mfd: Reentrance and revamp ab8500 gpadc fetching interface

This revamps the interface so that AB8500 GPADCs are fetched by
name. Probed GPADCs are added to a list and this list is searched
for a matching GPADC. This makes it possible to have multiple
AB8500 GPADC instances instead of it being a singleton, and
rids the need to keep a GPADC pointer around in the core AB8500
MFD struct.

Currently the match is made to the device name which is by default
numbered from the device instance such as "ab8500-gpadc.0" but
by using the .init_name field of the device a more intiutive
naming for the GPADC blocks can be achieved if desired.

Signed-off-by: Daniel Willerud <daniel.willerud@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 70 insertions, 45 deletions

diff --git a/drivers/mfd/ab8500-gpadc.c b/drivers/mfd/ab8500-gpadc.c
index f60f71f4b473..178cbc55caea 100644
--- a/drivers/mfd/ab8500-gpadc.c
+++ b/drivers/mfd/ab8500-gpadc.c
@@ -3,6 +3,7 @@
  *
  * License Terms: GNU General Public License v2
  * Author: Arun R Murthy <arun.murthy@stericsson.com>
+ * Author: Daniel Willerud <daniel.willerud@stericsson.com>
  */
 #include <linux/init.h>
 #include <linux/module.h>
@@ -15,6 +16,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/list.h>
 #include <linux/mfd/ab8500.h>
 #include <linux/mfd/abx500.h>
 #include <linux/mfd/ab8500/ab8500-gpadc.h>
@@ -48,21 +50,41 @@
 /**
  * struct ab8500_gpadc - ab8500 GPADC device information
  * @dev:                        pointer to the struct device
- * @parent:                     pointer to the parent device structure ab8500
+ * @node:                       a list of AB8500 GPADCs, hence prepared for
+                                reentrance
  * @ab8500_gpadc_complete:      pointer to the struct completion, to indicate
  *                              the completion of gpadc conversion
  * @ab8500_gpadc_lock:          structure of type mutex
  * @regu:                       pointer to the struct regulator
  * @irq:                        interrupt number that is used by gpadc
  */
-static struct ab8500_gpadc {
+struct ab8500_gpadc {
         struct device *dev;
-        struct ab8500 *parent;
+        struct list_head node;
         struct completion ab8500_gpadc_complete;
         struct mutex ab8500_gpadc_lock;
         struct regulator *regu;
         int irq;
-} *di;
+};
+
+static LIST_HEAD(ab8500_gpadc_list);
+
+/**
+ * ab8500_gpadc_get() - returns a reference to the primary AB8500 GPADC
+ * (i.e. the first GPADC in the instance list)
+ */
+struct ab8500_gpadc *ab8500_gpadc_get(char *name)
+{
+        struct ab8500_gpadc *gpadc;
+
+        list_for_each_entry(gpadc, &ab8500_gpadc_list, node) {
+                if (!strcmp(name, dev_name(gpadc->dev)))
+                    return gpadc;
+        }
+
+        return ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(ab8500_gpadc_get);
 
 /**
  * ab8500_gpadc_convert() - gpadc conversion
@@ -72,24 +94,24 @@ static struct ab8500_gpadc {
  * data. Thereafter calibration has to be made to obtain the
  * data in the required quantity measurement.
  */
-int ab8500_gpadc_convert(u8 input)
+int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
 {
         int ret;
         u16 data = 0;
         int looplimit = 0;
         u8 val, low_data, high_data;
 
-        if (!di)
+        if (!gpadc)
                 return -ENODEV;
 
-        mutex_lock(&di->ab8500_gpadc_lock);
+        mutex_lock(&gpadc->ab8500_gpadc_lock);
         /* Enable VTVout LDO this is required for GPADC */
-        regulator_enable(di->regu);
+        regulator_enable(gpadc->regu);
 
         /* Check if ADC is not busy, lock and proceed */
         do {
-                ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC,
-                        AB8500_GPADC_STAT_REG, &val);
+                ret = abx500_get_register_interruptible(gpadc->dev,
+                        AB8500_GPADC, AB8500_GPADC_STAT_REG, &val);
                 if (ret < 0)
                         goto out;
                 if (!(val & GPADC_BUSY))
@@ -97,75 +119,76 @@ int ab8500_gpadc_convert(u8 input)
                 msleep(10);
         } while (++looplimit < 10);
         if (looplimit >= 10 && (val & GPADC_BUSY)) {
-                dev_err(di->dev, "gpadc_conversion: GPADC busy");
+                dev_err(gpadc->dev, "gpadc_conversion: GPADC busy");
                 ret = -EINVAL;
                 goto out;
         }
 
         /* Enable GPADC */
-        ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC,
-                AB8500_GPADC_CTRL1_REG, EN_GPADC, EN_GPADC);
+        ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
+                AB8500_GPADC, AB8500_GPADC_CTRL1_REG, EN_GPADC, EN_GPADC);
         if (ret < 0) {
-                dev_err(di->dev, "gpadc_conversion: enable gpadc failed\n");
+                dev_err(gpadc->dev, "gpadc_conversion: enable gpadc failed\n");
                 goto out;
         }
         /* Select the input source and set average samples to 16 */
-        ret = abx500_set_register_interruptible(di->dev, AB8500_GPADC,
+        ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_CTRL2_REG, (input | SW_AVG_16));
         if (ret < 0) {
-                dev_err(di->dev,
+                dev_err(gpadc->dev,
                         "gpadc_conversion: set avg samples failed\n");
                 goto out;
         }
         /* Enable ADC, Buffering and select rising edge, start Conversion */
-        ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC,
-                AB8500_GPADC_CTRL1_REG, EN_BUF, EN_BUF);
+        ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
+                AB8500_GPADC, AB8500_GPADC_CTRL1_REG, EN_BUF, EN_BUF);
         if (ret < 0) {
-                dev_err(di->dev,
+                dev_err(gpadc->dev,
                         "gpadc_conversion: select falling edge failed\n");
                 goto out;
         }
-        ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC,
-                AB8500_GPADC_CTRL1_REG, ADC_SW_CONV, ADC_SW_CONV);
+        ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
+                AB8500_GPADC, AB8500_GPADC_CTRL1_REG, ADC_SW_CONV, ADC_SW_CONV);
         if (ret < 0) {
-                dev_err(di->dev,
+                dev_err(gpadc->dev,
                         "gpadc_conversion: start s/w conversion failed\n");
                 goto out;
         }
         /* wait for completion of conversion */
-        if (!wait_for_completion_timeout(&di->ab8500_gpadc_complete, 2*HZ)) {
-                dev_err(di->dev,
+        if (!wait_for_completion_timeout(&gpadc->ab8500_gpadc_complete, 2*HZ)) {
+                dev_err(gpadc->dev,
                         "timeout: didnt recieve GPADC conversion interrupt\n");
                 ret = -EINVAL;
                 goto out;
         }
 
         /* Read the converted RAW data */
-        ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC,
+        ret = abx500_get_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_MANDATAL_REG, &low_data);
         if (ret < 0) {
-                dev_err(di->dev, "gpadc_conversion: read low data failed\n");
+                dev_err(gpadc->dev, "gpadc_conversion: read low data failed\n");
                 goto out;
         }
 
-        ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC,
+        ret = abx500_get_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_MANDATAH_REG, &high_data);
         if (ret < 0) {
-                dev_err(di->dev, "gpadc_conversion: read high data failed\n");
+                dev_err(gpadc->dev,
+                        "gpadc_conversion: read high data failed\n");
                 goto out;
         }
 
         data = (high_data << 8) | low_data;
         /* Disable GPADC */
-        ret = abx500_set_register_interruptible(di->dev, AB8500_GPADC,
+        ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_CTRL1_REG, DIS_GPADC);
         if (ret < 0) {
-                dev_err(di->dev, "gpadc_conversion: disable gpadc failed\n");
+                dev_err(gpadc->dev, "gpadc_conversion: disable gpadc failed\n");
                 goto out;
         }
         /* Disable VTVout LDO this is required for GPADC */
-        regulator_disable(di->regu);
-        mutex_unlock(&di->ab8500_gpadc_lock);
+        regulator_disable(gpadc->regu);
+        mutex_unlock(&gpadc->ab8500_gpadc_lock);
         return data;
 
 out:
@@ -175,12 +198,12 @@ out:
          * GPADC status register to go low. In V1.1 there wait_for_completion
          * seems to timeout when waiting for an interrupt.. Not seen in V2.0
          */
-        (void) abx500_set_register_interruptible(di->dev, AB8500_GPADC,
+        (void) abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_CTRL1_REG, DIS_GPADC);
-        regulator_disable(di->regu);
-        mutex_unlock(&di->ab8500_gpadc_lock);
-        dev_err(di->dev, "gpadc_conversion: Failed to AD convert channel %d\n",
-                input);
+        regulator_disable(gpadc->regu);
+        mutex_unlock(&gpadc->ab8500_gpadc_lock);
+        dev_err(gpadc->dev,
+                "gpadc_conversion: Failed to AD convert channel %d\n", input);
         return ret;
 }
 EXPORT_SYMBOL(ab8500_gpadc_convert);
@@ -195,9 +218,9 @@ EXPORT_SYMBOL(ab8500_gpadc_convert);
  * can be read from the registers.
  * Returns IRQ status(IRQ_HANDLED)
  */
-static irqreturn_t ab8500_bm_gpswadcconvend_handler(int irq, void *_di)
+static irqreturn_t ab8500_bm_gpswadcconvend_handler(int irq, void *_gpadc)
 {
-        struct ab8500_gpadc *gpadc = _di;
+        struct ab8500_gpadc *gpadc = _gpadc;
 
         complete(&gpadc->ab8500_gpadc_complete);
 
@@ -215,16 +238,16 @@ static int __devinit ab8500_gpadc_probe(struct platform_device *pdev)
                 return -ENOMEM;
         }
 
-        gpadc->parent = dev_get_drvdata(pdev->dev.parent);
         gpadc->irq = platform_get_irq_byname(pdev, "SW_CONV_END");
         if (gpadc->irq < 0) {
-                dev_err(gpadc->dev, "failed to get platform irq-%d\n", di->irq);
+                dev_err(gpadc->dev, "failed to get platform irq-%d\n",
+                        gpadc->irq);
                 ret = gpadc->irq;
                 goto fail;
         }
 
         gpadc->dev = &pdev->dev;
-        mutex_init(&di->ab8500_gpadc_lock);
+        mutex_init(&gpadc->ab8500_gpadc_lock);
 
         /* Initialize completion used to notify completion of conversion */
         init_completion(&gpadc->ab8500_gpadc_complete);
@@ -246,7 +269,7 @@ static int __devinit ab8500_gpadc_probe(struct platform_device *pdev)
                 dev_err(gpadc->dev, "failed to get vtvout LDO\n");
                 goto fail;
         }
-        di = gpadc;
+        list_add_tail(&gpadc->node, &ab8500_gpadc_list);
         dev_dbg(gpadc->dev, "probe success\n");
         return 0;
 fail:
@@ -259,8 +282,10 @@ static int __devexit ab8500_gpadc_remove(struct platform_device *pdev)
 {
         struct ab8500_gpadc *gpadc = platform_get_drvdata(pdev);
 
+        /* remove this gpadc entry from the list */
+        list_del(&gpadc->node);
         /* remove interrupt  - completion of Sw ADC conversion */
-        free_irq(gpadc->irq, di);
+        free_irq(gpadc->irq, gpadc);
         /* disable VTVout LDO that is being used by GPADC */
         regulator_put(gpadc->regu);
         kfree(gpadc);
@@ -291,6 +316,6 @@ subsys_initcall_sync(ab8500_gpadc_init);
 module_exit(ab8500_gpadc_exit);
 
 MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Arun R Murthy");
+MODULE_AUTHOR("Arun R Murthy, Daniel Willerud");
 MODULE_ALIAS("platform:ab8500_gpadc");
 MODULE_DESCRIPTION("AB8500 GPADC driver");