spi: sirf: correct spi gpio and hardware chipselect behaviour

the old codes check the cs-gpios, if the gpio number is 0 like:
<&gpio, 0, 0>, the driver will use the only hardware chipselect.

this is wrong because of_spi_register_master() can read property
cs-gpios from device node and set the spi master's cs number and
gpio cs automatically based on whether the cs-gpios is valid.

this patch fixes the beviour of CSR spi driver and move to a core
level supported way.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-sirf.c

@@ -170,8 +170,7 @@ struct sirfsoc_spi {
 	 * command model
 	 */
 	bool	tx_by_cmd;
-
-	int chipselect[0];
+	bool	hw_cs;
 };
 
 static void spi_sirfsoc_rx_word_u8(struct sirfsoc_spi *sspi)
@@ -484,7 +483,7 @@ static void spi_sirfsoc_chipselect(struct spi_device *spi, int value)
 {
 	struct sirfsoc_spi *sspi = spi_master_get_devdata(spi->master);
 
-	if (sspi->chipselect[spi->chip_select] == 0) {
+	if (sspi->hw_cs) {
 		u32 regval = readl(sspi->base + SIRFSOC_SPI_CTRL);
 		switch (value) {
 		case BITBANG_CS_ACTIVE:
@@ -502,14 +501,13 @@ static void spi_sirfsoc_chipselect(struct spi_device *spi, int value)
 		}
 		writel(regval, sspi->base + SIRFSOC_SPI_CTRL);
 	} else {
-		int gpio = sspi->chipselect[spi->chip_select];
 		switch (value) {
 		case BITBANG_CS_ACTIVE:
-			gpio_direction_output(gpio,
+			gpio_direction_output(spi->cs_gpio,
 					spi->mode & SPI_CS_HIGH ? 1 : 0);
 			break;
 		case BITBANG_CS_INACTIVE:
-			gpio_direction_output(gpio,
+			gpio_direction_output(spi->cs_gpio,
 					spi->mode & SPI_CS_HIGH ? 0 : 1);
 			break;
 		}
@@ -603,8 +601,8 @@ spi_sirfsoc_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 		sspi->tx_by_cmd = false;
 	}
 	/*
-	 * set spi controller in RISC chipselect mode, we are controlling CS by
-	 * software BITBANG_CS_ACTIVE and BITBANG_CS_INACTIVE.
+	 * it should never set to hardware cs mode because in hardware cs mode,
+	 * cs signal can't controlled by driver.
 	 */
 	regval |= SIRFSOC_SPI_CS_IO_MODE;
 	writel(regval, sspi->base + SIRFSOC_SPI_CTRL);
@@ -627,9 +625,17 @@ spi_sirfsoc_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 
 static int spi_sirfsoc_setup(struct spi_device *spi)
 {
+	struct sirfsoc_spi *sspi;
+
 	if (!spi->max_speed_hz)
 		return -EINVAL;
 
+	sspi = spi_master_get_devdata(spi->master);
+
+	if (spi->cs_gpio == -ENOENT)
+		sspi->hw_cs = true;
+	else
+		sspi->hw_cs = false;
 	return spi_sirfsoc_setup_transfer(spi, NULL);
 }
 
@@ -638,52 +644,17 @@ static int spi_sirfsoc_probe(struct platform_device *pdev)
 	struct sirfsoc_spi *sspi;
 	struct spi_master *master;
 	struct resource *mem_res;
-	int num_cs, cs_gpio, irq;
-	int i;
-	int ret;
-
-	ret = of_property_read_u32(pdev->dev.of_node,
-			"sirf,spi-num-chipselects", &num_cs);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "Unable to get chip select number\n");
-		goto err_cs;
-	}
+	int irq;
+	int i, ret;
 
-	master = spi_alloc_master(&pdev->dev,
-			sizeof(*sspi) + sizeof(int) * num_cs);
+	master = spi_alloc_master(&pdev->dev, sizeof(*sspi));
 	if (!master) {
 		dev_err(&pdev->dev, "Unable to allocate SPI master\n");
 		return -ENOMEM;
 	}
 	platform_set_drvdata(pdev, master);
 	sspi = spi_master_get_devdata(master);
 
-	master->num_chipselect = num_cs;
-
-	for (i = 0; i < master->num_chipselect; i++) {
-		cs_gpio = of_get_named_gpio(pdev->dev.of_node, "cs-gpios", i);
-		if (cs_gpio < 0) {
-			dev_err(&pdev->dev, "can't get cs gpio from DT\n");
-			ret = -ENODEV;
-			goto free_master;
-		}
-
-		sspi->chipselect[i] = cs_gpio;
-		if (cs_gpio == 0)
-			continue; /* use cs from spi controller */
-
-		ret = gpio_request(cs_gpio, DRIVER_NAME);
-		if (ret) {
-			while (i > 0) {
-				i--;
-				if (sspi->chipselect[i] > 0)
-					gpio_free(sspi->chipselect[i]);
-			}
-			dev_err(&pdev->dev, "fail to request cs gpios\n");
-			goto free_master;
-		}
-	}
-
 	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	sspi->base = devm_ioremap_resource(&pdev->dev, mem_res);
 	if (IS_ERR(sspi->base)) {
@@ -753,7 +724,21 @@ static int spi_sirfsoc_probe(struct platform_device *pdev)
 	ret = spi_bitbang_start(&sspi->bitbang);
 	if (ret)
 		goto free_dummypage;
-
+	for (i = 0; master->cs_gpios && i < master->num_chipselect; i++) {
+		if (master->cs_gpios[i] == -ENOENT)
+			continue;
+		if (!gpio_is_valid(master->cs_gpios[i])) {
+			dev_err(&pdev->dev, "no valid gpio\n");
+			ret = -EINVAL;
+			goto free_dummypage;
+		}
+		ret = devm_gpio_request(&pdev->dev,
+				master->cs_gpios[i], DRIVER_NAME);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to request gpio\n");
+			goto free_dummypage;
+		}
+	}
 	dev_info(&pdev->dev, "registerred, bus number = %d\n", master->bus_num);
 
 	return 0;
@@ -768,24 +753,19 @@ static int spi_sirfsoc_probe(struct platform_device *pdev)
 	dma_release_channel(sspi->rx_chan);
 free_master:
 	spi_master_put(master);
-err_cs:
+
 	return ret;
 }
 
 static int  spi_sirfsoc_remove(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct sirfsoc_spi *sspi;
-	int i;
 
 	master = platform_get_drvdata(pdev);
 	sspi = spi_master_get_devdata(master);
 
 	spi_bitbang_stop(&sspi->bitbang);
-	for (i = 0; i < master->num_chipselect; i++) {
-		if (sspi->chipselect[i] > 0)
-			gpio_free(sspi->chipselect[i]);
-	}
 	kfree(sspi->dummypage);
 	clk_disable_unprepare(sspi->clk);
 	clk_put(sspi->clk);