/* * CLPS711X SPI bus driver * * Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include <linux/io.h> #include <linux/clk.h> #include <linux/gpio.h> #include <linux/module.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/mfd/syscon.h> #include <linux/mfd/syscon/clps711x.h> #include <linux/spi/spi.h> #define DRIVER_NAME "clps711x-spi" #define SYNCIO_FRMLEN(x) ((x) << 8) #define SYNCIO_TXFRMEN (1 << 14) struct spi_clps711x_data { void __iomem *syncio; struct regmap *syscon; struct clk *spi_clk; u8 *tx_buf; u8 *rx_buf; unsigned int bpw; int len; }; static int spi_clps711x_setup(struct spi_device *spi) { if (!spi->controller_state) { int ret; ret = devm_gpio_request(&spi->master->dev, spi->cs_gpio, dev_name(&spi->master->dev)); if (ret) return ret; spi->controller_state = spi; } /* We are expect that SPI-device is not selected */ gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); return 0; } static int spi_clps711x_prepare_message(struct spi_master *master, struct spi_message *msg) { struct spi_clps711x_data *hw = spi_master_get_devdata(master); struct spi_device *spi = msg->spi; /* Setup mode for transfer */ return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN, (spi->mode & SPI_CPHA) ? SYSCON3_ADCCKNSEN : 0); } static int spi_clps711x_transfer_one(struct spi_master *master, struct spi_device *spi, struct spi_transfer *xfer) { struct spi_clps711x_data *hw = spi_master_get_devdata(master); u8 data; clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz); hw->len = xfer->len; hw->bpw = xfer->bits_per_word; hw->tx_buf = (u8 *)xfer->tx_buf; hw->rx_buf = (u8 *)xfer->rx_buf; /* Initiate transfer */ data = hw->tx_buf ? *hw->tx_buf++ : 0; writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio); return 1; } static irqreturn_t spi_clps711x_isr(int irq, void *dev_id) { struct spi_master *master = dev_id; struct spi_clps711x_data *hw = spi_master_get_devdata(master); u8 data; /* Handle RX */ data = readb(hw->syncio); if (hw->rx_buf) *hw->rx_buf++ = data; /* Handle TX */ if (--hw->len > 0) { data = hw->tx_buf ? *hw->tx_buf++ : 0; writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio); } else spi_finalize_current_transfer(master); return IRQ_HANDLED; } static int spi_clps711x_probe(struct platform_device *pdev) { struct spi_clps711x_data *hw; struct spi_master *master; struct resource *res; int irq, ret; irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; master = spi_alloc_master(&pdev->dev, sizeof(*hw)); if (!master) return -ENOMEM; master->bus_num = -1; master->mode_bits = SPI_CPHA | SPI_CS_HIGH; master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8); master->dev.of_node = pdev->dev.of_node; master->setup = spi_clps711x_setup; master->prepare_message = spi_clps711x_prepare_message; master->transfer_one = spi_clps711x_transfer_one; hw = spi_master_get_devdata(master); hw->spi_clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(hw->spi_clk)) { ret = PTR_ERR(hw->spi_clk); goto err_out; } hw->syscon = syscon_regmap_lookup_by_compatible("cirrus,ep7209-syscon3"); if (IS_ERR(hw->syscon)) { ret = PTR_ERR(hw->syscon); goto err_out; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); hw->syncio = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(hw->syncio)) { ret = PTR_ERR(hw->syncio); goto err_out; } /* Disable extended mode due hardware problems */ regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0); /* Clear possible pending interrupt */ readl(hw->syncio); ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0, dev_name(&pdev->dev), master); if (ret) goto err_out; ret = devm_spi_register_master(&pdev->dev, master); if (!ret) return 0; err_out: spi_master_put(master); return ret; } static const struct of_device_id clps711x_spi_dt_ids[] = { { .compatible = "cirrus,ep7209-spi", }, { } }; MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids); static struct platform_driver clps711x_spi_driver = { .driver = { .name = DRIVER_NAME, .of_match_table = clps711x_spi_dt_ids, }, .probe = spi_clps711x_probe, }; module_platform_driver(clps711x_spi_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); MODULE_DESCRIPTION("CLPS711X SPI bus driver"); MODULE_ALIAS("platform:" DRIVER_NAME);