net/libertas: remove GPIO-CS handling in SPI interface code

This removes the dependency on GPIO framework and lets the SPI host
driver handle the chip select. The SPI host driver is required to keep
the CS active for the entire message unless cs_change says otherwise.
This patch collects the two/three single SPI transfers into a message.
Also the delay in read path in case use_dummy_writes are not used is
moved into the SPI host driver.

Tested-by: Mike Rapoport <mike@compulab.co.il>
Tested-by: Andrey Yurovsky <andrey@cozybit.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/Kconfig

@@ -153,7 +153,7 @@ config LIBERTAS_SDIO
 
 config LIBERTAS_SPI
 	tristate "Marvell Libertas 8686 SPI 802.11b/g cards"
-	depends on LIBERTAS && SPI && GENERIC_GPIO
+	depends on LIBERTAS && SPI
 	---help---
 	  A driver for Marvell Libertas 8686 SPI devices.
 

drivers/net/wireless/libertas/if_spi.c

@@ -19,7 +19,6 @@
 
 #include <linux/moduleparam.h>
 #include <linux/firmware.h>
-#include <linux/gpio.h>
 #include <linux/jiffies.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
@@ -51,13 +50,6 @@ struct if_spi_card {
 	u16				card_id;
 	u8				card_rev;
 
-	/* Pin number for our GPIO chip-select. */
-	/* TODO: Once the generic SPI layer has some additional features, we
-	 * should take this out and use the normal chip select here.
-	 * We need support for chip select delays, and not dropping chipselect
-	 * after each word. */
-	int				gpio_cs;
-
 	/* The last time that we initiated an SPU operation */
 	unsigned long			prev_xfer_time;
 
@@ -130,12 +122,10 @@ static void spu_transaction_init(struct if_spi_card *card)
 		 * If not, we have to busy-wait to be on the safe side. */
 		ndelay(400);
 	}
-	gpio_set_value(card->gpio_cs, 0); /* assert CS */
 }
 
 static void spu_transaction_finish(struct if_spi_card *card)
 {
-	gpio_set_value(card->gpio_cs, 1); /* drop CS */
 	card->prev_xfer_time = jiffies;
 }
 
@@ -145,6 +135,13 @@ static int spu_write(struct if_spi_card *card, u16 reg, const u8 *buf, int len)
 {
 	int err = 0;
 	u16 reg_out = cpu_to_le16(reg | IF_SPI_WRITE_OPERATION_MASK);
+	struct spi_message m;
+	struct spi_transfer reg_trans;
+	struct spi_transfer data_trans;
+
+	spi_message_init(&m);
+	memset(&reg_trans, 0, sizeof(reg_trans));
+	memset(&data_trans, 0, sizeof(data_trans));
 
 	/* You must give an even number of bytes to the SPU, even if it
 	 * doesn't care about the last one.  */
@@ -153,13 +150,16 @@ static int spu_write(struct if_spi_card *card, u16 reg, const u8 *buf, int len)
 	spu_transaction_init(card);
 
 	/* write SPU register index */
-	err = spi_write(card->spi, (u8 *)&reg_out, sizeof(u16));
-	if (err)
-		goto out;
+	reg_trans.tx_buf = &reg_out;
+	reg_trans.len = sizeof(reg_out);
 
-	err = spi_write(card->spi, buf, len);
+	data_trans.tx_buf = buf;
+	data_trans.len = len;
 
-out:
+	spi_message_add_tail(&reg_trans, &m);
+	spi_message_add_tail(&data_trans, &m);
+
+	err = spi_sync(card->spi, &m);
 	spu_transaction_finish(card);
 	return err;
 }
@@ -186,10 +186,13 @@ static inline int spu_reg_is_port_reg(u16 reg)
 
 static int spu_read(struct if_spi_card *card, u16 reg, u8 *buf, int len)
 {
-	unsigned int i, delay;
+	unsigned int delay;
 	int err = 0;
-	u16 zero = 0;
 	u16 reg_out = cpu_to_le16(reg | IF_SPI_READ_OPERATION_MASK);
+	struct spi_message m;
+	struct spi_transfer reg_trans;
+	struct spi_transfer dummy_trans;
+	struct spi_transfer data_trans;
 
 	/* You must take an even number of bytes from the SPU, even if you
 	 * don't care about the last one.  */
@@ -197,29 +200,34 @@ static int spu_read(struct if_spi_card *card, u16 reg, u8 *buf, int len)
 
 	spu_transaction_init(card);
 
+	spi_message_init(&m);
+	memset(&reg_trans, 0, sizeof(reg_trans));
+	memset(&dummy_trans, 0, sizeof(dummy_trans));
+	memset(&data_trans, 0, sizeof(data_trans));
+
 	/* write SPU register index */
-	err = spi_write(card->spi, (u8 *)&reg_out, sizeof(u16));
-	if (err)
-		goto out;
+	reg_trans.tx_buf = &reg_out;
+	reg_trans.len = sizeof(reg_out);
+	spi_message_add_tail(&reg_trans, &m);
 
 	delay = spu_reg_is_port_reg(reg) ? card->spu_port_delay :
 						card->spu_reg_delay;
 	if (card->use_dummy_writes) {
 		/* Clock in dummy cycles while the SPU fills the FIFO */
-		for (i = 0; i < delay / 16; ++i) {
-			err = spi_write(card->spi, (u8 *)&zero, sizeof(u16));
-			if (err)
-				return err;
-		}
+		dummy_trans.len = delay / 8;
+		spi_message_add_tail(&dummy_trans, &m);
 	} else {
 		/* Busy-wait while the SPU fills the FIFO */
-		ndelay(100 + (delay * 10));
+		reg_trans.delay_usecs =
+			DIV_ROUND_UP((100 + (delay * 10)), 1000);
 	}
 
 	/* read in data */
-	err = spi_read(card->spi, buf, len);
+	data_trans.rx_buf = buf;
+	data_trans.len = len;
+	spi_message_add_tail(&data_trans, &m);
 
-out:
+	err = spi_sync(card->spi, &m);
 	spu_transaction_finish(card);
 	return err;
 }
@@ -1049,7 +1057,6 @@ static int __devinit if_spi_probe(struct spi_device *spi)
 	spi_set_drvdata(spi, card);
 	card->pdata = pdata;
 	card->spi = spi;
-	card->gpio_cs = pdata->gpio_cs;
 	card->prev_xfer_time = jiffies;
 
 	sema_init(&card->spi_ready, 0);
@@ -1058,26 +1065,18 @@ static int __devinit if_spi_probe(struct spi_device *spi)
 	INIT_LIST_HEAD(&card->data_packet_list);
 	spin_lock_init(&card->buffer_lock);
 
-	/* set up GPIO CS line. TODO: use  regular CS line */
-	err = gpio_request(card->gpio_cs, "if_spi_gpio_chip_select");
-	if (err)
-		goto free_card;
-	err = gpio_direction_output(card->gpio_cs, 1);
-	if (err)
-		goto free_gpio;
-
 	/* Initialize the SPI Interface Unit */
 	err = spu_init(card, pdata->use_dummy_writes);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 	err = spu_get_chip_revision(card, &card->card_id, &card->card_rev);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 
 	/* Firmware load */
 	err = spu_read_u32(card, IF_SPI_SCRATCH_4_REG, &scratch);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 	if (scratch == SUCCESSFUL_FW_DOWNLOAD_MAGIC)
 		lbs_deb_spi("Firmware is already loaded for "
 			    "Marvell WLAN 802.11 adapter\n");
@@ -1085,7 +1084,7 @@ static int __devinit if_spi_probe(struct spi_device *spi)
 		err = if_spi_calculate_fw_names(card->card_id,
 				card->helper_fw_name, card->main_fw_name);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 
 		lbs_deb_spi("Initializing FW for Marvell WLAN 802.11 adapter "
 				"(chip_id = 0x%04x, chip_rev = 0x%02x) "
@@ -1096,23 +1095,23 @@ static int __devinit if_spi_probe(struct spi_device *spi)
 				spi->max_speed_hz);
 		err = if_spi_prog_helper_firmware(card);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 		err = if_spi_prog_main_firmware(card);
 		if (err)
-			goto free_gpio;
+			goto free_card;
 		lbs_deb_spi("loaded FW for Marvell WLAN 802.11 adapter\n");
 	}
 
 	err = spu_set_interrupt_mode(card, 0, 1);
 	if (err)
-		goto free_gpio;
+		goto free_card;
 
 	/* Register our card with libertas.
 	 * This will call alloc_etherdev */
 	priv = lbs_add_card(card, &spi->dev);
 	if (!priv) {
 		err = -ENOMEM;
-		goto free_gpio;
+		goto free_card;
 	}
 	card->priv = priv;
 	priv->card = card;
@@ -1157,8 +1156,6 @@ terminate_thread:
 	if_spi_terminate_spi_thread(card);
 remove_card:
 	lbs_remove_card(priv); /* will call free_netdev */
-free_gpio:
-	gpio_free(card->gpio_cs);
 free_card:
 	free_if_spi_card(card);
 out:
@@ -1179,7 +1176,6 @@ static int __devexit libertas_spi_remove(struct spi_device *spi)
 	free_irq(spi->irq, card);
 	if_spi_terminate_spi_thread(card);
 	lbs_remove_card(priv); /* will call free_netdev */
-	gpio_free(card->gpio_cs);
 	if (card->pdata->teardown)
 		card->pdata->teardown(spi);
 	free_if_spi_card(card);

include/linux/spi/libertas_spi.h

@@ -22,9 +22,6 @@ struct libertas_spi_platform_data {
 	 * speed, you may want to use 0 here. */
 	u16 use_dummy_writes;
 
-	/* GPIO number to use as chip select */
-	u16 gpio_cs;
-
 	/* Board specific setup/teardown */
 	int (*setup)(struct spi_device *spi);
 	int (*teardown)(struct spi_device *spi);