- Add support of Common Clock Framework for Uartlite driver
- Add support for suspend and resume operations
Signed-off-by: Tanvi Desai <tanvi.desai@xxxxxxxxxx>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
---
drivers/tty/serial/uartlite.c | 83 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
index 060ac12..eb8afd9 100644
--- a/drivers/tty/serial/uartlite.c
+++ b/drivers/tty/serial/uartlite.c
@@ -21,6 +21,7 @@
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
+#include <linux/clk.h>
#define ULITE_NAME "ttyUL"
#define ULITE_MAJOR 204
@@ -56,6 +57,7 @@
struct uartlite_data {
const struct uartlite_reg_ops *reg_ops;
+ struct clk *clk;
};
struct uartlite_reg_ops {
@@ -261,8 +263,15 @@ static void ulite_break_ctl(struct uart_port *port, int ctl)
static int ulite_startup(struct uart_port *port)
{
+ struct uartlite_data *pdata = port->private_data;
int ret;
+ ret = clk_enable(pdata->clk);
+ if (ret) {
+ dev_err(port->dev, "Failed to enable clock\n");
+ return ret;
+ }
+
ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
"uartlite", port);
if (ret)
@@ -277,9 +286,12 @@ static int ulite_startup(struct uart_port *port)
static void ulite_shutdown(struct uart_port *port)
{
+ struct uartlite_data *pdata = port->private_data;
+
uart_out32(0, ULITE_CONTROL, port);
uart_in32(ULITE_CONTROL, port); /* dummy */
free_irq(port->irq, port);
+ clk_disable(pdata->clk);
}
static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
@@ -370,6 +382,17 @@ static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
return -EINVAL;
}
+static void ulite_pm(struct uart_port *port, unsigned int state,
+ unsigned int oldstate)
+{
+ struct uartlite_data *pdata = port->private_data;
+
+ if (!state)
+ clk_enable(pdata->clk);
+ else
+ clk_disable(pdata->clk);
+}
+
#ifdef CONFIG_CONSOLE_POLL
static int ulite_get_poll_char(struct uart_port *port)
{
@@ -405,6 +428,7 @@ static const struct uart_ops ulite_ops = {
.request_port = ulite_request_port,
.config_port = ulite_config_port,
.verify_port = ulite_verify_port,
+ .pm = ulite_pm,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = ulite_get_poll_char,
.poll_put_char = ulite_put_poll_char,
@@ -666,10 +690,44 @@ static int ulite_release(struct device *dev)
return rc;
}
+/**
+ * ulite_suspend - Stop the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 always.
+ */
+static int __maybe_unused ulite_suspend(struct device *dev)
+{
+ struct uart_port *port = dev_get_drvdata(dev);
+
+ if (port)
+ uart_suspend_port(&ulite_uart_driver, port);
+
+ return 0;
+}
+
+/**
+ * ulite_resume - Resume the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 on success, errno otherwise.
+ */
+static int __maybe_unused ulite_resume(struct device *dev)
+{
+ struct uart_port *port = dev_get_drvdata(dev);
+
+ if (port)
+ uart_resume_port(&ulite_uart_driver, port);
+
+ return 0;
+}
+
/* ---------------------------------------------------------------------
* Platform bus binding
*/
+static SIMPLE_DEV_PM_OPS(ulite_pm_ops, ulite_suspend, ulite_resume);
+
#if defined(CONFIG_OF)
/* Match table for of_platform binding */
static const struct of_device_id ulite_of_match[] = {
@@ -684,7 +742,7 @@ static int ulite_probe(struct platform_device *pdev)
{
struct resource *res;
struct uartlite_data *pdata;
- int irq;
+ int irq, ret;
int id = pdev->id;
#ifdef CONFIG_OF
const __be32 *prop;
@@ -706,11 +764,33 @@ static int ulite_probe(struct platform_device *pdev)
if (irq <= 0)
return -ENXIO;
+ pdata->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
+ if (IS_ERR(pdata->clk)) {
+ if (PTR_ERR(pdata->clk) != -ENOENT)
+ return PTR_ERR(pdata->clk);
+
+ /*
+ * Clock framework support is optional, continue on
+ * anyways if we don't find a matching clock.
+ */
+ pdata->clk = NULL;
+ }
+
+ ret = clk_prepare(pdata->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to prepare clock\n");
+ return ret;
+ }
+
return ulite_assign(&pdev->dev, id, res->start, irq, pdata);
}
static int ulite_remove(struct platform_device *pdev)
{
+ struct uart_port *port = dev_get_drvdata(&pdev->dev);
+ struct uartlite_data *pdata = port->private_data;
+
+ clk_disable_unprepare(pdata->clk);
return ulite_release(&pdev->dev);
}
@@ -723,6 +803,7 @@ static struct platform_driver ulite_platform_driver = {
.driver = {
.name = "uartlite",
.of_match_table = of_match_ptr(ulite_of_match),
+ .pm = &ulite_pm_ops,
},
};
--
2.7.4
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