[PATCH v2 04/15] soc: renesas: rz-sysc: Add SoC detection support

[Claudiu]

From: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>

The RZ SYSC controller has registers that keep the SoC ID data. Add
driver support to retrieve the SoC ID and register a SoC driver.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
---

Changes in v2:
- this was patch 05/16 in v1
- changed patch title and description
- added SoC initialization code in its own function
- addressed the review comments
- introduced struct rz_sysc_soc_id_init_data and adjusted the code
  accordingly
- dropped the RZ/G3S SoC detection code (it will be introduced in
  a separate patch)

 drivers/soc/renesas/rz-sysc.c | 72 +++++++++++++++++++++++++++++++++--
 drivers/soc/renesas/rz-sysc.h | 18 +++++++++
 2 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/renesas/rz-sysc.c b/drivers/soc/renesas/rz-sysc.c
index dc0edacd7170..d34d295831b8 100644
--- a/drivers/soc/renesas/rz-sysc.c
+++ b/drivers/soc/renesas/rz-sysc.c
@@ -14,9 +14,12 @@
 #include <linux/refcount.h>
 #include <linux/regmap.h>
 #include <linux/seq_file.h>
+#include <linux/sys_soc.h>
 
 #include "rz-sysc.h"
 
+#define field_get(_mask, _reg) (((_reg) & (_mask)) >> (ffs(_mask) - 1))
+
 /**
  * struct rz_sysc - RZ SYSC private data structure
  * @base: SYSC base address
@@ -211,6 +214,59 @@ static int rz_sysc_signals_init(struct rz_sysc *sysc,
 	return 0;
 }
 
+static int rz_sysc_soc_init(struct rz_sysc *sysc, const struct of_device_id *match)
+{
+	const struct rz_sysc_init_data *sysc_data = match->data;
+	const struct rz_sysc_soc_id_init_data *soc_data = sysc_data->soc_id_init_data;
+	struct soc_device_attribute *soc_dev_attr;
+	const char *soc_id_start, *soc_id_end;
+	u32 val, revision, specific_id;
+	struct soc_device *soc_dev;
+	char soc_id[32] = {0};
+	u8 size;
+
+	if (!soc_data || !soc_data->family || !soc_data->offset ||
+	    !soc_data->revision_mask)
+		return -EINVAL;
+
+	soc_id_start = strchr(match->compatible, ',') + 1;
+	soc_id_end = strchr(match->compatible, '-');
+	size = soc_id_end - soc_id_start;
+	if (size > 32)
+		size = 32;
+	strscpy(soc_id, soc_id_start, size);
+
+	soc_dev_attr = devm_kzalloc(sysc->dev, sizeof(*soc_dev_attr), GFP_KERNEL);
+	if (!soc_dev_attr)
+		return -ENOMEM;
+
+	soc_dev_attr->family = soc_data->family;
+	soc_dev_attr->soc_id = devm_kstrdup(sysc->dev, soc_id, GFP_KERNEL);
+	if (!soc_dev_attr->soc_id)
+		return -ENOMEM;
+
+	val = readl(sysc->base + soc_data->offset);
+	revision = field_get(soc_data->revision_mask, val);
+	specific_id = field_get(soc_data->specific_id_mask, val);
+	soc_dev_attr->revision = devm_kasprintf(sysc->dev, GFP_KERNEL, "%u", revision);
+	if (!soc_dev_attr->revision)
+		return -ENOMEM;
+
+	if (soc_data->id && specific_id != soc_data->id) {
+		dev_warn(sysc->dev, "SoC mismatch (product = 0x%x)\n", specific_id);
+		return -ENODEV;
+	}
+
+	dev_info(sysc->dev, "Detected Renesas %s %s Rev %s\n", soc_dev_attr->family,
+		 soc_dev_attr->soc_id, soc_dev_attr->revision);
+
+	soc_dev = soc_device_register(soc_dev_attr);
+	if (IS_ERR(soc_dev))
+		return PTR_ERR(soc_dev);
+
+	return 0;
+}
+
 static struct regmap_config rz_sysc_regmap = {
 	.name = "rz_sysc_regs",
 	.reg_bits = 32,
@@ -235,14 +291,15 @@ MODULE_DEVICE_TABLE(of, rz_sysc_match);
 static int rz_sysc_probe(struct platform_device *pdev)
 {
 	const struct rz_sysc_init_data *data;
+	const struct of_device_id *match;
 	struct device *dev = &pdev->dev;
-	struct rz_sysc *sysc;
 	struct regmap *regmap;
+	struct rz_sysc *sysc;
 	int ret;
 
-	data = device_get_match_data(dev);
-	if (!data || !data->max_register_offset)
-		return -EINVAL;
+	match = of_match_node(rz_sysc_match, dev->of_node);
+	if (!match || !match->data)
+		return -ENODEV;
 
 	sysc = devm_kzalloc(dev, sizeof(*sysc), GFP_KERNEL);
 	if (!sysc)
@@ -253,6 +310,13 @@ static int rz_sysc_probe(struct platform_device *pdev)
 		return PTR_ERR(sysc->base);
 
 	sysc->dev = dev;
+	ret = rz_sysc_soc_init(sysc, match);
+	if (ret)
+		return ret;
+
+	data = match->data;
+	if (!data->max_register_offset)
+		return -EINVAL;
 
 	ret = rz_sysc_signals_init(sysc, data->signals_init_data, data->num_signals);
 	if (ret)
diff --git a/drivers/soc/renesas/rz-sysc.h b/drivers/soc/renesas/rz-sysc.h
index bb850310c931..babca9c743c7 100644
--- a/drivers/soc/renesas/rz-sysc.h
+++ b/drivers/soc/renesas/rz-sysc.h
@@ -35,13 +35,31 @@ struct rz_sysc_signal {
 	refcount_t refcnt;
 };
 
+/**
+ * struct rz_syc_soc_id_init_data - RZ SYSC SoC identification initialization data
+ * @family: RZ SoC family
+ * @id: RZ SoC expected ID
+ * @offset: SYSC SoC ID register offset
+ * @revision_mask: SYSC SoC ID revision mask
+ * @specific_id_mask: SYSC SoC ID specific ID mask
+ */
+struct rz_sysc_soc_id_init_data {
+	const char * const family;
+	u32 id;
+	u32 offset;
+	u32 revision_mask;
+	u32 specific_id_mask;
+};
+
 /**
  * struct rz_sysc_init_data - RZ SYSC initialization data
+ * @soc_id_init_data: RZ SYSC SoC ID initialization data
  * @signals_init_data: RZ SYSC signals initialization data
  * @num_signals: number of SYSC signals
  * @max_register_offset: Maximum SYSC register offset to be used by the regmap config
  */
 struct rz_sysc_init_data {
+	const struct rz_sysc_soc_id_init_data *soc_id_init_data;
 	const struct rz_sysc_signal_init_data *signals_init_data;
 	u32 num_signals;
 	u32 max_register_offset;
-- 
2.39.2