Re: [PATCH 2/5] hw/i2c: Added linear mode translation for pmbus devices

[Philippe Mathieu-Daudé]

On 7/1/22 00:09, Titus Rwantare wrote:

From: Shengtan Mao 

Signed-off-by: Shengtan Mao 
Reviewed-by: Titus Rwantare 
---
  hw/i2c/pmbus_device.c | 18 ++
  include/hw/i2c/pmbus_device.h | 20 +++-
  2 files changed, 37 insertions(+), 1 deletion(-)


Reviewed-by: Philippe Mathieu-Daudé 

[PATCH 2/5] hw/i2c: Added linear mode translation for pmbus devices

[Titus Rwantare]

From: Shengtan Mao 

Signed-off-by: Shengtan Mao 
Reviewed-by: Titus Rwantare 
---
 hw/i2c/pmbus_device.c | 18 ++
 include/hw/i2c/pmbus_device.h | 20 +++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
index 3beb02afad..1036c41c49 100644
--- a/hw/i2c/pmbus_device.c
+++ b/hw/i2c/pmbus_device.c
@@ -28,6 +28,24 @@ uint32_t pmbus_direct_mode2data(PMBusCoefficients c, 
uint16_t value)
 return x;
 }
 
+uint16_t pmbus_data2linear_mode(uint16_t value, int exp)
+{
+/* L = D * 2^(-e) */
+if (exp < 0) {
+return value << (-exp);
+}
+return value >> exp;
+}
+
+uint16_t pmbus_linear_mode2data(uint16_t value, int exp)
+{
+/* D = L * 2^e */
+if (exp < 0) {
+return value >> (-exp);
+}
+return value << exp;
+}
+
 void pmbus_send(PMBusDevice *pmdev, const uint8_t *data, uint16_t len)
 {
 if (pmdev->out_buf_len + len > SMBUS_DATA_MAX_LEN) {
diff --git a/include/hw/i2c/pmbus_device.h b/include/hw/i2c/pmbus_device.h
index 72c0483149..9a274247ab 100644
--- a/include/hw/i2c/pmbus_device.h
+++ b/include/hw/i2c/pmbus_device.h
@@ -446,7 +446,7 @@ typedef struct PMBusCoefficients {
  *
  * Y = (m * x - b) * 10^R
  *
- * @return uint32_t
+ * @return uint16_t
  */
 uint16_t pmbus_data2direct_mode(PMBusCoefficients c, uint32_t value);
 
@@ -459,6 +459,24 @@ uint16_t pmbus_data2direct_mode(PMBusCoefficients c, 
uint32_t value);
  */
 uint32_t pmbus_direct_mode2data(PMBusCoefficients c, uint16_t value);
 
+/**
+ * Convert sensor values to linear mode format
+ *
+ * L = D * 2^(-e)
+ *
+ * @return uint16
+ */
+uint16_t pmbus_data2linear_mode(uint16_t value, int exp);
+
+/**
+ * Convert linear mode formatted data into sensor reading
+ *
+ * D = L * 2^e
+ *
+ * @return uint16
+ */
+uint16_t pmbus_linear_mode2data(uint16_t value, int exp);
+
 /**
  * @brief Send a block of data over PMBus
  * Assumes that the bytes in the block are already ordered correctly,
-- 
2.34.1.448.ga2b2bfdf31-goog