[PATCH 05/20] serial: stm32: add debugfs

From: Bich HEMON
Date: Mon Jun 26 2017 - 08:56:58 EST


From: Bich Hemon <bich.hemon@xxxxxx>

Adding debugfs infrastructure and one virtual
file allowing to change fifoen value.
This value change is taken into account on next
port setup or enabling.

Signed-off-by: Gerald Baeza <gerald.baeza@xxxxxx>
---
drivers/tty/serial/stm32-usart.c | 49 ++++++++++++++++++++++++++++++++++++++++
drivers/tty/serial/stm32-usart.h | 3 +++
2 files changed, 52 insertions(+)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 34e31d1..3ce0f7a 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -34,6 +34,51 @@

#include "stm32-usart.h"

+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+
+static struct dentry *stm32_debugfs_root;
+static atomic_t stm32_debugfs_cnt = ATOMIC_INIT(0);
+
+static void stm32_serial_debugfs(struct stm32_port *stm32port,
+ phys_addr_t phys_addr)
+{
+ struct device *dev = stm32port->port.dev;
+
+ if (!stm32_debugfs_root)
+ stm32_debugfs_root = debugfs_create_dir("usart-stm32", NULL);
+
+ stm32port->debugfs_dir = debugfs_create_dir(dev_name(dev),
+ stm32_debugfs_root);
+
+ debugfs_create_bool("fifoen", 0644,
+ stm32port->debugfs_dir, &stm32port->fifoen);
+
+ atomic_inc(&stm32_debugfs_cnt);
+}
+
+static void stm32_serial_debugfs_rm(struct stm32_port *stm32port)
+{
+ debugfs_remove_recursive(stm32port->debugfs_dir);
+ if (atomic_dec_and_test(&stm32_debugfs_cnt)) {
+ debugfs_remove_recursive(stm32_debugfs_root);
+ stm32_debugfs_root = NULL;
+ }
+}
+#else
+static void stm32_serial_debugfs(struct stm32_port *stm32port,
+ phys_addr_t phys_addr)
+{
+}
+
+static void stm32_serial_debugfs_rm(struct stm32_port *stm32port)
+{
+}
+#endif
+
static void stm32_stop_tx(struct uart_port *port);
static void stm32_transmit_chars(struct uart_port *port);

@@ -672,6 +717,8 @@ static int stm32_init_port(struct stm32_port *stm32port,
return PTR_ERR(port->membase);
port->mapbase = res->start;

+ stm32_serial_debugfs(stm32port, res->start);
+
spin_lock_init(&port->lock);

stm32port->clk = devm_clk_get(&pdev->dev, NULL);
@@ -914,6 +961,8 @@ static int stm32_serial_remove(struct platform_device *pdev)

clk_disable_unprepare(stm32_port->clk);

+ stm32_serial_debugfs_rm(stm32_port);
+
return uart_remove_one_port(&stm32_usart_driver, port);
}

diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index 9429baf..a8999a1 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -216,6 +216,9 @@ struct stm32_port {
struct uart_port port;
struct clk *clk;
struct stm32_usart_info *info;
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *debugfs_dir;
+#endif
struct dma_chan *rx_ch; /* dma rx channel */
dma_addr_t rx_dma_buf; /* dma rx buffer bus address */
unsigned char *rx_buf; /* dma rx buffer cpu address */
--
1.9.1