+From 2ade0172154e50c8a2bfd8634c6eff943cffea29 Mon Sep 17 00:00:00 2001
+From: "SkyLake.Huang" <skylake.huang@mediatek.com>
+Date: Thu, 23 Jun 2022 18:35:52 +0800
+Subject: [PATCH 2/6] drivers: spi: Add support for dynamic calibration
+
+Signed-off-by: SkyLake.Huang <skylake.huang@mediatek.com>
+---
+ drivers/spi/spi.c | 137 ++++++++++++++++++++++++++++++++++++++++
+ include/linux/spi/spi.h | 42 ++++++++++++
+ 2 files changed, 179 insertions(+)
+
+--- a/drivers/spi/spi.c
++++ b/drivers/spi/spi.c
+@@ -1234,6 +1234,70 @@ static int spi_transfer_wait(struct spi_
+ return 0;
+ }
+
++int spi_do_calibration(struct spi_controller *ctlr, struct spi_device *spi,
++ int (*cal_read)(void *priv, u32 *addr, int addrlen, u8 *buf, int readlen), void *drv_priv)
++{
++ int datalen = ctlr->cal_rule->datalen;
++ int addrlen = ctlr->cal_rule->addrlen;
++ u8 *buf;
++ int ret;
++ int i;
++ struct list_head *cal_head, *listptr;
++ struct spi_cal_target *target;
++
++ /* Calculate calibration result */
++ int hit_val, total_hit, origin;
++ bool hit;
++
++ /* Make sure we can start calibration */
++ if(!ctlr->cal_target || !ctlr->cal_rule || !ctlr->append_caldata)
++ return 0;
++
++ buf = kzalloc(datalen * sizeof(u8), GFP_KERNEL);
++ if(!buf)
++ return -ENOMEM;
++
++ ret = ctlr->append_caldata(ctlr);
++ if (ret)
++ goto cal_end;
++
++ cal_head = ctlr->cal_target;
++ list_for_each(listptr, cal_head) {
++ target = list_entry(listptr, struct spi_cal_target, list);
++
++ hit = false;
++ hit_val = 0;
++ total_hit = 0;
++ origin = *target->cal_item;
++
++ for(i=target->cal_min; i<=target->cal_max; i+=target->step) {
++ *target->cal_item = i;
++ ret = (*cal_read)(drv_priv, ctlr->cal_rule->addr, addrlen, buf, datalen);
++ if(ret)
++ break;
++ dev_dbg(&spi->dev, "controller cal item value: 0x%x\n", i);
++ if(memcmp(ctlr->cal_rule->match_data, buf, datalen * sizeof(u8)) == 0) {
++ hit = true;
++ hit_val += i;
++ total_hit++;
++ dev_dbg(&spi->dev, "golden data matches data read!\n");
++ }
++ }
++ if(hit) {
++ *target->cal_item = DIV_ROUND_CLOSEST(hit_val, total_hit);
++ dev_info(&spi->dev, "calibration result: 0x%x", *target->cal_item);
++ } else {
++ *target->cal_item = origin;
++ dev_warn(&spi->dev, "calibration failed, fallback to default: 0x%x", origin);
++ }
++ }
++
++cal_end:
++ kfree(buf);
++ return ret? ret: 0;
++}
++EXPORT_SYMBOL_GPL(spi_do_calibration);
++
+ static void _spi_transfer_delay_ns(u32 ns)
+ {
+ if (!ns)
+@@ -2021,6 +2085,75 @@ void spi_flush_queue(struct spi_controll
+ /*-------------------------------------------------------------------------*/
+
+ #if defined(CONFIG_OF)
++static inline void alloc_cal_data(struct list_head **cal_target,
++ struct spi_cal_rule **cal_rule, bool enable)
++{
++ if(enable) {
++ *cal_target = kmalloc(sizeof(struct list_head), GFP_KERNEL);
++ INIT_LIST_HEAD(*cal_target);
++ *cal_rule = kmalloc(sizeof(struct spi_cal_rule), GFP_KERNEL);
++ } else {
++ kfree(*cal_target);
++ kfree(*cal_rule);
++ }
++}
++
++static int of_spi_parse_cal_dt(struct spi_controller *ctlr, struct spi_device *spi,
++ struct device_node *nc)
++{
++ u32 value;
++ int rc;
++ const char *cal_mode;
++
++ rc = of_property_read_bool(nc, "spi-cal-enable");
++ if (rc)
++ alloc_cal_data(&ctlr->cal_target, &ctlr->cal_rule, true);
++ else
++ return 0;
++
++ rc = of_property_read_string(nc, "spi-cal-mode", &cal_mode);
++ if(!rc) {
++ if(strcmp("read-data", cal_mode) == 0){
++ ctlr->cal_rule->mode = SPI_CAL_READ_DATA;
++ } else if(strcmp("read-pp", cal_mode) == 0) {
++ ctlr->cal_rule->mode = SPI_CAL_READ_PP;
++ return 0;
++ } else if(strcmp("read-sfdp", cal_mode) == 0){
++ ctlr->cal_rule->mode = SPI_CAL_READ_SFDP;
++ return 0;
++ }
++ } else
++ goto err;
++
++ ctlr->cal_rule->datalen = 0;
++ rc = of_property_read_u32(nc, "spi-cal-datalen", &value);
++ if(!rc && value > 0) {
++ ctlr->cal_rule->datalen = value;
++
++ ctlr->cal_rule->match_data = kzalloc(value * sizeof(u8), GFP_KERNEL);
++ rc = of_property_read_u8_array(nc, "spi-cal-data",
++ ctlr->cal_rule->match_data, value);
++ if(rc)
++ kfree(ctlr->cal_rule->match_data);
++ }
++
++ rc = of_property_read_u32(nc, "spi-cal-addrlen", &value);
++ if(!rc && value > 0) {
++ ctlr->cal_rule->addrlen = value;
++
++ ctlr->cal_rule->addr = kzalloc(value * sizeof(u32), GFP_KERNEL);
++ rc = of_property_read_u32_array(nc, "spi-cal-addr",
++ ctlr->cal_rule->addr, value);
++ if(rc)
++ kfree(ctlr->cal_rule->addr);
++ }
++ return 0;
++
++err:
++ alloc_cal_data(&ctlr->cal_target, &ctlr->cal_rule, false);
++ return 0;
++}
++
+ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
+ struct device_node *nc)
+ {
+@@ -2139,6 +2272,10 @@ of_register_spi_device(struct spi_contro
+ if (rc)
+ goto err_out;
+
++ rc = of_spi_parse_cal_dt(ctlr, spi, nc);
++ if (rc)
++ goto err_out;
++
+ /* Store a pointer to the node in the device structure */
+ of_node_get(nc);
+ spi->dev.of_node = nc;
+--- a/include/linux/spi/spi.h
++++ b/include/linux/spi/spi.h
+@@ -290,6 +290,40 @@ struct spi_driver {
+ struct device_driver driver;
+ };
+
++enum {
++ SPI_CAL_READ_DATA = 0,
++ SPI_CAL_READ_PP = 1, /* only for SPI-NAND */
++ SPI_CAL_READ_SFDP = 2, /* only for SPI-NOR */
++};
++
++struct nand_addr {
++ unsigned int lun;
++ unsigned int plane;
++ unsigned int eraseblock;
++ unsigned int page;
++ unsigned int dataoffs;
++};
++
++/**
++ * Read calibration rule from device dts node.
++ * Once calibration result matches the rule, we regard is as success.
++ */
++struct spi_cal_rule {
++ int datalen;
++ u8 *match_data;
++ int addrlen;
++ u32 *addr;
++ int mode;
++};
++
++struct spi_cal_target {
++ u32 *cal_item;
++ int cal_min; /* min of cal_item */
++ int cal_max; /* max of cal_item */
++ int step; /* Increase/decrease cal_item */
++ struct list_head list;
++};
++
+ static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
+ {
+ return drv ? container_of(drv, struct spi_driver, driver) : NULL;
+@@ -665,6 +699,11 @@ struct spi_controller {
+ void *dummy_rx;
+ void *dummy_tx;
+
++ /* For calibration */
++ int (*append_caldata)(struct spi_controller *ctlr);
++ struct list_head *cal_target;
++ struct spi_cal_rule *cal_rule;
++
+ int (*fw_translate_cs)(struct spi_controller *ctlr, unsigned cs);
+
+ /*
+@@ -1477,6 +1516,9 @@ spi_register_board_info(struct spi_board
+ { return 0; }
+ #endif
+
++extern int spi_do_calibration(struct spi_controller *ctlr,
++ struct spi_device *spi, int (*cal_read)(void *, u32 *, int, u8 *, int), void *drv_priv);
++
+ /* If you're hotplugging an adapter with devices (parport, usb, etc)
+ * use spi_new_device() to describe each device. You can also call
+ * spi_unregister_device() to start making that device vanish, but