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path: root/drivers/mfd/sm501.c
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Diffstat (limited to 'drivers/mfd/sm501.c')
-rw-r--r--drivers/mfd/sm501.c33
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
index 3a0ecfc404e..e14d70e0741 100644
--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -855,6 +855,24 @@ static void sm501_init_regs(struct sm501_devdata *sm,
dev_info(sm->dev, "setting MCLK to %ld\n", init->mclk);
sm501_set_clock(sm->dev, SM501_CLOCK_MCLK, init->mclk);
}
+
+}
+
+/* Check the PLL sources for the M1CLK and M1XCLK
+ *
+ * If the M1CLK and M1XCLKs are not sourced from the same PLL, then
+ * there is a risk (see errata AB-5) that the SM501 will cease proper
+ * function. If this happens, then it is likely the SM501 will
+ * hang the system.
+*/
+
+static int sm501_check_clocks(struct sm501_devdata *sm)
+{
+ unsigned long pwrmode = readl(sm->regs + SM501_CURRENT_CLOCK);
+ unsigned long msrc = (pwrmode & SM501_POWERMODE_M_SRC);
+ unsigned long m1src = (pwrmode & SM501_POWERMODE_M1_SRC);
+
+ return ((msrc == 0 && m1src != 0) || (msrc != 0 && m1src == 0));
}
static unsigned int sm501_mem_local[] = {
@@ -911,6 +929,13 @@ static int sm501_init_dev(struct sm501_devdata *sm)
}
}
+ ret = sm501_check_clocks(sm);
+ if (ret) {
+ dev_err(sm->dev, "M1X and M clocks sourced from different "
+ "PLLs\n");
+ return -EINVAL;
+ }
+
/* always create a framebuffer */
sm501_register_display(sm, &mem_avail);
@@ -1048,8 +1073,12 @@ static struct sm501_initdata sm501_pci_initdata = {
},
.devices = SM501_USE_ALL,
- .mclk = 100 * MHZ,
- .m1xclk = 160 * MHZ,
+
+ /* Errata AB-3 says that 72MHz is the fastest available
+ * for 33MHZ PCI with proper bus-mastering operation */
+
+ .mclk = 72 * MHZ,
+ .m1xclk = 144 * MHZ,
};
static struct sm501_platdata_fbsub sm501_pdata_fbsub = {