1 // SPDX-License-Identifier: GPL-2.0+
3 * Actions Semi OWL SoCs UART driver
5 * Copyright (C) 2015 Actions Semi Co., Ltd.
6 * Copyright (C) 2018 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
16 #include <asm/types.h>
19 #define OWL_UART_CTL (0x0000)
20 #define OWL_UART_RXDAT (0x0004)
21 #define OWL_UART_TXDAT (0x0008)
22 #define OWL_UART_STAT (0x000C)
24 /* UART_CTL Register Definitions */
25 #define OWL_UART_CTL_PRS_NONE GENMASK(6, 4)
26 #define OWL_UART_CTL_STPS BIT(2)
27 #define OWL_UART_CTL_DWLS 3
29 /* UART_STAT Register Definitions */
30 #define OWL_UART_STAT_TFES BIT(10) /* TX FIFO Empty Status */
31 #define OWL_UART_STAT_RFFS BIT(9) /* RX FIFO full Status */
32 #define OWL_UART_STAT_TFFU BIT(6) /* TX FIFO full Status */
33 #define OWL_UART_STAT_RFEM BIT(5) /* RX FIFO Empty Status */
35 struct owl_serial_priv {
39 int owl_serial_setbrg(struct udevice *dev, int baudrate)
41 /* Driver supports only fixed baudrate */
45 static int owl_serial_getc(struct udevice *dev)
47 struct owl_serial_priv *priv = dev_get_priv(dev);
49 if (readl(priv->base + OWL_UART_STAT) & OWL_UART_STAT_RFEM)
52 return (int)(readl(priv->base + OWL_UART_RXDAT));
55 static int owl_serial_putc(struct udevice *dev, const char ch)
57 struct owl_serial_priv *priv = dev_get_priv(dev);
59 if (readl(priv->base + OWL_UART_STAT) & OWL_UART_STAT_TFFU)
62 writel(ch, priv->base + OWL_UART_TXDAT);
67 static int owl_serial_pending(struct udevice *dev, bool input)
69 struct owl_serial_priv *priv = dev_get_priv(dev);
70 unsigned int stat = readl(priv->base + OWL_UART_STAT);
73 return !(stat & OWL_UART_STAT_RFEM);
75 return !(stat & OWL_UART_STAT_TFES);
78 static int owl_serial_probe(struct udevice *dev)
80 struct owl_serial_priv *priv = dev_get_priv(dev);
85 /* Set data, parity and stop bits */
86 uart_ctl = readl(priv->base + OWL_UART_CTL);
87 uart_ctl &= ~(OWL_UART_CTL_PRS_NONE);
88 uart_ctl &= ~(OWL_UART_CTL_STPS);
89 uart_ctl |= OWL_UART_CTL_DWLS;
90 writel(uart_ctl, priv->base + OWL_UART_CTL);
92 /* Enable UART clock */
93 ret = clk_get_by_index(dev, 0, &clk);
97 ret = clk_enable(&clk);
104 static int owl_serial_ofdata_to_platdata(struct udevice *dev)
106 struct owl_serial_priv *priv = dev_get_priv(dev);
108 priv->base = dev_read_addr(dev);
109 if (priv->base == FDT_ADDR_T_NONE)
115 static const struct dm_serial_ops owl_serial_ops = {
116 .putc = owl_serial_putc,
117 .pending = owl_serial_pending,
118 .getc = owl_serial_getc,
119 .setbrg = owl_serial_setbrg,
122 static const struct udevice_id owl_serial_ids[] = {
123 { .compatible = "actions,s900-serial" },
127 U_BOOT_DRIVER(serial_owl) = {
128 .name = "serial_owl",
130 .of_match = owl_serial_ids,
131 .ofdata_to_platdata = owl_serial_ofdata_to_platdata,
132 .priv_auto_alloc_size = sizeof(struct owl_serial_priv),
133 .probe = owl_serial_probe,
134 .ops = &owl_serial_ops,