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/*
* CLPS711X SPI bus driver
*
* Copyright (C) 2012 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/init.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/platform_data/spi-clps711x.h>
#include <mach/hardware.h>
#define DRIVER_NAME "spi-clps711x"
struct spi_clps711x_data {
struct completion done;
struct clk *spi_clk;
u32 max_speed_hz;
u8 *tx_buf;
u8 *rx_buf;
int count;
int len;
int chipselect[0];
};
static int spi_clps711x_setup(struct spi_device *spi)
{
struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
/* We are expect that SPI-device is not selected */
gpio_direction_output(hw->chipselect[spi->chip_select],
!(spi->mode & SPI_CS_HIGH));
return 0;
}
static void spi_clps711x_setup_mode(struct spi_device *spi)
{
/* Setup edge for transfer */
if (spi->mode & SPI_CPHA)
clps_writew(clps_readw(SYSCON3) | SYSCON3_ADCCKNSEN, SYSCON3);
else
clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCKNSEN, SYSCON3);
}
static int spi_clps711x_setup_xfer(struct spi_device *spi,
struct spi_transfer *xfer)
{
u32 speed = xfer->speed_hz ? : spi->max_speed_hz;
u8 bpw = xfer->bits_per_word;
struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master);
if (bpw != 8) {
dev_err(&spi->dev, "Unsupported master bus width %i\n", bpw);
return -EINVAL;
}
/* Setup SPI frequency divider */
if (!speed || (speed >= hw->max_speed_hz))
clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
SYSCON1_ADCKSEL(3), SYSCON1);
else if (speed >= (hw->max_speed_hz / 2))
clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
SYSCON1_ADCKSEL(2), SYSCON1);
else if (speed >= (hw->max_speed_hz / 8))
clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
SYSCON1_ADCKSEL(1), SYSCON1);
else
clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) |
SYSCON1_ADCKSEL(0), SYSCON1);
return 0;
}
static int spi_clps711x_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct spi_clps711x_data *hw = spi_master_get_devdata(master);
struct spi_transfer *xfer;
int status = 0, cs = hw->chipselect[msg->spi->chip_select];
u32 data;
spi_clps711x_setup_mode(msg->spi);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (spi_clps711x_setup_xfer(msg->spi, xfer)) {
status = -EINVAL;
goto out_xfr;
}
gpio_set_value(cs, !!(msg->spi->mode & SPI_CS_HIGH));
INIT_COMPLETION(hw->done);
hw->count = 0;
hw->len = xfer->len;
hw->tx_buf = (u8 *)xfer->tx_buf;
hw->rx_buf = (u8 *)xfer->rx_buf;
/* Initiate transfer */
data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
wait_for_completion(&hw->done);
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
if (xfer->cs_change ||
list_is_last(&xfer->transfer_list, &msg->transfers))
gpio_set_value(cs, !(msg->spi->mode & SPI_CS_HIGH));
msg->actual_length += xfer->len;
}
out_xfr:
msg->status = status;
spi_finalize_current_message(master);
return 0;
}
static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
{
struct spi_clps711x_data *hw = (struct spi_clps711x_data *)dev_id;
u32 data;
/* Handle RX */
data = clps_readb(SYNCIO);
if (hw->rx_buf)
hw->rx_buf[hw->count] = (u8)data;
hw->count++;
/* Handle TX */
if (hw->count < hw->len) {
data = hw->tx_buf ? hw->tx_buf[hw->count] : 0;
clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO);
} else
complete(&hw->done);
return IRQ_HANDLED;
}
static int spi_clps711x_probe(struct platform_device *pdev)
{
int i, ret;
struct spi_master *master;
struct spi_clps711x_data *hw;
struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);
if (!pdata) {
dev_err(&pdev->dev, "No platform data supplied\n");
return -EINVAL;
}
if (pdata->num_chipselect < 1) {
dev_err(&pdev->dev, "At least one CS must be defined\n");
return -EINVAL;
}
master = spi_alloc_master(&pdev->dev,
sizeof(struct spi_clps711x_data) +
sizeof(int) * pdata->num_chipselect);
if (!master) {
dev_err(&pdev->dev, "SPI allocating memory error\n");
return -ENOMEM;
}
master->bus_num = pdev->id;
master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->num_chipselect = pdata->num_chipselect;
master->setup = spi_clps711x_setup;
master->transfer_one_message = spi_clps711x_transfer_one_message;
hw = spi_master_get_devdata(master);
for (i = 0; i < master->num_chipselect; i++) {
hw->chipselect[i] = pdata->chipselect[i];
if (!gpio_is_valid(hw->chipselect[i])) {
dev_err(&pdev->dev, "Invalid CS GPIO %i\n", i);
ret = -EINVAL;
goto err_out;
}
if (gpio_request(hw->chipselect[i], DRIVER_NAME)) {
dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
ret = -EINVAL;
goto err_out;
}
}
hw->spi_clk = devm_clk_get(&pdev->dev, "spi");
if (IS_ERR(hw->spi_clk)) {
dev_err(&pdev->dev, "Can't get clocks\n");
ret = PTR_ERR(hw->spi_clk);
goto err_out;
}
hw->max_speed_hz = clk_get_rate(hw->spi_clk);
init_completion(&hw->done);
platform_set_drvdata(pdev, master);
/* Disable extended mode due hardware problems */
clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCON, SYSCON3);
/* Clear possible pending interrupt */
clps_readl(SYNCIO);
ret = devm_request_irq(&pdev->dev, IRQ_SSEOTI, spi_clps711x_isr, 0,
dev_name(&pdev->dev), hw);
if (ret) {
dev_err(&pdev->dev, "Can't request IRQ\n");
goto err_out;
}
ret = devm_spi_register_master(&pdev->dev, master);
if (!ret) {
dev_info(&pdev->dev,
"SPI bus driver initialized. Master clock %u Hz\n",
hw->max_speed_hz);
return 0;
}
dev_err(&pdev->dev, "Failed to register master\n");
err_out:
while (--i >= 0)
if (gpio_is_valid(hw->chipselect[i]))
gpio_free(hw->chipselect[i]);
spi_master_put(master);
return ret;
}
static int spi_clps711x_remove(struct platform_device *pdev)
{
int i;
struct spi_master *master = platform_get_drvdata(pdev);
struct spi_clps711x_data *hw = spi_master_get_devdata(master);
for (i = 0; i < master->num_chipselect; i++)
if (gpio_is_valid(hw->chipselect[i]))
gpio_free(hw->chipselect[i]);
return 0;
}
static struct platform_driver clps711x_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
.probe = spi_clps711x_probe,
.remove = spi_clps711x_remove,
};
module_platform_driver(clps711x_spi_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("CLPS711X SPI bus driver");
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