rtc: ds3232: get SRAM access using NVMEM Framework

DS3232 RTC has 236 bytes of persistent memory.

Add RTC SRAM read and write access using
the NVMEM Framework.

Signed-off-by: Han Nandor <nandor.han@vaisala.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
index 7184e5145f12da07e01a837cef7bf1376cff75fa..1e9312f960214c469b4c392afa18495f9fc614ce 100644 (file)
--- a/drivers/rtc/rtc-ds3232.c
+++ b/drivers/rtc/rtc-ds3232.c
@@ -48,6 +48,10 @@
 #       define DS3232_REG_SR_A1F     0x01
 
 #define DS3232_REG_TEMPERATURE 0x11
+#define DS3232_REG_SRAM_START   0x14
+#define DS3232_REG_SRAM_END     0xFF
+
+#define DS3232_REG_SRAM_SIZE    236
 
 struct ds3232 {
        struct device *dev;
@@ -461,11 +465,39 @@ static const struct rtc_class_ops ds3232_rtc_ops = {
        .alarm_irq_enable = ds3232_alarm_irq_enable,
 };
 
+static int ds3232_nvmem_read(void *priv, unsigned int offset, void *val,
+                            size_t bytes)
+{
+       struct regmap *ds3232_regmap = (struct regmap *)priv;
+
+       return regmap_bulk_read(ds3232_regmap, DS3232_REG_SRAM_START + offset,
+                               val, bytes);
+}
+
+static int ds3232_nvmem_write(void *priv, unsigned int offset, void *val,
+                             size_t bytes)
+{
+       struct regmap *ds3232_regmap = (struct regmap *)priv;
+
+       return regmap_bulk_write(ds3232_regmap, DS3232_REG_SRAM_START + offset,
+                                val, bytes);
+}
+
 static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
                        const char *name)
 {
        struct ds3232 *ds3232;
        int ret;
+       struct nvmem_config nvmem_cfg = {
+               .name = "ds3232_sram",
+               .stride = 1,
+               .size = DS3232_REG_SRAM_SIZE,
+               .word_size = 1,
+               .reg_read = ds3232_nvmem_read,
+               .reg_write = ds3232_nvmem_write,
+               .priv = regmap,
+               .type = NVMEM_TYPE_BATTERY_BACKED
+       };
 
        ds3232 = devm_kzalloc(dev, sizeof(*ds3232), GFP_KERNEL);
        if (!ds3232)
@@ -490,6 +522,10 @@ static int ds3232_probe(struct device *dev, struct regmap *regmap, int irq,
        if (IS_ERR(ds3232->rtc))
                return PTR_ERR(ds3232->rtc);
 
+       ret = rtc_nvmem_register(ds3232->rtc, &nvmem_cfg);
+       if(ret)
+               return ret;
+
        if (ds3232->irq > 0) {
                ret = devm_request_threaded_irq(dev, ds3232->irq, NULL,
                                                ds3232_irq,
@@ -542,7 +578,7 @@ static int ds3232_i2c_probe(struct i2c_client *client,
        static const struct regmap_config config = {
                .reg_bits = 8,
                .val_bits = 8,
-               .max_register = 0x13,
+               .max_register = DS3232_REG_SRAM_END,
        };
 
        regmap = devm_regmap_init_i2c(client, &config);
@@ -609,7 +645,7 @@ static int ds3234_probe(struct spi_device *spi)
        static const struct regmap_config config = {
                .reg_bits = 8,
                .val_bits = 8,
-               .max_register = 0x13,
+               .max_register = DS3232_REG_SRAM_END,
                .write_flag_mask = 0x80,
        };
        struct regmap *regmap;