[PATCH v3 4/4] media: qcom: camss: Report hardware version via media controller

[Loic Poulain <loic.poulain@oss.qualcomm.com>]

Populate media_dev.hw_revision with the top-level CAMSS hardware version
so that user space can query the exact hardware variant through the media
controller (e.g. via media-ctl or MEDIA_IOC_DEVICE_INFO). This can help
identify the platform variant and adapt behaviour accordingly, for example
allowing libcamera to apply quirks or enable features that cannot be
discovered through standard V4L2 or media-controller APIs.

The version register is exposed by some platforms through the top-level
"top" reg region (offset 0). When present, map it and read the version
once at probe. This is a no-op on platforms not mapping the region (yet).

Reported media info on Agatti/CM2290 (Spectra 520):
Media Driver Info:
        Driver name      : qcom-camss
        Model            : Qualcomm Camera Subsystem
        Bus info         : platform:5c11000.camss
        Hardware revision: 0x00050200 (328192)

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
---
 drivers/media/platform/qcom/camss/camss.c | 40 +++++++++++++++++++++++++++++++
 drivers/media/platform/qcom/camss/camss.h |  1 +
 2 files changed, 41 insertions(+)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 2301aa3868d26692c0c67034ebccac2a4f9abc4a..c5f3d4f405ed02e7fd6b397c6ff18c15c92ca824 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -33,6 +33,9 @@
 #define CAMSS_CLOCK_MARGIN_NUMERATOR 105
 #define CAMSS_CLOCK_MARGIN_DENOMINATOR 100
 
+/* Top-level CAMSS version register */
+#define CAMSS_HW_VERSION		0x0
+
 static const struct parent_dev_ops vfe_parent_dev_ops;
 
 static const struct camss_subdev_resources csiphy_res_8x16[] = {
@@ -4677,6 +4680,29 @@ void camss_pm_domain_off(struct camss *camss, int id)
 	}
 }
 
+static int camss_read_version(struct camss *camss)
+{
+	u32 hw_version;
+	int ret;
+
+	if (!camss->top_base || !camss->res->pm_clks[0])
+		return 0;
+
+	ret = pm_runtime_resume_and_get(camss->dev);
+	if (ret < 0)
+		return ret;
+
+	hw_version = readl_relaxed(camss->top_base + CAMSS_HW_VERSION);
+
+	pm_runtime_put_sync(camss->dev);
+
+	dev_dbg(camss->dev, "CAMSS HW Version = 0x%08x\n", hw_version);
+
+	camss->media_dev.hw_revision = hw_version;
+
+	return 0;
+}
+
 static int vfe_parent_dev_ops_get(struct camss *camss, int id)
 {
 	int ret = -EINVAL;
@@ -4866,6 +4892,16 @@ static int camss_init_subdevices(struct camss *camss)
 		camss->csid_wrapper_base = base;
 	}
 
+	/* Optional top register for hardware version info */
+	if (platform_get_resource_byname(pdev, IORESOURCE_MEM, "top")) {
+		void __iomem *base;
+
+		base = devm_platform_ioremap_resource_byname(pdev, "top");
+		if (IS_ERR(base))
+			return PTR_ERR(base);
+		camss->top_base = base;
+	}
+
 	for (i = 0; i < camss->res->csid_num; i++) {
 		ret = msm_csid_subdev_init(camss, &camss->csid[i],
 					   &res->csid_res[i], i);
@@ -5456,6 +5492,10 @@ static int camss_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_v4l2_device_unregister;
 
+	ret = camss_read_version(camss);
+	if (ret)
+		goto err_v4l2_device_unregister;
+
 	ret = camss_parse_ports(camss);
 	if (ret < 0)
 		goto err_v4l2_device_unregister;
diff --git a/drivers/media/platform/qcom/camss/camss.h b/drivers/media/platform/qcom/camss/camss.h
index fe5fe25d5f18d8a3ce35b48077a975f1453c341f..cce79e56f58c8bdc0097f4a1702df22c4248f2fa 100644
--- a/drivers/media/platform/qcom/camss/camss.h
+++ b/drivers/media/platform/qcom/camss/camss.h
@@ -133,6 +133,7 @@ struct camss {
 	struct ispif_device *ispif;
 	struct vfe_device *vfe;
 	void __iomem *csid_wrapper_base;
+	void __iomem *top_base;
 	atomic_t ref_count;
 	int genpd_num;
 	struct device *genpd;

-- 
2.34.1