linux-kernel - [PATCH 7/7] serial: max310x: use separate regmap name for each port

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Message-Id: <20231130191050.3165862-8-hugo@hugovil.com>
Date:   Thu, 30 Nov 2023 14:10:49 -0500
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     gregkh@...uxfoundation.org, jirislaby@...nel.org,
        hvilleneuve@...onoff.com
Cc:     linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        hugo@...ovil.com
Subject: [PATCH 7/7] serial: max310x: use separate regmap name for each port

From: Hugo Villeneuve <hvilleneuve@...onoff.com>

Use a separate regmap name for each port so that each port can have its own
debugfs entry, allowing to access each port registers independently.

For example, a four channels/ports device like the MAX14830 will have four
entries in its regmap debugfs:

$ find /sys/kernel/debug/regmap -type d | grep spi0.0
/sys/kernel/debug/regmap/spi0.0-port0
/sys/kernel/debug/regmap/spi0.0-port1
/sys/kernel/debug/regmap/spi0.0-port2
/sys/kernel/debug/regmap/spi0.0-port3

Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
---
 drivers/tty/serial/max310x.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 58dd5cc62014..d2eca05a6966 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -27,6 +27,7 @@
 #include <linux/uaccess.h>
 
 #define MAX310X_NAME			"max310x"
+#define MAX310X_PORT_NAME_SUFFIX	"port"
 #define MAX310X_MAJOR			204
 #define MAX310X_MINOR			209
 #define MAX310X_UART_NRMAX		16
@@ -1486,6 +1487,15 @@ static struct regmap_config regcfg = {
 	.max_raw_write = MAX310X_FIFO_SIZE,
 };
 
+static const char *max310x_regmap_name(unsigned int port_id)
+{
+	static char buf[sizeof(MAX310X_PORT_NAME_SUFFIX __stringify(MAX310X_MAX_PORTS))];
+
+	snprintf(buf, sizeof(buf), MAX310X_PORT_NAME_SUFFIX "%u", port_id);
+
+	return buf;
+}
+
 #ifdef CONFIG_SPI_MASTER
 static int max310x_spi_extended_reg_enable(struct device *dev, bool enable)
 {
@@ -1521,6 +1531,8 @@ static int max310x_spi_probe(struct spi_device *spi)
 
 	for (i = 0; i < devtype->nr; i++) {
 		u8 port_mask = i * 0x20;
+
+		regcfg.name = max310x_regmap_name(i);
 		regcfg.read_flag_mask = port_mask;
 		regcfg.write_flag_mask = port_mask | MAX310X_WRITE_BIT;
 		regmaps[i] = devm_regmap_init_spi(spi, &regcfg);
@@ -1617,6 +1629,7 @@ static int max310x_i2c_probe(struct i2c_client *client)
 				     client->addr, devtype->slave_addr.min,
 				     devtype->slave_addr.max);
 
+	regcfg_i2c.name = max310x_regmap_name(0);
 	regmaps[0] = devm_regmap_init_i2c(client, &regcfg_i2c);
 
 	for (i = 1; i < devtype->nr; i++) {
@@ -1625,6 +1638,7 @@ static int max310x_i2c_probe(struct i2c_client *client)
 							client->adapter,
 							port_addr);
 
+		regcfg_i2c.name = max310x_regmap_name(i);
 		regmaps[i] = devm_regmap_init_i2c(port_client, &regcfg_i2c);
 	}
 
-- 
2.39.2