[PATCH v3] i2c: designware: platdrv: Set class based on dmi

From: Ricardo Ribalda
Date: Thu Jul 02 2020 - 05:38:40 EST


Current AMD's zen-based APUs use this core for some of its i2c-buses.

With this patch we re-enable autodetection of hwmon-alike devices, so
lm-sensors will be able to work automatically.

It does not affect the boot-time of embedded devices, as the class is
set based on the dmi information.

Dmi is probed only on Qtechnology QT5222 Industrial Camera Platform
https://qtec.com/camera-technology-camera-platforms/

Fixes: 3eddad96c439 ("i2c: designware: reverts "i2c: designware: Add support for AMD I2C controller"")
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxx>
---

v3: Comment by Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
- Add Fixes tag
- Do not user strstr for dmidecode
Comment by Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
- Use dmi_check_system()
drivers/i2c/busses/i2c-designware-platdrv.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index c2efaaaac252..a9f2d416b7d1 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -12,6 +12,7 @@
#include <linux/clk-provider.h>
#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/i2c.h>
@@ -191,6 +192,18 @@ static int dw_i2c_plat_request_regs(struct dw_i2c_dev *dev)
return ret;
}

+static const struct dmi_system_id allow_probe[] = {
+ {
+ .ident = "Qtechnology QT5222",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Qtechnology"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "QT5222")
+ }
+ },
+
+ { }
+};
+
static int dw_i2c_plat_probe(struct platform_device *pdev)
{
struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
@@ -267,7 +280,8 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)

adap = &dev->adapter;
adap->owner = THIS_MODULE;
- adap->class = I2C_CLASS_DEPRECATED;
+ adap->class = dmi_check_system(allow_probe) ?
+ I2C_CLASS_HWMON : I2C_CLASS_DEPRECATED;
ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
adap->dev.of_node = pdev->dev.of_node;
adap->nr = -1;
--
2.27.0