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>

diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
index a14e9fd..2193d90 100644 (file)
--- 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);