/* * SuperH HSPI bus driver * * Copyright (C) 2011 Kuninori Morimoto * * Based on spi-sh.c: * Based on pxa2xx_spi.c: * Copyright (C) 2011 Renesas Solutions Corp. * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs * * 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; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * */ #include <linux/clk.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/timer.h> #include <linux/delay.h> #include <linux/list.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/io.h> #include <linux/spi/spi.h> #include <linux/spi/sh_hspi.h> #define SPCR 0x00 #define SPSR 0x04 #define SPSCR 0x08 #define SPTBR 0x0C #define SPRBR 0x10 #define SPCR2 0x14 /* SPSR */ #define RXFL (1 << 2) struct hspi_priv { void __iomem *addr; struct spi_master *master; struct device *dev; struct clk *clk; }; /* * basic function */ static void hspi_write(struct hspi_priv *hspi, int reg, u32 val) { iowrite32(val, hspi->addr + reg); } static u32 hspi_read(struct hspi_priv *hspi, int reg) { return ioread32(hspi->addr + reg); } static void hspi_bit_set(struct hspi_priv *hspi, int reg, u32 mask, u32 set) { u32 val = hspi_read(hspi, reg); val &= ~mask; val |= set & mask; hspi_write(hspi, reg, val); } /* * transfer function */ static int hspi_status_check_timeout(struct hspi_priv *hspi, u32 mask, u32 val) { int t = 256; while (t--) { if ((mask & hspi_read(hspi, SPSR)) == val) return 0; udelay(10); } dev_err(hspi->dev, "timeout\n"); return -ETIMEDOUT; } /* * spi master function */ #define hspi_hw_cs_enable(hspi) hspi_hw_cs_ctrl(hspi, 0) #define hspi_hw_cs_disable(hspi) hspi_hw_cs_ctrl(hspi, 1) static void hspi_hw_cs_ctrl(struct hspi_priv *hspi, int hi) { hspi_bit_set(hspi, SPSCR, (1 << 6), (hi) << 6); } static void hspi_hw_setup(struct hspi_priv *hspi, struct spi_message *msg, struct spi_transfer *t) { struct spi_device *spi = msg->spi; struct device *dev = hspi->dev; u32 spcr, idiv_clk; u32 rate, best_rate, min, tmp; /* * find best IDIV/CLKCx settings */ min = ~0; best_rate = 0; spcr = 0; for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) { rate = clk_get_rate(hspi->clk); /* IDIV calculation */ if (idiv_clk & (1 << 5)) rate /= 128; else rate /= 16; /* CLKCx calculation */ rate /= (((idiv_clk & 0x1F) + 1) * 2); /* save best settings */ tmp = abs(t->speed_hz - rate); if (tmp < min) { min = tmp; spcr = idiv_clk; best_rate = rate; } } if (spi->mode & SPI_CPHA) spcr |= 1 << 7; if (spi->mode & SPI_CPOL) spcr |= 1 << 6; dev_dbg(dev, "speed %d/%d\n", t->speed_hz, best_rate); hspi_write(hspi, SPCR, spcr); hspi_write(hspi, SPSR, 0x0); hspi_write(hspi, SPSCR, 0x21); /* master mode / CS control */ } static int hspi_transfer_one_message(struct spi_master *master, struct spi_message *msg) { struct hspi_priv *hspi = spi_master_get_devdata(master); struct spi_transfer *t; u32 tx; u32 rx; int ret, i; unsigned int cs_change; const int nsecs = 50; dev_dbg(hspi->dev, "%s\n", __func__); cs_change = 1; ret = 0; list_for_each_entry(t, &msg->transfers, transfer_list) { if (cs_change) { hspi_hw_setup(hspi, msg, t); hspi_hw_cs_enable(hspi); ndelay(nsecs); } cs_change = t->cs_change; for (i = 0; i < t->len; i++) { /* wait remains */ ret = hspi_status_check_timeout(hspi, 0x1, 0); if (ret < 0) break; tx = 0; if (t->tx_buf) tx = (u32)((u8 *)t->tx_buf)[i]; hspi_write(hspi, SPTBR, tx); /* wait receive */ ret = hspi_status_check_timeout(hspi, 0x4, 0x4); if (ret < 0) break; rx = hspi_read(hspi, SPRBR); if (t->rx_buf) ((u8 *)t->rx_buf)[i] = (u8)rx; } msg->actual_length += t->len; if (t->delay_usecs) udelay(t->delay_usecs); if (cs_change) { ndelay(nsecs); hspi_hw_cs_disable(hspi); ndelay(nsecs); } } msg->status = ret; if (!cs_change) { ndelay(nsecs); hspi_hw_cs_disable(hspi); } spi_finalize_current_message(master); return ret; } static int hspi_probe(struct platform_device *pdev) { struct resource *res; struct spi_master *master; struct hspi_priv *hspi; struct clk *clk; int ret; /* get base addr */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "invalid resource\n"); return -EINVAL; } master = spi_alloc_master(&pdev->dev, sizeof(*hspi)); if (!master) { dev_err(&pdev->dev, "spi_alloc_master error.\n"); return -ENOMEM; } clk = clk_get(&pdev->dev, NULL); if (IS_ERR(clk)) { dev_err(&pdev->dev, "couldn't get clock\n"); ret = -EINVAL; goto error0; } hspi = spi_master_get_devdata(master); platform_set_drvdata(pdev, hspi); /* init hspi */ hspi->master = master; hspi->dev = &pdev->dev; hspi->clk = clk; hspi->addr = devm_ioremap(hspi->dev, res->start, resource_size(res)); if (!hspi->addr) { dev_err(&pdev->dev, "ioremap error.\n"); ret = -ENOMEM; goto error1; } pm_runtime_enable(&pdev->dev); master->bus_num = pdev->id; master->mode_bits = SPI_CPOL | SPI_CPHA; master->dev.of_node = pdev->dev.of_node; master->auto_runtime_pm = true; master->transfer_one_message = hspi_transfer_one_message; master->bits_per_word_mask = SPI_BPW_MASK(8); ret = devm_spi_register_master(&pdev->dev, master); if (ret < 0) { dev_err(&pdev->dev, "spi_register_master error.\n"); goto error2; } return 0; error2: pm_runtime_disable(&pdev->dev); error1: clk_put(clk); error0: spi_master_put(master); return ret; } static int hspi_remove(struct platform_device *pdev) { struct hspi_priv *hspi = platform_get_drvdata(pdev); pm_runtime_disable(&pdev->dev); clk_put(hspi->clk); return 0; } static struct of_device_id hspi_of_match[] = { { .compatible = "renesas,hspi", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, hspi_of_match); static struct platform_driver hspi_driver = { .probe = hspi_probe, .remove = hspi_remove, .driver = { .name = "sh-hspi", .owner = THIS_MODULE, .of_match_table = hspi_of_match, }, }; module_platform_driver(hspi_driver); MODULE_DESCRIPTION("SuperH HSPI bus driver"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>"); MODULE_ALIAS("platform:sh-hspi");