spi/mpc52xx-psc-spi: check for valid PSC

This driver calls mpc52xx_set_psc_clkdiv() but doesn't check its return value
to see if the PSC is actually valid for SPI use. Add the check and a hint for
the user.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
index a14e9fdc0065..2193d908cad6 100644
--- a/drivers/spi/mpc52xx_psc_spi.c
+++ b/drivers/spi/mpc52xx_psc_spi.c
@@ -314,11 +314,13 @@ static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
         struct mpc52xx_psc __iomem *psc = mps->psc;
         struct mpc52xx_psc_fifo __iomem *fifo = mps->fifo;
         u32 mclken_div;
-        int ret = 0;
+        int ret;
 
         /* default sysclk is 512MHz */
         mclken_div = (mps->sysclk ? mps->sysclk : 512000000) / MCLK;
-        mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
+        ret = mpc52xx_set_psc_clkdiv(psc_id, mclken_div);
+        if (ret)
+                return ret;
 
         /* Reset the PSC into a known state */
         out_8(&psc->command, MPC52xx_PSC_RST_RX);
@@ -342,7 +344,7 @@ static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)
 
         mps->bits_per_word = 8;
 
-        return ret;
+        return 0;
 }
 
 static irqreturn_t mpc52xx_psc_spi_isr(int irq, void *dev_id)
@@ -411,8 +413,10 @@ static int __init mpc52xx_psc_spi_do_probe(struct device *dev, u32 regaddr,
                 goto free_master;
 
         ret = mpc52xx_psc_spi_port_config(master->bus_num, mps);
-        if (ret < 0)
+        if (ret < 0) {
+                dev_err(dev, "can't configure PSC! Is it capable of SPI?\n");
                 goto free_irq;
+        }
 
         spin_lock_init(&mps->lock);
         init_completion(&mps->done);