mfd: Add LP3943 MFD driver

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@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/include/linux/mfd/lp3943.h b/include/linux/mfd/lp3943.h
new file mode 100644
index 000000000000..3490db782988
--- /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@ti.com>
+ *
+ * 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