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Message-ID: <547725F8.1050106@st.com>
Date: Thu, 27 Nov 2014 14:24:08 +0100
From: Maxime Coquelin <maxime.coquelin@...com>
To: Lee Jones <lee.jones@...aro.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
Cc: <devicetree@...r.kernel.org>, <broonie@...nel.org>,
<kernel@...inux.com>, <linux-spi@...r.kernel.org>
Subject: Re: [PATCH 1/4] spi: Add new driver for STMicroelectronics' SPI Controller
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@...aro.org>
> ---
> 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@...com>");
> +MODULE_DESCRIPTION("STM SSC SPI driver");
> +MODULE_LICENSE("GPL v2");
--
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