[PATCH v2 08/17] thermal: Add support for TI LM74

Christophe Leroy
2024-04-15T06:09:20Z

LM74 is a SPI temperature sensor.

Implement a driver to read temperature from it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
drivers/thermal/Kconfig | 6 +++++
drivers/thermal/Makefile | 1 +
drivers/thermal/ti-lm74.c | 52 +++++++++++++++++++++++++++++++++++++++
3 files changed, 59 insertions(+)
create mode 100644 drivers/thermal/ti-lm74.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 681b621760..440eb64a56 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -41,4 +41,10 @@ config TI_DRA7_THERMAL
Enable thermal support for for the Texas Instruments DRA752 SoC family.
The driver supports reading CPU temperature.

+config TI_LM74_THERMAL
+ bool "Temperature sensor driver for TI LM74 chip"
+ help
+ Enable thermal support for the Texas Instruments LM74 chip.
+ The driver supports reading CPU temperature.
+
endif # if DM_THERMAL
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 8acc7d20cb..b5ab0fc221 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_IMX_THERMAL) += imx_thermal.o
obj-$(CONFIG_IMX_SCU_THERMAL) += imx_scu_thermal.o
obj-$(CONFIG_TI_DRA7_THERMAL) += ti-bandgap.o
obj-$(CONFIG_IMX_TMU) += imx_tmu.o
+obj-$(CONFIG_TI_LM74_THERMAL) += ti-lm74.o
diff --git a/drivers/thermal/ti-lm74.c b/drivers/thermal/ti-lm74.c
new file mode 100644
index 0000000000..7d56f75df0
--- /dev/null
+++ b/drivers/thermal/ti-lm74.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * TI LM74 temperature sensor driver
+ *
+ * Copyright (C) 2024 CS GROUP France
+ *
+ */
+
+#include <dm.h>
+#include <thermal.h>
+#include <spi.h>
+
+static int ti_lm74_get_temp(struct udevice *dev, int *temp)
+{
+ char buf[2];
+ s16 raw;
+ int ret;
+
+ ret = dm_spi_claim_bus(dev);
+ if (ret)
+ return ret;
+
+ ret = dm_spi_xfer(dev, 16, NULL, buf, SPI_XFER_BEGIN | SPI_XFER_END);
+
+ dm_spi_release_bus(dev);
+ if (ret)
+ return ret;
+
+ raw = ((buf[0] << 8) + buf[1]) >> 3;
+
+ *temp = (((int)raw * 125) + 1000) / 2000;
+
+ return 0;
+}
+
+static struct dm_thermal_ops ti_lm74_ops = {
+ .get_temp = ti_lm74_get_temp,
+};
+
+static const struct udevice_id of_ti_lm74_match[] = {
+ {
+ .compatible = "ti,lm74",
+ },
+ {},
+};
+
+U_BOOT_DRIVER(ti_bandgap_thermal) = {
+ .name = "ti_lm74_thermal",
+ .id = UCLASS_THERMAL,
+ .ops = &ti_lm74_ops,
+ .of_match = of_ti_lm74_match,
+};
--
2.43.0