From c82036b6da3eb59c9350513c5ebf384a14aebaff Mon Sep 17 00:00:00 2001
From: Steve Jeong <how2soft@gmail.com>
Date: Fri, 7 Apr 2023 12:03:14 +0900
Subject: [PATCH] ODROID-M1: driver/i2c: Add driver "speed" attribution

for change i2c bus freq dynamically.

e.g.
  $ echo 400000 | sudo tee /sys/bus/i2c/devices/i2c-0/device/speed

Signed-off-by: Steve Jeong <how2soft@gmail.com>
Change-Id: Ifcccf9bb61ed65133b64c803b53fb4e46d470e26
---
 drivers/i2c/busses/i2c-rk3x.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 8372214f062e..f0e1726aa7a5 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -1897,6 +1897,32 @@ static void rk3x_i2c_tb_cb(void *data)
 	enable_irq(i2c->irq);
 }
 
+static ssize_t rk3x_i2c_speed_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct rk3x_i2c *i2c = dev_get_drvdata(dev);
+	struct i2c_timings *t = &i2c->t;
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", t->bus_freq_hz);
+}
+
+static ssize_t rk3x_i2c_speed_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct rk3x_i2c *i2c = dev_get_drvdata(dev);
+	struct i2c_timings *t = &i2c->t;
+	int ret, freq;
+
+	ret = kstrtoint(buf, 10, &freq);
+	if (ret < 0)
+		return ret;
+
+	t->bus_freq_hz = (uint32_t)freq;
+	rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
+
+	return count;
+}
+
+static DEVICE_ATTR(speed, S_IRUGO | S_IWUSR, rk3x_i2c_speed_show, rk3x_i2c_speed_store);
+
 static int rk3x_i2c_probe(struct platform_device *pdev)
 {
 	struct fwnode_handle *fw = dev_fwnode(&pdev->dev);
@@ -1911,6 +1937,11 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
 	if (!i2c)
 		return -ENOMEM;
 
+	ret = device_create_file(&pdev->dev, &dev_attr_speed);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to create speed attribute file: %d\n", ret);
+	}
+
 	i2c->soc_data = (struct rk3x_i2c_soc_data *)device_get_match_data(&pdev->dev);
 
 	ret = rk3x_i2c_acpi_get_bus_id(&pdev->dev, i2c);
@@ -2097,6 +2128,7 @@ static int rk3x_i2c_remove(struct platform_device *pdev)
 	if (i2c->soc_data->dma_control)
 		i2c->soc_data->dma_control(pdev, false);
 
+	device_remove_file(&pdev->dev, &dev_attr_speed);
 	unregister_restart_handler(&i2c->i2c_restart_nb);
 	clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
 	clk_unprepare(i2c->pclk);