From: Felipe Balbi <felipe.balbi@xxxxxxxxx>
gpio_direction_input might fail and we have
to handle that possibility. While at that,
also add the device pointer to struct cbus_host
and use that for printing debugging messages and
make cbus_receive_bit return int.
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxx>
---
drivers/cbus/cbus.c | 68 +++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 53 insertions(+), 15 deletions(-)
diff --git a/drivers/cbus/cbus.c b/drivers/cbus/cbus.c
index 285bf23..0791251 100644
--- a/drivers/cbus/cbus.c
+++ b/drivers/cbus/cbus.c
@@ -47,35 +47,44 @@
struct cbus_host {
/* host lock */
- spinlock_t lock;
+ spinlock_t lock;
- int clk_gpio;
- int dat_gpio;
- int sel_gpio;
+ struct device *dev;
+
+ int clk_gpio;
+ int dat_gpio;
+ int sel_gpio;
};
static struct cbus_host *cbus_host;
-static void cbus_send_bit(struct cbus_host *host, int bit, int set_to_input)
+static int cbus_send_bit(struct cbus_host *host, int bit, int set_to_input)
{
+ int ret = 0;
+
gpio_set_value(host->dat_gpio, bit ? 1 : 0);
gpio_set_value(host->clk_gpio, 1);
/* The data bit is read on the rising edge of CLK */
if (set_to_input)
- gpio_direction_input(host->dat_gpio);
+ ret = gpio_direction_input(host->dat_gpio);
gpio_set_value(host->clk_gpio, 0);
+
+ return ret;
}
-static u8 cbus_receive_bit(struct cbus_host *host)
+static int cbus_receive_bit(struct cbus_host *host)
{
- u8 ret;
+ int ret;
gpio_set_value(host->clk_gpio, 1);
ret = gpio_get_value(host->dat_gpio);
+ if (ret < 0)
+ goto out;
gpio_set_value(host->clk_gpio, 0);
+out:
return ret;
}
@@ -83,6 +92,7 @@ static int cbus_transfer(struct cbus_host *host, unsigned rw, unsigned dev,
unsigned reg, unsigned data)
{
unsigned long flags;
+ int ret = 0;
int i;
/* We don't want interrupts disturbing our transfer */
@@ -95,11 +105,20 @@ static int cbus_transfer(struct cbus_host *host, unsigned rw, unsigned dev,
gpio_direction_output(host->dat_gpio, 1);
/* Send the device address */
- for (i = 3; i > 0; i--)
- cbus_send_bit(host, dev & (1 << (i - 1)), 0);
+ for (i = 3; i > 0; i--) {
+ ret = cbus_send_bit(host, dev & (1 << (i - 1)), 0);
+ if (ret < 0) {
+ dev_dbg(host->dev, "failed sending device addr\n");
+ goto out;
+ }
+ }
/* Send the rw flag */
- cbus_send_bit(host, rw, 0);
+ ret = cbus_send_bit(host, rw, 0);
+ if (ret < 0) {
+ dev_dbg(host->dev, "failed sending read/write flag\n");
+ goto out;
+ }
/* Send the register address */
for (i = 5; i > 0; i--) {
@@ -108,21 +127,38 @@ static int cbus_transfer(struct cbus_host *host, unsigned rw, unsigned dev,
if (rw && i == 1)
set_to_input = 1;
- cbus_send_bit(host, reg & (1 << (i - 1)), set_to_input);
+ ret = cbus_send_bit(host, reg & (1 << (i - 1)), set_to_input);
+ if (ret < 0) {
+ dev_dbg(host->dev, "failed sending register addr\n");
+ goto out;
+ }
}
if (!rw) {
- for (i = 16; i > 0; i--)
- cbus_send_bit(host, data & (1 << (i - 1)), 0);
+ for (i = 16; i > 0; i--) {
+ ret = cbus_send_bit(host, data & (1 << (i - 1)), 0);
+ if (ret < 0) {
+ dev_dbg(host->dev, "failed sending data\n");
+ goto out;
+ }
+ }
} else {
gpio_set_value(host->clk_gpio, 1);
for (i = 16; i > 0; i--) {
u8 bit = cbus_receive_bit(host);
+ if (bit < 0) {
+ dev_dbg(host->dev, "failed receiving data\n");
+ goto out;
+ }
+
if (bit)
data |= 1 << (i - 1);
}
+
+ /* return the data received */
+ ret = data;
}
/* Indicate end of transfer, SEL goes up until next transfer */
@@ -130,9 +166,10 @@ static int cbus_transfer(struct cbus_host *host, unsigned rw, unsigned dev,
gpio_set_value(host->clk_gpio, 1);
gpio_set_value(host->clk_gpio, 0);
+out:
spin_unlock_irqrestore(&host->lock, flags);
- return data;
+ return ret;
}
/*
@@ -168,6 +205,7 @@ static int __init cbus_bus_probe(struct platform_device *pdev)
chost->clk_gpio = pdata->clk_gpio;
chost->dat_gpio = pdata->dat_gpio;
chost->sel_gpio = pdata->sel_gpio;
+ chost->dev = &pdev->dev;
ret = gpio_request(chost->clk_gpio, "CBUS clk");
if (ret < 0)
--
1.7.0.rc0.33.g7c3932
--
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