diff options
Diffstat (limited to 'drivers/spi/spi-clps711x.c')
| -rw-r--r-- | drivers/spi/spi-clps711x.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/spi/spi-clps711x.c b/drivers/spi/spi-clps711x.c new file mode 100644 index 000000000..18193df2e --- /dev/null +++ b/drivers/spi/spi-clps711x.c @@ -0,0 +1,197 @@ +/* + * 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); |