[PATCH 2/3] misc: aspeed-lpc: Request and enable LPC clock

From: Joel Stanley
Date: Mon Feb 12 2018 - 02:09:22 EST


The LPC device needs to ensure it's clock is enabled before it can do
anything.

In the past the clock was enabled and left running by u-boot, however
Linux now has an upstream clock driver that disables unused clocks.

Tested-by: Lei YU <mine260309@xxxxxxxxx>
Reviewed-by: Andrew Jeffery <andrew@xxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
---
drivers/misc/aspeed-lpc-ctrl.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/aspeed-lpc-ctrl.c b/drivers/misc/aspeed-lpc-ctrl.c
index b5439643f54b..1827b7aa6674 100644
--- a/drivers/misc/aspeed-lpc-ctrl.c
+++ b/drivers/misc/aspeed-lpc-ctrl.c
@@ -7,6 +7,7 @@
* 2 of the License, or (at your option) any later version.
*/

+#include <linux/clk.h>
#include <linux/mfd/syscon.h>
#include <linux/miscdevice.h>
#include <linux/mm.h>
@@ -26,6 +27,7 @@
struct aspeed_lpc_ctrl {
struct miscdevice miscdev;
struct regmap *regmap;
+ struct clk *clk;
phys_addr_t mem_base;
resource_size_t mem_size;
u32 pnor_size;
@@ -221,16 +223,33 @@ static int aspeed_lpc_ctrl_probe(struct platform_device *pdev)
return -ENODEV;
}

+ lpc_ctrl->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(lpc_ctrl->clk)) {
+ dev_err(dev, "couldn't get clock\n");
+ return PTR_ERR(lpc_ctrl->clk);
+ }
+ rc = clk_prepare_enable(lpc_ctrl->clk);
+ if (rc) {
+ dev_err(dev, "couldn't enable clock\n");
+ return rc;
+ }
+
lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
lpc_ctrl->miscdev.name = DEVICE_NAME;
lpc_ctrl->miscdev.fops = &aspeed_lpc_ctrl_fops;
lpc_ctrl->miscdev.parent = dev;
rc = misc_register(&lpc_ctrl->miscdev);
- if (rc)
+ if (rc) {
dev_err(dev, "Unable to register device\n");
- else
- dev_info(dev, "Loaded at %pr\n", &resm);
+ goto err;
+ }
+
+ dev_info(dev, "Loaded at %pr\n", &resm);
+
+ return 0;

+err:
+ clk_disable_unprepare(lpc_ctrl->clk);
return rc;
}

@@ -239,6 +258,7 @@ static int aspeed_lpc_ctrl_remove(struct platform_device *pdev)
struct aspeed_lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);

misc_deregister(&lpc_ctrl->miscdev);
+ clk_disable_unprepare(lpc_ctrl->clk);

return 0;
}
--
2.15.1