diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_em.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_em.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_em.c b/drivers/tty/serial/8250/8250_em.c new file mode 100644 index 000000000..d94c3811a --- /dev/null +++ b/drivers/tty/serial/8250/8250_em.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas Emma Mobile 8250 driver + * + * Copyright (C) 2012 Magnus Damm + */ + +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/serial_8250.h> +#include <linux/serial_reg.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/slab.h> + +#include "8250.h" + +#define UART_DLL_EM 9 +#define UART_DLM_EM 10 + +struct serial8250_em_priv { + struct clk *sclk; + int line; +}; + +static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) +{ + switch (offset) { + case UART_TX: /* TX @ 0x00 */ + writeb(value, p->membase); + break; + case UART_FCR: /* FCR @ 0x0c (+1) */ + case UART_LCR: /* LCR @ 0x10 (+1) */ + case UART_MCR: /* MCR @ 0x14 (+1) */ + case UART_SCR: /* SCR @ 0x20 (+1) */ + writel(value, p->membase + ((offset + 1) << 2)); + break; + case UART_IER: /* IER @ 0x04 */ + value &= 0x0f; /* only 4 valid bits - not Xscale */ + fallthrough; + case UART_DLL_EM: /* DLL @ 0x24 (+9) */ + case UART_DLM_EM: /* DLM @ 0x28 (+9) */ + writel(value, p->membase + (offset << 2)); + } +} + +static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) +{ + switch (offset) { + case UART_RX: /* RX @ 0x00 */ + return readb(p->membase); + case UART_MCR: /* MCR @ 0x14 (+1) */ + case UART_LSR: /* LSR @ 0x18 (+1) */ + case UART_MSR: /* MSR @ 0x1c (+1) */ + case UART_SCR: /* SCR @ 0x20 (+1) */ + return readl(p->membase + ((offset + 1) << 2)); + case UART_IER: /* IER @ 0x04 */ + case UART_IIR: /* IIR @ 0x08 */ + case UART_DLL_EM: /* DLL @ 0x24 (+9) */ + case UART_DLM_EM: /* DLM @ 0x28 (+9) */ + return readl(p->membase + (offset << 2)); + } + return 0; +} + +static int serial8250_em_serial_dl_read(struct uart_8250_port *up) +{ + return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; +} + +static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) +{ + serial_out(up, UART_DLL_EM, value & 0xff); + serial_out(up, UART_DLM_EM, value >> 8 & 0xff); +} + +static int serial8250_em_probe(struct platform_device *pdev) +{ + struct serial8250_em_priv *priv; + struct uart_8250_port up; + struct resource *regs; + int irq, ret; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) { + dev_err(&pdev->dev, "missing registers\n"); + return -EINVAL; + } + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->sclk = devm_clk_get(&pdev->dev, "sclk"); + if (IS_ERR(priv->sclk)) { + dev_err(&pdev->dev, "unable to get clock\n"); + return PTR_ERR(priv->sclk); + } + + memset(&up, 0, sizeof(up)); + up.port.mapbase = regs->start; + up.port.irq = irq; + up.port.type = PORT_16750; + up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE; + up.port.dev = &pdev->dev; + up.port.private_data = priv; + + clk_prepare_enable(priv->sclk); + up.port.uartclk = clk_get_rate(priv->sclk); + + up.port.iotype = UPIO_MEM32; + up.port.serial_in = serial8250_em_serial_in; + up.port.serial_out = serial8250_em_serial_out; + up.dl_read = serial8250_em_serial_dl_read; + up.dl_write = serial8250_em_serial_dl_write; + + ret = serial8250_register_8250_port(&up); + if (ret < 0) { + dev_err(&pdev->dev, "unable to register 8250 port\n"); + clk_disable_unprepare(priv->sclk); + return ret; + } + + priv->line = ret; + platform_set_drvdata(pdev, priv); + return 0; +} + +static int serial8250_em_remove(struct platform_device *pdev) +{ + struct serial8250_em_priv *priv = platform_get_drvdata(pdev); + + serial8250_unregister_port(priv->line); + clk_disable_unprepare(priv->sclk); + return 0; +} + +static const struct of_device_id serial8250_em_dt_ids[] = { + { .compatible = "renesas,em-uart", }, + {}, +}; +MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); + +static struct platform_driver serial8250_em_platform_driver = { + .driver = { + .name = "serial8250-em", + .of_match_table = serial8250_em_dt_ids, + }, + .probe = serial8250_em_probe, + .remove = serial8250_em_remove, +}; + +module_platform_driver(serial8250_em_platform_driver); + +MODULE_AUTHOR("Magnus Damm"); +MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); +MODULE_LICENSE("GPL v2"); |