6030-pwm.o

 obj-$(CONFIG_MFD_MC13783)	+= mc13783-core.o

@@ -63,4 +64,4 @@ obj-$(CONFIG_AB3100_OTP)	+= ab3100-otp.o
 obj-$(CONFIG_AB4500_CORE)	+= ab4500-core.o
 obj-$(CONFIG_MFD_TIMBERDALE)    += timberdale.o
 obj-$(CONFIG_PMIC_ADP5520)	+= adp5520.o
-obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
\ No newline at end of file
+obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
diff --git a/drivers/mfd/twl6030-pwm.c b/drivers/mfd/twl6030-pwm.c
new file mode 100644
index 0000000..5d25bdc
--- /dev/null
+++ b/drivers/mfd/twl6030-pwm.c
@@ -0,0 +1,163 @@
+/*
+ * twl6030_pwm.c
+ * Driver for PHOENIX (TWL6030) Pulse Width Modulator
+ *
+ * Copyright (C) 2010 Texas Instruments
+ * Author: Hemanth V <hemanthv@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License 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.
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/i2c/twl.h>
+#include <linux/slab.h>
+
+#define LED_PWM_CTRL1	0xF4
+#define LED_PWM_CTRL2	0xF5
+
+/* Max value for CTRL1 register */
+#define PWM_CTRL1_MAX	255
+
+/* Pull down disable */
+#define PWM_CTRL2_DIS_PD	(1 << 6)
+
+/* Current control 2.5 milli Amps */
+#define PWM_CTRL2_CURR_02	(2 << 4)
+
+/* LED supply source */
+#define PWM_CTRL2_SRC_VAC	(1 << 2)
+
+/* LED modes */
+#define PWM_CTRL2_MODE_HW	(0 << 0)
+#define PWM_CTRL2_MODE_SW	(1 << 0)
+#define PWM_CTRL2_MODE_DIS	(2 << 0)
+
+#define PWM_CTRL2_MODE_MASK	0x3
+
+struct pwm_device {
+	const char *label;
+	unsigned int pwm_id;
+};
+
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+	u8 duty_cycle;
+	int ret;
+
+	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+		return -EINVAL;
+
+	duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
+
+	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1);
+
+	if (ret < 0) {
+		pr_err("%s: Failed to configure PWM, Error %d\n",
+			pwm->label, ret);
+		return ret;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+	u8 val;
+	int ret;
+
+	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
+	if (ret < 0) {
+		pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
+		return ret;
+	}
+
+	/* Change mode to software control */
+	val &= ~PWM_CTRL2_MODE_MASK;
+	val |= PWM_CTRL2_MODE_SW;
+
+	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
+	if (ret < 0) {
+		pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret);
+		return ret;
+	}
+
+	twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
+	return 0;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+	u8 val;
+	int ret;
+
+	ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
+	if (ret < 0) {
+		pr_err("%s: Failed to disable PWM, Error %d\n",
+			pwm->label, ret);
+		return;
+	}
+
+	val &= ~PWM_CTRL2_MODE_MASK;
+	val |= PWM_CTRL2_MODE_HW;
+
+	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
+	if (ret < 0) {
+		pr_err("%s: Failed to disable PWM, Error %d\n",
+			pwm->label, ret);
+		return;
+	}
+	return;
+}
+EXPORT_SYMBOL(pwm_disable);
+
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+	u8 val;
+	int ret;
+	struct pwm_device *pwm;
+
+	pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+	if (pwm == NULL) {
+		pr_err("%s: failed to allocate memory\n", label);
+		return NULL;
+	}
+
+	pwm->label = label;
+	pwm->pwm_id = pwm_id;
+
+	/* Configure PWM */
+	val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC |
+		PWM_CTRL2_MODE_HW;
+
+	ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
+
+	if (ret < 0) {
+		pr_err("%s: Failed to configure PWM, Error %d\n",
+			 pwm->label, ret);
+
+		kfree(pwm);
+		return NULL;
+	}
+
+	return pwm;
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwm)
+{
+	pwm_disable(pwm);
+	kfree(pwm);
+}
+EXPORT_SYMBOL(pwm_free);
-- 
1.5.4.3


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