mfd: Add lp8788 mfd driver

TI LP8788 PMU provides regulators, battery charger, ADC,
RTC, backlight driver and current sinks.

This MFD patch supports the I2C communication using the regmap,
the interrupt handling using the linear IRQ domain and
configurable platform data structures for each driver module.

 (Driver Architecture)

                                         < mfd devices >
  LP8788 HW  ..........  mfd  .......... regulator drivers
                I2C                      power supply driver
                IRQs                     iio adc driver
                                         rtc driver
                                         backlight driver
                                         current sink drivers

  o regulators    : LDOs and BUCKs
  o power supply  : Battery charger
  o iio adc       : Battery voltage/temperature
  o rtc           : RTC and alarm
  o backlight
  o current sink  : LED and vibrator

All MFD device modules are registered by LP8788 MFD core driver.
For sharing information such like the virtual IRQ number,
MFD core driver uses the resource structure.
Then each module can retrieve the specific IRQ number and detect it
in the IRQ thread.

Configurable platform data is handled in each driver module.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 198 insertions, 0 deletions

diff --git a/drivers/mfd/lp8788-irq.c b/drivers/mfd/lp8788-irq.c
new file mode 100644
index 000000000000..c84ded5f8ece
--- /dev/null
+++ b/drivers/mfd/lp8788-irq.c
@@ -0,0 +1,198 @@
+/*
+ * TI LP8788 MFD - interrupt handler
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * Author: Milo(Woogyom) 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.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/device.h>
+#include <linux/mfd/lp8788.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+/* register address */
+#define LP8788_INT_1			0x00
+#define LP8788_INTEN_1			0x03
+
+#define BASE_INTEN_ADDR			LP8788_INTEN_1
+#define SIZE_REG			8
+#define NUM_REGS			3
+
+/*
+ * struct lp8788_irq_data
+ * @lp               : used for accessing to lp8788 registers
+ * @irq_lock         : mutex for enabling/disabling the interrupt
+ * @domain           : IRQ domain for handling nested interrupt
+ * @enabled          : status of enabled interrupt
+ */
+struct lp8788_irq_data {
+	struct lp8788 *lp;
+	struct mutex irq_lock;
+	struct irq_domain *domain;
+	int enabled[LP8788_INT_MAX];
+};
+
+static inline u8 _irq_to_addr(enum lp8788_int_id id)
+{
+	return id / SIZE_REG;
+}
+
+static inline u8 _irq_to_enable_addr(enum lp8788_int_id id)
+{
+	return _irq_to_addr(id) + BASE_INTEN_ADDR;
+}
+
+static inline u8 _irq_to_mask(enum lp8788_int_id id)
+{
+	return 1 << (id % SIZE_REG);
+}
+
+static inline u8 _irq_to_val(enum lp8788_int_id id, int enable)
+{
+	return enable << (id % SIZE_REG);
+}
+
+static void lp8788_irq_enable(struct irq_data *data)
+{
+	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
+	irqd->enabled[data->hwirq] = 1;
+}
+
+static void lp8788_irq_disable(struct irq_data *data)
+{
+	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
+	irqd->enabled[data->hwirq] = 0;
+}
+
+static void lp8788_irq_bus_lock(struct irq_data *data)
+{
+	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
+
+	mutex_lock(&irqd->irq_lock);
+}
+
+static void lp8788_irq_bus_sync_unlock(struct irq_data *data)
+{
+	struct lp8788_irq_data *irqd = irq_data_get_irq_chip_data(data);
+	enum lp8788_int_id irq = data->hwirq;
+	u8 addr, mask, val;
+
+	addr = _irq_to_enable_addr(irq);
+	mask = _irq_to_mask(irq);
+	val = _irq_to_val(irq, irqd->enabled[irq]);
+
+	lp8788_update_bits(irqd->lp, addr, mask, val);
+
+	mutex_unlock(&irqd->irq_lock);
+}
+
+static struct irq_chip lp8788_irq_chip = {
+	.name			= "lp8788",
+	.irq_enable		= lp8788_irq_enable,
+	.irq_disable		= lp8788_irq_disable,
+	.irq_bus_lock		= lp8788_irq_bus_lock,
+	.irq_bus_sync_unlock	= lp8788_irq_bus_sync_unlock,
+};
+
+static irqreturn_t lp8788_irq_handler(int irq, void *ptr)
+{
+	struct lp8788_irq_data *irqd = ptr;
+	struct lp8788 *lp = irqd->lp;
+	u8 status[NUM_REGS], addr, mask;
+	bool handled;
+	int i;
+
+	if (lp8788_read_multi_bytes(lp, LP8788_INT_1, status, NUM_REGS))
+		return IRQ_NONE;
+
+	for (i = 0 ; i < LP8788_INT_MAX ; i++) {
+		addr = _irq_to_addr(i);
+		mask = _irq_to_mask(i);
+
+		/* reporting only if the irq is enabled */
+		if (status[addr] & mask) {
+			handle_nested_irq(irq_find_mapping(irqd->domain, i));
+			handled = true;
+		}
+	}
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int lp8788_irq_map(struct irq_domain *d, unsigned int virq,
+			irq_hw_number_t hwirq)
+{
+	struct lp8788_irq_data *irqd = d->host_data;
+	struct irq_chip *chip = &lp8788_irq_chip;
+
+	irq_set_chip_data(virq, irqd);
+	irq_set_chip_and_handler(virq, chip, handle_edge_irq);
+	irq_set_nested_thread(virq, 1);
+
+#ifdef CONFIG_ARM
+	set_irq_flags(virq, IRQF_VALID);
+#else
+	irq_set_noprobe(virq);
+#endif
+
+	return 0;
+}
+
+static struct irq_domain_ops lp8788_domain_ops = {
+	.map = lp8788_irq_map,
+};
+
+int lp8788_irq_init(struct lp8788 *lp, int irq)
+{
+	struct lp8788_irq_data *irqd;
+	int ret;
+
+	if (irq <= 0) {
+		dev_warn(lp->dev, "invalid irq number: %d\n", irq);
+		return 0;
+	}
+
+	irqd = devm_kzalloc(lp->dev, sizeof(*irqd), GFP_KERNEL);
+	if (!irqd)
+		return -ENOMEM;
+
+	irqd->lp = lp;
+	irqd->domain = irq_domain_add_linear(lp->dev->of_node, LP8788_INT_MAX,
+					&lp8788_domain_ops, irqd);
+	if (!irqd->domain) {
+		dev_err(lp->dev, "failed to add irq domain err\n");
+		return -EINVAL;
+	}
+
+	lp->irqdm = irqd->domain;
+	mutex_init(&irqd->irq_lock);
+
+	ret = request_threaded_irq(irq, NULL, lp8788_irq_handler,
+				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				"lp8788-irq", irqd);
+	if (ret) {
+		dev_err(lp->dev, "failed to create a thread for IRQ_N\n");
+		return ret;
+	}
+
+	lp->irq = irq;
+
+	return 0;
+}
+
+void lp8788_irq_exit(struct lp8788 *lp)
+{
+	if (lp->irq)
+		free_irq(lp->irq, lp->irqdm);
+}