[PATCH v2 13/14] mfd: zl3073x: Load mfg file into HW if it is present

[Ivan Vecera]

Add support for loading mfg file that can be provided by a user. The mfg
file can be generated by Microchip tool and contains snippets of device
configuration that is different from the one stored in the flash memory
inside the chip.

Signed-off-by: Ivan Vecera <ivecera@xxxxxxxxxx>
---
 drivers/mfd/zl3073x-core.c | 110 +++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)

diff --git a/drivers/mfd/zl3073x-core.c b/drivers/mfd/zl3073x-core.c
index a1fb5af5b3d9f..110071b28cab9 100644
--- a/drivers/mfd/zl3073x-core.c
+++ b/drivers/mfd/zl3073x-core.c
@@ -4,15 +4,19 @@
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/cleanup.h>
+#include <linux/delay.h>
 #include <linux/dev_printk.h>
 #include <linux/device.h>
 #include <linux/export.h>
+#include <linux/firmware.h>
+#include <linux/kstrtox.h>
 #include <linux/lockdep.h>
 #include <linux/mfd/zl3073x.h>
 #include <linux/module.h>
 #include <linux/netlink.h>
 #include <linux/regmap.h>
 #include <linux/sprintf.h>
+#include <linux/string.h>
 #include <linux/unaligned.h>
 #include <net/devlink.h>
 #include "zl3073x.h"
@@ -464,6 +468,108 @@ static void zl3073x_devlink_unregister(void *ptr)
 	devlink_unregister(ptr);
 }
 
+static int zl3073x_fw_parse_line(struct zl3073x_dev *zldev, const char *line)
+{
+#define ZL3073X_FW_WHITESPACES_SIZE	3
+#define ZL3073X_FW_COMMAND_SIZE		1
+	const char *ptr = line;
+	char *endp;
+	u32 delay;
+	u16 addr;
+	u8 val;
+
+	switch (ptr[0]) {
+	case 'X':
+		/* The line looks like this:
+		 * X , ADDR , VAL
+		 * Where:
+		 *  - X means that is a command that needs to be executed
+		 *  - ADDR represents the addr and is always 2 bytes and the
+		 *         value is in hex, for example 0x0232
+		 *  - VAL represents the value that is written and is always 1
+		 *        byte and the value is in hex, for example 0x12
+		 */
+		ptr += ZL3073X_FW_COMMAND_SIZE;
+		ptr += ZL3073X_FW_WHITESPACES_SIZE;
+		addr = simple_strtoul(ptr, &endp, 16);
+
+		ptr = endp;
+		ptr += ZL3073X_FW_WHITESPACES_SIZE;
+		val = simple_strtoul(ptr, NULL, 16);
+
+		/* Write requested value to given register */
+		return zl3073x_write_reg(zldev, addr, 1, &val);
+	case 'W':
+		/* The line looks like this:
+		 * W , DELAY
+		 * Where:
+		 *  - W means that is a wait command
+		 *  - DELAY represents the delay in microseconds and the value
+		 *    is in decimal
+		 */
+		ptr += ZL3073X_FW_COMMAND_SIZE;
+		ptr += ZL3073X_FW_WHITESPACES_SIZE;
+		delay = simple_strtoul(ptr, NULL, 10);
+
+		fsleep(delay);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+#define ZL3073X_MFG_FILE "microchip/zl3073x.mfg"
+
+static void zl3073x_fw_load(struct zl3073x_dev *zldev)
+{
+	const struct firmware *fw;
+	const char *ptr, *end;
+	char buf[128];
+	int rc;
+
+	rc = firmware_request_nowarn(&fw, ZL3073X_MFG_FILE, zldev->dev);
+	if (rc)
+		return;
+
+	dev_info(zldev->dev, "Applying mfg file %s...\n", ZL3073X_MFG_FILE);
+
+	guard(zl3073x)(zldev);
+
+	ptr = fw->data;
+	end = ptr + fw->size;
+	while (ptr < end) {
+		/* Get next end of the line or end of buffer */
+		char *eol = strnchrnul(ptr, end - ptr, '\n');
+		size_t len = eol - ptr;
+
+		/* Check line length */
+		if (len >= sizeof(buf)) {
+			dev_err(zldev->dev, "Line in firmware is too long\n");
+			return;
+		}
+
+		/* Copy line from buffer */
+		memcpy(buf, ptr, len);
+		buf[len] = '\0';
+
+		/* Parse and process the line */
+		rc = zl3073x_fw_parse_line(zldev, buf);
+		if (rc) {
+			dev_err(zldev->dev,
+				"Failed to parse firmware line: %pe\n",
+				ERR_PTR(rc));
+			break;
+		}
+
+		/* Move to next line */
+		ptr = eol + 1;
+	}
+
+	release_firmware(fw);
+}
+
 /**
  * zl3073x_dev_init - initialize zl3073x device
  * @zldev: pointer to zl3073x device
@@ -505,6 +611,9 @@ int zl3073x_dev_init(struct zl3073x_dev *zldev, u8 dev_id)
 	/* Use chip ID and given dev ID as clock ID */
 	zldev->clock_id = ((u64)id << 8) | dev_id;
 
+	/* Load mfg file if present */
+	zl3073x_fw_load(zldev);
+
 	dev_info(zldev->dev, "ChipID(%X), ChipRev(%X), FwVer(%u)\n",
 		 id, revision, fw_ver);
 	dev_info(zldev->dev, "Custom config version: %lu.%lu.%lu.%lu\n",
@@ -528,3 +637,4 @@ EXPORT_SYMBOL_NS_GPL(zl3073x_dev_init, "ZL3073X");
 MODULE_AUTHOR("Ivan Vecera <ivecera@xxxxxxxxxx>");
 MODULE_DESCRIPTION("Microchip ZL3073x core driver");
 MODULE_LICENSE("GPL");
+MODULE_FIRMWARE(ZL3073X_MFG_FILE);
-- 
2.48.1