[PATCH v1 2/2] i2c: i2c-stm32f7: SYSCFG Fast Mode Plus support for I2C STM32F7

Pierre-Yves MORDRET
2018-11-16T12:20:22Z

Read SYSCFG bindings to set Fast Mode Plus bits if Fast Mode Plus
speed is selected.

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
Version history:
v1:
* Initial
---
---
drivers/i2c/busses/i2c-stm32f7.c | 37 ++++++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 62d023e..8e381b7 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -21,6 +21,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
@@ -276,6 +277,7 @@ struct stm32f7_i2c_msg {
* slave)
* @dma: dma data
* @use_dma: boolean to know if dma is used in the current transfer
+ * @regmap: holds SYSCFG phandle for Fast Mode Plus bits
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
@@ -296,6 +298,7 @@ struct stm32f7_i2c_dev {
bool master_mode;
struct stm32_i2c_dma *dma;
bool use_dma;
+ struct regmap *regmap;
};

/**
@@ -1763,6 +1766,30 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
return 0;
}

+static int stm32f7_i2c_setup_fm_plus_bits(struct platform_device *pdev,
+ struct stm32f7_i2c_dev *i2c_dev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ int ret;
+ u32 reg, mask;
+
+ i2c_dev->regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg-fmp");
+ if (IS_ERR(i2c_dev->regmap)) {
+ /* Optional */
+ return 0;
+ }
+
+ ret = of_property_read_u32_index(np, "st,syscfg-fmp", 1, &reg);
+ if (ret)
+ return ret;
+
+ ret = of_property_read_u32_index(np, "st,syscfg-fmp", 2, &mask);
+ if (ret)
+ return ret;
+
+ return regmap_update_bits(i2c_dev->regmap, reg, mask, mask);
+}
+
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
@@ -1828,12 +1855,16 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
ret = device_property_read_u32(&pdev->dev, "clock-frequency",
&clk_rate);
- if (!ret && clk_rate >= 1000000)
+ if (!ret && clk_rate >= 1000000) {
i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS;
- else if (!ret && clk_rate >= 400000)
+ ret = stm32f7_i2c_setup_fm_plus_bits(pdev, i2c_dev);
+ if (ret)
+ goto clk_free;
+ } else if (!ret && clk_rate >= 400000) {
i2c_dev->speed = STM32_I2C_SPEED_FAST;
- else if (!ret && clk_rate >= 100000)
+ } else if (!ret && clk_rate >= 100000) {
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
+ }

rst = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(rst)) {
--
2.7.4