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path: root/drivers/i2c/busses/i2c-meson.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-meson.c')
-rw-r--r--drivers/i2c/busses/i2c-meson.c146
1 files changed, 106 insertions, 40 deletions
diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index c5dec572fc48..0d9032953e48 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -5,6 +5,7 @@
* Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
*/
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/i2c.h>
@@ -14,7 +15,6 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
-#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/types.h>
@@ -29,16 +29,24 @@
#define REG_TOK_RDATA1 0x1c
/* Control register fields */
-#define REG_CTRL_START BIT(0)
-#define REG_CTRL_ACK_IGNORE BIT(1)
-#define REG_CTRL_STATUS BIT(2)
-#define REG_CTRL_ERROR BIT(3)
-#define REG_CTRL_CLKDIV_SHIFT 12
-#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12)
-#define REG_CTRL_CLKDIVEXT_SHIFT 28
-#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
+#define REG_CTRL_START BIT(0)
+#define REG_CTRL_ACK_IGNORE BIT(1)
+#define REG_CTRL_STATUS BIT(2)
+#define REG_CTRL_ERROR BIT(3)
+#define REG_CTRL_CLKDIV_SHIFT 12
+#define REG_CTRL_CLKDIV_MASK GENMASK(21, REG_CTRL_CLKDIV_SHIFT)
+#define REG_CTRL_CLKDIVEXT_SHIFT 28
+#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, REG_CTRL_CLKDIVEXT_SHIFT)
+
+#define REG_SLV_ADDR_MASK GENMASK(7, 0)
+#define REG_SLV_SDA_FILTER_MASK GENMASK(10, 8)
+#define REG_SLV_SCL_FILTER_MASK GENMASK(13, 11)
+#define REG_SLV_SCL_LOW_SHIFT 16
+#define REG_SLV_SCL_LOW_MASK GENMASK(27, REG_SLV_SCL_LOW_SHIFT)
+#define REG_SLV_SCL_LOW_EN BIT(28)
#define I2C_TIMEOUT_MS 500
+#define FILTER_DELAY 15
enum {
TOKEN_END = 0,
@@ -56,10 +64,6 @@ enum {
STATE_WRITE,
};
-struct meson_i2c_data {
- unsigned char div_factor;
-};
-
/**
* struct meson_i2c - Meson I2C device private data
*
@@ -77,7 +81,7 @@ struct meson_i2c_data {
* @done: Completion used to wait for transfer termination
* @tokens: Sequence of tokens to be written to the device
* @num_tokens: Number of tokens
- * @data: Pointer to the controlller's platform data
+ * @data: Pointer to the controller's platform data
*/
struct meson_i2c {
struct i2c_adapter adap;
@@ -100,6 +104,10 @@ struct meson_i2c {
const struct meson_i2c_data *data;
};
+struct meson_i2c_data {
+ void (*set_clk_div)(struct meson_i2c *i2c, unsigned int freq);
+};
+
static void meson_i2c_set_mask(struct meson_i2c *i2c, int reg, u32 mask,
u32 val)
{
@@ -128,24 +136,77 @@ static void meson_i2c_add_token(struct meson_i2c *i2c, int token)
i2c->num_tokens++;
}
-static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
+static void meson_gxbb_axg_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
+{
+ unsigned long clk_rate = clk_get_rate(i2c->clk);
+ unsigned int div_h, div_l;
+
+ /* According to I2C-BUS Spec 2.1, in FAST-MODE, the minimum LOW period is 1.3uS, and
+ * minimum HIGH is least 0.6us.
+ * For 400000 freq, the period is 2.5us. To keep within the specs, give 40% of period to
+ * HIGH and 60% to LOW. This means HIGH at 1.0us and LOW 1.5us.
+ * The same applies for Fast-mode plus, where LOW is 0.5us and HIGH is 0.26us.
+ * Duty = H/(H + L) = 2/5
+ */
+ if (freq <= I2C_MAX_STANDARD_MODE_FREQ) {
+ div_h = DIV_ROUND_UP(clk_rate, freq);
+ div_l = DIV_ROUND_UP(div_h, 4);
+ div_h = DIV_ROUND_UP(div_h, 2) - FILTER_DELAY;
+ } else {
+ div_h = DIV_ROUND_UP(clk_rate * 2, freq * 5) - FILTER_DELAY;
+ div_l = DIV_ROUND_UP(clk_rate * 3, freq * 5 * 2);
+ }
+
+ /* clock divider has 12 bits */
+ if (div_h > GENMASK(11, 0)) {
+ dev_err(i2c->dev, "requested bus frequency too low\n");
+ div_h = GENMASK(11, 0);
+ }
+ if (div_l > GENMASK(11, 0)) {
+ dev_err(i2c->dev, "requested bus frequency too low\n");
+ div_l = GENMASK(11, 0);
+ }
+
+ meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK,
+ FIELD_PREP(REG_CTRL_CLKDIV_MASK, div_h & GENMASK(9, 0)));
+
+ meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK,
+ FIELD_PREP(REG_CTRL_CLKDIVEXT_MASK, div_h >> 10));
+
+ /* set SCL low delay */
+ meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_SCL_LOW_MASK,
+ FIELD_PREP(REG_SLV_SCL_LOW_MASK, div_l));
+
+ /* Enable HIGH/LOW mode */
+ meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_SCL_LOW_EN, REG_SLV_SCL_LOW_EN);
+
+ dev_dbg(i2c->dev, "%s: clk %lu, freq %u, divh %u, divl %u\n", __func__,
+ clk_rate, freq, div_h, div_l);
+}
+
+static void meson6_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
{
unsigned long clk_rate = clk_get_rate(i2c->clk);
unsigned int div;
- div = DIV_ROUND_UP(clk_rate, freq * i2c->data->div_factor);
+ div = DIV_ROUND_UP(clk_rate, freq);
+ div -= FILTER_DELAY;
+ div = DIV_ROUND_UP(div, 4);
/* clock divider has 12 bits */
- if (div >= (1 << 12)) {
+ if (div > GENMASK(11, 0)) {
dev_err(i2c->dev, "requested bus frequency too low\n");
- div = (1 << 12) - 1;
+ div = GENMASK(11, 0);
}
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK,
- (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT);
+ FIELD_PREP(REG_CTRL_CLKDIV_MASK, div & GENMASK(9, 0)));
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK,
- (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
+ FIELD_PREP(REG_CTRL_CLKDIVEXT_MASK, div >> 10));
+
+ /* Disable HIGH/LOW mode */
+ meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_SCL_LOW_EN, 0);
dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
clk_rate, freq, div);
@@ -280,7 +341,10 @@ static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ :
TOKEN_SLAVE_ADDR_WRITE;
- writel(msg->addr << 1, i2c->regs + REG_SLAVE_ADDR);
+
+ meson_i2c_set_mask(i2c, REG_SLAVE_ADDR, REG_SLV_ADDR_MASK,
+ FIELD_PREP(REG_SLV_ADDR_MASK, msg->addr << 1));
+
meson_i2c_add_token(i2c, TOKEN_START);
meson_i2c_add_token(i2c, token);
}
@@ -357,16 +421,12 @@ static int meson_i2c_xfer_messages(struct i2c_adapter *adap,
struct meson_i2c *i2c = adap->algo_data;
int i, ret = 0;
- clk_enable(i2c->clk);
-
for (i = 0; i < num; i++) {
ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1, atomic);
if (ret)
break;
}
- clk_disable(i2c->clk);
-
return ret ?: i;
}
@@ -388,8 +448,8 @@ static u32 meson_i2c_func(struct i2c_adapter *adap)
}
static const struct i2c_algorithm meson_i2c_algorithm = {
- .master_xfer = meson_i2c_xfer,
- .master_xfer_atomic = meson_i2c_xfer_atomic,
+ .xfer = meson_i2c_xfer,
+ .xfer_atomic = meson_i2c_xfer_atomic,
.functionality = meson_i2c_func,
};
@@ -435,13 +495,13 @@ static int meson_i2c_probe(struct platform_device *pdev)
return ret;
}
- ret = clk_prepare(i2c->clk);
+ ret = clk_prepare_enable(i2c->clk);
if (ret < 0) {
dev_err(&pdev->dev, "can't prepare clock\n");
return ret;
}
- strlcpy(i2c->adap.name, "Meson I2C adapter",
+ strscpy(i2c->adap.name, "Meson I2C adapter",
sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
i2c->adap.algo = &meson_i2c_algorithm;
@@ -455,37 +515,43 @@ static int meson_i2c_probe(struct platform_device *pdev)
*/
meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
+ /* Disable filtering */
+ meson_i2c_set_mask(i2c, REG_SLAVE_ADDR,
+ REG_SLV_SDA_FILTER_MASK | REG_SLV_SCL_FILTER_MASK, 0);
+
+ if (!i2c->data->set_clk_div) {
+ clk_disable_unprepare(i2c->clk);
+ return -EINVAL;
+ }
+ i2c->data->set_clk_div(i2c, timings.bus_freq_hz);
+
ret = i2c_add_adapter(&i2c->adap);
if (ret < 0) {
- clk_unprepare(i2c->clk);
+ clk_disable_unprepare(i2c->clk);
return ret;
}
- meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
-
return 0;
}
-static int meson_i2c_remove(struct platform_device *pdev)
+static void meson_i2c_remove(struct platform_device *pdev)
{
struct meson_i2c *i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c->adap);
- clk_unprepare(i2c->clk);
-
- return 0;
+ clk_disable_unprepare(i2c->clk);
}
static const struct meson_i2c_data i2c_meson6_data = {
- .div_factor = 4,
+ .set_clk_div = meson6_i2c_set_clk_div,
};
static const struct meson_i2c_data i2c_gxbb_data = {
- .div_factor = 4,
+ .set_clk_div = meson_gxbb_axg_i2c_set_clk_div,
};
static const struct meson_i2c_data i2c_axg_data = {
- .div_factor = 3,
+ .set_clk_div = meson_gxbb_axg_i2c_set_clk_div,
};
static const struct of_device_id meson_i2c_match[] = {
@@ -499,7 +565,7 @@ MODULE_DEVICE_TABLE(of, meson_i2c_match);
static struct platform_driver meson_i2c_driver = {
.probe = meson_i2c_probe,
- .remove = meson_i2c_remove,
+ .remove = meson_i2c_remove,
.driver = {
.name = "meson-i2c",
.of_match_table = meson_i2c_match,
generated by cgit (git 2.34.1) at 2025-12-26 09:24:11 +0000