Commit 8eeb611b authored by Lorenz Brun's avatar Lorenz Brun Committed by Alexandre Belloni
Browse files

rtc: s35390a: implement nvmem support 



This RTC has one "free" register which can be used to store arbitrary
data. Expose it as a nvmem resource in Linux.

Signed-off-by: default avatarLorenz Brun <lorenz@monogon.tech>
Link: https://patch.msgid.link/20251223125728.346073-1-lorenz@monogon.tech


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 770a54ac

drivers/rtc/rtc-s35390a.c

+32 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#define S35390A_CMD_TIME1	2

#define S35390A_CMD_TIME2	3

#define S35390A_CMD_INT2_REG1	5

#define S35390A_CMD_FREE_REG    7



#define S35390A_BYTE_YEAR	0

#define S35390A_BYTE_MONTH	1
@@ -416,6 +417,23 @@ static const struct rtc_class_ops s35390a_rtc_ops = { 
	.ioctl          = s35390a_rtc_ioctl,

};



static int s35390a_nvmem_read(void *priv, unsigned int offset, void *val,

			      size_t bytes)

{

	struct s35390a *s35390a = priv;



	/* The offset is ignored because the NVMEM region is only 1 byte */

	return s35390a_get_reg(s35390a, S35390A_CMD_FREE_REG, val, bytes);

}



static int s35390a_nvmem_write(void *priv, unsigned int offset, void *val,

			       size_t bytes)

{

	struct s35390a *s35390a = priv;



	return s35390a_set_reg(s35390a, S35390A_CMD_FREE_REG, val, bytes);

}



static int s35390a_probe(struct i2c_client *client)

{

	int err, err_read;
@@ -424,6 +442,15 @@ static int s35390a_probe(struct i2c_client *client) 
	struct rtc_device *rtc;

	u8 buf, status1;

	struct device *dev = &client->dev;

	struct nvmem_config nvmem_cfg = {

		.name = "s35390a_nvram",

		.type = NVMEM_TYPE_BATTERY_BACKED,

		.word_size = 1,

		.stride = 1,

		.size = 1,

		.reg_read = s35390a_nvmem_read,

		.reg_write = s35390a_nvmem_write,

	};



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))

		return -ENODEV;
@@ -490,6 +517,11 @@ static int s35390a_probe(struct i2c_client *client) 
	if (status1 & S35390A_FLAG_INT2)

		rtc_update_irq(rtc, 1, RTC_AF);



	nvmem_cfg.priv = s35390a;

	err = devm_rtc_nvmem_register(rtc, &nvmem_cfg);

	if (err)

		return err;



	return devm_rtc_register_device(rtc);

}