Re: [PATCH 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

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On 11/27/2014 12:43 PM, Lee Jones wrote:
This patch adds support for the SPI portion of ST's SSC device.

Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
---
  drivers/spi/Kconfig  |   8 +
  drivers/spi/Makefile |   1 +
  drivers/spi/spi-st.c | 535 +++++++++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 544 insertions(+)
  create mode 100644 drivers/spi/spi-st.c
<snip>

+
+static int spi_st_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	struct spi_master *master;
+	struct resource *res;
+	struct spi_st *spi_st;
+	int num_cs, cs_gpio, i, ret = 0;
+	u32 var;
+	
+	printk("LEE: %s: %s()[%d]: Probing\n", __FILE__, __func__, __LINE__);
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*spi_st));
+	if (!master) {
+		dev_err(&pdev->dev, "failed to allocate spi master\n");
+		return -ENOMEM;
+	}
+	spi_st = spi_master_get_devdata(master);
+
+	if (!IS_ERR(dev->pins->p)) {
+		spi_st->pins_sleep =
+			pinctrl_lookup_state(dev->pins->p, PINCTRL_STATE_SLEEP);
+		if (IS_ERR(spi_st->pins_sleep))
+			dev_warn(&pdev->dev, "could not get sleep pinstate\n");
+	}
+
+	num_cs = of_gpio_named_count(np, "cs-gpios");
+
+	for (i = 0; i < num_cs; i++) {
+		cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
+
+		if (!gpio_is_valid(cs_gpio)) {
+			dev_err(&pdev->dev,
+				"%d is not a valid gpio\n", cs_gpio);
+			return -EINVAL;
+		}
+			
+		if (devm_gpio_request(&pdev->dev, cs_gpio, pdev->name)) {
+			dev_err(&pdev->dev,
+				"could not request %d gpio\n", cs_gpio);
+			return -EINVAL;
+		}
+	}
+
+	spi_st->clk = of_clk_get_by_name(np, "ssc");
+	if (IS_ERR(spi_st->clk)) {
+		dev_err(&pdev->dev, "Unable to request clock\n");
+		ret = PTR_ERR(spi_st->clk);
+		goto free_master;
+	}
+
+	ret = clk_prepare_enable(spi_st->clk);
+	if (ret)
+		goto free_master;
+
+	master->dev.of_node		= np;
+	master->bus_num			= pdev->id;
+	master->mode_bits		= MODEBITS;
+	spi_st->bitbang.master		= spi_master_get(master);
+	spi_st->bitbang.setup_transfer	= spi_st_setup_transfer;
+	spi_st->bitbang.txrx_bufs	= spi_st_txrx_bufs;
+	spi_st->bitbang.master->setup	= spi_st_setup;
+	spi_st->bitbang.master->cleanup	= spi_st_cleanup;
+	spi_st->bitbang.chipselect	= spi_st_gpio_chipselect;
+	spi_st->dev			= dev;
+
+	init_completion(&spi_st->done);
+
+	/* Get resources */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spi_st->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spi_st->base)) {
+		ret = PTR_ERR(spi_st->base);
+		goto clk_disable;
+	}
+
+	spi_st->irq = irq_of_parse_and_map(np, 0);
+	if (!spi_st->irq) {
+		dev_err(&pdev->dev, "IRQ missing or invalid\n");
+		ret = -EINVAL;
+		goto clk_disable;
+	}
+
+	ret = devm_request_irq(&pdev->dev, spi_st->irq, spi_st_irq, 0,
+			       pdev->name, spi_st);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request irq %d\n", spi_st->irq);
+		goto clk_disable;
+	}
+
+	/* Disable I2C and Reset SSC */
+	writel_relaxed(0x0, spi_st->base + SSC_I2C);
+	var = readw(spi_st->base + SSC_CTL);
Why not readw_relaxed to be consistent with readl:s?
+	var |= SSC_CTL_SR;
+	writel_relaxed(var, spi_st->base + SSC_CTL);
+
+	udelay(1);
+	var = readl_relaxed(spi_st->base + SSC_CTL);
+	var &= ~SSC_CTL_SR;
+	writel_relaxed(var, spi_st->base + SSC_CTL);
+
+	/* Set SSC into slave mode before reconfiguring PIO pins */
+	var = readl_relaxed(spi_st->base + SSC_CTL);
+	var &= ~SSC_CTL_MS;
+	writel_relaxed(var, spi_st->base + SSC_CTL);
+
+	/* Start "bitbang" worker */
+	ret = spi_bitbang_start(&spi_st->bitbang);
+	if (ret) {
+		dev_err(&pdev->dev, "bitbang start failed [%d]\n", ret);
+		goto clk_disable;
+	}
+
+	dev_info(&pdev->dev, "registered SPI Bus %d\n", master->bus_num);
+
+	platform_set_drvdata(pdev, master);

Shouldn't you call devm_spi_register_master ?
+
+	/* by default the device is on */
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+
+clk_disable:
+	clk_disable_unprepare(spi_st->clk);
+free_master:
+	spi_master_put(master);
+
+	return ret;
+}
+
+static int spi_st_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct spi_st *spi_st = spi_master_get_devdata(master);
+
+	spi_bitbang_stop(&spi_st->bitbang);
+	clk_disable_unprepare(spi_st->clk);
+
+	if (spi_st->pins_sleep)
+		pinctrl_select_state(pdev->dev.pins->p, spi_st->pins_sleep);
You should use pinctrl_pm_select_sleep_state(dev); instead.

+
+	spi_master_put(spi_st->bitbang.master);
If you use devm_spi_register_master at probe time,
you shouldn't need to call spi_master_put IIUC.

+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int spi_st_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct spi_st *spi_st = spi_master_get_devdata(master);
+
+	writel_relaxed(0, spi_st->base + SSC_IEN);
+
+	if (!IS_ERR(spi_st->pins_sleep))
+		pinctrl_select_state(dev->pins->p, spi_st->pins_sleep);
Ditto
+
+	clk_disable_unprepare(spi_st->clk);
+
+	return 0;
+}
+
+static int spi_st_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct spi_st *spi_st = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(spi_st->clk);
+
+	if (!IS_ERR(dev->pins->default_state))
+		pinctrl_select_state(dev->pins->p, dev->pins->default_state);
    pinctrl_pm_select_default_state(i2c_dev->dev);
    pinctrl_pm_select_idle_state(i2c_dev->dev);

+
+	return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(spi_st_pm, spi_st_suspend, spi_st_resume);
+
+static struct of_device_id stm_spi_match[] = {
+	{ .compatible = "st,comms-ssc-spi", },
+	{ .compatible = "st,comms-ssc4-spi", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm_spi_match);
+
+static struct platform_driver spi_st_driver = {
+	.driver = {
+		.name = "spi-st",
+		.pm = &spi_st_pm,
+		.of_match_table = of_match_ptr(stm_spi_match),
+	},
+	.probe = spi_st_probe,
+	.remove = spi_st_remove,
+};
+module_platform_driver(spi_st_driver);
+
+MODULE_AUTHOR("Patrice Chotard <patrice.chotard@xxxxxx>");
+MODULE_DESCRIPTION("STM SSC SPI driver");
+MODULE_LICENSE("GPL v2");

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