serial: msm-geni: don't rely on parent misc device
commit 1b15483deb3f ("misc: add Qualcomm GENI SE QUP device driver")
introduced support for platform-specific oversampling values, necessary
to configure the UART clocks on all platforms at runtime. However it
relies in probing a parent device. Despite the DM_FLAG_PRE_RELOC flag,
this is not done consistently during boot.
Instead, take another approach by relying on ofnode_ helpers to read the
serial engine base address and do the read directly. This fixes early
UART on boards with a non-default oversampling rate.
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/drivers/serial/serial_msm_geni.c b/drivers/serial/serial_msm_geni.c
index b8bc614..0e52e32 100644
--- a/drivers/serial/serial_msm_geni.c
+++ b/drivers/serial/serial_msm_geni.c
@@ -485,12 +485,12 @@
.setbrg = msm_serial_setbrg,
};
-static void geni_set_oversampling(struct udevice *dev)
+static int geni_set_oversampling(struct udevice *dev)
{
struct msm_serial_data *priv = dev_get_priv(dev);
- struct udevice *parent_dev = dev_get_parent(dev);
+ ofnode parent_node = ofnode_get_parent(dev_ofnode(dev));
u32 geni_se_version;
- int ret;
+ fdt_addr_t addr;
priv->oversampling = UART_OVERSAMPLING;
@@ -498,16 +498,20 @@
* It could happen that GENI SE IP is missing in the board's device
* tree or GENI UART node is a direct child of SoC device tree node.
*/
- if (device_get_uclass_id(parent_dev) != UCLASS_MISC)
- return;
+ if (!ofnode_device_is_compatible(parent_node, "qcom,geni-se-qup")) {
+ pr_err("%s: UART node must be a child of geniqup node\n",
+ __func__);
+ return -ENODEV;
+ }
- ret = misc_read(parent_dev, QUP_HW_VER_REG,
- &geni_se_version, sizeof(geni_se_version));
- if (ret != sizeof(geni_se_version))
- return;
+ /* Read the HW_VER register relative to the parents address space */
+ addr = ofnode_get_addr(parent_node);
+ geni_se_version = readl(addr + QUP_HW_VER_REG);
if (geni_se_version >= QUP_SE_VERSION_2_5)
priv->oversampling /= 2;
+
+ return 0;
}
static inline void geni_serial_init(struct udevice *dev)
@@ -552,8 +556,11 @@
static int msm_serial_probe(struct udevice *dev)
{
struct msm_serial_data *priv = dev_get_priv(dev);
+ int ret;
- geni_set_oversampling(dev);
+ ret = geni_set_oversampling(dev);
+ if (ret < 0)
+ return ret;
/* No need to reinitialize the UART after relocation */
if (gd->flags & GD_FLG_RELOC)