[PATCH v5 1/4] mfd: add LP3943 MFD driver

From: Milo Kim
Date: Thu Dec 05 2013 - 21:09:36 EST

LP3943 has 16 output pins which can be used as GPIO expander and PWM generator.

* Regmap I2C interface for R/W LP3943 registers

* Atomic operations for output pin assignment
The driver should check whether requested pin is available or not.
If the pin is already used, pin request returns as a failure.
A driver data, 'pin_used' is checked when gpio_request() and
pwm_request() are called. If the pin is available, then pin_used is set.
And it is cleared when gpio_free() and pwm_free().

* Device tree support
Compatible strings for GPIO and PWM driver.
LP3943 platform data is PWM related, so parsing the device tree is
implemented in the PWM driver.

Signed-off-by: Milo Kim <milo.kim@xxxxxx>
Acked-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
* Patch v5
Same as v4

* Patch v4
Driver description was moved from the documentation in patch v3.

* Patch v3
Now, output pin number is exactly matched with enum value of '
lp3943_pwm_output'.
Use dev_get_platdata() helper function in probe().
Use module_i2c_driver() for initcall.

* Patch v2
Handle atomic operations for output pin assignment.

drivers/mfd/Kconfig | 11 +++
drivers/mfd/Makefile | 1 +
drivers/mfd/lp3943.c | 167 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/mfd/lp3943.h | 114 ++++++++++++++++++++++++++++++
4 files changed, 293 insertions(+)
create mode 100644 drivers/mfd/lp3943.c
create mode 100644 include/linux/mfd/lp3943.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b7c74a7..eb16bd8 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -725,6 +725,17 @@ config MFD_DM355EVM_MSP
boards. MSP430 firmware manages resets and power sequencing,
inputs from buttons and the IR remote, LEDs, an RTC, and more.

+config MFD_LP3943
+ tristate "TI/National Semiconductor LP3943 MFD Driver"
+ depends on I2C
+ select MFD_CORE
+ select REGMAP_I2C
+ help
+ Support for the TI/National Semiconductor LP3943.
+ This driver consists of GPIO and PWM drivers.
+ With these functionalities, it can be used for LED string control or
+ general usage such like a GPIO controller and a PWM controller.
+
config MFD_LP8788
bool "TI LP8788 Power Management Unit Driver"
depends on I2C=y
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 8a28dc9..58554f1 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_PMIC_DA9052) += da9052-core.o
obj-$(CONFIG_MFD_DA9052_SPI) += da9052-spi.o
obj-$(CONFIG_MFD_DA9052_I2C) += da9052-i2c.o

+obj-$(CONFIG_MFD_LP3943) += lp3943.o
obj-$(CONFIG_MFD_LP8788) += lp8788.o lp8788-irq.o

da9055-objs := da9055-core.o da9055-i2c.o
diff --git a/drivers/mfd/lp3943.c b/drivers/mfd/lp3943.c
new file mode 100644
index 0000000..e322268
--- /dev/null
+++ b/drivers/mfd/lp3943.c
@@ -0,0 +1,167 @@
+/*
+ * TI/National Semiconductor LP3943 MFD Core Driver
+ *
+ * Copyright 2013 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@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.
+ *
+ * Driver structure:
+ * LP3943 is an integrated device capable of driving 16 output channels.
+ * It can be used for a GPIO expander and PWM generators.
+ *
+ * LED control General usage for a device
+ * ___________ ____________________________
+ *
+ * LP3943 MFD ---- GPIO expander leds-gpio eg) HW enable pin
+ * |
+ * --- PWM generator leds-pwm eg) PWM input
+ *
+ * Internal two PWM channels are used for LED dimming effect.
+ * And each output pin can be used as a GPIO as well.
+ * The LED functionality can work with GPIOs or PWMs.
+ * LEDs can be controlled with legacy leds-gpio(static brightness) or
+ * leds-pwm drivers(dynamic brightness control).
+ * Alternatively, it can be used for generic GPIO and PWM controller.
+ * For example, a GPIO is HW enable pin of a device.
+ * A PWM is input pin of a backlight device.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/lp3943.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#define LP3943_MAX_REGISTERS 0x09
+
+/* Register configuration for pin MUX */
+static const struct lp3943_reg_cfg lp3943_mux_cfg[] = {
+ /* address, mask, shift */
+ { LP3943_REG_MUX0, 0x03, 0 },
+ { LP3943_REG_MUX0, 0x0C, 2 },
+ { LP3943_REG_MUX0, 0x30, 4 },
+ { LP3943_REG_MUX0, 0xC0, 6 },
+ { LP3943_REG_MUX1, 0x03, 0 },
+ { LP3943_REG_MUX1, 0x0C, 2 },
+ { LP3943_REG_MUX1, 0x30, 4 },
+ { LP3943_REG_MUX1, 0xC0, 6 },
+ { LP3943_REG_MUX2, 0x03, 0 },
+ { LP3943_REG_MUX2, 0x0C, 2 },
+ { LP3943_REG_MUX2, 0x30, 4 },
+ { LP3943_REG_MUX2, 0xC0, 6 },
+ { LP3943_REG_MUX3, 0x03, 0 },
+ { LP3943_REG_MUX3, 0x0C, 2 },
+ { LP3943_REG_MUX3, 0x30, 4 },
+ { LP3943_REG_MUX3, 0xC0, 6 },
+};
+
+static struct mfd_cell lp3943_devs[] = {
+ {
+ .name = "lp3943-pwm",
+ .of_compatible = "ti,lp3943-pwm",
+ },
+ {
+ .name = "lp3943-gpio",
+ .of_compatible = "ti,lp3943-gpio",
+ },
+};
+
+int lp3943_read_byte(struct lp3943 *lp3943, u8 reg, u8 *read)
+{
+ int ret;
+ unsigned int val;
+
+ ret = regmap_read(lp3943->regmap, reg, &val);
+ if (ret < 0)
+ return ret;
+
+ *read = (u8)val;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(lp3943_read_byte);
+
+int lp3943_write_byte(struct lp3943 *lp3943, u8 reg, u8 data)
+{
+ return regmap_write(lp3943->regmap, reg, data);
+}
+EXPORT_SYMBOL_GPL(lp3943_write_byte);
+
+int lp3943_update_bits(struct lp3943 *lp3943, u8 reg, u8 mask, u8 data)
+{
+ return regmap_update_bits(lp3943->regmap, reg, mask, data);
+}
+EXPORT_SYMBOL_GPL(lp3943_update_bits);
+
+static const struct regmap_config lp3943_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = LP3943_MAX_REGISTERS,
+};
+
+static int lp3943_probe(struct i2c_client *cl, const struct i2c_device_id *id)
+{
+ struct lp3943 *lp3943;
+ struct device *dev = &cl->dev;
+
+ lp3943 = devm_kzalloc(dev, sizeof(*lp3943), GFP_KERNEL);
+ if (!lp3943)
+ return -ENOMEM;
+
+ lp3943->regmap = devm_regmap_init_i2c(cl, &lp3943_regmap_config);
+ if (IS_ERR(lp3943->regmap))
+ return PTR_ERR(lp3943->regmap);
+
+ lp3943->pdata = dev_get_platdata(dev);
+ lp3943->dev = dev;
+ lp3943->mux_cfg = lp3943_mux_cfg;
+ i2c_set_clientdata(cl, lp3943);
+
+ return mfd_add_devices(dev, -1, lp3943_devs, ARRAY_SIZE(lp3943_devs),
+ NULL, 0, NULL);
+}
+
+static int lp3943_remove(struct i2c_client *cl)
+{
+ struct lp3943 *lp3943 = i2c_get_clientdata(cl);
+
+ mfd_remove_devices(lp3943->dev);
+ return 0;
+}
+
+static const struct i2c_device_id lp3943_ids[] = {
+ { "lp3943", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lp3943_ids);
+
+#ifdef CONFIG_OF
+static const struct of_device_id lp3943_of_match[] = {
+ { .compatible = "ti,lp3943", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, lp3943_of_match);
+#endif
+
+static struct i2c_driver lp3943_driver = {
+ .probe = lp3943_probe,
+ .remove = lp3943_remove,
+ .driver = {
+ .name = "lp3943",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(lp3943_of_match),
+ },
+ .id_table = lp3943_ids,
+};
+
+module_i2c_driver(lp3943_driver);
+
+MODULE_DESCRIPTION("LP3943 MFD Core Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/lp3943.h b/include/linux/mfd/lp3943.h
new file mode 100644
index 0000000..3490db7
--- /dev/null
+++ b/include/linux/mfd/lp3943.h
@@ -0,0 +1,114 @@
+/*
+ * TI/National Semiconductor LP3943 Device
+ *
+ * Copyright 2013 Texas Instruments
+ *
+ * Author: Milo Kim <milo.kim@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.
+ *
+ */
+
+#ifndef __MFD_LP3943_H__
+#define __MFD_LP3943_H__
+
+#include <linux/gpio.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+/* Registers */
+#define LP3943_REG_GPIO_A 0x00
+#define LP3943_REG_GPIO_B 0x01
+#define LP3943_REG_PRESCALE0 0x02
+#define LP3943_REG_PWM0 0x03
+#define LP3943_REG_PRESCALE1 0x04
+#define LP3943_REG_PWM1 0x05
+#define LP3943_REG_MUX0 0x06
+#define LP3943_REG_MUX1 0x07
+#define LP3943_REG_MUX2 0x08
+#define LP3943_REG_MUX3 0x09
+
+/* Bit description for LP3943_REG_MUX0 ~ 3 */
+#define LP3943_GPIO_IN 0x00
+#define LP3943_GPIO_OUT_HIGH 0x00
+#define LP3943_GPIO_OUT_LOW 0x01
+#define LP3943_DIM_PWM0 0x02
+#define LP3943_DIM_PWM1 0x03
+
+#define LP3943_NUM_PWMS 2
+
+enum lp3943_pwm_output {
+ LP3943_PWM_OUT0,
+ LP3943_PWM_OUT1,
+ LP3943_PWM_OUT2,
+ LP3943_PWM_OUT3,
+ LP3943_PWM_OUT4,
+ LP3943_PWM_OUT5,
+ LP3943_PWM_OUT6,
+ LP3943_PWM_OUT7,
+ LP3943_PWM_OUT8,
+ LP3943_PWM_OUT9,
+ LP3943_PWM_OUT10,
+ LP3943_PWM_OUT11,
+ LP3943_PWM_OUT12,
+ LP3943_PWM_OUT13,
+ LP3943_PWM_OUT14,
+ LP3943_PWM_OUT15,
+};
+
+/*
+ * struct lp3943_pwm_map
+ * @output: Output pins which are mapped to each PWM channel
+ * @num_outputs: Number of outputs
+ */
+struct lp3943_pwm_map {
+ enum lp3943_pwm_output *output;
+ int num_outputs;
+};
+
+/*
+ * struct lp3943_platform_data
+ * @pwms: Output channel definitions for PWM channel 0 and 1
+ */
+struct lp3943_platform_data {
+ struct lp3943_pwm_map *pwms[LP3943_NUM_PWMS];
+};
+
+/*
+ * struct lp3943_reg_cfg
+ * @reg: Register address
+ * @mask: Register bit mask to be updated
+ * @shift: Register bit shift
+ */
+struct lp3943_reg_cfg {
+ u8 reg;
+ u8 mask;
+ u8 shift;
+};
+
+/*
+ * struct lp3943
+ * @dev: Parent device pointer
+ * @regmap: Used for I2C communication on accessing registers
+ * @pdata: LP3943 platform specific data
+ * @mux_cfg: Register configuration for pin MUX
+ * @pin_used: Bit mask for output pin used.
+ * This bitmask is used for pin assignment management.
+ * 1 = pin used, 0 = available.
+ * Only LSB 16 bits are used, but it is unsigned long type
+ * for atomic bitwise operations.
+ */
+struct lp3943 {
+ struct device *dev;
+ struct regmap *regmap;
+ struct lp3943_platform_data *pdata;
+ const struct lp3943_reg_cfg *mux_cfg;
+ unsigned long pin_used;
+};
+
+int lp3943_read_byte(struct lp3943 *lp3943, u8 reg, u8 *read);
+int lp3943_write_byte(struct lp3943 *lp3943, u8 reg, u8 data);
+int lp3943_update_bits(struct lp3943 *lp3943, u8 reg, u8 mask, u8 data);
+#endif
--
1.7.10.4

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