mfd: Add WM831x interrupt support

The WM831x includes an interrupt controller managing interrupts for
the various functions on the chip. This patch adds support for the
core interrupt block on the device.

Ideally this would be supported by genirq, particularly for the
GPIOs, but currently genirq is unable to cope with controllers on
interrupt driven buses so we cut'n'paste the generic interface.
Once genirq is able to cope chips like this it should be a case
of filing the prefixes off the code and redoing wm831x-irq.c to
move over.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 569 insertions, 2 deletions

diff --git a/drivers/mfd/wm831x-core.c b/drivers/mfd/wm831x-core.c
index cc1040c9d46c..eb63d22160d1 100644
--- a/drivers/mfd/wm831x-core.c
+++ b/drivers/mfd/wm831x-core.c
@@ -19,6 +19,7 @@
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/pdata.h>
+#include <linux/mfd/wm831x/irq.h>
 
 enum wm831x_parent {
 	WM8310 = 0,
@@ -1189,6 +1190,10 @@ static int wm831x_device_init(struct wm831x *wm831x, unsigned long id, int irq)
 		}
 	}
 
+	ret = wm831x_irq_init(wm831x, irq);
+	if (ret != 0)
+		goto err;
+
 	/* The core device is up, instantiate the subdevices. */
 	switch (parent) {
 	case WM8310:
@@ -1216,19 +1221,21 @@ static int wm831x_device_init(struct wm831x *wm831x, unsigned long id, int irq)
 
 	if (ret != 0) {
 		dev_err(wm831x->dev, "Failed to add children\n");
-		goto err;
+		goto err_irq;
 	}
 
 	if (pdata && pdata->post_init) {
 		ret = pdata->post_init(wm831x);
 		if (ret != 0) {
 			dev_err(wm831x->dev, "post_init() failed: %d\n", ret);
-			goto err;
+			goto err_irq;
 		}
 	}
 
 	return 0;
 
+err_irq:
+	wm831x_irq_exit(wm831x);
 err:
 	mfd_remove_devices(wm831x->dev);
 	kfree(wm831x);
@@ -1238,6 +1245,7 @@ err:
 static void wm831x_device_exit(struct wm831x *wm831x)
 {
 	mfd_remove_devices(wm831x->dev);
+	wm831x_irq_exit(wm831x);
 	kfree(wm831x);
 }
 
diff --git a/drivers/mfd/wm831x-irq.c b/drivers/mfd/wm831x-irq.c
new file mode 100644
index 000000000000..d3015dfb9134
--- /dev/null
+++ b/drivers/mfd/wm831x-irq.c
@@ -0,0 +1,559 @@
+/*
+ * wm831x-irq.c  --  Interrupt controller support for Wolfson WM831x PMICs
+ *
+ * Copyright 2009 Wolfson Microelectronics PLC.
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/interrupt.h>
+
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/pdata.h>
+#include <linux/mfd/wm831x/irq.h>
+
+#include <linux/delay.h>
+
+/*
+ * Since generic IRQs don't currently support interrupt controllers on
+ * interrupt driven buses we don't use genirq but instead provide an
+ * interface that looks very much like the standard ones.  This leads
+ * to some bodges, including storing interrupt handler information in
+ * the static irq_data table we use to look up the data for individual
+ * interrupts, but hopefully won't last too long.
+ */
+
+struct wm831x_irq_data {
+	int primary;
+	int reg;
+	int mask;
+	irq_handler_t handler;
+	void *handler_data;
+};
+
+static struct wm831x_irq_data wm831x_irqs[] = {
+	[WM831X_IRQ_TEMP_THW] = {
+		.primary = WM831X_TEMP_INT,
+		.reg = 1,
+		.mask = WM831X_TEMP_THW_EINT,
+	},
+	[WM831X_IRQ_GPIO_1] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP1_EINT,
+	},
+	[WM831X_IRQ_GPIO_2] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP2_EINT,
+	},
+	[WM831X_IRQ_GPIO_3] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP3_EINT,
+	},
+	[WM831X_IRQ_GPIO_4] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP4_EINT,
+	},
+	[WM831X_IRQ_GPIO_5] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP5_EINT,
+	},
+	[WM831X_IRQ_GPIO_6] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP6_EINT,
+	},
+	[WM831X_IRQ_GPIO_7] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP7_EINT,
+	},
+	[WM831X_IRQ_GPIO_8] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP8_EINT,
+	},
+	[WM831X_IRQ_GPIO_9] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP9_EINT,
+	},
+	[WM831X_IRQ_GPIO_10] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP10_EINT,
+	},
+	[WM831X_IRQ_GPIO_11] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP11_EINT,
+	},
+	[WM831X_IRQ_GPIO_12] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP12_EINT,
+	},
+	[WM831X_IRQ_GPIO_13] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP13_EINT,
+	},
+	[WM831X_IRQ_GPIO_14] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP14_EINT,
+	},
+	[WM831X_IRQ_GPIO_15] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP15_EINT,
+	},
+	[WM831X_IRQ_GPIO_16] = {
+		.primary = WM831X_GP_INT,
+		.reg = 5,
+		.mask = WM831X_GP16_EINT,
+	},
+	[WM831X_IRQ_ON] = {
+		.primary = WM831X_ON_PIN_INT,
+		.reg = 1,
+		.mask = WM831X_ON_PIN_EINT,
+	},
+	[WM831X_IRQ_PPM_SYSLO] = {
+		.primary = WM831X_PPM_INT,
+		.reg = 1,
+		.mask = WM831X_PPM_SYSLO_EINT,
+	},
+	[WM831X_IRQ_PPM_PWR_SRC] = {
+		.primary = WM831X_PPM_INT,
+		.reg = 1,
+		.mask = WM831X_PPM_PWR_SRC_EINT,
+	},
+	[WM831X_IRQ_PPM_USB_CURR] = {
+		.primary = WM831X_PPM_INT,
+		.reg = 1,
+		.mask = WM831X_PPM_USB_CURR_EINT,
+	},
+	[WM831X_IRQ_WDOG_TO] = {
+		.primary = WM831X_WDOG_INT,
+		.reg = 1,
+		.mask = WM831X_WDOG_TO_EINT,
+	},
+	[WM831X_IRQ_RTC_PER] = {
+		.primary = WM831X_RTC_INT,
+		.reg = 1,
+		.mask = WM831X_RTC_PER_EINT,
+	},
+	[WM831X_IRQ_RTC_ALM] = {
+		.primary = WM831X_RTC_INT,
+		.reg = 1,
+		.mask = WM831X_RTC_ALM_EINT,
+	},
+	[WM831X_IRQ_CHG_BATT_HOT] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_BATT_HOT_EINT,
+	},
+	[WM831X_IRQ_CHG_BATT_COLD] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_BATT_COLD_EINT,
+	},
+	[WM831X_IRQ_CHG_BATT_FAIL] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_BATT_FAIL_EINT,
+	},
+	[WM831X_IRQ_CHG_OV] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_OV_EINT,
+	},
+	[WM831X_IRQ_CHG_END] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_END_EINT,
+	},
+	[WM831X_IRQ_CHG_TO] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_TO_EINT,
+	},
+	[WM831X_IRQ_CHG_MODE] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_MODE_EINT,
+	},
+	[WM831X_IRQ_CHG_START] = {
+		.primary = WM831X_CHG_INT,
+		.reg = 2,
+		.mask = WM831X_CHG_START_EINT,
+	},
+	[WM831X_IRQ_TCHDATA] = {
+		.primary = WM831X_TCHDATA_INT,
+		.reg = 1,
+		.mask = WM831X_TCHDATA_EINT,
+	},
+	[WM831X_IRQ_TCHPD] = {
+		.primary = WM831X_TCHPD_INT,
+		.reg = 1,
+		.mask = WM831X_TCHPD_EINT,
+	},
+	[WM831X_IRQ_AUXADC_DATA] = {
+		.primary = WM831X_AUXADC_INT,
+		.reg = 1,
+		.mask = WM831X_AUXADC_DATA_EINT,
+	},
+	[WM831X_IRQ_AUXADC_DCOMP1] = {
+		.primary = WM831X_AUXADC_INT,
+		.reg = 1,
+		.mask = WM831X_AUXADC_DCOMP1_EINT,
+	},
+	[WM831X_IRQ_AUXADC_DCOMP2] = {
+		.primary = WM831X_AUXADC_INT,
+		.reg = 1,
+		.mask = WM831X_AUXADC_DCOMP2_EINT,
+	},
+	[WM831X_IRQ_AUXADC_DCOMP3] = {
+		.primary = WM831X_AUXADC_INT,
+		.reg = 1,
+		.mask = WM831X_AUXADC_DCOMP3_EINT,
+	},
+	[WM831X_IRQ_AUXADC_DCOMP4] = {
+		.primary = WM831X_AUXADC_INT,
+		.reg = 1,
+		.mask = WM831X_AUXADC_DCOMP4_EINT,
+	},
+	[WM831X_IRQ_CS1] = {
+		.primary = WM831X_CS_INT,
+		.reg = 2,
+		.mask = WM831X_CS1_EINT,
+	},
+	[WM831X_IRQ_CS2] = {
+		.primary = WM831X_CS_INT,
+		.reg = 2,
+		.mask = WM831X_CS2_EINT,
+	},
+	[WM831X_IRQ_HC_DC1] = {
+		.primary = WM831X_HC_INT,
+		.reg = 4,
+		.mask = WM831X_HC_DC1_EINT,
+	},
+	[WM831X_IRQ_HC_DC2] = {
+		.primary = WM831X_HC_INT,
+		.reg = 4,
+		.mask = WM831X_HC_DC2_EINT,
+	},
+	[WM831X_IRQ_UV_LDO1] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO1_EINT,
+	},
+	[WM831X_IRQ_UV_LDO2] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO2_EINT,
+	},
+	[WM831X_IRQ_UV_LDO3] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO3_EINT,
+	},
+	[WM831X_IRQ_UV_LDO4] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO4_EINT,
+	},
+	[WM831X_IRQ_UV_LDO5] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO5_EINT,
+	},
+	[WM831X_IRQ_UV_LDO6] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO6_EINT,
+	},
+	[WM831X_IRQ_UV_LDO7] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO7_EINT,
+	},
+	[WM831X_IRQ_UV_LDO8] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO8_EINT,
+	},
+	[WM831X_IRQ_UV_LDO9] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO9_EINT,
+	},
+	[WM831X_IRQ_UV_LDO10] = {
+		.primary = WM831X_UV_INT,
+		.reg = 3,
+		.mask = WM831X_UV_LDO10_EINT,
+	},
+	[WM831X_IRQ_UV_DC1] = {
+		.primary = WM831X_UV_INT,
+		.reg = 4,
+		.mask = WM831X_UV_DC1_EINT,
+	},
+	[WM831X_IRQ_UV_DC2] = {
+		.primary = WM831X_UV_INT,
+		.reg = 4,
+		.mask = WM831X_UV_DC2_EINT,
+	},
+	[WM831X_IRQ_UV_DC3] = {
+		.primary = WM831X_UV_INT,
+		.reg = 4,
+		.mask = WM831X_UV_DC3_EINT,
+	},
+	[WM831X_IRQ_UV_DC4] = {
+		.primary = WM831X_UV_INT,
+		.reg = 4,
+		.mask = WM831X_UV_DC4_EINT,
+	},
+};
+
+static inline int irq_data_to_status_reg(struct wm831x_irq_data *irq_data)
+{
+	return WM831X_INTERRUPT_STATUS_1 - 1 + irq_data->reg;
+}
+
+static inline int irq_data_to_mask_reg(struct wm831x_irq_data *irq_data)
+{
+	return WM831X_INTERRUPT_STATUS_1_MASK - 1 + irq_data->reg;
+}
+
+static void __wm831x_enable_irq(struct wm831x *wm831x, int irq)
+{
+	struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
+
+	wm831x->irq_masks[irq_data->reg - 1] &= ~irq_data->mask;
+	wm831x_reg_write(wm831x, irq_data_to_mask_reg(irq_data),
+			 wm831x->irq_masks[irq_data->reg - 1]);
+}
+
+void wm831x_enable_irq(struct wm831x *wm831x, int irq)
+{
+	mutex_lock(&wm831x->irq_lock);
+	__wm831x_enable_irq(wm831x, irq);
+	mutex_unlock(&wm831x->irq_lock);
+}
+EXPORT_SYMBOL_GPL(wm831x_enable_irq);
+
+static void __wm831x_disable_irq(struct wm831x *wm831x, int irq)
+{
+	struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
+
+	wm831x->irq_masks[irq_data->reg - 1] |= irq_data->mask;
+	wm831x_reg_write(wm831x, irq_data_to_mask_reg(irq_data),
+			 wm831x->irq_masks[irq_data->reg - 1]);
+}
+
+void wm831x_disable_irq(struct wm831x *wm831x, int irq)
+{
+	mutex_lock(&wm831x->irq_lock);
+	__wm831x_disable_irq(wm831x, irq);
+	mutex_unlock(&wm831x->irq_lock);
+}
+EXPORT_SYMBOL_GPL(wm831x_disable_irq);
+
+int wm831x_request_irq(struct wm831x *wm831x,
+		       unsigned int irq, irq_handler_t handler,
+		       unsigned long flags, const char *name,
+		       void *dev)
+{
+	int ret = 0;
+
+	if (irq < 0 || irq >= WM831X_NUM_IRQS)
+		return -EINVAL;
+
+	mutex_lock(&wm831x->irq_lock);
+
+	if (wm831x_irqs[irq].handler) {
+		dev_err(wm831x->dev, "Already have handler for IRQ %d\n", irq);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	wm831x_irqs[irq].handler = handler;
+	wm831x_irqs[irq].handler_data = dev;
+
+	__wm831x_enable_irq(wm831x, irq);
+
+out:
+	mutex_unlock(&wm831x->irq_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(wm831x_request_irq);
+
+void wm831x_free_irq(struct wm831x *wm831x, unsigned int irq, void *data)
+{
+	if (irq < 0 || irq >= WM831X_NUM_IRQS)
+		return;
+
+	mutex_lock(&wm831x->irq_lock);
+
+	wm831x_irqs[irq].handler = NULL;
+	wm831x_irqs[irq].handler_data = NULL;
+
+	__wm831x_disable_irq(wm831x, irq);
+
+	mutex_unlock(&wm831x->irq_lock);
+}
+EXPORT_SYMBOL_GPL(wm831x_free_irq);
+
+
+static void wm831x_handle_irq(struct wm831x *wm831x, int irq, int status)
+{
+	struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
+
+	if (irq_data->handler) {
+		irq_data->handler(irq, irq_data->handler_data);
+		wm831x_reg_write(wm831x, irq_data_to_status_reg(irq_data),
+				 irq_data->mask);
+	} else {
+		dev_err(wm831x->dev, "Unhandled IRQ %d, masking\n", irq);
+		__wm831x_disable_irq(wm831x, irq);
+	}
+}
+
+/* Main interrupt handling occurs in a workqueue since we need
+ * interrupts enabled to interact with the chip. */
+static void wm831x_irq_worker(struct work_struct *work)
+{
+	struct wm831x *wm831x = container_of(work, struct wm831x, irq_work);
+	unsigned int i;
+	int primary;
+	int status_regs[5];
+	int read[5] = { 0 };
+	int *status;
+
+	primary = wm831x_reg_read(wm831x, WM831X_SYSTEM_INTERRUPTS);
+	if (primary < 0) {
+		dev_err(wm831x->dev, "Failed to read system interrupt: %d\n",
+			primary);
+		goto out;
+	}
+
+	mutex_lock(&wm831x->irq_lock);
+
+	for (i = 0; i < ARRAY_SIZE(wm831x_irqs); i++) {
+		int offset = wm831x_irqs[i].reg - 1;
+
+		if (!(primary & wm831x_irqs[i].primary))
+			continue;
+
+		status = &status_regs[offset];
+
+		/* Hopefully there should only be one register to read
+		 * each time otherwise we ought to do a block read. */
+		if (!read[offset]) {
+			*status = wm831x_reg_read(wm831x,
+				     irq_data_to_status_reg(&wm831x_irqs[i]));
+			if (*status < 0) {
+				dev_err(wm831x->dev,
+					"Failed to read IRQ status: %d\n",
+					*status);
+				goto out_lock;
+			}
+
+			/* Mask out the disabled IRQs */
+			*status &= ~wm831x->irq_masks[offset];
+			read[offset] = 1;
+		}
+
+		if (*status & wm831x_irqs[i].mask)
+			wm831x_handle_irq(wm831x, i, *status);
+	}
+
+out_lock:
+	mutex_unlock(&wm831x->irq_lock);
+out:
+	enable_irq(wm831x->irq);
+}
+
+
+static irqreturn_t wm831x_cpu_irq(int irq, void *data)
+{
+	struct wm831x *wm831x = data;
+
+	/* Shut the interrupt to the CPU up and schedule the actual
+	 * handler; we can't check that the IRQ is asserted. */
+	disable_irq_nosync(irq);
+
+	queue_work(wm831x->irq_wq, &wm831x->irq_work);
+
+	return IRQ_HANDLED;
+}
+
+int wm831x_irq_init(struct wm831x *wm831x, int irq)
+{
+	int i, ret;
+
+	if (!irq) {
+		dev_warn(wm831x->dev,
+			 "No interrupt specified - functionality limited\n");
+		return 0;
+	}
+
+
+	wm831x->irq_wq = create_singlethread_workqueue("wm831x-irq");
+	if (!wm831x->irq_wq) {
+		dev_err(wm831x->dev, "Failed to allocate IRQ worker\n");
+		return -ESRCH;
+	}
+
+	wm831x->irq = irq;
+	mutex_init(&wm831x->irq_lock);
+	INIT_WORK(&wm831x->irq_work, wm831x_irq_worker);
+
+	/* Mask the individual interrupt sources */
+	for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks); i++) {
+		wm831x->irq_masks[i] = 0xffff;
+		wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1_MASK + i,
+				 0xffff);
+	}
+
+	/* Enable top level interrupts, we mask at secondary level */
+	wm831x_reg_write(wm831x, WM831X_SYSTEM_INTERRUPTS_MASK, 0);
+
+	/* We're good to go.  We set IRQF_SHARED since there's a
+	 * chance the driver will interoperate with another driver but
+	 * the need to disable the IRQ while handing via I2C/SPI means
+	 * that this may break and performance will be impacted.  If
+	 * this does happen it's a hardware design issue and the only
+	 * other alternative would be polling.
+	 */
+	ret = request_irq(irq, wm831x_cpu_irq, IRQF_TRIGGER_LOW | IRQF_SHARED,
+			  "wm831x", wm831x);
+	if (ret != 0) {
+		dev_err(wm831x->dev, "Failed to request IRQ %d: %d\n",
+			irq, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+void wm831x_irq_exit(struct wm831x *wm831x)
+{
+	if (wm831x->irq)
+		free_irq(wm831x->irq, wm831x);
+}