ARM: S3C: Add ADC synchronous read call.

To add HWMON support, we need a synchronous read() call that blocks
until completion. Add the client that is being service to the select
and convert callbacks to make the code easier.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 53 insertions, 11 deletions

diff --git a/arch/arm/plat-s3c24xx/adc.c b/arch/arm/plat-s3c24xx/adc.c
index ee1baf11ad9e..11117a7ba911 100644
--- a/arch/arm/plat-s3c24xx/adc.c
+++ b/arch/arm/plat-s3c24xx/adc.c
@@ -39,13 +39,16 @@
 struct s3c_adc_client {
         struct platform_device  *pdev;
         struct list_head         pend;
+        wait_queue_head_t       *wait;
 
         unsigned int             nr_samples;
+        int                      result;
         unsigned char            is_ts;
         unsigned char            channel;
 
-        void    (*select_cb)(unsigned selected);
-        void    (*convert_cb)(unsigned val1, unsigned val2,
+        void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
+        void    (*convert_cb)(struct s3c_adc_client *c,
+                              unsigned val1, unsigned val2,
                               unsigned *samples_left);
 };
 
@@ -81,7 +84,7 @@ static inline void s3c_adc_select(struct adc_device *adc,
 {
         unsigned con = readl(adc->regs + S3C2410_ADCCON);
 
-        client->select_cb(1);
+        client->select_cb(client, 1);
 
         con &= ~S3C2410_ADCCON_MUXMASK;
         con &= ~S3C2410_ADCCON_STDBM;
@@ -153,25 +156,61 @@ int s3c_adc_start(struct s3c_adc_client *client,
 }
 EXPORT_SYMBOL_GPL(s3c_adc_start);
 
-static void s3c_adc_default_select(unsigned select)
+static void s3c_convert_done(struct s3c_adc_client *client,
+                             unsigned v, unsigned u, unsigned *left)
+{
+        client->result = v;
+        wake_up(client->wait);
+}
+
+int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
+{
+        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
+        int ret;
+
+        client->convert_cb = s3c_convert_done;
+        client->wait = &wake;
+        client->result = -1;
+
+        ret = s3c_adc_start(client, ch, 1);
+        if (ret < 0)
+                goto err;
+
+        ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
+        if (client->result < 0) {
+                ret = -ETIMEDOUT;
+                goto err;
+        }
+
+        client->convert_cb = NULL;
+        return client->result;
+
+err:
+        return ret;
+}
+EXPORT_SYMBOL_GPL(s3c_adc_convert);
+
+static void s3c_adc_default_select(struct s3c_adc_client *client,
+                                   unsigned select)
 {
 }
 
 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
-                                        void (*select)(unsigned int selected),
-                                        void (*conv)(unsigned d0, unsigned d1,
+                                        void (*select)(struct s3c_adc_client *client,
+                                                       unsigned int selected),
+                                        void (*conv)(struct s3c_adc_client *client,
+                                                     unsigned d0, unsigned d1,
                                                      unsigned *samples_left),
                                         unsigned int is_ts)
 {
         struct s3c_adc_client *client;
 
         WARN_ON(!pdev);
-        WARN_ON(!conv);
 
         if (!select)
                 select = s3c_adc_default_select;
 
-        if (!conv || !pdev)
+        if (!pdev)
                 return ERR_PTR(-EINVAL);
 
         client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
@@ -230,16 +269,19 @@ static irqreturn_t s3c_adc_irq(int irq, void *pw)
         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 
         client->nr_samples--;
-        (client->convert_cb)(data0 & 0x3ff, data1 & 0x3ff, &client->nr_samples);
+
+        if (client->convert_cb)
+                (client->convert_cb)(client, data0 & 0x3ff, data1 & 0x3ff,
+                                     &client->nr_samples);
 
         if (client->nr_samples > 0) {
                 /* fire another conversion for this */
 
-                client->select_cb(1);
+                client->select_cb(client, 1);
                 s3c_adc_convert(adc);
         } else {
                 local_irq_save(flags);
-                (client->select_cb)(0);
+                (client->select_cb)(client, 0);
                 adc->cur = NULL;
 
                 s3c_adc_try(adc);