2 * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
4 * Derived from pl01x code:
7 * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
11 * Philippe Robin, <philippe.robin@arm.com>
13 * SPDX-License-Identifier: GPL-2.0+
16 /* Simple U-Boot driver for the BCM283x mini UART */
24 #include <dm/platform_data/serial_bcm283x_mu.h>
25 #include <linux/compiler.h>
28 DECLARE_GLOBAL_DATA_PTR;
30 struct bcm283x_mu_regs {
44 #define BCM283X_MU_LCR_DATA_SIZE_8 3
46 #define BCM283X_MU_LSR_TX_IDLE BIT(6)
47 /* This actually means not full, but is named not empty in the docs */
48 #define BCM283X_MU_LSR_TX_EMPTY BIT(5)
49 #define BCM283X_MU_LSR_RX_READY BIT(0)
51 struct bcm283x_mu_priv {
52 struct bcm283x_mu_regs *regs;
55 static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
57 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
58 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
59 struct bcm283x_mu_regs *regs = priv->regs;
65 divider = plat->clock / (baudrate * 8);
67 writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);
68 writel(divider - 1, ®s->baud);
73 static int bcm283x_mu_serial_probe(struct udevice *dev)
75 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
76 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
81 priv->regs = (struct bcm283x_mu_regs *)plat->base;
86 static int bcm283x_mu_serial_getc(struct udevice *dev)
88 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
89 struct bcm283x_mu_regs *regs = priv->regs;
92 /* Wait until there is data in the FIFO */
93 if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))
96 data = readl(®s->io);
101 static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
103 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
104 struct bcm283x_mu_regs *regs = priv->regs;
106 /* Wait until there is space in the FIFO */
107 if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))
110 /* Send the character */
111 writel(data, ®s->io);
116 static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
118 struct bcm283x_mu_priv *priv = dev_get_priv(dev);
119 struct bcm283x_mu_regs *regs = priv->regs;
120 unsigned int lsr = readl(®s->lsr);
124 return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0;
126 return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1;
130 static const struct dm_serial_ops bcm283x_mu_serial_ops = {
131 .putc = bcm283x_mu_serial_putc,
132 .pending = bcm283x_mu_serial_pending,
133 .getc = bcm283x_mu_serial_getc,
134 .setbrg = bcm283x_mu_serial_setbrg,
137 #if CONFIG_IS_ENABLED(OF_CONTROL)
138 static const struct udevice_id bcm283x_mu_serial_id[] = {
139 {.compatible = "brcm,bcm2835-aux-uart"},
143 static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
145 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
148 addr = dev_get_addr(dev);
149 if (addr == FDT_ADDR_T_NONE)
153 plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "clock", 1);
154 plat->skip_init = fdtdec_get_bool(gd->fdt_blob, dev->of_offset,
156 plat->disabled = false;
161 U_BOOT_DRIVER(serial_bcm283x_mu) = {
162 .name = "serial_bcm283x_mu",
164 .of_match = of_match_ptr(bcm283x_mu_serial_id),
165 .ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata),
166 .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
167 .probe = bcm283x_mu_serial_probe,
168 .ops = &bcm283x_mu_serial_ops,
169 .flags = DM_FLAG_PRE_RELOC,
170 .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),