media: cxd2880-spi: Add optional vcc regulator

This patchset adds an optional VCC regulator to the driver probe function
to make sure power is enabled to the module before starting attaching to
the device.

Signed-off-by: Neil Armstrong <[e-mail]>
Acked-by: Yasunari Takiguchi <[e-mail]>
Signed-off-by: Sean Young <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/spi/cxd2880-spi.c

···
 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
 
 #include <linux/spi/spi.h>
+#include <linux/regulator/consumer.h>
 #include <linux/ktime.h>
 
 #include <media/dvb_demux.h>
···
 	struct mutex spi_mutex; /* For SPI access exclusive control */
 	int feed_count;
 	int all_pid_feed_count;
+	struct regulator *vcc_supply;
 	u8 *ts_buf;
 	struct cxd2880_pid_filter_config filter_config;
 };
···
 	if (!dvb_spi)
 		return -ENOMEM;
 
+	dvb_spi->vcc_supply = devm_regulator_get_optional(&spi->dev, "vcc");
+	if (IS_ERR(dvb_spi->vcc_supply)) {
+		if (PTR_ERR(dvb_spi->vcc_supply) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		dvb_spi->vcc_supply = NULL;
+	} else {
+		ret = regulator_enable(dvb_spi->vcc_supply);
+		if (ret)
+			return ret;
+	}
+
 	dvb_spi->spi = spi;
 	mutex_init(&dvb_spi->spi_mutex);
 	dev_set_drvdata(&spi->dev, dvb_spi);
···
 	dvb_unregister_frontend(&dvb_spi->dvb_fe);
 	dvb_frontend_detach(&dvb_spi->dvb_fe);
 	dvb_unregister_adapter(&dvb_spi->adapter);
+
+	if (dvb_spi->vcc_supply)
+		regulator_disable(dvb_spi->vcc_supply);
 
 	kfree(dvb_spi);
 	pr_info("cxd2880_spi remove ok.\n");