rtc: twl: add NVRAM support

Export SRAM using nvmem.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/ZDf7qZTiml0ijD2g@lenoch
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c
index 81b3694..f8f0d77 100644 (file)
--- a/drivers/rtc/rtc-twl.c
+++ b/drivers/rtc/rtc-twl.c
@@ -487,11 +487,24 @@ static const struct rtc_class_ops twl_rtc_ops = {
        .alarm_irq_enable = twl_rtc_alarm_irq_enable,
 };
 
+static int twl_nvram_read(void *priv, unsigned int offset, void *val,
+                         size_t bytes)
+{
+       return twl_i2c_read((long)priv, val, offset, bytes);
+}
+
+static int twl_nvram_write(void *priv, unsigned int offset, void *val,
+                          size_t bytes)
+{
+       return twl_i2c_write((long)priv, val, offset, bytes);
+}
+
 /*----------------------------------------------------------------------*/
 
 static int twl_rtc_probe(struct platform_device *pdev)
 {
        struct twl_rtc *twl_rtc;
+       struct nvmem_config nvmem_cfg;
        struct device_node *np = pdev->dev.of_node;
        int ret = -EINVAL;
        int irq = platform_get_irq(pdev, 0);
@@ -579,6 +592,30 @@ static int twl_rtc_probe(struct platform_device *pdev)
                return ret;
        }
 
+       memset(&nvmem_cfg, 0, sizeof(nvmem_cfg));
+       nvmem_cfg.name = "twl-secured-";
+       nvmem_cfg.type = NVMEM_TYPE_BATTERY_BACKED;
+       nvmem_cfg.reg_read = twl_nvram_read,
+       nvmem_cfg.reg_write = twl_nvram_write,
+       nvmem_cfg.word_size = 1;
+       nvmem_cfg.stride = 1;
+       if (twl_class_is_4030()) {
+               /* 20 bytes SECURED_REG area */
+               nvmem_cfg.size = 20;
+               nvmem_cfg.priv = (void *)TWL_MODULE_SECURED_REG;
+               devm_rtc_nvmem_register(twl_rtc->rtc, &nvmem_cfg);
+               /* 8 bytes BACKUP area */
+               nvmem_cfg.name = "twl-backup-";
+               nvmem_cfg.size = 8;
+               nvmem_cfg.priv = (void *)TWL4030_MODULE_BACKUP;
+               devm_rtc_nvmem_register(twl_rtc->rtc, &nvmem_cfg);
+       } else {
+               /* 8 bytes SECURED_REG area */
+               nvmem_cfg.size = 8;
+               nvmem_cfg.priv = (void *)TWL_MODULE_SECURED_REG;
+               devm_rtc_nvmem_register(twl_rtc->rtc, &nvmem_cfg);
+       }
+
        return 0;
 }